Constipation, diarrhoea, rectal bleeding

What is the anatomical definition of 'lower' GI haemorrhage?

'Lower' GI haemorrhage refers to bleeding that arises distal to the ligament of Treitz at the duodeno-jejunal junction.

How do serum ferritin and total iron-binding capacity (TIBC) help distinguish between iron-deficiency anaemia and anaemia of chronic disease? What is the role of CRP?

*Ferritin* is an indirect marker of the iron stored in the body: (therefore low in IDA and high in anaemia of chronic disease where iron is sequestered in cells). Ferritin is also an acute-phase reactant and may be elevated by infection, inflammation, or malignancy, and is also increased by excess alcohol consumption. By requesting CRP in addition to ferritin you can establish the significance of a raised ferritin level. The only way of identifying iron-deficiency anaemia in the presence of a raised CRP level is by also looking at the *TIBC*. - TIBC reflects the amount of transferrin in the blood. transferrin levels increase in response to low iron (IDA) and decrease in response to iron overload.

What is the most important aspect in the management of any of the infectious diarrhoeas?

*Fluid balance*. Patients with infectious diarrhoea are at risk of dehydration due to the constant watery faeces they pass, and it is dehydration which most commonly kills patients with infective diarrhoea worldwide. Maintaining adequate hydration with oral rehydration salts in patients with diarrhoea is more important than establishing the identity of the pathogen or treating it with antimicrobial agents.

questions in the HPC for those with rectal bleeding...

*How much blood passed?* - eg. tsp, egg cup, wine glass. - easy to overestimate if mixed with water - enquire for symptoms of hypovolaemia eg. postural hypotension, light-headed, collapse. *Duration and frequency of symptoms?* *What did blood look like?* - large bleeds in proximal GI tract may present with melaena (jet black liquid stool caused by bacterial oxidation of haem) or may present as frank blood (haematochezia) if transit times are sufficiently rapid. - You may need to specifically ask the patient about melaena. *Relationship of blood to stool?*- to localise bleeding. - *blood mixed with stool*: proximal to the sigmoid colon (transit time enables mixing). - *blood streaked on stool*: sigmoid or anorectal source. - *Blood separate from stool*: blood is passed immediately AFTER stool, the likelihood is that this is an anal condition such as haemorrhoids. If ON ITS OWN this implies that there has been sufficient bleeding to dilate the rectum and produce a defecation stimulus eg. with diverticular disease, angiodysplasia, IBD, or sometimes a rapidly bleeding cancer (upper GI haemorrhage is another small-print cause). - *Blood just on tissue paper*: implies relatively minor bleeding from the anal canal, most likely due to haemorrhoids or an anal fissure. *Is there any pain or prolapse when opening the bowels?* - Most of the conditions resulting in rectal bleeding are non-painful. - except anal fissure, which produces intense/tearing pain during defecation and perhaps lasting for several hours post-defecation; may also complain of an itch or perianal irritation. - Colitis may be associated with abdominal cramping, and lower anal cancers may present with pain. - Haemorrhoids are not typically associated with pain unless they have thrombosed, but patients may have noticed prolapse. *Any tenesmus* (sensation of incomplete evacuation)? - specific for rectal cancer, where a luminal mass in the rectum can cause the feeling of incomplete bowel evacuation after defecation. - It can also be a symptom of colitis. *Has there been any change of bowel habit?* - The passage of blood per rectum may be associated with *diarrhoea* (such as with colitis) or *mucus* (think of colitis, proctitis, rectal cancer, and villous adenomas of the rectum). - Extensive haemorrhoids may also be associated with the passage of mucus per rectum. *wt loss* - eg. rectal cancer may lead to substantial wt loss in absence of metastatic spread. *Sx of anaemia* - current overt bleed may represent an occult bleed that has been unmasked, for example by anticoagulant drugs. Hence it is useful to ask about symptoms of anaemia such as lethargy and shortness of breath.

What is angiodysplasia? diagnosis and treatment.

- common cause of intermittent and occult lower GI bleeding in pts over the age of 65 (colon and cecum) - Submucosal arteriovenous malformation that is believed to be acquired. - cause of these lesions is unknown, but the predominance of lesions in the right colon raises the possibility that high wall tension may be a contributory factor. - Typically, lesions are less than 1 cm in diameter, but they can bleed out of proportion to their size. - venous blood loss (unlike blood from colonic diverticular disease). DIAGNOSIS - Angiodysplasia produces a characteristic 'cherry red spot' appearance at endoscopy (although blood will frequently obscure the field of view during acute haemorrhage). - The diagnosis has become more common since the advent of mesenteric angiography. - It may present with frank rectal bleeding or may result in occult blood loss and subsequent anaemic symptoms. TREATMENT Treatment options include embolization, surgical resection, or endoscopic laser electrocoagulation.

Patients often ask what can be done to reduce the risk of colon cancer when one of their family members has been diagnosed with this condition. Do you know of any key studies that have investigated modifiable risk factors for colorectal cancer?

- smoking - Exercise and obesity: people who exercise regularly (>4 hours a week) and are not obese were about 40% less likely to develop colorectal cancer than people who are sedentary (<1 hour of exercise a week) and obese. - Fibre: disputed but still recommend fibre as protective effect of a fibre-rich diet on the incidence of cardiovascular disease. - Other dietary factors: many studies have looked at the relationship between other details of dietary intake (e.g. red meat, saturated fats, fresh vegetables) and colorectal cancer. The short answer is that the data from these studies are contradictory. This probably reflects the fact that people's diets are complex and that the contribution of any one type of food to colorectal cancer may be too small to detect using an observational study. In lung cancer, the contribution of smoking is su ciently large to avoid being confounded in observational studies. However, in colorectal cancer, the contribution of red meat or saturated fats may be small and therefore easily masked by other confounding factors (e.g. people who eat less red meat may eat more soya products, and both may increase the risk of colorectal cancer by a similarly small amount). - Aspirin. The BDAT and UKTIA studies were randomized controlled trials investigating the role of high-dose daily aspirin in the prophylaxis of cerebrovascular thrombosis (TIAs and strokes). A meta-analysis of their data by Flossmann and Rothwell6 incidentally found that patients on *high-dose aspirin were about 50% less likely to develop colorectal cancer. However, the massive Women's Health Study7 and Physicians Health Study8 failed to find any association between low-dose aspirin and colorectal cancer.

What is the difference between (1) a fluid challenge, (2) maintenance fluids, and (3) replacement fluids?

1) *Fluid challenge:* this is an IV bolus of 250−500mL of normal saline given over 30 minutes to a patient who is hypovolaemic (thirsty, dry mucous membranes, tachycardic, and with a narrow and/or low blood pressure). After the fluid challenge is given, one must reassess the patient. Three outcomes are possible: − No response: blood pressure remains low. The patient has not received enough fluids or they weren't actually hypovolaemic to begin with. Reassess the patient clinically (to double check they really are hypovolaemic) and repeat a fluid challenge. − Transient response (increase) in blood pressure: the patient was indeed hypovolaemic but you either haven't given them enough fluids or they are losing them very rapidly (e.g. haemorrhage). Give them more fluids and consider possible explanations for continuing fluid loss. − Sustained response (increase) in blood pressure: the patient was indeed hypovolaemic and you have restored them to normal fluid balance. 2) *Maintenance fluids:* Fluids and electrolytes must be replaced daily to replace those lost normally to maintain fluid balance, and this is normally achieved by drinking about 2 L of fluids a day and eating normally. If a patient cannot drink, they need maintenance IV fluids to restore their 2.5 L fluid, 100 mM Na+, and 70 mM K+ a day. This is usually achieved on the wards by prescribing: − Bag1: 1L of normal saline (=1L of H2O, 154mM Na+, 154mM Cl−) (with 20mM K+), IV over 8 hours. − Bag2: 1L of 5% dextrose (=1L of H2O, 50g of dextrose), (with 20mM K+), IV over 8 hours. − Bag3: same as bag 2. − Total: 3L of H2O, 154mM Na+, 60mM K+ over 24 hours. (Note that the above prescription is not precise − it gives slightly too much Na+ and slightly too little K+. However, the exact requirements vary depending on a patient's weight and current electrolyte concentrations. Indeed, the above formula is increasingly recognized as a cause of hyponatraemia in some patients, hence it is increasingly common to prescribe two or three bags of normal saline a day rather than the traditional single bag.) 3) Replacement fluids: to replace the extra abnormal fluid losses. Examples of patients requiring extra, replacement fluids are: − *Fever*: febrile patients need an extra 500 mL of fluid for every 1oC above 37oC. − *Burns patients*: patients with burns need extra fluids and this can be calculated using the Parkland formula: Fluids (mL) = 4 × weight (kg) × % SA burnt − *Stoma patients*: patients with intestinal stomas lose fluids because these exit the bowel before fluids can be reabsorbed. Small bowel stomas obviously result in greater fluid loss than large bowel stomas as more fluid will have been reabsorbed by the time faeces exit a large bowel stoma than a small bowel stoma. The only way to calculate how much excess fluid is being lost is by measuring and recording how much fluid a stoma drains, keeping in mind that normal faecal loss of fluid is only 200 mL/day. - *Third spacing:* Estimating how much fluid has been 'third spaced' in a patient is difficult, and one usually relies on trial and error (giving replacement fluids and then assessing the patient) to work out how much replacement fluid to give.

