Malabsorption Flashcards
what is malabsorption
defective mucosal absorption
what leads to malabsorption
defective luminal digestion,
mucosal disease,
structural disorders
what are the common causes of malabsorption
coeliac disease, crohns disease, post infectious, biliary obstruction, cirrhosis
what are the uncommon causes of malabsorption
pancreatic cancer, parasites, bacteria overgrowth, drugs, short bowel
what are the two types of protein malabsorption
digestive and absorptive
what are the digestive causes of protein malabsorption
partial/total gastrectomy (poor mixing),
exocrine pancreatic insufficiency
trypsinogen deficiency
congenital deficiency of intestinal enterokinase
what are the absorptive cause of protein malabsorption
celiac disease and tropical sprue
methionine malabsorptive syndrome & blue diaper syndrome
SBS
jejunoileal bypass
defects in neutral amino acid transporters
cystinuria I-III
occulocerebral syndrome of lowe
where does the digestive process of fat digestion occur
pancreas and liver
where does the absorptive process of fat digestion occur
jejunal mucosa
where does the post absorptive process (delivery) of fat digestion occur
in the lymphatics
what can cause digestive fat malabsorption
(less time mixing)
gastric resection, autonomic neuropathy, amyloidosis
decreased bile secretion- cirrhosis, biliary obstruction, CCK deficiency
(decreased lipolysis)
CF, chronic pancreatitis, tumours, low pH
what can cause absorptive fat malabsorption
descreased chlyomicron formation/ absorption, coeliac disease, chylomicron retention disease
what can cause post absorptive fat malabsorbtion
defective lymphatic transport- lymphoma, trauma, retroperitoneal fibrosis
what can cause digestive carb malabsorbtion
severe pancreatic insufficiency (alpha- amylase deficiency)
what can cause absorptive carb malabsorption
primary or acquired lactase deficiency
- post infectious lactase deficiency
- celiac disease
- crohns
- sucrase-isomaltase deficiency
- trehalase deficiency
what vitamins are commonly malabsorbed
B12, folic acid, fat soluble vitamins (ADEK) - anything that disrupts fat absorption
what minerals are common malabsorbed
calcium, magnesium, iron (most common), zinc, copper
describe coeliac disease and the pathology behind it
exposure to wheat, barley or rye induces a characteristic mucosal lesion
intestinal antigen-presenting cells in people expressing HLA-DQ2, or HLA-DG8, bind with dietary gluten peptides in their antigen-binding grooves activate specific mucosal T lymphocytes, producing cytokine mucosal damage
what are the symptoms of coeliac disease
weight loss, diarrhoea, excess flatus and abdominal discomfort
how is coeliac disease diagnosed
IgA anti tissue transglutaminase test (tTGA), biopsy confirmative
what causes lactose malabsorption
deficiency of lactase
what are the clinical features of lactose malabsorption
history of the induction of diarrhoea, abdominal discomfort, flatulence following the ingestion of dairy products
how is lactose malabsorption diagnosed
lactose breath hydrogen test, oral lactose intolerance test
how is lactose intolerance treated
lactose free diet
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
diarrhoea, steatorrhea, weight loss, nausea, anorexia, anaemia, biopsy
how is tropical sprue treated
tetracycline + folic acid
what is whipples disease
commonly in white males, absorption in intestine reduced. caused by tropheryma whipplei, multi system involvement
what are the clinical features of whipples disease
weight loss, diarrhoea, steatorrhea, abdominal distention, arthritis, fever, nutritional deficiency syndromes
how is whipples disease diagnosed
demonstration of T. whipplei in involved tissues by microscopy
how is whipples disease treated
antimicroial
crohns disease patients with what other co-morbidities can develop severe malabsorption
extensive ileal involvement, extensive intestinal resections, enterocolic fistulas, strictures leading to small intestine bacterial overgrowth
what are the clinical features of crohns disease
abdominal pain and diarrhoea, fever, weight loss, abdominal tenderness - most classically in the right lower quandrant
how is crohns disease diagnosed
endoscopy, barium imaging of small bowel mucosal disease, CT, MRI, colonoscopy
how is crohns disease treated
steroids, immunosuppresants, azathioprine 6-MP, biological therapy (anti TNF)
what are the risk factors for the parasitic infection giardia Iamblia
travel to areas where the water supply may be contaminated/ swimming in ponds
what are the clinical features of giardia Iamblia
diarrhoea, flatulence, abdominal cramps, epigastric pain, nausea
steatorrhea and weight loss may develop
how is giardia Iamblia diagnosed
stool examination for ova and parasites
how is giardia iamblia treated
metronidazole 1 week
what other parasites can cause malabsorption
coccidial, stronglyoides
what are the symptoms of small bowel bacterial overgrowth
diarrhoea, steatorrhoea, macrocytic anemia (B12)
what bacteria commonly cause a small bowel overgrowth
E.Coli or bacteroides
what can predispose someone to a small bowl overgrowth
diverticula, fistulas and strictures relating to crohns,
bypass surgeries, functional stasis
what is a small bowl overgrowth
the presence of excess bacteria in the intestine
how is a small bowel overgrowth diagnosed
low cobalamin and high folate levels, schillling test
how is small bowel bacterial overgrowth breated
surgical correction of an anatomical loop, tetracyclines 2-3 weeks
what past medical history would make you think malabsorption
gastric or small bowel resection, gastrointestinal diversion (bariatric), radiation exposure, travel
what are the gastrointestinal symptoms of malabsorption
diarrhoea, weight loss, flatulence, abdominal bleeding, abdominal cramps, pain, oedema
what signs could be found on examination in malabsorption
easy bruising, acrodermatits enteropathica, dermatitis herpetiformis, glossitis and angular stomatitis, spooning of the nails,
what can cause easy bruising
vitamin C def ‘scurvy’, vit k def
what causes acrodermatits enteropathica
autosomal recessive, impaired zinc uptake
what causes dermatitis herpetiformis
may indicate coeliac disease
what cause glossitis and angular stomatitis
B vit and iron def
what causes spooning of the nails
iron def (thyroid)
what are the base line investigations in malabsorption
full blood count (anaemic, vit def) coagulation (vit k test) liver function test, albulmin, calcium/ magnesium, stool culture
what anatomic investigations can be done in malabsorption
endoscopy, imaging
how is malabsorption treated
treat underlying cause, replace the deficiency, support nutritionally,
