Washington Manual of Surgery - Acute Abd Pain & Appendicitis
What is the incidence of SBO for non perforated vs perforated appendicitis?
4x more likely for peforated appendicitis
What percentage of urinary stones versus gallstones can be seen on Xray?
90% of urinary stones contain Ca and are visible on KUB, while only 15% of gallstones are calcified
What liver enzyme derangements might you see in a patient with acute cholecystitis?
A mild elevation of transaminases (<2x normal), alk phos, and T bili
What liver enzyme derangements might you see in a patient with a CBD stone?
A moderate elevation of transaminases (>3x normal; usu precedes rise in T bill and alk phos.
What antibiotic therapy is used in prevention of postop infectious complications with an appendectomy?
- 2nd Gen cephalosporin (cefotetan, cefoxitin) - Abx should be continued 3-5 days for perforated appendicitis
What is the incidence of wound infection rate for non perforated vs perforated appendicitis?
- 3% for non perforated, 4.7% for perforated or gangrenous appendix - Primary closure is not recommended in the setting of perforation
What criteria do you use to decide to safely observe or discharge children being evaluated for appendicitis without use of imaging studies?
- Absence of nausea, lack of maximal tenderness in the RLQ, and absolute neutrophil count < 6.7 - Negative predictive value 98%
What US findings suggest appendicitis?
- Appendiceal diameter > 6 mm - Lack of luminal compressibility - Presece of an appendicolith - Perforated appendix is characterized by loss of echogenic submucosa and presence of located periappendiceal or pelvic fluid collection - Sensitivity 86%, specificity 81%
Describe the pathophysiology behind appendicitis.
- Appendix becomes obstructed - Intraluminal pressure increases d/t continued mucous secretion/bacterial overgrowth; the appendices wall thins & lymphatic & venous obstruction occurs - Necrosis and perforation develop when the arterial flow is compromised
Describe the classic presentation of appendicitis.
- Begins with progressive mid abdominal discomfort (visceral pain from T8-T10) - Anorexia and low-grade fever follow - Venous congestion stimulatels intestinal peristalsis, causing cramping sensation followed by N/V; sx include anorexia (90%), N/V (70%), & diarrhea (10%) - Once parietal peritoeum inflamed, develop localized RLQ pain with movement, mild fever, and tacky - Avg onset of sx to time of presentation is < 24 hrs
What helps distinguish PID from appendicitis?
- Cervical motion tenderness and milky vaginal discharge strengthen dx of PID - PID pain usu BL with intense guarding - Transvaginal US can visualize ovaries
Describe the iliopsoas sign.
- Classically seen in a rhetorical appendicitis - Best done with patient lying on left side - Hyperextend the thigh with the knee flexed - Also can be done by having pt lie supine and raise leg against you providing resistance to thigh
What does rapidly accelerating (within minutes) pain suggest?
- Colic syndromes (biliary, ureteral, SBO - Inflammatory processes (acute happy, pancreatitis, diverticulitis) - Ischemic processes (mesenteric ischemia, strangulated intestinal obstruction, volvulus
How do you manage a periappendiceal abscess?
- Controversial - but immediate happy has higher complication rate/longer hospital stay - Systemic abx, ?perc US or CT guided catheter drainage - ? Elective appy 6-12 weeks later
What are contraindications for an incidental appendectomy?
- Crohn's dz involving cecum, radiation tx to cecum, immunosuppression, and vascular grafts or other bioprosthesis d/t increased risk of infectious complications or appendices stump leak - Benefit decreases once person is > 30 yo d/t decreased incidence of appendicitis as we age
Describe the obturator sign.
- D/t inflammation adjacent to the internal obturator muscle - Internally and externally rotate the hip while pt is supine with knee and hip flexed - Positive if hypogastric pain during maneuver
Describe factors that make it difficult to dx appendicitis in children!
- Delayed dx is common - Atypical signs - 50% lack migration of pain to RLQ, 40% will not have anorexia, 52% will not have rebound tenderness
What CT findings suggest appendicitis?
- Distended, thick-walled appendix with inflammatory streaking of surrounding fat - Pericecal phlegmon or abscess - Appendicotlith - RLQ intra-abdominal free air that signals perforation - Particularly useful in distinguishing btw periappediceal abscesses & phlegm - Sensitivity 94%, specificity 95%
What US findings suggest acute cholecystitis?
