Diarrhea, Malabsorption, Small Intestinal Neoplasia Flashcards
inflammatory diarrhea features
- small volume
- frank or occult blood
- rectal urgency
- abd pain
- NOCTURNAL DIARRHEA
examples of inflammatory diarrhea
inflammatory bowel disease
ischemic colitis
radiation colitis
microscopic colitis
microscopic colitis usually presents with bloody or non-blood diarrhea?
non-bloody diarrhea
T/F
osmotic diarrhea resolves with eating
F
resolves w/o eating
exp of osmotic diarrhea
- carb malabsorption (lactose intolerance)
- ingestion of poorly absorbed sugars (sorbitol, xylitol)
- laxatives w/ Mg
secretory diarrhea
large volume watery diarrhea, minimal resolution w/ fasting
bile acid malabsorption
endocrine disorders
meds (abx, chemo, PPIs)
neoplasms (carcinoid, gastrinoma)
dysmotility
intermittent, small volume, watery diarrhea
irritable bowel syndrome
postvagotomy
causes of steatorrhea
- impaired fat solubilization (bile salt deficiency/inactivation)
- defective nutrient hydrolysis (exocrine pancreatic insufficiency)
- mucosal disease (celiac, chronic mesenteric ischemia, Chron’s)
celiac disease
-immune mediated enteropathy triggered by gluten in genetically susceptible patients
- type IV HS
- Abs to tissue transglutaminase (TTG)
- T cell chronic inflamm in SI; proximal small intestine > distal
predisposing genetics of celiac
HLA-DQ2
HLA-DQ8
celiac epidemiology
- usu dx during childhood, but can be any age
- Northern Europe comm but everywhere
Celiac pathogenesis
- gluten proteins resist degradation, lg peptides pass epithelium
- CD4+ T mediate disease
- TTG Abs
celiac presentation
crampy abd pain chronic diarrhea Fe deficiency osteoporosis easy bruising peripheral neuropathy seizures
dermatitis herpetiformis
celiac
- IgA deposits, pruritis, blistering
- resolves w/ gluten free diet
celiac assoc conditions
SI adenocarcinoma
SI intestinal adenocarcinoma
lymphocytic gastritis and colitis (microscopic colitis)
tissue transglutaminase Abs
dx for
celiac
celiac histo
increased intraepithelial lymphocytes
villous atrophy
crypt hyperplasia
Celiac tx
gluten free diet
Fe, vitamin D/B12, Ca supp
SI bacterial overgrowth syndrome
Intestinal stasis
Abnormal connections between proximal/distal bowel (fistulas)
bacterial overgrowth
- reduced nutrient availability
- bile salt inactivation
dx of SI bacterial overgrowth syndrome
- direct aspiration of jejunal contents
- H breath tests
early peak in elevation of H2 concentration (in H breath test)
bacterial overgrowth syndrome
inc bile salt losses
mucosal disease in terminal ileum (Chron’s)
surgical resection/bypass of ileum
overwhelmed absorptive capacity of ileum
bile acid sequestrations
+ charged resin bunds to - bile salts and inc excretion
leads to liver inc bile acid synthesis which completes w/ CHL synthesis and ultimately lowers CHL levels
diarrhea tx
most common cause of chronic pancreatitis
EtOH
cystic fibrosis is a cause of ___ pancreatitis
chronic
most sensitive/specific test for pancreatic insufficiency
fecal elastase (low in exocrine insufficiency)
fat malabsorption tests
clinical hx
measure fat soluble vitamins
atrophy of intestinal villi with inc intraepithelial lymphocytes
celiac
late peak in H+ breath test
lactose intolerance
fecal osmotic gap
osmotic diarrhea > 125
osmotic diarrhea
lactose intolerance
lactose –> bacteria –> fermentation products –> water drawn in
secretory diarrhea
abnormal ion transport in intestinal epithelial cells
dec absorption of electrolytes or inc secretion of electrolytes
major solutes in intestinal lumen
account for most of luminal osmolality
most common location of GI neuroendocrine tumors
ileum
type 1 gastric NET
assoc w/ atrophic gastritis
type 2 gastric NETs
assoc w/ multiple endocrine neoplasia syndrome (MEN-1)
type 3 gastric NETs
sporadic
no underlying risk fx
carcinoid syndrome
- uncommon in pts w/ carcinoid tumors
- diarrhea, cutaneous flushing, bronchoconstriction, R sided HF
flushing/diarrhea due to secretion of amines (serotonin) and peptides (bradykinin, tachykinins)
carcinoid syndrome is often seen in metastatic disease to
liver
carcinoid syndrome dx
labs: serotonin level, serum chromogranin A
Imaging (CT, ocreotide scans)
tx: surgical resection
positive stains for carcinoid tumor
synaptophysin
chromogranin
ocreotide
analog of somatostatin
- somatostatin receptors found on carcinoid cells
- inhibits secretion of serotonin, gastrin, vasoactive intestinal polypeptide, insulin, other hormones
- improves diarrhea, flushing
- also a splanchnic vasoconstrictor (used in GI bleeds)
benign neoplasms of small bowel
adenomas
puetz-jeghers hamartomas
GIST
malignant tumors of small bowel
adenocarcinoma ampullarf carcinoma primary intestinal lymphoma (MALT) carcinoid (neuroendocrine) tumor metastatic tumors ** most comm
irritable bowel syndrome
functional GI disorder
abd pain + altered bowel habits
no biochemical or structural abnormalities
IBS hx
older adult
nocturnal wakening
labs: anemia, inc WBC, inc ESR, CRP
+ fecal occult blood
pathophys of IBS
- poorly understood
- altered intestinal motility
- heightened visceral sensitivity
- visceral hyper responsiveness to luminal GI events
IBS tx
- diet adjustments
- antispasmodics (hyoscyamine and dicyclomine)
- bulking agents
- antidiarrheals
- antidepressants
- alosetron
- behavioral therapy
- probiotics
- antibiotics
rifaximin
- antimicrobial agent that interferes w/ bacterial protein synthesis
- use: IBS-diarrhea
