bowel diseases: small intestine Flashcards
diseases of the sm. intestine: Malabsorption
Celiac disease Whipple disease Bacterial overgrowth Short bowel syndrome Lactase Deficiency
Celiac disease is also called ??
is what??
sprue, celiac sprue, and gluten enteropathy
is a permanent dietary disorder caused by an immunologic response to gluten, a storage protein found in certain grains, that results in diffuse damage to the proximal small intestinal mucosa with malabsorption of nutrients
celiac disease prevalence??
Disease is present in 1:100 whites of Northern European ancestry, in whom a clinical diagnosis of celiac disease is made in only 10% (most go undiagnosed)
Symptoms and signs of celiac disease depend on ??
“Classic” symptoms ??
the length of small intestine involved and the patient’s age
Malabsorption!
Diarrhea, steatorrhea, weight loss, abdominal distention, weakness, muscle wasting, or growth retardation
*slide 8,9: dermatitis herpatiformis (complication of celiac disease)
Celiac disease labs
Microcytic anemia due to iron deficiency Megaloblastic anemia due to folate or vitamin B12 deficiency Low serum calcium Elevated alkaline phosphatase Elevations of prothrombin time Decreased vitamin A, vitamin D Low serum albumin Nonanion gap acidosis Hypokalemia Mild elevations of aminotransferases
chart on pg. 11
*steaorrhea: dec. serum cholesterol, dec. serum carotene, vit A, D
malabsorbed TGs, FAs, PLs, cholesterol, vit ADEK
*paresthesia: tetany, + Trousseaus’s/Chvostek signs: dec. serum Ca2+, Mg+
case: ddx
appendicitis ectopic pregnancy uterine fibroids pancreatitis Crohn's diverticulitis malrotatio/vovulus medial edematous polypsis *just bc it is in lower quadrant doesn't mean it can't be an UQ problem ascending cholangitis (RUQ, fever, jaundice (Charcot's triad) cholelithiasis (other choles) viral gastroenteritis FBI
case: labs
CBC (anemia) CNP (LFT's) lipase (pancreatitis) UA (pyelonephritis) hemoccult
case: imaging
US
possible CT
Celiac disease Abs dx
IgA tissue transglutaminase (IgA tTG) antibody
Antigliadin antibodies are NOT recommended
IgA antiendomysial antibodies are NOT recommended
??? is the gold standard method for confirmation of the diagnosis in patients with a positive serologic test for celiac disease or patients with negative serologies when symptoms and laboratory studies are strongly suggestive of celiac disease
Histology reveals ??
Endoscopic mucosal biopsy of the proximal duodenum (bulb) and distal duodenum
*Atrophy or scalloping of the duodenal folds may be observed (slide 13)
Histology reveals abnormalities ranging from intraepithelial lymphocytosis alone to extensive infiltration of the lamina propria with lymphocytes and plasma cells with hypertrophy of the intestinal crypts and blunting or complete loss of intestinal villi
slide 14: “lawn mower effect?”
celiac disease tx
Removal of all gluten from the diet is essential to therapy: all wheat, rye, and barley
- may also have lactose intolerance either temporarily or permanently and should avoid dairy products
- Dietary supplements (folate, iron, calcium, and vitamins A, B12, D, and E) initially
- Confirmed osteoporosis may require long-term calcium, vitamin D, and bisphosphonate therapy
celiac disease px
Associated with ??
Celiac disease that is truly refractory to gluten withdrawal occurs in ??
Excellent prognosis**
-other autoimmune disorders, including Addison disease, Graves disease, type 1 diabetes mellitus, myasthenia gravis, scleroderma, Sjögren syndrome, atrophic gastritis, and pancreatic insufficiency
-less than 5% and generally carries a poor prognosis
Whipple disease
Rare multisystem illness caused by infection with the bacillus Tropheryma whippelii
Most commonly affects white men in the fourth to sixth decades (30s-50s)
“foamy whipped cream in a can”
Whipple disease clinical manifestations
*Arthralgias (80%, migratory, nondeforming)
Diarrhea, abdominal pain (75%)
*Weight loss (almost 100%) with protein-losing enteropathy with hypoalbuminemia and edema
Intermittent low-grade fever (50%) of cases
Generalized lymphadenopathy
*Cardiac involvement: Heart failure, Valvular regurgitation
*CNS: Dementia, lethargy, coma, seizures, myoclonus, or hypothalamic signs, Ophthalmoplegia, nystagmus
Whipple disease clinical manifestations 2
Low-grade fever Malabsorption Lymphadenopathy Heart murmurs Peripheral joints edema, erythema Neurological findings Hyperpigmentation on sun-exposed areas Hypotension ** (happens later)
Whipple dx
Endoscopic biopsy of the duodenum with histologic evaluation:
- Infiltration of the lamina propria with PAS+ macrophages that contain G+ bacilli (which are not acid-fast) and -dilation of the lacteals
- Whipple bacillus has a characteristic trimellar wall appearance on electron microscopy
Because asymptomatic central nervous system infection occurs in 40% of patients, examination of the ??
