GIT 4 Flashcards
(8 cards)
What are the clinical features of chronic malabsorption syndrome?
Chronic malabsorption can be accompanied by weight loss, anorexia, abdominal distention, and muscle wasting. A hallmark of malabsorption is steatorrhea (excessive fecal fat; bulky, frothy, greasy, and yellow or clay-colored stools).
What are the four main disturbances that can lead to malabsorption?
- Intraluminal digestion of proteins, carbohydrates, and fats into absorbable form (e.g., Chronic pancreatitis/insufficiency).
- Terminal digestion: Hydrolysis of carbohydrates and peptides by disaccharidases and peptidases in the brush border of the small bowel (e.g., disaccharidase deficiency and brush border damage by bacteria).
- Transepithelial transport, in which nutrients, fluid, and electrolytes are transported and processed within the small intestinal epithelium (e.g., Abetalipoproteinemia).
- Other (e.g., reduced mucosal surface area, lymphatic obstruction, infection).
What are the pathological features of celiac disease?
Biopsy specimens from the second portion of the duodenum or proximal jejunum show increased numbers of intraepithelial T lymphocytes, crypt hyperplasia, and villous atrophy.
What is the difference between partial and subtotal villous atrophy?
Partial villous atrophy: The villi are shorter and broader than normal.
Subtotal villous atrophy: There is severe shortening of the villi, and the mucosa looks flat.
What is environmental enteric dysfunction, and how does it differ from celiac disease?
Environmental enteric dysfunction, also called environmental enteropathy, tropical enteropathy, or tropical sprue, occurs in people living or visiting tropical areas (e.g., sub-Saharan Africa, India, Southeast Asia, and northern Australia). It is NOT related to gluten and responds to antibiotics. Small intestinal biopsy shows partial villous atrophy and inflammation of the intestinal mucosa.
What are the common features of Crohn disease and ulcerative colitis?
Both are idiopathic, involve colonic inflammation, and have similar treatments.
Both have systemic, extraintestinal inflammatory manifestations and a cancer risk.
What are the gross morphological features of Crohn disease?
Skipped lesions: presence of multiple, separate, sharp demarcations of diseased bowel segments from adjacent uninvolved bowel wall.
The mucosa is edematous and hyperemic and shows linear longitudinal ulcers causing fissures.
Cobblestone appearance: the combination of linear ulceration and mucosal remnants.
Creeping fat: mesenteric fat extends around the serosal surface in cases with extensive transmural disease.
In advanced stages, fibrosis of the wall occurs, causing thickened wall and narrowed lumen leading to stricture formation.
What are the microscopic features of Crohn disease?
Transmural inflammation (affects all layers of the wall) characterized by infiltration of lymphocytes, plasma cells, and macrophages.
Crypt architectural distortion.
Features of active disease include abundant neutrophils that infiltrate and damage the crypt epithelium and crypt abscesses (clusters of neutrophils within a crypt).
Non-caseating epithelioid granuloma: a hallmark of Crohn disease (found in 35% of cases, in all tissue layers).
