Small Intestine Diseases

Question 1

Luminal Phase Malabsorption

Answer 1

Fat malabsorption caused by deficiency or inactivation of pancreatic lipase or reduced bile salt concentration

Question 2

Mucosal Phase Malabsorption

Answer 2

Fat malabsorption due to problems in uptake, transport to ER, transformation into TG, chylomicron formation, or lymphatic transport/delivery

Question 3

Vitamin B12 Malabsorption

Answer 3

Caused by deficiency in diet, pernicious anemia (no intrinsic factor to bind to), bacterial overgrowth, pancreatic insufficiency (no lipase to hydrolyze from R factor), or ileal disease/resection. Diagnose with Schillings Test.

Question 4

Protein Energy Malnutrition

Answer 4

Caused by: chronic low energy and protein intake, exclusive breast feeding for too long, dilution of formula, non-nutritious foods of low energy and micronutrient density, infection, xenobiotics (aflatoxins?)

Kawashikor vs. Marasmus type.

Treatment: small, frequent re-feedings

Question 5

Cholera

Answer 5

Acute diarrheal illness caused by V. cholerae. Toxin inhibits absorption in villus and stimulates secretion in crypts (blocks NHE3 in absorptive cells, opens CFTR in secretory cells). Treatment is oral rehydration therapy.

Question 6

Tropical Sprue

Answer 6

Malabsorptive disorder with cause unknown. Looks histologically/endoscopically similar to celiac disease; abnormal D-xylose test; vitamin deficiencies (folate, B12, A, D, K) can occur. Treatment is antibiotics for 3-6 months, vitamin repletion

Question 7

Whipple Disease

Answer 7

Infection caused by Tropheryma whipplei. Cardiac symptoms, arthralgias and neurologic symptoms due to infiltration by the organism. Diarrhea and steatorrhea occur later in the course due to infiltration of the lamina propria and disruption of normal villi function. On histology, expansion of lamina propria with histiocytes. Treat with IV Ceftrixone and Bactrim.

Question 8

“Pancreatic Cholera” or Verner-Morrison Syndrome

Answer 8

Neuroendocrine islet cell tumor of pancreas that excessively secretes vasoactive intestinal polypeptide (VIP). Findings include secretory watery diarrhea, hypokalemia, hypochlorhydria, pancreatic mass, elevated VIP level, increased cAMP level (thanks to VIP)

Question 9

Celiac Disease

Answer 9

Chronic, autoimmune disorder. Inability to tolerate gliadin, ingestion of which would cause an inflammatory response, leading to villous atrophy and malabsorption. Associated with other symptoms in other organ systems (dermatitis herpetiformis, aphthous stomatitis). Diagnosed with serology, genetic testing, and endoscopy + biopsy.

Question 10

Carbohydrate Malabsorption

Answer 10

Carbohydrate fermented by the bacterial flora, with release of CO2 and H2 gases and short-chain fatty acids. Causes gas, bloating, abdominal pain and diarrhea. Undigested carbohydrate pulls in water and sodium, leading to osmotic diarrhea.

Most common: lactose intolerance