drug history may contribute to rectal bleeding in 4 ways...

1) *Increased risk of bleeding*. = Anticoagulant and antiplatelet medications can accentuate bleeding from established lesions (a previously occult bleed may become overt). = Long-term anticoagulation makes any existing angiodysplasia more likely to bleed. = Non-steroidal anti-inflammatory drugs (NSAIDs) are known to increase the likelihood of bleeds from diverticular disease. 2) *Increased risk of peptic ulcers*. = NSAIDs, steroids, and bisphosphonates predispose to peptic ulceration. 3) *Increased risk of infectious colitis*. Antibiotic use may predispose to Clostridium difficile colitis, as may use of proton-pump inhibitors. 4) *Decreased heart response to hypovolaemia*. β-Blockers can stop patients from mounting the usual tachycardic response to hypovolaemia.

Management by UC:

1) *Medical therapy*: UC is a systemic inflammatory disease that responds well to anti-inflammatories. - Salicylate derivatives (e.g. sulfasalazine, mesalazine), - methotrexate, - azathioprine, - corticosteroids, and - anti-TNF antibodies (e.g. infliximab) can all be used to control the inflammation. 2) *Disease monitoring*: due to the high rates of colonic adenocarcinoma in UC, patients are monitored with colonoscopy for early signs of cancer on a regular basis. 3) *Surgical therapy*: surgery for UC involves removing the portion of affected bowel. is approach is potentially curative as it removes the main symptomatic focus of the disease and eliminates the risk of colonic adenocarcinoma. However, the removal of the rectum has traditionally resulted in a lifelong end ileostomy which put many patients off the idea of surgery. The development of the ileal pouch-anal anastomosis (IPAA), whereby a pouch of ileum is used to fashion a rectum and connected to the anus to allow almost normal defecation, has been an important development in surgery for UC patients.

What are the main advantages and disadvantages of the following methods for visualizing colon masses? (1) Rigid sigmoidoscopy (2) Flexible sigmoidoscopy (3) Colonoscopy (4) CT colon (5) CT colonography ('virtual colonoscopy' or 'CT pneumocolon') (6) DCBE

1) Rigidsigmoidoscopy • Advantages: quick, can be performed on the wards with minimal expertise and allows both visualization of the rectum and biopsy taking. • Disadvantages: will only visualize the rectum, thus missing many masses. 2) Flexible sigmoidoscopy • Advantages: allows visualization as far as the splenic flexure, which is not bad given that 75% of sporadic, non-familial colorectal cancers will be in the left colon. • Disadvantages: will obviously miss 25% of sporadic colorectal cancers and a greater proportion of familial ones. 3) Colonoscopy • Advantages: allows visualization and biopsy of the entire colon. • Disadvantages: uncomfortable as it requires the bowel to be filled with gas (gas insufflation) and has a risk of 1/500 for GI bleeding, 1/1000 for bowel perforation, and 1/10,000 for death. Requires 2 days of special diet ('bowel preparation') to empty the bowel of its contents. Limited visibility if bowel preparation is inadequate. 4) CT colon • Advantages: rapid and non-invasive visualization of the entire colon. Does not involve any bowel preparation and is thus suitable for frail patients. • Disadvantages: does not allow for biopsies and has a poorer sensitivity at detecting lesions than CT colonography because of the lack of bowel preparation (it can be hard to distinguish a malignant lesion from faeces). 5) CT colonography (aka virtual colonoscopy/CT pneumocolon) • Advantages: quick. Because it visualizes all the organs of the abdomen (rather than just the bowel lumen), it allows one to assess the degree of invasion of any bowel masses and look for masses in other organs, therefore allowing one not only to identify a cancer (e.g. colon, ovarian) but also assess how far it has spread (staging) all in one go. • Disadvantages: does not allow for biopsies. Also requires uncomfortable bowel preparation and gas insufflation. The radiation probably contributes to fatal cancer in about 1/2000 patient scans (0.05%). This may sound like a lot, but fatal cancer is so common (20%) that this would only increase the risk from 20% to 20.05%. 6) DCBE (double-contrast barium enema) • Advantages: readily available in many hospitals. • Disadvantages: does not allow for biopsies. Less specificity and sensitivity for picking up colon cancer unless the lesion is large.

intermittent rectal bleeds that are difficult to visualise? (2)

1. Angiodysplasia (visualise via mesenteric angiography). 2. Dieulafoy lesion (a ruptured submucosal artery, most commonly at the oesophagogastric junction, but also in the small bowel and rectum)

Four further investigations for rectal bleeding? after a rigid sigmoidoscopy/proctoscopy.

1. Colonoscopy Is method of choice in a stable patient may need lavage to see otherwise too much blood. - also therapeutic as can control haemorrhage with adrenaline injection, argon plasma coagulation, diathermy, clipping. - on-table colonoscopy in those who present with profuse haemorrhage and proceed straight to theatre. The colon can be irrigated via a caecal catheter to maximise visualisation. 2. Mesenteric angiography (if available) (arterial) If colonoscopy not possible eg. too much blood or re-bleeds often. useful for detecting *angiodysplasia* as evidenced by early filling of vessels and/or bleeding during the capillary phase. In order to demonstrate active bleeding there must be blood loss of 0.5-1ml/min. embolisation of the bleeding vessel can be performed during the procedure. 3. CT angiography (venous): Multi-slice CT detects minor bleeds and fewer complications than arterial mesenteric angiography. allows rapid imaging and other abdominal pathology related to bleeding but not therapeutic. 4. Technetium-99m-labelled red blood cell scintigraphy (if available) - For those who fail to find bleed. usually those with short-lived intermittent bleeds (e.g. Meckel's diverticulum). detects bleeds of >0.1ml/min (but low specificity) and can be used to detect bleeding lesions up to 24hrs after tracer administration. Not therapeutic but can guide surgical resection. doesn't require bowel prep. (Small bowel visualisation by enteroscopy or video capsule endoscopy: not in acute situation unless all else fails)

history of a relatively large, non-painful, bright red rectal bleed with no other associated symptoms is most suggestive of either:

1. diverticular disease (can get LIF pain if its diverticulITIS- however lack of pain in rectal bleeding isn't surprising as it is rare for bleeding and diverticulitis to co-exist) 2. or angiodysplasia

A 61-year-old patient presents to their GP with rectal bleeding, and internal haemorrhoids are identified as a probable culprit lesion. Should the patient also be referred for colonoscopy with a view to excluding colorectal carcinoma?

