Flashcards in Malabsorption Deck (44)
Defective mucosal absorption caused by:
defective luminal digestion
List some common and uncommon causes of malabsorption.
Short bowel (including resections)
What are different malabsorptive states?
vitamins and minerals
List some digestive causes of protein malabsorption.
Partial or total gastrectomy (poor mixing)
Exocrine pancreatic insufficiency
Congenital deficiency of intestinal enterokinase
List some absorptive causes of protein malabsorption
Short bowel syndrome
Defects in neutral AA transporters (Hartsnup disease)
Oculocerebral syndrome of Lowe
List some digestive causes of fat malabsorption.
Less time to mix: gastric resection, autonomic neuropathy, amyloidosis
Decreased micelle formation caused by a decreased bile acid synthesis/secretion: Cirrhosis, Biliary obstruction, CCK deficiency, small intestinal bacterial overgrowth
Decreased Lipolysis: Chronic pancreatitis, cystic fibrosis, Pancreatic/ampullary tumours, Low luminal pH, Excessive calcium ingestion, Lipase/co-lipase deficiency (rare)
List some absorptive causes of fat malabsorption
Decreased chylomicron formation and/or mucosal absorption:
Chylomicron retention disease
List some post-absorptive causes of fat malabsorption
Defective lymphatic transport:
Name a digestive cause of carbohydrate malabsorption
Name some absorptive causes of carbohydrate malabsorption
List some causes of Vitamin B12 malabsorption
Deficiency of gastric intrinsic factor
Pancreatic insufficiency/Z-E syndrome (Reduced release of B12 from R-binding protein)
Ileal Crohn's disease
List some causes of Folic acid malabsorption
Caused by diseases affecting the proximal small bowel
What are the fat soluble vitamins?
What could cause malabsorption of these?
Vitamins A, D, E and K
Anything that disrupts fat absorption will result in one or more than one deficiency
What are the clinical features of lactose malabsorption (i.e. lactase deficiency)
History of the induction of the diarrhoea, abdominal discomfort and flatulence following the ingestion of dairy products.
How is lactase deficiency diagnosed?
It is diagnosed clinically, and confirmed using the lactose breath hydrogen test, or the oral lactose intolerance test.
What is tropical sprue?
Colonisation of the intestine by an infectious agent or alterations in the intestinal bacterial flora induced by the exposure to another environmental agent.
What are the clinical features of tropical sprue?
What is the treatment for tropical sprue?
Tetracycline + folic acid
What is whipple's disease?
A rare infectious bacterial disease caused by Tropheryma whipplei.
There is multi-system involvement and increase in the frequency of HLA-B27.
What are the clinical features of whipple's disease?
Weight loss, diarrhoea, steatorrhea, abdominal distension, arthritis, fever, nutritional deficiency symptoms
How is whipple's disease diagnosed?
Biopsy and demonstration of T.whipplei in involved tissues by microscopy
What is the treatment for Whipple's disease?
What are the clinical features of Crohn's disease?
Abdominal pain and diarrhoea
Fever and weight loss
Abdominal tenderness, most commonly in the right lower quadrant
How is Crohn's disease diagnosed?
Barium imaging of small bowel mucosal disease, including strictures, ulcerations and fistulae
What is the treatment for Crohn's disease?
Steroids, immunosuppressants (azathioprine), biological therapy (anti-TNF)
What does Giardia lamblia/ giardia intestinalis cause?
What are risk factors for contracting this parasitic infection?
What are other intestinal parasites?
Risk factors are travel to areas where the water supply may be contaminated and swimming in ponds
Other parasites: Coccidial, strongyloides
What are the clinical features of giardiasis?
Significant malabsorption with steatorrhoea and weight loss may develop
How is giardia lamblia confirmed in the lab?
Stool examination for ova and parasites
Three separate stool samples increases the yield of positive examinations to 80-90%
How is giardiasis treated?
Metronidazole for 1 week