Pathology: Malabsorption

Question 1

What are the four major causes of Malabsorption?

Answer 1

Defective Digestion, Absorption, Transepithelial Transport and Lymphatic transport or absorbed lipids.

Question 2

What are the most common malabsorptive disorders in the US?

Answer 2

Pancreatic insufficiency, celiac disease, and Crohn disease

Question 3

What are some clinical features of Malabsorption?

Answer 3

Foul smelling stool, edema, Weight loss, Skeletal changes, Vitamin deficiencies, Diarrhea

Question 4

What are the 4 types of Diarrhea?

Answer 4

Secretory: Isotonic stool persists during fasting
Osmotic: abates with fasting
Malabsorptive: steatorrhea, abates with fasting.
Exudative: Purulent and blood stools, persist during fasting; inflammatory disease

Question 5

Etiology of Whipple Disease

Answer 5

Etiology: Gram positive rod shaped bacilli detected in macrophages, Tropheryma whippelii

Question 6

Morphology of Whipple Disease

Answer 6

Small intestinal villi are distended by foamy macrophages laden with granules that can be stained with PAS stain.
White-Yellow mucosal plaques

Question 7

Pathogenesis of Whipple Disease

Answer 7

Macrophages in lamina propria of small intestine. Lymphatic obstruction via macrophges in lymph nodes.

Question 8

Symptoms of Whipple Disease

Answer 8

Malabsorption, Diarrhea, Steatorrhea, abdominal cramps, weight loss and POLYARTHRITIS

Question 9

Pathogenesis of Cystic Fibrosis

Answer 9

Absence of CFTR, defect in chloride ion, defect in luminal hydration, intraductal concretions, autodigestion of pancreas, pancreatic insuffiency. Treat with oral enzyme supplementation

Question 10

Pathogenesis of Celiac Sprue

Answer 10

Immune reaction to gliadin that results in damage to villi.

Question 11

Morphology of Celiac Sprue

Answer 11

Villous atrophy, crypt hyperplasia, intraepithelial lymphocytosis

NOT SPECIFIC FOR CELIAC

Question 12

Diagnosis of Celiac Sprue

Answer 12

Serologic: IgA against tissue transglutaminase, gliadin and endomysial antibodies. Presence of HLA-DQ2 or DQ8

Question 13

Associated Conditions of Celiac Sprue

Answer 13

Dermatitis Herpetiformis, Enteropathy associated T-cell lymphoma

Question 14

Morphology of Tropical Sprue

Answer 14

Villous atrophy, B12 deficiency due to terminal ileum involvement, Megaloblastic nuclei of epithelial cells

Question 15

Pathogenesis of Abetalipoproteinemia

Answer 15

Lack of beta-lipoprotein prevents mucosal transport of lipoproteins and FFAs. Failure to absorb FFAs cause defective lipid RBC membranes

Question 16

Morphology of Abetalipoproteinemia

Answer 16

Lipid vacuolization of mucosal cells (see with oil red O). Acantholytic RBCs ‘spur cell’

Question 17

Discuss Collagenous and Lymphocyic Colitis

Answer 17

Idiopathic, Watery diarrhea. Intestines are grossly normal.
Collagenous colitis has the presence of a dense subepithelial collagen layer.
Lymphocytic Colitis doesn’t have thick collagen layer but has intraepithelial lymphocytes. Associated with celiac

Question 18

Morphology of GVHD

Answer 18

Epithelial apoptosis in crypt cells. Sparse lymphocytic infiltrate in lamina propria.