Although these guidelines were intended for use by GPs, they also serve as a useful reference for investigation of inpatients. It is recommended by NICE (2005) that patients are referred for urgent specialist investigation in the following instances: • Aged 40 years and older, reporting rectal bleeding with a change of bowel habit towards looser stools and/or increased stool frequency persisting 6 weeks or more. • Aged 60 years and older, with rectal bleeding persisting for 6 weeks or more without a change in bowel habit and without anal symptoms. • Aged 60 years and older, with a change in bowel habit to looser stools and/or more frequent stools persisting for 6 weeks or more without rectal bleeding. • Any age with a right lower abdominal mass consistent with involvement of the large bowel. • Any age with a palpable rectal mass (intraluminal and not pelvic; a pelvic mass outside the bowel would warrant an urgent referral to a urologist or gynaecologist). • Men of any age with unexplained iron-deficiency anaemia (Hb ≤11 g/dL).† • Non-menstruating women with unexplained iron-deficiency anaemia (Hb ≤10 g/dL).†

Erythema nodosum causes

BELTY SLIPS B ehcets E strogen (eg. COCP) L ofgran's T B Y = V iral (#2) S trep (#1) L ymphoma (NHL) and Leukemia I BD P CN S ulpha Both Crohn's disease and UC are systemic inflammatory diseases that can manifest in the skin in the form of erythema nodosum (tender, raised, red nodules) or, less commonly, pyoderma gangrenosum (necrotic ulcers). However, bear in mind that the combined oral contraceptive pill is also a common cause of erythema nodosum in young women.

investigations for someone with diarrhoea?

BLOOD TESTS • *FBC*: coeliac disease, Crohn's disease, and UC can all cause anaemia from malabsorption of iron, folate, or vitamin B12; from GI blood loss caused by the disease (especially UC); or from the chronic disease process per se. They can also cause a high platelet count as this is an inflammatory marker. • *ESR*: Crohn's disease and UC are systemic inflammatory diseases and usually lead to elevated ESR. • *CRP*: infectious diarrhoea, Crohn's disease, and UC can all cause a rise in CRP levels. • *Tissue transglutaminase (TTG) and IgA levels*: a positive result has a sensitivity and specificity of over 90% for coeliac disease. You should always check the IgA levels, too, as IgA deficiency can cause false negative results. Anti- endomysial antibodies can be used instead of TTG but are more susceptible to IgA deficiency causing false negatives. Antigliadin antibodies have been used to test for coeliac disease but are less sensitive and specific. • *Thyroid function tests (TFTs)*: a low thyroid-stimulating hormone (TSH) and a high tri-iodothyronine/thyroxine (T3/T4) level would strongly suggest hyperthyroidism. • *Urea and electrolytes (U&Es)*: the patient may be dehydrated or suffering electrolyte disturbances from the diarrhoea itself (loss of ions) or secondary to acidaemia caused by hypoperfusion and ischaemia. • *Albumin*: this will below in patients with chronic diarrhoea and malabsorption, e.g. IBD. • *Capillary glucose*: a simple bedside blood glucose test will tell you if this patient is diabetic. Whilst diarrhoea would be an unusual presenting complaint for diabetes mellitus, it is easy to exclude. FAECAL TESTS • *Faecal occult blood test (FOBT)*: This would point towards infection or UC, and away from hyperthyroidism, coeliac disease, and IBS. However, this should only be requested after stopping any drugs that can cause bleeding (e.g. aspirin, warfarin), as these will give a false positive result. If they cannot be stopped, a positive result does not help the diagnosis and therefore you should not order the test. • *Faeces microscopy and culture*: to exclude infection by the microbiologists. Pus cells may be visible and can indicate inflammation in IBD. Remember that Giardia can be very hard to visualize under the microscope even if it is present (i.e. false negative). • *C.difficile toxin test*: If the patient did have recent antibiotic use, you should consider testing for C. difficile toxin.

have characterised the diarrhoea of a patient. now asking about their bowel habits, associated symptoms and risk factors for diarrhoea...

BOWEL HABIT • *Is there nocturnal diarrhoea?* If so, this suggests an 'organic' aetiology (rather than a 'functional' aetiology as in IBS). • *Does she ever find herself having to rush to the toilet to pass motions?* Urgency to defecate is suggestive of infectious diarrhoea or IBD. • *After passing motions, does she ever feel that she hasn't fully evacuated her bowel?* This sensation is called tenesmus and is suggestive of a space-occupying lesion in the rectum (e.g. carcinoma). • *Has she had a variable bowel habit?* Both IBS (in younger patients) and colorectal cancer (in older patients) can present as alternating habit that varies from diarrhoea to normal stools to constipation. • *How often does she suffer from diarrhoea?* Infectious diarrhoea is typically a one-off event (although we will nearly all have had this at some point), whereas other pathologies are usually recurrent. However, remember that chronic diseases still have to present for the first time! ASSOCIATED SYMPTOMS • Has there been any vomiting? - infectious gastroenteritis . • Has there been any abdominal pain? − Pain in the right iliac fossa associated with diarrhoea is suggestive of terminal ileum inflammation (e.g. Crohn's disease, Yersinia enterocolitica infection). − Pain in the left iliac fossa associated with diarrhoea is suggestive of diverticular disease. − Pain relieved by passing motions is suggestive of IBS. • Has she noticed any (significant) weight loss?Try to quantify this in terms of amount over which time period. Significant weight loss over months suggests a chronic pathological process, e.g. IBD, rather than an acute pathology, e.g. infection. • *Has she had any eye problems, joint pains, or skin rashes?* Uveitis (painful red eye with loss of vision), scleritis (painful red eye with no loss of vision), episcleritis (uncomfortable red eye with no loss of vision), enteric arthritis, erythema nodosum (painful, dark red nodules on shins), and pyoderma gangrenosum (ulcers with a surrounding purple halo) are all associated with IBD (UC and Crohn's disease). RISK FACTORS • Been abroad recently? eaten anything unusual? know others with similar symptoms? - Foreign travel and eating certain types of meals (e.g. barbeques, kebabs...) are significant risk factors for infectious diarrhoea. Knowing other people with similar symptoms at the same time is also suggestive of an infectious aetiology. • Been stressed as of late?What is her diet like?Stress and a low-fibre diet are associated with IBS. • What medications does she take? Changed recently? Remember that diarrhoea is one of the commonest side-effects of all oral medications. Look out in particular for antibiotics and proton-pump inhibitors (PPIs), which are associated with Clostridium difficile diarrhoea. FAMILY HISTORY • Family history of bowel disease? Is there a FH of Chrons disease, UC, coeliac disease, or rarer conditions such as hereditary non-polyposis colorectal cancer (HNPCC)? The questions above can help to narrow your differential diagnosis. However, it is also helpful for management to find out whether the patient is still eating and drinking and what medications they have tried for their diarrhoea (e.g. loperamide? oral rehydration salts?).

Hypercalcaemia is confirmed by checking serum calcium. Now how do you ascertain the underlying cause of hypercalcaemia?

Bone metastases cause increased turnover of bones, hence the high ALP. This releases both calcium and phosphate from the bones. Myeloma (malignant tumour of BM) causes a similar picture to bone metastases. However, in myeloma, osteoclasts are activated and osteoblasts are inhibited. As ALP comes from osteoblasts, it remains normal. In primary and tertiary hyperparathyroidism, PTH causes increased bone turnover; hence you also get high ALP (although this can be normal if the bone turnover is slow). Bone turnover releases both calcium and phosphate, but as PTH increases renal excretion of phosphate, this is low. - Note that PTH levels are often in the 'normal range' but that this is actually abnormal as they should be low in the presence of high calcium (remember that PTH release is normally inhibited by high calcium levels). Vitamin D causes increased gut absorption of both calcium and phosphate. As there is no increased bone turnover, ALP is low, and because calcium levels are high, PTH is suppressed and also low.

What are bulk producers? What are stool softeners? what are osmotic laxatives? what are peristalsis stimulants?