cerebrospinal fluid by PCR for T whippelii should be performed routinely
Whipple disease tx
Antibiotic therapy results in a dramatic clinical improvement within several weeks
- Complete clinical response usually is evident within 1–3 months
- Relapse may occur in up to one-third of patients after discontinuation of treatment
- Prolonged treatment for at least 1 year is required
- Drugs that cross the BBB are preferred
- If untreated, the disease is fatal
- Prevent neurological progression
Bacterial overgrowth in the small intestine of whatever cause may result in malabsorption via a number of mechanisms
- Bacterial deconjugation of bile salts may lead to inadequate micelle formation, resulting in decreased fat absorption with steatorrhea and malabsorption of fat-soluble vitamins (A, D)
- Microbial uptake of specific nutrients reduces absorption of vitamin B12 and carbohydrates
- Bacterial proliferation also causes direct damage to intestinal epithelial cells and the brush border, further impairing absorption of proteins, carbohydrates, and minerals
- Passage of the malabsorbed bile acids and carbohydrates into the colon leads to an osmotic and secretory diarrhea and increased flatulence
Bac OG
Gastric achlorhydria (PPIs) Anatomic abnormalities of the small intestine with stagnation Small intestine motility disorders Gastrocolic or coloenteric fistula Miscellaneous disorders
Bac OG presentation
Many asymptomatic* Flatulence Weight loss Abdominal pain Diarrhea Steatorrhea Vitamin and mineral deficiencies Fat-soluble vitamins A or D, vitamin B12, and iron
Bac OG labs
Qualitative or quantitative fecal fat assessment typically is abnormal
Stool collection should be obtained for confirmation of steatorrhea
Measure vitamins A, D, B12
Measure serum iron should be measured
Small bowel barium radiography or CT enterography study
Bac OG Gold standard for diagnosis: ??
next one??
another one??
aspirate and culture of proximal jejunal secretion that demonstrates over 105 organisms/mL
Noninvasive breath tests are easier to perform: Breath hydrogen and methane tests with glucose or lactulose
Empiric antibiotic trial **Brown doesn’t advocate
bac OG tx
Fix anatomic defect if one exists
1–2 weeks with oral broad-spectrum antibiotics effective against enteric aerobes and anaerobes usually leads to dramatic improvement
bac OG tx: In patients in whom symptoms recur off antibiotics, ??
For severe intestinal dysmotility use ??
cyclic therapy; continuous antibiotics should be avoided, if possible, to avoid development of bacterial antibiotic resistance.
octreotide
Short Bowel Syndrome
Malabsorptive condition that arises secondary to removal of significant segments of the small intestine: Crohn disease Mesenteric infarction Radiation enteritis Volvulus Tumor resection Trauma
Short Bowel Syndrome: Type and degree of malabsorption depend on ??
the length and site of the resection and the degree of adaptation of the remaining bowel
Short Bowel Syndrome: Resection of the terminal ileum
Malabsorption of bile salts and vitamin B12
- Low serum vitamin B12 levels or resection of over 50 cm of ileum require monthly subcutaneous or intramuscular vitamin B12 injections
- In patients with less than 100 cm of ileal resection, bile salt malabsorption stimulates fluid secretion from the colon, resulting in watery diarrhea treated with bile salt-binding resins
- Resection of over 100 cm of ileum leads to a reduction in the bile salt pool that results in steatorrhea and malabsorption of fat-soluble vitamins treatment is with a low-fat diet and vitamins supplemented with medium-chain triglycerides
- Unabsorbed fatty acids bind with calcium, reducing its absorption and enhancing the absorption of oxalate and oxalate kidney stones may develop
- Calcium supplements should be administered to bind oxalate and increase serum calcium
Short Bowel Syndrome: Resection of up to ?? of the total length of small intestine usually is well tolerated
A more massive resection may result in ??
40–50%
“short-bowel syndrome”:
-Weight loss and diarrhea due to nutrient, water, and electrolyte malabsorption
Patients with less than 100–200 cm of proximal jejunum remaining almost always require parenteral nutrition (TPN, only want to use temporarily)
-Death is most commonly due to TPN-induced liver disease, sepsis, or loss of venous access
-Teduglutide is a glucagon-like peptide-2 analogue that stimulates small bowel growth and absorption and is FDA approved for the treatment of short-bowel syndrome **