- GB wall thickening > 3 mm - Pericholecystic fluid - Stone impacted in BG neck - Sonographic Murphy's sign (inspiratory arrest while continuous pressure is maintained in RUQ)
What causes colicky (waxes and wanes) pain?
- Hyperperistalsis of smooth muscle against a mechanical site of obstruction (SBO, renal stone) - Exception: biliary colic - pain constant, intense, lasts at least 30 min and up to several hours
What is typhlitis?
- Inflammation of the wall of the cecum or TI - Seen MC in immunosuppressed pts undergoing chemotherapy for leukemia and in HIV-positive puts - Manage nonop, but it is difficult to distinguish preop from happy
What does gradual onset pain suggest?
- Inflammatory conditions (appy, cholecystitis) - Obstructive processes (non strangulated bowel obstruction, urinary retention) - Mechanical processes (ectopic pregnancy and penetrating/perforating tumors)
Describe the innervation of the visceral peritoneum.
- Innervated bilaterally by the autonomic nervous system - BL innervation causes pain to be midline vague, deep, dull, and poorly localized - Embryologic origin determines location of pain: foregut (stomach to 2nd portion of duodenum, hepatobiliary tract, pancreas, spleen) present with epigastric pain, midgut (2nd portion duodenum to proximal 2/3 of tx colon) with periumbilical, and hindgut (distal tx colon to anal verge) with suprapubic
Describe the innervation of the parietal peritoneum.
- Innervated unilaterally via spinal somatic walls, which causes pain to localize to abdominal quadrants (inflamed appendix producing parietal peritoneal irritation) - Sharp, severe, well-localized - Triggered by irritation of the parietal peritoneum by an inflammatory process or by mechanical stimulation like surgical incision - Causes PE findings of local or diffuse peritonitis
How do you change laparoscopic appendectomy in pregnancy?
- Insuflate lower, usu at 8 mmHg, no higher than 12 mmHg - Place umbilical port 6 cm above the uterine fundus
What value of serum B-Human chorionic gonadotrophin is seen in ectopic pregnancy?
- Low level (<4,000 mIU) - Levels > 4,000 mIU indicate intrauterine pregnancy that can be seen on US
How does the presentation of an appendix located in the pelvis from the classic presentation?
- May simulate acute gastroenteritis with diffuse pain, nausea, vomiting, and diarrhea
Describe factors that make it difficult to dx appendicitis in pregnancy!
- N/V confused with morning sickness - Tachycardia normal in preg - Fever not common with appendicitis in preg - Leukocytosis is common in pre (WBC 12 normal), but left shift is always abnormal - MC location for pain in pregnant woman is RLQ pain
What medications are espimportant to pay attention to when taking a history in a patient with abdominal pain?
- NSAIDs place puts at risk for complications of PUD - Corticosteroids may mask signs of inflammation such as fever and peritoneal irritation - Abx may hinder dx d/t partially treating source
What helps distinguish ureteral colic from appendicitis?
- Pain radiating to the groin but little localized tenderness; hematuria suggests the dx but confirmed by iV pyelography or non contrast CT - UA is frequently abnormal in appy - pyuria, albuminuria, and hematuria are common
What does sudden onset of pain suggest?
- Perforation or rupture (e.g. peptic ulcer, ruptured AAA) - Infarction (MI or acute mesenteric occlusion) can also present this way
Describe an open appendectomy.
- Pt position: supine - Incision: tx incision lateral to the rectus at McBurney's point - Split external and internal oblique and transverses abdominis muscle layers in the direction of their fibers - Purulent fluid in peritoneal cavity can be sent for Gram stain - Identify cecum, follow anterior tania to the base of appendix - Deliver appendix into wound and dissect surrounding adhesions; remove appendix
Describe a laparoscopic appendectomy.
- Pt position: supine, foley placed, with L arm tucked - Port placement: 10-mm at umbilicus, 5-mm LLQ (alternatively RUQ), 5-mm midline suprapubic - Then place pt Trendelenburg with R side up - Splay out the mesoappendix, make a window in it, divide with a vascular stapler, then divide appendix with endoscopic stapler
How does the presentation of an appendix located retrocecal or behind the ileum differ from the classic presentation?
- Separated from anterior abdominal peritoneum and abdominal localizing signs may be absent - Irritation of adjacent structures may cause diarrhea, urinary frequency, pyuria, or microscopic hematuria
What is pylephlebitis?
- Septic portal thrombosis caused by E. coli - Presents with high fevers, jaundice, and eventually hepatic abscesses - CT findings of thrombus & gas in the portal vein - Prompt tx (operative or percutaneous) of the primary infection is critical, along with broad-spec IV abx
Describe Xray findings in a SBO.