Bulk producers: fibre helps constipation by providing bulk (which activates stretch receptors in the bowel and triggers peristalsis) and by retaining water (which makes faeces softer). Various fibre supplements exist for patients who cannot achieve sufficient bulk by modifying their diet alone (e.g. methylcellulose tablets, ispaghula husk). Stool softeners: liquid paraffin and arachis oil enemas can be used to soften stool. They should only be used in the short term as they can lead to unpleasant side-effects such as steatorrhoea and anal seepage. Osmotic laxatives: lactulose or magnesium salts act by retaining fluid in the bowel, thus causing a mild osmotic diarrhoea. These should only ever be used as a short-term remedy as they can cause dehydration and tolerance without addressing the underlying cause. Peristalsis stimulants: glycerol suppositories, bisacodyl, or Senna can all be used to stimulate peristalsis. Phosphate enemas: these should only be used as a last resort.

clinical features to suggest haemodynamic instability

Can be defined as perfusion failure, represented by clinical features of circulatory shock and advanced heart failure (Weil 2005). e.g. hypotension, tachycardia, cool peripheries, tachypnoea, or decreased consciousness

What staging classifications do you know for colon cancer? (general type and specific type)

Cancers are often staged using the international [[TNM]] classification which, at its most basic, stands for: [[Tumour size]]: scored from 1-4 depending on either size or local invasion. [[Nodes]]: scored from 0 (none) to 3 (many and distant) depending on the lymph nodes affected by the cancer. [[Metastasis]]: scored either 0 (none) or 1 (present) depending on spread of cancer in other organs. Some cancers also have specific staging systems. For colon cancer, the older *Dukes' classification* is still often used:

Diagnosis of Hashimoto's thyroiditis

Clinical signs of hypothyroidism. Blood test revealing a high TSH level, which is due to the lack of sufficient thyroxine to negatively feed back on its production. If this is Hashimoto's hypothyroidism, one will also find high antithyroid peroxidase antibodies.

Colitis definition

Colitis refers to inflammation of the inner lining of the colon. There are numerous causes of colitis including infection, inflammatory bowel disease (Crohn's disease, ulcerative colitis), ischemic colitis, allergic reactions, and microscopic colitis. Symptoms of colitis depend upon the cause and may include.

• Dermatitis herpetiformis

DH is a cutaneous manifestation of *celiac disease*. Despite its name, DH is neither related to nor caused by herpes virus: the name means that it is a skin inflammation having an appearance similar to herpes. The rash is typically found over the extensor surfaces of the limbs and over the scalp. The rash is very itchy, so its papules are usually raw or crusted from the patient scratching them.

clinical definition of diarrhoea

Diarrhoea is an increase in the amount of stool passed daily to over 300 g of stool per day. This is usually accompanied by increased frequency and loosening of the stools. However, many patients will talk of 'diarrhoea' when they actually have haematochezia (bright red stools from frank blood), melaena (dark, tarry stools from digested blood), steatorrhoea (pale, floating stools from undigested lipid), or simply loose stools (soft faeces but no increase in frequency or quantity).

How is Dukes' staging system used for guiding management and prognosis?

Dukes' A • 90% survival at 5 years. • Such patients are offered *surgical removal* of the tumour-affected portion of bowel, together with its enveloping blood vessels, adipose tissue, and lymph nodes. This was traditionally done via a laparotomy but is increasingly done laparascopically as studies have shown this is just as effective but has fewer complications in expert hands. Indeed, patients having a laparoscopic colectomy are often walking and eating with 24 hours of surgery. Some studies suggest that the use of pre-operative radiotherapy may further improve survival rates if the cancer is rectal but note that radiotherapy is not done if the tumour is proximal to the rectum as there is then a risk of damaging the highly radiosensitive small bowel. Dukes' B and C • Approximately 65% and 30-45% survival at 5 years, respectively. • Such patients will get surgical removal of the tumour plus multidrug adjuvant chemotherapy. Some patients with rectal tumours may also get pre-operative radiotherapy. Multiple chemotherapy agents are needed because colon cancers are intrinsically very resistant to chemotherapy. This is a reflection of their adaptation to constant exposure to toxins in the diet (e.g. they naturally express multidrug efflux pumps such as P-glycoprotein). Dukes' D • Approximately 5-10% survival at 5 years. • Treatment in such patients is largely palliative. Patients may have surgical resection of the tumour and larger metastases (e.g. liver), chemotherapy (standard or experimental), stenting of the tumour if the patient is unfit for resection surgery, and/or palliative radiotherapy.

rectal bleeding. nothing found on abdominal exam or DRE. first line investigations?

FBC: see if anaemia (chronic blood loss) or has low platelets. Clotting: want to know if has bleeding tendency. Group and Save: if unstable and/or showed signs of continued bleeding. Urea: a rise in urea is consistent with a recent upper GI bleed (urea is a breakdown product of digested red blood cells). Proctoscopy and rigid sigmoidoscopy: unless painful anal lesions such as an anal fissure. nb. view of the rectum may be unsatisfactory if there is a lot of blood. Proctoscopy ± rigid sigmoidoscopy will enable the identification of bleeding haemorrhoids or a rectal cancer, and can be performed at the bedside in A&E.

What must you always do (and mention in Objective Structured Clinical Examinations!) with any patient who is receiving IV fluids of any sort?

If a patient is receiving IV fluids, you must always *document fluid input/output* and *always reassess* the patient clinically and biochemically. That is why, on ward rounds, patients on IV fluids get examined clinically and have bloods taken for (amongst other things) electrolyte levels. *Clinical examination* may reveal a patient who is still thirsty, with dry mucous membranes, tachycardia, a narrow pulse pressure, and a urine output <30 mL/h despite IV fluids, suggesting they are not receiving enough fluids. Alternatively, it may reveal a the patient who looks puffy (oedematous), has crackles in the bases of their lungs, and a raised jugular venous pressure, suggesting they are receiving too much fluid. *Blood biochemistry* may reveal a patient who is hyponatraemic (they may need more normal saline and less 5% dextrose) or hyperkalaemic (they may need less K+ supplementation in their fluids).

Electrolyte or pH disturbance in diarrhoea: and management of this dehydration and electrolyte imbalance?

It is common for patients with diarrhoea to lose multiple electrolytes in their faeces and thus have low K+, low Na+, low Cl−, and low HCO3−. All that is needed to correct these imbalances if the patient's kidneys are functioning adequately is fluid rehydration. However may also get hyperkalaemia secondary to the hypovolaemia and ischaemia (therefore acidosis) of tissues Management: - This patient is essentially dehydrated due to her ongoing diarrhoea. - She therefore needs a cannula placed, bloods taken (so you don't have to bleed her again later), and fluids given. - One way to administer fluids is orally, but the fact that she is hypovolaemic after 3 days suggests she is not managing to hydrate orally. - The alternative is therefore intravenous (IV) fluids. At this stage, one could give a *'fluid challenge'* of 250 mL normal saline and then reassess the patient's blood pressure after 30 minutes. - If her blood pressure remains low, she needs more fluids. If her blood pressure has improved you can switch to providing *maintenance fluids IV or orally*. - The metabolic acidosis and electrolyte disturbances will all *self-correct with adequate restoration of fluid balance*, assuming her kidney function is normal.

if dehydrated what acidosis are you likely to have?

It is likely that this patient's tissues are ischaemic due to the hypovolaemia and therefore relying on anaerobic glycolysis for energy, producing lactic acidosis. This is therefore a metabolic acidosis (if it was respiratory, the CO2 would be high and driving the acidosis). Her anion gap (Na+ + K+ − Cl− − HCO3−) is elevated* (>18 mM) suggesting the presence of extra acids (e.g. lactic acid? aspirin? ketone bodies?).

