Malabsorption Flashcards
what are the classifications of malabsorption ?
either generalized ( all major nutrient classes ) or specific ( single nutrient )
what is the normal range for fecal fat testing ?
2 to 7 grams over a 24 hour period
what is the minimum time for collection of faecal fat ?
3 days
what is a rapid way for testing absorption of fat in the small bowel ?
14 C triolein breath test
what are the contraindications to using the 14C triolein breath test ?
pregnancy
children
COAD ( chronic obstructive airway disease )
how can jejunal absorptive capacity be tested (intestinal permeability )?
xylose absorption test
what additional test to xylose absorption test must be used for children ?
blood levels of xylose
what can cause problems when interpreting xylose absorption test ?
inaccurate urine collection
low GFR
delayed gastric emptying
oedema
how is the detection of bacterial overgrowth achieved ?
14C glycocholate breath test ( bile acid breath test)
what are the contraindications to 14C glycocholate breath test ?
pregnancy
children
chronic airway disease
what specific test is used for cystic fibrosis ?
sweat electrolytes
what can be used to diagnose a disaccharide deficiency ?
brush border biopsy
example of a disaccharidase deficiency ?
lactase deficiency
how can a diagnosis of impaired B12 absorption ?
Schilling test
what is the malabsorbed nutrient in a patient with easy bruising ?
vitamin K
vitamin C
what are the expected lab findings in a patient with easy bruising ?
increased prothrombin time
what is thee malabsorbed nutrient in a patient with oedema and what is the expected lab findings ?
deficiency in protein
low albumin
if a patient presents with abdominal pain/distention/flatulence/ diarrhea what is the malbsorbed nutrient ?
lactose
bacterial overgrowth
what are the expected lab findings in a patient with steatorrhea ?
low fat soluble vitamins ( ADEK )
what is the initial investigation for lactose intolerance?
hydrogen breath test
what is the initial investigation for bacterial overgrowth ?
14C Glycocholate breath test
what is the initial investigation for diarrhea associated with hyperthyroidism ?
TFT from serum
what is the initial investigation for a patient with malabsorption due to EPI ?
faecal elastase
what diseases cause pancreatic insufficiency ?
chronic pancreatitis
cystic fibrosis
IBD
zollinger ellison syndrome
if the cause of malabsorption is Coeliac what is the initial investigation ?
IgA and anti-tTG antibodies
if the cause of malabsorption is due to IBD what is the initial investigation ?
faecal calprotectin
what are the differentials of megaloblastic anemia ?
cobalamin deficiency (B12 deficiency )
folate deficiency
liver disease
hypothyroidism
hemolytic anemia
what are the causes of b12 deficiency ?
inadequate intake
pernicious anemia
gastrectomy
pancreatic insufficiency
bacterial overgrowth
fish tapeworm
abnormal intrinsic factor
what are the causes of pernicious anemia ?
autoimmune disorder - atrophic gastritis, loss of parietal cellss
where does b12 absorption occur ?
the terminal ileum
what is the serology for pernicious anemia ?
parietal cell antibodies but intrinsic factor antibodies are more specific
what other autoimmune diseases are associated with pernicious anemia ?
addison’s disease
vitiligo
thyroid disease
what is the classic triad of pernicious anemia ?
weakness
sore tongue - glossitis
symmetrical paraesthesia inn thee finger and the toes
if a patient with neurological complications associated with b12 deficiency , what is the most app management ?
higher doses of b12
why must periodic evaluation of patients with pernicious anemia be done ?
in fear of gastric carcinoma
what is the criteria for the diagnosis of IBS ?
