Small Bowel Disorders, Acute/Chronic Diarrhea Flashcards
Name the layers of the intestinal wall from outside to inside.
serosa longitudinal muscle myenteric plexus circular muscle submucosa muscular mucosae mucosa
What are the two patterns of motility in the small intestine?
fed pattern: isolated contractions, short lengths
fasting pattern: phase I (inactivity), phase II (irregular contractions, phase III (MMC)
Which of of nutritional units can be absorbed without energy being expended?
fructose- facilitated diffusion
long/short chain fatty acids - simple diffusion
NOT:
glucose, galactose: secondary active transport with Na
amino acids: secondary active transport with H+
What is the classic presentation of acute and chronic bowel ischemia?
acute: pain out of proportion to exam, dx with labs (WBC and lactate) and CT caused by ebolus (atrial fib), thrombosis (hyper coagulable)
chronic: post prandial abdominal pain, dx with angiography caused by atherosclerosis, vascultits, DM, PAD
can progress to bowel infarction, sepsis, and bowel perforation
What are treatments for acute v. chronic bowel ischemia?
acute: interventional radiology to perform thrombolysis via TPA and anticoagulation
Chronic: difficult to tx, vascular surgery, stents and anti-thrombotic medications
What are the causes of obstruction and how do you treat it?
post op adhesions, tumors, strictures esp due to Crohn’s and incarcerated hernias
tx with NPO, IVF, NG tube to suction; treat underlying condition, surgery for lysis of adhesions, resections of tumors, stricturoplasty of fibrotic Crohn’s
List acute and chronic causes of ileus?
acute: post-op, electrolyte imbalance, medications (narcotics, CCB, anticholinergics, sepsis, peritonitis)
chronic: visceral myopathy (scleroderma), Parkinson’s, anti-psychotic meds
What additional treatments might you try in ileus in addition to those used in obstruction?
acutely: try to ambulate or exercise in bed,
chronic: pro kinetics: regional and erythromycin (mild results)
What layers compose a diverticula and what are the major sequalae?
typically composed of mucosa and submucosa, either incidentally or as part of intestinal motility disorder
major sequelae is bacterial overgrowth
Describe the causes, dx and tx of diverticula.
caused by scleroderma, visceral neuropathies, visceral myopathies (presents with discomfort, pain and bloating)
dx: small bowel follow through +/- hydrogen breath test
What are common causes of short gut syndrome? How is it treated?
massive bowel resection due to Crohn’s, malignancy, vascular insufficiency, radiation etc
tx: tube feed/ TPN-IVF, anti-diarrheal agents (imodium, lomtil) and octreotide/ growth hormone to decrease fluid losses from diarrhea
What types of primary (rare) tumors that occur in the small intestine?
carcinoid, adenocarcinoma, GIST (gastrointestinal stream cell tumors)
note metastatic lesions form sarcoma, breast and lymphoma are common
What is intussusception?
telescoping phenomenon of the small bowel, often due to tumors or large polyps in adults
Name 4 underlying mechanism for diarrhea.
abnormal motor function
increased net secretion (secretory)
impaired absorption (osmotic)
inflammation
What are common causes of decreased motility causing diarrhea?
diabetes: autonomic neuropathy- propulsion is altered, typically worse at night
hyperthyroidism: hyper motility treated by addressing underlying thyroid disorder
amyloidosis: accumulation of insoluble protein in extracellular space causing autonomic neuropathy and infiltration of intentional submucosa
scleroderma: causes dysmotility and sm. bowel diverticula with bacterial overgrowth