Treatment for haemorrhoids:

Lifestyle modification • Increased dietary fibre, which may soften faeces and minimize straining at stool (although study evidence is somewhat lacking) • Keep well hydrated • Avoid straining at stool Medical management • Local anaesthetic creams can be used to relieve soreness and itching • Steroidal creams/suppositories can be used to reduce local inflammation • Evidence of efficacy for both is limited Surgical management There are numerous surgical options, the suitability of which may differ according to patient and the haemorrhoid characteristics: • Rubber band ligation • Injection sclerotherapy • Infrared coagulation/photocoagulation • Haemorrhoidectomy • Stapled haemorrhoidopexy • Doppler-guided haemorrhoidal artery ligation and recto-anal repair (DG-HAL-RAR)

Anal fissure treatment

Most anal fissures are shallow and will heal spontaneously within a few weeks. Deep fissures have poor healing because sphincter spasm impairs the anal blood supply. The main aim of treatment is to *relieve anal sphincter spasm* and *tearing of the anal mucosa*, in addition to promoting healing. MEDICAL TREATMENT • A *high-fibre* diet coupled with laxative and non-constipating analgesics (e.g. avoid opioids) may prevent further damage (caused by hard stool) and relieve pain. • *Topical anaesthetics* (e.g. lidocaine gel) can help with the pain. • *Topical glyceryl trinitrate* (GTN) may increase local blood flow and relax the internal anal sphincter, thus promoting healing, but GTN often causes headaches. *Topical diltiazem* (calcium-channel blocker) has been advocated for use when topical GTN has been ineffective, but the evidence base is weak. • *Botox injections* into the anal sphincter can relieve spasm and promote healing in patients with chronic fissures. SURGICAL MANAGEMENT • *Lateral internal sphincterotomy* is very effective at reducing sphincter spasm in those patients who have failed to respond to medical therapies. The integrity of the external anal sphincter must be checked with an ultrasound scan before surgery because cutting the internal sphincter in the presence of a damaged external sphincter (e.g. due to childbirth) would cause disastrous faecal incontinence. Indeed, previously, both anal sphincters used to be manually dilated under general anaesthetic but this is no longer done as, unsurprisingly, it resulted in anal incontinence for many patients. • *Anal advancement flap* is also used by some specialists.

what increases risk of diverticular haemorrhage?

NSAIDs eg. diclofenac Warfarin

Why should patients with UC be offered regular colonoscopies?

Patients with UC are at increased risk (five-fold) of colon cancer, and for this reason they are offered regular colonoscopic studies looking for early signs of malignancy. If malignancy is detected, the usual procedure is to excise the entire colon (colectomy). Traditionally, this resulted in the patient needing a permanent colostomy but modern surgical techniques allow for the creation of a new rectum and preservation of anorectal function by performing an ileo-rectal anastomosis with an ileal pouch.

Crohn's versus UC presentation and Crohn's pathophysiology

Presentation: - gastroduodenal: vomiting, nausea, anorexia. -if small bowel: evidence of malabsorption, including diarrhea, abdominal pain, weight loss, and anorexia - colonic Crohn disease may be clinically indistinguishable from ulcerative colitis, with symptoms of bloody mucopurulent diarrhea, cramping abdominal pain, and urgency to defecate. - In Miss Bowles' case, the lack of bloody diarrhoea and the fact that the abdominal pain often starts in her right lower quadrant are suggestive of Crohn's disease. - In UC, the pain is usually diffuse and the diarrhoea is often bloody. - In addition, patients with Crohn's disease are more likely to suffer with weight loss and failure to thrive between attacks, whereas patients with UC are more likely to be relatively well between acute attacks. Pathophysiology of Crohns: - Crohn's disease is believed to be due to mutations in genes responsible for clearing up phagocytosed bacteria. - The inability of macrophages to correctly clear the bacteria they ingest leads to them secreting cytokines that make the immune system try to 'wall off ' the aberrant situation, forming a granuloma (a situation analogous to what happens in Tb, where macrophages also have difficulty clearing the mycobacteria). The granuloma leads to chronic inflammation. - Locally, this leads to diarrhoea, ulcers, strictures of the bowel, and fistulae between the bowel and other compartments (or the outer world). - Associated systemic complications include inflammation of the eyes (iritis, episcleritis, scleritis), the joints (arthritis), and the skin (erythema nodosum); as well as anaemia (either through malabsorption or chronic inflammation per se), weight loss, and fatigue- ALSO with UC.

A common symptom of hyperthyroidism is increased bowel movements, often resulting in frank diarrhoea. Why does hyperthyroidism cause diarrhoea?

T3 is a hormone that results in cells expressing more adrenergic receptors and modifying the components of the adrenergic response pathway so that they are more sensitive to catecholamine stimulus. The net result is that cells become more sensitive to catecholamines such as adrenaline and noradrenaline, and therefore more sensitive to sympathetic stimulation. Many physiology textbooks claim that sympathetic stimulation of the bowel results in constipation, but as many students nervous before exams will testify, the prolonged effect of catecholamines on the bowel is to increase bowel movements.

Why is constipation very common after surgery?

The combination of *anaesthesia, opiate analgesia*, and (in abdominal surgery) *bowel manipulation* often sends the bowel into a state of paralysis called *ileus*. Electrolyte disturbances (e.g. hypokalaemia, hypomagnesaemia) can further exacerbate this situation. On top of this, patients may find it difficult to pass faeces because of pain or the embarrassment of having to use a 'commode' on the public wards. Post-operative ileus is usually self-limiting, with normal peristalsis returning 24-72 hours after surgery. However, whilst the bowel is in a state of paralysis, it continues to secrete fluid into its lumen but fails to reabsorb it. The consequence is that fluid remains trapped in a 'third space' and for this reason, patients often require IV fluids post-operatively to ensure a urine output of at least 0.5 mL/kg/hour (but not so much fluid that one causes oedema or shortness of breath). After 24-72 hours, the bowel usually starts working again, the 'third space' fluid is reabsorbed, and there is often a sudden diuresis by the patient. The risk of post-operative ileus can be minimized by: using local/epidural anaesthesia where possible; minimizing opiate analgesia (e.g. by using more local anaesthetics); minimizing bowel manipulation; and encouraging early mobilization of patients.

What is the anatomical significance of the dentate line?

The dentate or pectinate line represents an anatomical watershed that separates zones of different epithelial cell types, arterial supply, venous drainage, lymphatic drainage, and nervous supply (see Fig. 21.3 and Table 21.3):

How do you classify internal haemorrhoids?

The most commonly used grading system for internal haemorrhoids reflects the degree of prolapse and reducibility, but does not necessarily reflect symptom severity: • First degree: bleed but do not prolapse • Second degree: prolapse but reduce spontaneously • Third degree: prolapse and do not reduce spontaneously, but can be manually reduced • Fourth degree: prolapse and are irreducible

ddx of rectal bleeding split by anatomy

The prevalence refers to overt bleeding (as occult will not be noticed by the patients) nb: upper GI sources of haemorrhage may occasionally present with rectal bleeding alone though usually with haemetemesis. - This is because large volumes of blood in the GI tract can act as a cathartic (stimulant of peristalsis) and the resultant rapid transit through the intestine leads to the passage of red blood per rectum.

What are the most likely infective organisms in each of the following diarrhoea scenarios? 1) An outbreak of vomiting and diarrhoea in an old persons' nursing home 2) An outbreak of bloody diarrhoea at a local primary school 3) A university student with watery diarrhoea a few days after a barbeque 4) A group of guests with sudden-onset diarrhoea a few hours after a wedding reception 5) An 82-year-old gentleman in hospital receiving antibiotics for pneumonia 6) A young woman who has just returned from Ghana and has right iliac fossa pain and diarrhoea

The reality is that it is often hard to predict the pathogenic organism in cases of infectious diarrhoea and microbiological culture often reveals the pathogen to be multiple organisms or an unexpected organism. However, certain patterns are typical for certain pathogens and these are frequently asked about in exams and vivas. Hence: 1) Outbreaks of vomiting and diarrhoea in institutions are usually due to viruses of the small structured round virus (SSRV) type, such as *Norovirus*. 2) Outbreaks of dysentery (bloody diarrhoea) are often associated with bacteria of the Shigella species or with *Escherichia coli strain O157*. 3) In truth, this could be due to a multitude of organisms, but in exams and vivas the answer is that *Campylobacter jejuni* would be a good candidate for a post-barbeque case of diarrhoea. 4) Rapid-onset diarrhoea after a meal suggests that the meal was contaminated with bacteria that have excreted active toxins, hence the rapid onset of symptoms. When the diarrhoea is caused by the pathogen's growth in the bowel, the onset of symptoms is usually much slower. *Staphylococcus aureus and Bacillus cereus* are both bacteria that grow on warm food and produce toxins that result in rapid-onset diarrhoea. 5) The diarrhoea could be caused by a multitude of organisms or even the antibiotics per se, but in elderly patients receiving antibiotics you should always be wary of *Clostridium difficile*. 6) Again, the diarrhoea could be simple 'traveller's diarrhoea' caused by an *enterotoxigenic strain of E. coli* but the right iliac fossa pain should make you suspicious of *Yersinia enterocolitica.*

What are the known risk factors for colorectal carcinoma?