1- recurrent abdominal pain at least once a week for the last 3 months, associated with 2 or more of the following :
- pain associated with defecation
- associated with a change in stool frequency
- associated with a change in stool form
should be fulfilled for the last 3 months with onset over 6 months prior to diagnosis
what is the most sensitive and specific antibodies for the confirmation of celiac disease ?
tIgA and endomysial IgA
IgA TTG
what is the pathology in celiac disease ?
villous atrophy
what are the dietary requirements for tesstiing in ccelliac disease ?
must be done on gluten containing diet ( 1 gluten containing meal every day for at least 6 weeks)
what dermatological disease is associated with celiac disease ?
dermatitis herpetiformis
what does a gluten free diet consist of ?
strict avoidance of any products containing wheat, barley and rye
what should diabetic patients with digestive issues be tested for ?
celiac disease
if there is found to be elevated ALT levels with no other explanation what should be sought after ?
celiac disease
what is the gold standard for the stimulation off pancreatic function ?
CCK and Secretin
where are bile salts and B12 reabsorbed ?
in the ileum
what does the presence of steatorrhea indicate ?
small bowel involvement / terminal ileum
what structure prevents the retrograde translocation of bacteria from the colon to the small intestine ?
ileocecal valve
how is a hydrogen breath test carried out ?
it is indicated in patients with diarrhea and/or abdominal discomfort
given glucose for bacterial overgrowth
lactose for lactose intolerance
fructose for fructose malabsorption
a baseline breath test is taken then one every 30 minutes
intestinal failure vs intestinal insufficiency ?
failure : reduction in the gut function that requires IV supplementation
deficiency : reduction in the gut function but does not require IV supplementation
what are the pathological classifications of intestinal failure ?
short bowel
intestinal fistula
intestinal dysmotility
mechanical obstruction
extensive small bowel mucosal disease
what are the types of intestinal failure ?
Type I : acute, short term and self limiting
Type II : prolonged acute condition, in metabolically unstable patients, require IV supplementation
Type III : chronic condition, metabolically stable patient, requiring IV supplementation, may be reversible or irreversible
what are the main causes of short bowel syndrome ?
surgical resection
mesenteric vessel occlusion
radiation enteritis
what is better tolerated when it comes to the resection of the small bowel ?
resection of the jejunum is better tolerated than thee resection of the ileum
what are the consequences of ileal resection ?
b12 deficiency
bile salt induced diarrhea
steatorrhea and gallstone formation
oxaluria and oxalate stones
what is the pharmacological therapy in short bowel syndrome ?
antisecretory agents : H2 receptor antagonist
PPI
antimotility agents : loperamide
what are the indications of intestinal transplantation in cases of intestinal failure ?
- failure of home parenteral nutrition
- high risk of death attributable to the underlying disease
- intestinal failure with high morbidity or low acceptance of HPN
what are the signs of failure of HPN ?
impending or overt liver failure
central venous catheter related thrombosis
frequent central line sepsis
severe dehydration despite IV fluids
what is the clinical presentation of whipple infection?
affection of the heart, brain and lungs
peripheral lymphadenopathy
arthritis and arthralgia
abdominal pain
flank pain and hematuria
steatorrhea
how is a diagnosis of whipple confirmed ?
biopsy
acid-schiff staining of macrophages
electron microscopy
then DNA
what is the treatment for whipple disease ?
must be treated with antibiotics that cross the blood-brain barrier ( co-trimoxazole) daily for one year
this is preceded by a 2 week course of streptomycin and penicillin or ceftriaxone
at what Gy of radiation is damage to the intestine caused ?
40
when is pelvic irradiation usually used ?
gynecological and urinary tract malignancies ( affection of the ileum and the rectum )
what does radiation do to the rectum ?
radiation proctitis - with diarrhea and tenesmus, with or without blood
what can resistant anemia in cases of radiation proctitis be treated with ?
argon plasma coagulation
why does malbasorption happen in chronic radiation enteritis ?
bacterial overrgrowth in dilated segments and mucosal damage
what drugs can cause malbasorpttion ?
ccholestyramine , neomycin , orlistat
how can HIV patientts have malabsorption ?
more prone to parasitic infeections which can cause malabsorption
