Malabsorption Exam 1

What is the approximate prevalence of celiac disease in the general population? 1.1: 3000 2.1:1000 3.1:100 1:10

1:100

•Severe liver disease -Primary biliary cirrhosis -Extrahepatic biliary tract obstruction with secondary biliary cirrhosis •Interruption of enterohepatic circulation of bile salts -Ileal bypass -Diseased terminal ileum (Crohn's disease) •Bacterial overgrowth (bile salt deconjugation) -Postgastrectomy blind loop syndrome -Jejunal diverticulosis -Strictures -Fistulas Scleroderma and pseudo-obstruction

Bile Salt deficiency

•Characterized by villous atrophy of the small intestine resulting in malabsorption and diarrhea •Cause is unknown, but may be related to the immunomorphologic response of the proximal small intestine to the ingestion of gluten, specific the gliadin fraction. •Can present in infancy or later in life !!!!Histologically characterized by diffuse infiltration of the lamina propria with plasma cells and lymphocytes.!!!! •Effects 1% of general population Women > Men

CELIAC SPRUE (Gluten-sensitive enteropathy)

•made on the basis of small intestinal biopsy and confirmed by the therapeutic response to gluten withdrawal from the diet and normal small intestine histological findings 3-6 months later. •Serum antibodies are present in some patients -Antigliadin, antireticulin, antiendomysial. -Tissue transglutamase (tTG -IgA/IgG) - most sensitive / specific -Major genetic predisposition HLA-DQ2>HLA-DQ8 -10-15% risk of CD in 1st degree relatives •Roentgenographic studies: -dilatation of small intestine -marked coarsening or complete obliteration of the mucosal folds -fragmentation and flocculation of the barium meal within the gut lumen.

Celiac disease

•Best noninvasive method to indicate malabsorption secondary to intestinal mucosal dysfunction •25 gm dose of D-xylose is given to patient orally immediately after emptying his/her bladder on the morning after an overnight fast. •Urine is collected for the next 5 hours •In addition, 1 hour after ingestion of the D-xylose, a venous sample can be collected to ensure D-xylose concentration. •The patient needs to drink at least one glass of water each hour during collection of the urine to ensure adequate urine volume. •Less than 4 gm of D-xylose in the 5-hr collection and a concentration of <20 mg/dL of D-xylose in the serum sample represents abnormal intestinal absorption of D-xylose.

D-Xylose Absorption Test

A 15 y/o boy has recurrent respiratory, urogenital, and gastrointestinal infections. After a lengthy evaluation, he is diagnosed with a selective IgA deficiency. This immundeficiency disorder has been strongly associated with which of the following? 1.Gluten-sensitive enteropathy 2.Chagas' disease 3.IBD IBS

Gluten-sensitive enteropathy

•Characterized by dilatation of intestinal lacteals (lymphangiectasia) •May lead to steatorrhea -protein-losing enteropathy -enteric lymphocyte loss •Fat malabsorption is usually only mild •Diagnosis confirmed by biopsy (small intestine) •Therapy involves treatment of underlying disease •Major goal of dietary therapy is to limit enteric fat, protein, and lymphocyte losses by reducing intestinal lymph flow with a low fat (low long-chain triglyceride) diet.

Lymphatic obstruction

Test requires a collection of stool over a 72-hour period with the patients consuming a diet of 100 gm/day of fat. If the amount of fat in the stool is <6gm/24 hr and the weight of stool is <200gm/24 hr, the patient is not likely to have a malabsorption disease

Quantitative Fecal Fat Test

Which of the following statements about small intestinal bacterial overgrowth (SIBO) is most accurate? A.SIBO is a common cause of malabsorption in developed countries B.SIBO has been proven to cause IBS C.Gold standard for diagnosis of SIBO is C14-xylose breath testing D.Treatment with antibiotics such as metronidazole, amoxicillin, clavulanate, and ciprofloxacin is usually ineffective.

SIBO is a common cause of malabsorption in developed countries

•Used to determine the etiology of vitamin B12 (cobalamin) deficiency •Performed by administering orally 1.0 mcg of 57Co-cyanocobalamin followed by 100 mcg of nonlabeled cobalamin given IM to wash out the fraction of isotope that was absorbed. 4 stages

Schilling Test

•Acute episode of watery non-bloody diarrhea •Development of chronic diarrhea •Development of malabsorption -development of anorexia (folate deficiency) -weight loss -glossitis (B12 deficiency) -megaloblastic anemia -hypoalbuminemia Lab abnormalities •Megaloblastic anemia -deficiency of folate / B12 •Low carotene •Low vitamin A •Hypocholesterolemia •Hypocalcemia •Hypoalbuminemia