The risk factors with the strongest evidence base include: • Increasing age • Male sex (only for rectal carcinoma) • Central obesity • Colorectal disease: − Inflammatory bowel disease (especially ulcerative colitis, but also Crohn's) − Previous history of colorectal cancer − Colorectal polyps − Colorectal irradiation • Familial conditions including: − Familial adenomatous polyposis (FAP) − Hereditary non-polyposis colorectal cancer (HNPCC) − Peutz-Jeghers − Juvenile polyposis − Cowden's disease − MYH-related polyposis • Sedantary lifestyle (lack of regular exercise) Dietary factors such as red meat, high fat, and low fibre may also be risk factors, but the evidence base for these is weaker

Treatment of Crohn's disease

The symptoms of Crohn's disease are due to chronic activation of the immune system in various tissues (e.g. the bowel wall). Because of this, immunosuppressant medications are used to treat the symptoms of the disease. Medications such as *sulfasalazine* (a sulfa drug of unknown mechanism) and *budesonide* (a steroid) are both poorly absorbed immunosuppressants whose action is therefore greatest in the intestine, and both drugs are good at achieving remission from an acute attack of Crohn's disease. The disease can then often be kept at bay using immunosuppressants such as *methotrexate* (a folate antagonist), *azathioprine* (a purine synthesis inhibitor), or newer medications such as *anti-tumour necrosis factor-α* (anti-TNFα) *monoclonal antibodies* (e.g. infliximab). A large proportion of Crohn's patients ultimately require surgery to resect the most affected portions of their bowel, although the emphasis is on managing the disease medically because surgery is only a temporary solution and other portions of bowel will ultimately become affected, too. provided the disease becomes well managed, it is likely that they will be able to lead their usual active lifestyle.

UC presentation and associations.

This is a form of IBD whose aetiology is unknown. The GI tract is affected in a distal to proximal fashion (i.e. from the rectum upwards) and shows gross, uniform inflammation with a clear cut-off point between abnormal and normal bowel. Patients typically present with painless, bloody diarrhoea. Unlike Crohn's disease, UC has a much stronger association with colonic adenocarcinoma (1% risk per year); primary sclerosing cholangitis (obstructive jaundice and liver failure), and cholangiocarcinoma (cancer of the common bile duct).

What is overflow diarrhoea

This is caused by an obstruction that allows only fluid and air to bypass, causing a liquid diarrhoea that is hard to control. The obstruction may be due to a mass within the lumen (e.g. solid, impacted faeces due to dehydration and lack of fibre); a mass within the bowel wall (e.g. colonic adenocarcinoma), or a mass outside the bowel wall (e.g. a large ovarian tumour compressing the bowel).

What surgery do surgeons do to resect abnormal bowel in a patient?

Traditionally, patients undergo a Hartmann's procedure to resect the abnormal bowel. Some centres now advocate primary anastomosis at the time of resection

A patient presents to you with a known diagnosis of haemorrhoids. He is now suffering acute anal pain. What is your differential diagnosis?

Uncomplicated haemorrhoids are not normally painful, thus acute pain in the anal region suggests either a complication of haemorrhoids or an additional pathology. The differential diagnosis includes: • Thrombosed external haemorrhoid • Anal fissure • Proctalgia fugax (a poorly understood stabbing/cramp-like sensation in the anus, that may last up to 30 minutes, and is more common at night) • Anal abscess • Lower anal cancer

elderly pt in hospital being treated for CAP and just had a right hip replacement. explosive diarrhoea. what are you worried about? how manage this?

You should be worried that this patient may have developed C. difficile colitis (in those taking abx or immunosuppressed). Early management is essential and should include: 1) ABC: this lady's blood pressure is low for an elderly patient and her mucous membranes are dry, suggesting she is indeed hypovolaemic, which is unsur- prising if the nurses are having to change her bed every hour due to diar- rhoea. She needs IV fluid resuscitation urgently (e.g. 250 mL boluses of IV normal saline until clinical signs and blood pressure suggest she is no longer hypovolaemic). 2) Faeces analysis: send a stool sample off immediately to microbiology for microscopy, culture, and analysis for C. difficile toxin. 3) Isolation: an obvious, effective, and simple solution to preventing the spread of pathogenic C. difficile on the wards, but one that is often hard to implement in many overcrowded and under-resourced hospitals. 4) Meticulous hygiene: all staff and visitors should 'glove and gown' and hands must be washed between patients using warm water and soap (alcohol gels will not inactivate C. difficile which forms highly durable spores). 5) Antibiotics: if the faeces analysis is positive for C. difficile toxin, you should start appropriate antibiotic therapy without delay. e choice of antibiotic will depend on local guidelines, which you should always consult.

Non-trivial GI bleeding in a patient who has had previous aortic surgery should make you suspect what?

aorto-enteric fistula until proven otherwise.

how to check for dehydration

check the heart rate (tachycardia?), the blood pressure (narrow mean arterial pres- sure or low blood pressure?), mucous membranes (dry lips?), and whether the patient feels thirsty.

Management of Hashimoto's thyroiditis

daily oral levothyroxine and prognosis is very good (all symp- toms should resolve), although patients have to remain on levothyroxine for life.

haemodynamic instability def and features.

defined as perfusion failure, represented by clinical features of circulatory shock and advanced heart failure (Weil 2005). - such as hypotension, tachycardia, cool peripheries, tachypnoea, or decreased consciousness

why do an upper GI endoscopy in some cases of rectal bleeding?

do this investigation esp if haemdynamic compromise and you can't find cause lower down GI tract. Not only is upper GI haemorrhage more common than lower GI haemorrhage (80% of acute GI haemorrhage is upper), it is less likely to stop spontaneously and thus more life-threatening.

Lax or asymmetric anal tone suggests...?

is suggests neurological pathology, such as diabetic neuropathy, multiple sclerosis, or cauda equina compression.

causes of large bowel obstruction

mechanical obstruction by a colorectal tumour, sigmoid volvulus (twisting of the sigmoid colon), or inflamed diverticula (diverticulitis) functional causes (e.g. hypothyroidism)

drug for treating opiod-induced constipation

methylnaltrexone

ddx for rectal bleeding

nb the prevalence values are for overt rectal bleeding as occult will not be picked up by the patient. upper GI sources of haemorrhage may present with rectal bleeding alone as large volumes of blood act as cathartic (stimulate peristalsis) leading to rapid passage of red blood to recut. although most also present with haematemesis. MOST COMMON: diverticular disease, angiodysplasia, haemorrhoids, colitis, anal fissures, and lower GI tumours are the most common causes of rectal bleeding.

PMH and Past surgical HISTORY of someone with rectal bleeding?

previous episodes? UC? Recent procedures that may= bowel trauma? aortic surgery? - aorta-enteric fistula. radiotherapy to rectum? Bleeding tendency? - haemophilia, warfarin, platelet dysfunction. upper GI lesion risk factors? eg. PUD, CLD.

