Flashcards in small bowel disorders Deck (30)
What is celiac disease?
- autoimmune disorder that is triggered by an enviro agent (gliaden component in gluten) in genetically predisposed individuals
- it occurs primarily in whites of N european ancestry but has not increased in other ethnic groups
- reported prevalence in most countries: 1:70 to 1:300
2 components of gluten?
- gliadin and glutenin
What studies are used to follow course of CD?
- IgA abs to gliadin
- IgA abs to endomysium: a structure of smooth muscle CT, presence is nearly pathognomonic for CD
- gliadin receptors on intestinal epithelial cells may mediate the transport of gliadin peptides into lamina propria where T cell activation occurs - this may someday lead to drug therapy for CD
Mechanism of gluten irritation? Diff in bowel structure?
-gluten triggers release of protein that controls gut permeability
- intestinal lining cells are pried apart by protein, zonulin
- undigested food enters blood system
- immune system cells react by releasing cytokines. Which can trigger inflammation and disruption throughout the body
- this inflammation attracts more immune cells (macrophages) - just leads to more inflammation
Clinical manifestations of CD: classic?
- diarrhea with bulking, foul smelling, floating stools due to steatorrhea (malabsorption)
- wt loss
- vit deficiences: B vitamins, iron, copper, zinc, vit A, D, E and magnesium
- on small bowel bx: villous atrophy
Atypical disease presentation of CD?
- minor GI sxs
- can have anemia, osteoporosis, arthritis
- increased LFTs, neuro sxs, or infertility (due to abs)
- most show severe mucosal damage and possess the CD ab pattern
What is silent CD?
- recognized incidentally based upon screening for abs
- often have some changes in mucosa of small bowel
- they don't show clinical sxs but many complain of fatigue
Pts with CD have a slight increased risk for what malignancies?
- non-hodgkin lymphoma
- small intestinal adenocarcinoma
- hepatocellular carcinoma
- GI cancer
- lymphoproliferative disease
- hodgkin lymphoma
- decreased risk of breast cancer
Assoc conditions with CD?
- dermatitia herpetifromis (autoimmune rash)
- type 1 DM
- down syndrome
- liver disease
- autoimmune thyroid disease
- menstrual and repoductive issues in women
- infertility in men
How do you dx CD?
- begin with IgA anti-tissue transglutaminase (TTG): autoab against body's own transglutiminases
this is used for anyone over the age of 2, it is the single PREFERRED test for detection of CD
- if high prob of disease and IgA based serology is negative: test total IgA or IgG- deaminated gliadin peptides (DGP)
- pts with positive serology should undergo a small bowel bx:
- 1-2 bx from duodenal bulb
- at least 4 from 2nd and 3rd portion of duodenum
Other dx tests for CD?
- pts on gluten free diet who have negative serology's should have HLA/DQ1/DQ8 testing: determine if pt is genetically susceptible to disease, if negative CD is ruled out
- if serology is positive but small bowel bx is negative the pt can be put on high gluten diet and be rebx after 6-12 weeks
- individuals with low pretest probability (chinese, japanese, adn sub-saharan african descent): recommend - IgA endomysial ab test - it has a higher specifity but it is more costly
What is gluten sensitivity?
- some people are sensitive to gluten w/o having CD
- they get diarrhea, feel ill and bloated and find if they eliminate gluten from their diet they feel better
Tx of CD?
- consult with skilled dietitian
- education about disease
- lifelong adherence to gluten free diet
- Id and tx of nutritional deficiencies
- access to advocacy group
- continuous ongoing f/u by multidisciplinary team
What foods should be avoided in gluten free diet? What foods are ok?
- foods containing wheat, barley: avoid
- soybean or tapioca flours, rice, corn, buckwheat and potatoes are safe
- read labels: distilled alcohol, vinegar, and wine are gluten free
- beers, ales and malt vinegars often made with gluten
- dairy products may not be well tolerated initially since many pts with CD have secondary lactose intolerance - initially dairy should be avoided
- oats should be introduced into diet with caution (may be some cross reactivity)
How common is lactose intolerance in US - what ethnicities are mostly affected?
- 7-20% caucasian adults
- 80-90% native americans
- 55-65% african americans and africans
- 50% hispanics
- over 90% of some pops in East Asia
Sxs of lactose intolerance?
- due to low levels of lactase in small bowel:
- abdominal pain
Mechanism of lactose intolerance?
- if you lose lactase - lactoce isn't being broken down this leads to bacterial fermentation- this is what causes sxs: loose stools, bloating, abd pain
Explain what racial/ethnic lactose malabsorption is?
- genetically regulated reduction in lactase activity determined by ethnic factors in healthy individuals
- majority of caucasians of N. European ancestry maintain elevated lactase levels as adults
- in US lactase activity is normal in all healthy children until 5
Explain what developmental lactase deficiency is?
- results from low lactase levels as result of prematurity
- infants born at 28-32 wks gestation have reduced lactase activity
- tx: use elemental (predigested) formula
What is congenital lactase deficiency?
- rare autosomal recessive disorder
- absence of any lactase activity in small intestine
- largest number of reported cases have been described in Finnish pop
What is secondary lactase malabsorption?
- bacterial overgrowth or stasis may be assoc with increased fermentation of dietary lactose in small bowel
- seen with any mucosal injury to small bowel such as gastroenteritis (avoid dairy products for a couple of weeks to allow mucosa to heal), CD, IBD
Clinical manifestations of lacose intolerance?
- abdominal pain: crampy, periumbilical and lower quadrants
- vomiting: adolescents
Dx of lactose intolerance?
lactose tolerance test:
- 50 g test dose given in adults
- blood glucose levels drawn at 0, 60, and 120 min
- an increase in blood glucose by less than 20 mg/dL plus sxs is dx
- this is cumbersome and time consuming
lactose breath hydrogen test:
- oral lactose given in fasting state (2 gm/kg - max: 25 mg)
- breath hydrogen levels measured at baseline and 30 min intervals for 3 hrs after lactose ingestion
- values over 20 ppm dx
Tx of lactose intolerance?
- dietary restriction of lactose intake: read labels, usually some lactose containing foods (cheese) can be tolerated
- substition of alt sources to maintain energy and protein intake
- admin of commercially available enzyme substrate: lactaid
- maintenance of Ca and Vit D intake
What is ileus?
- temporary absence of normal contractile movements to intestinal wall
Etiologies of ileus?
- post op: esp abdominal when the intestine's have been manipulated
- drugs: opioids and anticholinergics
- lyte disorders: hypokalemia, hypercalcemia
- intestinal peritonitis: going to have rebound tenderness
- kidney failure
- pancreatitis - inflamed pancreas bothersome to bowel
Clinical manifestations of ileus?
- crampy abdominal pain: pain precedes vomiting when assoc with acute surgical etiology
- severe constipation
- loss of appetite
DDx of ileus?
-adynamic (paralytic) ileus (slowed down)
- acute abdomen
- post-op adhesive disease
Dx of ileus?
- CMP including Mg