- Small bowel dilation (valvular convenes) - Air-fluid levels proximal to obstruction - Absence of air in rectum suggests complete obstruction
Describe alleviating factors for intestinal obstruction.
- Transient relief after vomiting.
What helps distinguish Mesenteric Lymphadenitis from appendicitis?
- Usu occurs in patients younger than 20 yrs old - No rebound tenderness or muscular rigidity - Nodal histology & cx obtained at operation can identify etiology, usu Yersinia and Shigella or Mycobacterium tuberculosis; associated with URI
Describe alleviating/aggravating factors for diffuse peritonitis.
- Worsening of pain with movement, improved by lying still - Renal colic - pts usu writhe in pain, unable to find a comfortable position
What is the risk of fetal demise in the case of appendicitis in pregnancy?
- up to 35% in the setting of perforation & diffuse peritonitis - negative laparotomy has fetal loss risk up to 3%
What is the most common calcification seen in the abdomen?
-"Phleboliths," or benign calcifications of the pelvic veins - Can be distinguished from renal stones by their central lucency, which represents the lumen
Where is McBurney's point?
2/3 distance from the umbilicus to the anterosuperior iliac spine
What are some nonsurgical causes of acute abdominal pain?
Acute MI, gastroenteritis, Pna, DKA, acute pancreatitis, hepatitis
Name some causes of lumbar back referred pain.
Acute pancreatitis, renal colic.
What UA findings suggests a UTI?
Bacteriuria, pyuria (> 20 WBCs per HPF), and a positive leukocyte esterase (>30 RBCs per HPF)
Name a cause of low thoracic back referred pain.
Biliary colic.
What diagnosis is suggested by the "omega" sign?
Cecal volvulus
What US finding suggests biliary obstruction?
Dilation of CBD (> 8 mm, or larger in elderly pts)
What metabolic derangement do you expect to see in a patient with volume depletion?
Elevated BUN or Cr
What helps distinguish gastroenteritis from appendicitis?
Gastroenteritis has N/V before abdominal pain; also, WBC often normal
What do you do when a patient has a fever and elevated white count beyond POD7 from appendectomy?
Get a CT to evaluate for abscess
What helps distinguish pyelonephritis from appendicitis?
High fevers, rigors, costovertebral pain, tenderness
What are the most common etiologies of appendices obstruction?
Hyperplasia of the submucosal lymphoid follicles of the appendix and appendices fecalith
What metabolic derangement do you expect to see in a patient with prolonged vomiting & severe volume depletion?
Hypokalemic, hypochloremic metabolic alkalosis
What causes sharp, severe, persistent, and steadily increasing pain?
Infectious or inflammatory process (appy; these are often accompanied by fever & chills)
What triggers visceral pain?
Inflammation, ischemia, and geometric changes such as distention, traction, and pressure
What enzyme elevation is more specific for pancreatic parenchymal damage?
Lipase
What causes a sentinel loop (single, dilated loop of bowel)?
Localized ileum near an inflamed organ (as in pancreatitis
What metabolic derangement do you expect to see in a patient with general tissue hypoperfusion, e.g. intestinal ischemia?
Low serum bicarbonate or metabolic acidosis
What liver enzyme derangements might you see in a patient with acute hepatitis or ischemia?
Markedly elevated transaminases (>1,000 IU/L)
When do you see hematuria?
Nephrolithiasis and renal & urothelial cancer
What does a HIDA scan help diagnose?
Nonfilling implies cystic duct obstruction, may indicate acute cholecystitis
Name some causes of referred pain to the shoulder.
Perforated duodenal ulcer, ruptured spleen
What helps distinguish Meckel diverticulitis from appendicitis?
S/S indistinguishable from appy, but characteristically occurs in infants
What diagnosis is suggested by the "bent inner tube" sign?
Sigmoid volvulus
What test is used to evaluate for a Meckel diverticulum?
Technetium-99m pertechnetate scan as it concentrates in ectopic gastric mucosa frequently found in diverticulum
What helps distinguish ovarian torsion from appendicitis?
Twisted viscous differs b/c produces sudden, acute intense pain with simultaneous frequent and persistent emesis; confirm with Dopper US
What incision is used for an appendectomy?
Tx incicion (Rocky-Davis and Fowler-Weir)
Name some causes of sacral back referred pain.
Uterine and rectal pain.