Radiotherapy to the rectum can induce..

proctitis - inflammation of the rectum and anus.

constipation definition

stool that is passed infrequently and/or with difficulty. The most important thing to elucidate is what the patient means by 'constipation'. Therefore, writing 'constipation' in the notes is inadequate - you must say something about *frequency, ease of passage, and volume*.

how a normal adult loses fluid and electrolytes?

the average, normal adult loses about 2.5 L of fluid every day: - in urine (1.5 L/day), - faeces (200 mL/day), and - 'insensible losses' (i.e. those you aren't aware of such as sweating and respiration, 800 mL/day). Lost fluids contain dissolved electrolytes and so the average, normal adult also loses about 100 mM of Na+ and about 70 mM of K+ every day.

what is third space fluid loss?

traditionally, fluid found in the vasculature is said to be in the 'first space' whereas fluid found in interstitial tissue space is said to be in the 'second space', as both of these 'spaces' contain volumes of fluid that are variable (intracellular fluid is usually fairly constant). The 'third space' refers to areas of the body that accumulate fluid only in disease, thus draining, fluids away from the first and second spaces. Thus, patients may have: - fluid in their peritoneal cavity (for example due to ascites in liver cirrhosis or inflammatory exudate around the pancreas in pancreatitis), - fluid in their intrapleural space (pleural effusion as in parapneumonic effusions for example), - build- up of excess fluid in their GI tract (for example in small bowel obstruction), etc. Estimating how much fluid has been 'third spaced' in a patient is di cult, and one usually relies on trial and error (giving replacement fluids and then assessing the patient) to work out how much replacement fluid to give.

sigmoid volvulus presentation

twisting of the sigmoid colon 'coffee bean' sign (an enormous, dilated loop of bowel, shaped like a coffee bean and extending from the pelvis up to the diaphragm), caused by the sigmoid portion of the bowel twisting on itself. complete large bowel obstruction. distended abdomen and constipation, colicky abdominal pain

causes of primary hyperparathyroidism

usually solitary, benign parathyroid adenoma, although: parathyroid hyperplasia, parathyroid carcinoma, or PTH-secreting ectopic tumours also occur.

for a young adult with acute (eg. 3 days) diarrhoea, what is the ddx list? what would this list look like for a 64 yr old?

young patients: see pic In elderly patients: - neoplastic disease (villous polyps, colonic adenocarcinoma, pancreatic cancer), - diverticular disease, - ischaemic colitis, - microscopic colitis, and - bacterial overgrowth (e.g. in patients with diabetes mellitus) are much more likely, - whereas immune-related diseases such as coeliac disease and UC are less likely to present for the first time (as they tend to present in younger patients). Curiously, Crohn's disease has a second incidence peak at ages 50−80.

treatment of large bowel obstruction. eg. sigmoid volvulus, colorectal cancer, diverticulitis.

• 'Drip and suck'. The patient is placed nil by mouth, a nasogastric tube is inserted, and intravenous (IV) fluids are given, all in an effort to rest the bowel and replace the fluids and electrolytes that are building up in the obstructed bowel. • Remove the obstruction. - In sigmoid volvulus, this is done using a sigmoidoscope with a long, soft flatus tube to untwist the bowel, or surgery if this is unsuccessful or the patient is peritonitic. -In colorectal cancer, a metallic stent can be used to relieve the obstruction until the tumour is removed surgically. - In diverticulitis, reduction of the inflammation with bowel rest and antibiotics may be enough to reduce the obstruction, although surgical resection is occasionally necessary.

Second-line investigations to confirm or exclude Crohn's disease:

• *Abdominal (plain) radiograph*: this may show signs of bowel inflammation. If localized to discrete areas (skip lesions), this would be in keeping with Crohn's disease. Abdominal radiographs are essential for patients with severe UC as they are at risk of toxic megacolon (which can perforate), and this can be detected as a large bowel loop that is >6 cm in diameter. • *DCBE radiograph*: this may show discrete lesions and strictures in the colon, suggestive of Crohn's disease. • *Colonoscopy*: this can help visualize the discrete, interrupted lesions of Crohn's disease (or the diffuse, erythematous inflammation of UC) and allows for biopsies to be taken in search of non-caseating granulomas in the bowel mucosa (the hallmark of Crohn's disease).

patient with diarrhoea. How to characterise the stools?

• *Are the faeces bloody?* if so, then describe the faeces. − If the blood is only on the paper when they wipe, or the faeces are streaked with blood, it suggests anal pathology (e.g. anal fissure, haemorrrhoids, vigorous wiping secondary to the diarrhoea). − If the blood is red and mixed in with the faeces it suggests colorectal pathology (e.g. UC, dysentery, colorectal carcinoma). • *Are the faeces mucoid or jelly-like?* this classically suggests infection by Salmonella or villous polyps in the colon, but can be seen in any disease causing inflammation of the bowel wall. • *Are they foul smelling and floating?* This suggests malabsorption, due to coeliac disease, pancreatic duct obstruction (pancreatic cancer, cystic fibrosis), or biliary insufficiency (e.g. recent cholecystectomy). • *Are the faeces unusually pale?* This suggests lack of bile salts in the faeces due to obstruction of the biliary or pancreatic ducts (e.g. chronic pancreatitis, gallstones).

Constipation risk factors

• *History of bowel disease, neurological disorders, back problems, or endocrine disease?* • *FH of bowel disorders?* In particular, look for a FH of bowel disorders that increase the risk of colorectal cancer such as colorectal cancer per se, familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC), or Peutz-Jegher's disease. • *What medications are they on?* Check the British National Formulary (BNF) to see if the patient's medications can cause constipation as a side-effect. Opiates, anticholinergics, tricyclic antidepressants, calcium-channel blockers, and iron supplements are notorious for causing constipation. • *Diet?* Do they eat a healthy, varied, fibre-rich diet? Do they keep adequately hydrated? Ask what colour their urine is (persistently yellow urine can suggest a degree of dehydration).

causes of diarrhoea

• *Infection* of the bowel (infectious diarrhoea) • *Inflammation* of the bowel (e.g. IBD, diverticular disease) • Increased bowel *motility* (e.g. hyperthyroidism, anxiety, irritable bowel syndrome (IBS)) • *Malabsorption of lipids* (e.g.coeliac disease, pancreatic insufficiency) • *Obstruction overflow* (e.g.colon cancer, ovarian cancer) • *Medications* (e.g. laxatives, digoxin, metformin, thiazides, some antibiotics, etc.)

Imaging of her upper and lower GI tract includes...:

• *Proctoscopy.* A transparent dilator is used to visualize the anus. Can be done in the clinic or on the wards. • *Rigid sigmoidoscopy*. Visualizes as far as the sigmoid colon. Canal so be done in the clinic or on the wards. • *Colonoscopy*. This involves a flexible colonoscope, often with sedation (but not general anaesthetic) and bowel preparation, and can visualize as far as the ileo-caecal valve. Can be done as an outpatient. • *Computed tomography (CT) colonography*. Also known as 'virtual colonoscopy' or 'CT pneumocolon'; this involves an abdominal CT scan after bowel preparation and insufflation (filling the colon with air). It shows the bowel lumen and surrounding structures (e.g. liver, ovaries). • *Double-contrast barium enema (DCBE)*. As the name suggests, a barium enema is given to the patient and plain radiographs are taken at various times. Thus the lumen of the bowel can be visualized. • *Oesophagogastroduodenoscopy (OGD)*. An endoscope is inserted via the mouth and used to visualize as far as the duodenum. An OGD should always be performed in the context of iron-deficiency anaemia to exclude an upper GI bleed.

Management of IBS

• *Reassurance:* patients benefit greatly from reassurance that they do not have any serious bowel pathology. • *Antispasmodics:* medications that decrease smooth muscle activity in the bowel (e.g. mebeverine, hyoscine) can alleviate symptoms of IBS. Loperamide is a particularly strong inhibitor of smooth muscle activity in the bowel and should be reserved only for acute episodes of diarrhoea. • *Antidepressants:* tricyclic antidepressant medications have been found to slow colonic transit time and alleviate symptoms of IBS at doses that are lower than those required for their antidepressive effect, suggesting their effect in IBS is independent of any effect on depression. It is important that the patient understands that using medications that are given at higher doses to other patients for depression does not imply they are depressed. • *Diet and herbal remedies:* many patients report improvement by avoiding certain foods (e.g. beans that cause bloating), increasing the fibre content in their diet, or by using certain herbal drinks (e.g. peppermint tea).