Tropical spruee

A 30 y/o female with history of IBS is seen in the dermatology clinic for evaluation of a papulovesicular rash on her elbows. A biopsy is performed & dermatitis herpetiformis is diagnosed. Her rash is likely to improve by excluding which of the following foods from her diet? 1.Wheat, soy, & dairy 2.Wheat, soy, & peanuts 3.Wheat, rye, & barley Wheat, corn, & peanuts

Wheat, rye, & barley

•Intestinal malabsorption with WEIGHT LOSS / DIARRHEA •ABDOMINAL PAIN •Fever •Increased skin pigmentation •Anemia •Lymphadenopathy •ARTHRALGIA and arthritis •Pleuritis •Pericarditis •Valvular endocarditis •CNS symptoms •D-xylose - abnormal •Steatorrhea - present •Roentgenography -irregular thickening of the mucosal folds particularly in the duodenum and proximal jejunum •Small intestinal biopsy -infiltration of the lamina propria of the small intestine by PAS-positive macrophage-containing Gr(+), acid-fast (-) bacilli accompanied by lymphatic dilatation is specific and diagnostic. •likely causative organism: Tropheryma whippleii

Whipple

•An uncommon systemic disease that may affect virtually any organ system in the body and in the great majority of instances involves the small intestines •First described in 1907 by GH Whipple with suspicion then, that this was an infectious disease, verified in 1992 - T. whipplei (gram-positive bacillus)

Whipple disease

Disease in which there is: 1.malabsorption of nutrients by that portion of the small intestine that is damaged 2.a characteristic, though not specific, lesion of the small intestinal mucosa 3.prompt clinical improvement following withdrawal of certain cereal grains from the diet. •Most Common: Diarrhea -Flatulence -Weight loss -Fatigue/weakness •Others may include: -Dermatitis herpetiformis •skin disorder characterized by a diffuse papulovesicular eruption -Anemia -Tetany -Osteomalacia Malnutrition

celiac sprue

-When lactose is not digested, it creates an osmotic diarrhea by its large molecular size -Fermentation of lactose also creates considerable gas formation -Diagnosis made by lactose tolerance test -Treatment involves avoidance of lactose products or the addition of synthetic lactase products to dairy products.

lactose malabsorption (lactase deficiency)

diarrhea

malabsoprtion of OH-fatty acids

abdominal distension

malabsoprtion of sugars

•defective mucosal absorption of nutrients

malabsorption

tetany

malabsorption of Ca, Mg

weight loss

malabsorption of calories

steatorrhea

malabsorption of fat

anema

malabsorption of iron, B12 or folic acid

edema

malabsorption of protein

Osteomalacia

malabsorption of vit D and Ca

bleeding and bruising

malabsorption of vit K

•impaired nutritional hydrolysis

maldigestion

•Chronic disorder acquired in endemic tropical areas (TRAVEL) characterized by abnormalities of small intestinal structure and function that become progressively more severe. •Eventually leads to the development of nutritional deficiencies, and are either ameliorated or cured by treatment with folic acid and/or tetracycline

tropical sprue

Causes of Pancreatic Exocrine Insufficiency

•Chronic pancreatitis •Pancreatic neoplasm •Operative resection •Ductal stricture or fistula •Cystic fibrosis •Hereditary pancreatitis •Schwachman's syndrome

Clinical Conditions associated withBacterial Overgrowth

•Gastric proliferation -hypo- or achlorhydria •Small intestine stagnation -Anatomic •Motor -Scleroderma -Idiopathic intestinal pseudo-obstruction -Absence or disordered migrating motor complex (MMC) •Abnormal communication between proximal and distal GI tract -Gastrocolic or jejunocolic fistula -Resection of diseased ileocecal valve •Miscellaneous -Chronic pancreatitis Immunodeficiency syndrome

-pancreatic lipase deficiency -bile salt deficiency

•Intraluminal defects (maldigestion)

Mechanisms of post-gastric surgery malabsorption

•Loss of gastric acid and pepsin •Loss of gastric mixing and grinding •Loss of fractional chyme delivery •Rapid transit •Poor endogenous pancreatic stimulation •Asynchrony of pancreatic and biliary secretions and chyme

-lymphoma -lymphangiectasia

•Lymphatic obstruction (impaired transport)

What are complications of celiac sprue

•Malignant disease -Lymphomas T-cell type (both intestinal and extraintestinal) -Squamous cell carcinoma of esophagus -Adenocarcinoma of small intestine •Evolution of disease - refractory/unclassified sprue -relapse despite strict adherence to diet -may require corticosteroids/immunosuppressive drugs -Ulceration/Stricture of the small intestine

-small bowel disease --Celiac disease (nontropical sprue) --Tropical Sprue --Whipple's disease --Eosinophilic gastroenteritis --Crohn's disease --Giardiasis (esp. with IgA deficiency) -small bowel resection -small bowel bypass

•Mucosal defects (malabsorption)