malabsorption 1 W7 Flashcards
what is absorbed in just the duodenum?
iron
calcium
monosaccharides
what is absorbed in the jejunum and duodenum?
disaccharides
fatty acids
mono and di-glycerides
fat soluble vitamins
what is absorbed in just the jejunum?
water soluble vitamins
amino acids
peptides
what is absorbed in the whole small bowel?
water
sodium
magnesium
what is absorbed in the ileum?
bile acid
vitamin B12
what is absorbed in the colon?
water
sodium
potassium
vitamin K
what is malabsorption?
the inadequate absorption of fluid, macro or micronutrients to maintain health
what can malabsorption be caused by
maldigestion and malabsorption
what is maldigestion? what is it normally caused by?
problems in any digestive phase of food or nutrient processing
most commonly relating to digestive enzyme insufficiency or inefficiency
what mechanism is malabsorption normally caused by
loss of absorptive surface area
7 mechanisms of malabsorption?
reduced absorptive capacity
enzyme deficiencies
enzyme dysfunction
bile acid deficiency
competition for nutrients
dysmotility/dyssynchrony
impaired transport
what causes reduced absorptive capacity?
villous atrophy (eg Coeliac disease)
mucosal damage (eg Crohn’s)
small bowel resection or bypass
infiltration (eg amyloidosis)
what causes enzyme deficiencies?
disaccharidase deficiency (eg lactase)
lipase or proteolytic enzyme deficiency (eg pancreatic exocrine insufficiency)
causes of enzyme dysfunction?
Zollinger Ellison syndrome, Menetriere disease
orlistat
causes of bile acid deficiency?
obstructive jaundice/cirrhosis
bile acid malabsorption
deconjugation of bile acids by bacterial colonisation
causes of competition for nutrients?
parasites
causes of dysmotility/dyssynchrony?
rapid transit (eg resection, loss of ileal brake, gastroenteritis, diabetes, laxatives)
slow transport (eg diabetes, Parkinson’s)
anatomical dyssynchrony
causes of impaired transport?
intestinal lymphangiectasia
secondary glucose malabsorption, post surgical, protein-energy undernutrition, gastroenteritis, thiamine deficiency
how does malabsorption present - GI symptoms?
diarrhoea (steatorrhea - excess fat)
bloating
abdominal distension
flatulence
borborygmi (rumbling)
abdominal pain
nutritional deficiencies causing hair loss?
zinc, iron, protein
nutritional deficiencies causing night blindness
vit A
nutritional deficiencies causing cheilitis (inflamed lips), glossitis (inflamed tongue), bleeding gums, metallic taste?
riboflavin, niacin, iron, vit C, zinc
nutritional deficiencies causing cardiomyopathy, arrhythmias?
thiamine, B12, selenium, electrolytes
nutritional deficiencies causing diarrhoea
protein, niacin, folate, B12, zinc
nutritional deficiencies causing metabolic bone disease, joint pain, muscle wasting, muscle cramps?
calcium, vit D, vit C, protein, fluid, electrolytes
nutritional deficiencies causing peripheral oedema?
protein, thiamine
nutritional deficiencies causing confusion?
B12, thiamine niacin
nutritional deficiencies causing paraesthesia?
thiamine, electrolytes
nutritional deficiencies causing tetany (involuntary muscle contraction)
Ca, Mg
nutritional deficiencies causing goitre
idodine
nutritional deficiencies causing rashes
niacin, zinc, essential fatty acids
nutritional deficiencies causing easy bruising?
vit K, vit C
nutritional deficiencies causing impaired healing
zinc, copper, iron, protein
nutritional deficiencies causing anaemia?
iron, B12, folate, copper