Associated symptoms of constipation

• *Weight loss, night sweats, fevers?* May suggest malignancy. • *Diarrhoea?* Intermittent diarrhoea and constipation can suggest irritable bowel syndrome (in younger patients), colorectal cancer (in patients >45 years, especially if the diarrhoea is mucoid), or diverticular disease (in patients >60 years, especially if they have had episodes of left iliac fossa pain). • *Tenesmus?* Suggests a persistent mass in the rectum (e.g.tumour). • *Blood on faeces, per rectum, or when wiping?* May suggest haemorrhoids, anal fissure, diverticular disease, or colorectal cancer (see Chapter 21). • *Bloating?* A feature of IBS. • Feeling cold, reduced appetite, gaining weight?May suggest hypothyroidism. • *Bone pains?* Could suggest bone metastases, which would lead to hypercalcaemia that can cause constipation. • *Polyuria, thirst?* May suggest hypercalcaemia. You should note any abdominal pain but it is unhelpful in narrowing the diagnosis as constipation itself can be a source of pain.

investigations for constipation that cannot be diagnosed clinically ... (before the imaging steps)

• Blood tests: − *FBC*: a colonic mass can bleed and cause anaemia − *Electrolytes and calcium*: hypokalaemia and hypercalcaemia can cause constipation − *Thyroid function tests*: the history and examination do not suggest hypothyroidism as a cause of constipation, but it is easily excluded biochemically − *Glucose and HbA1c*: not routine examinations for constipation, but if patient is diabetic you should investigate her diabetic control at present (glucose) and over the last few months (HbA1c) Use this if suspect cancer (not routinely): • *Faecal occult blood test (FOBT)*: although this test is increasingly being used to screen for asymptomatic colon cancer, it should be remembered that faecal blood can also be due to colonic angiodysplasia, colonic polyps, haemorrhoids, aspirin, or warfarin. The test has a low specificity and sensitivity for colon cancer, but a positive test warrants further investigation. • Carcino embryonic antigen (CEA)/CA19-9/CA125: these are all markers of colon cancer. However, they lack specificity (e.g. CA125 is more commonly elevated in ovarian malignancy) and sensitivity and therefore are not used in diagnosis. They are, however, used to monitor response, relapse, and recurrence in patients with confirmed GI cancer.

questions to ask about the constipation itself

• Characterize what the patient means by 'constipation': Passing hard, lumpy stools suggests lack of fibre or dehydration, but not obstruction. No longer passing any faeces nor flatus ('absolute constipation') suggests complete bowel obstruction. • When did this start? Recent change in bowel habit suggests pathology, whereas chronic constipation is usually benign.

signs to look for in a patient with diarrhoea

• Clubbing? = Crohn's disease, UC, hyperthyroidism, and coeliac disease are causes of nail clubbing although in practice this association is rarely seen as few patients in the Western world with these diseases get unwell enough for long enough to develop clubbing. • Iritis (akaanterioruveitis)? Episcleritis?Scleritis? = associated with both Crohn's disease and UC. • Mouth ulcers? = Crohn's disease produces ulcers anywhere in the gastrointestinal (GI) tract − from mouth to anus. • Erythema nodosum? = Both Crohn's disease and UC are systemic inflammatory diseases that can manifest in the skin in the form of erythema nodosum (tender, raised, red nodules) or, less commonly, pyoderma gangrenosum (necrotic ulcers). However, bear in mind that the combined oral contraceptive pill is also a common cause of erythema nodosum in young women. • Dermatitis herpetiformis? = Coeliac disease is often associated with an itchy rash known as dermatitis herpetiformis. The rash is typically found over the extensor surfaces of the limbs and over the scalp. The rash is very itchy, so its papules are usually raw or crusted from the patient scratching them. • Virchow's lymphadenopathy? = The stomach, and small and large bowel all have lymphatic drainage that travels via the central thoracic duct and joins the venous system in the left subclavian vein. Lymphadenopathy in the left supra- clavicular fossa (Troisier's sign) is strongly suggestive of bowel malignancy that has spread. • Abdominal masses? = A mass in the right lower quadrant is often found in Crohn's disease (due to inflammation of the terminal ileum). Masses elsewhere in the abdomen, in particular the left lower quadrant, could indicate a malignancy. • Anal ulcers or fistulae? = Crohn's disease can cause both ulcers and fistulae around the anus, and the patient may well be unaware of these so be sure to inspect for them. • Digital rectal examination. = This is part of any abdominal examination and should be performed in the presence of a chaperone. You are looking for causes of obstruction that could lead to overflow diarrhoea: a malignant rectal carcinoma, or an enlarged prostate (in a man). You are also looking at the faeces themselves: are they mucoid or bloody?

What is the difference between diverticulosis, diverticular disease, and diverticulitis?

• Diverticulosis refers to the presence of diverticula (out-pouchings of the mucosa) in the intestine • Symptomatic diverticulosis (e.g. bleeding, producing pain) is referred to as diverticular disease • Diverticulitis refers to diverticular inflammation [As an aside, colonic diverticula are not actually 'true' diverticula (out-pouchings covered by all layers of the bowel wall, as in a Meckel's diverticulum). Since colonic diverticula lack the outer coat of muscularis propria they are 'false' diverticula.]

elderly patient with metastatic breast cancer + bone mets. takes opiates medication. low appetite. bone tenderness. recently constipated. what could be the causes?

• Medications, particularly opiates which reduce gut motility, but her calcium- channel blocker may be contributing. • Hypercalcaemia from bone metastases. • Immobility. unwell and elderly. • Weakness. difficult to strain • Poor diet and dehydration .Patients with cancer often lose their appetite and it is likely that her fibre intake is inadequate. Her fluid intake might also be low. • Megarectum. Patients with chronic constipation can develop a dilated rectum that is susceptible to constipation. One might also consider the possibility of the constipation being due to either spinal cord or cauda equina compression, although this is less likely to be the case given the normal peripheral neurological examination.

Patients with IBD (Crohn's disease or UC) can experience a number of complications outside the bowel. What are these complications?

• Nails: clubbing of finger nails • Eyes: inflammation leading to iritis (anterior uveitis), episcleritis, or scleritis • Skin: erythema nodosum (inflammation of subcutaneous fat nodules leading to raised, red nodules) or pyoderma gangrenosum (inflammatory ulceration and necrosis of the skin) • Joints: inflammation leading to enteric arthritis • Blood: iron-deficiency anaemia (from blood loss in the bowel, especially in UC), folate or vitamin B12 deficiency anaemias (from malabsorption due to irritation of the bowel) • Biliary system: primary sclerosing cholangitis (associated with UC), cholesterol gallstones (due to reduced reabsorption of bile salts by the inflamed bowel, leading to precipitation of insoluble cholesterol) • Kidneys: kidney stones, because fat malabsorption leads to (fat-soluble) Ca2+ being sequestered in the bowel. The lack of Ca2+ (which usually binds to oxalate in the blood) allows oxalate to precipitate and form stones • Bones: the lack of Ca2+ (due to malabsorption of fat) can lead to osteomalacia or even osteoporosis • Amyloidosis: chronic systemic inflammatory disorders can lead to deposition of serum amyloid A protein in multiple organs

Most cases of constipation are benign causes (eg. lack of fibre). what red flag signs at GP point to sinister causes?

• Severe, persistent constipation that is unresponsive to treatment • Rectal bleeding, tenesmus, or intermittent mucoid diarrhoea • Significant weight loss, iron-deficiency anaemia, and/or night sweats • Past medical history of ulcerative colitis or colonic polyps • Strong FH of colon cancer or colonic polyps, particularly if affected family members were <60 years old.

diagnosis of IBS based on ROME III criteria:

• at least 6 months previously of recurrent abdominal pain or discomfort associated with two or more of the following (at least 3 months): − Improvement with defecation; and/or − Onset associated with a change in frequency of stool; and/or − Onset associated with a change in form (appearance) of stool.