IBS & SIBO

Question 1

What is the 9 proposed etiologies of IBS? what %age of IBS pts also have SIBO?

Answer 1

1. changes in GI motility
2. hypersensitivity of visceral afferent nerves of the gut
3. increased mast cell in gut= histamine release
4. colonic muscle hyper-reactivity & neural and immunological alterations of the colon & small bowel may persist after gastroenteritis
5. abn glutamate activation of NMDA receptors= NO synthetase, activation of neurokinin receptors & induction of calcitonin gene-related peptide
6. limbic system mediation of emotion & ANS response enhances bowel motility & decreases gastric motility
7. HPA may be involved in origin, CRF production in response to stress
8. SIBO provides unifying mech for common sxs of bloating & gaseous distention
   * >50% of IBS pts have SIBO
9. diet: low fiver, intolerance to lactose & other sugars & gluten leads to congestion, bronchitis, asthma, mucus

Question 2

Diagnosis of IBS?

Answer 2

in the absence of ‘alarm features’ or ‘red flags’ and /or any positive screening studies, additional diagnostic testing is typically not necessary

Question 3

6 red flags or alarm sxs that may r/o IBS?

Answer 3

1. sxs onset >50 yo
2. severe, unrelenting diarrhea
3. nocturnal sxs
4. unintentional wt loss
5. hematochezia
6. FHx or organic GI dzs like IBD, celiac sprue or CA

Question 4

What is Rome III criteria?

Answer 4

for diagnosis of IBS: pts must have recurrent abd pain or discomfort at least 3 d/mo during previous 3 mos assoc w/2 or more of following:

1. relieved by defecation
2. onset assoc w/change in stool frequency
3. onset assoc w/change in stool formation or appearance

Question 5

What is a clinical pic of IBS?

Answer 5

crampy, abd pain
constipation, diarrhea or both
increased colonic mucus production
flatulence, bloating/distention, nausea, anorexia
anxiety, depression
ssxs related to stress
appearance of health not good

Question 6

PEs for IBS?

Answer 6

diffuse abd tenderness over colon

Question 7

Labs for IBS?

Answer 7

ONLY TO CONFIRM OTHER POSSIBLE DX
CBC for anemia, inflam & infxn
CMP for metabolic d/o’s, r/o dehydration/electrolyte abnormalities
hemoccult test
stool exams
hydrogen breath tests for lactose intolerance
celiac testing

Question 8

Imaging for IBS?

Answer 8

xray may show altered motility

sigmoidoscopy may show increased mucus & spasm

Question 9

How does one actually diagnose IBS? pts >50 need to be ruled out for what and by doing what?

Answer 9

diagnosis by presence of typical sxs, complete PE & exclusion of alarm featuers
>50= nee dto rule out colorectal CA via colonoscopy

Question 10

What is SIBO? gases produced? enteric toxins produced? what is overgrowth prevented by normally?

Answer 10

increased # of bac in small intestine leading to fermentation, inflam & malabsorption
gases: hydrogen, methane
enteric toxins: ammonia, D-lactic acidosis, bac endotoxin stimulating cytokine release
prevention normally: antegrade peristalsis, gastric acid, bile, proteolytic enzymes, sIgA, intact ileocecal valve

Question 11

Causes of SIBO?

Answer 11

anatomical anomalies: stricture
insufficient enzymes: hypochlorhydria, PPI use
abn motility: obstruction, DM
abn communications b/w sm & lg bowel: fistual, defective valve
immunocompromised, alcoholism, cirrhosis, pancreatitis

Question 12

Hx of pt w/SIBO?

Answer 12

transient improvement in IBS after abx tx
worsening sxs on probiotic/prebiotic tx
worsening of IBS when eating more fiber

Question 13

Ssxs of SIBO?

Answer 13

abd pain/cramps, borborygmus, eructation, flatulence, bloating, diarrhea may alternate w/constipation, dyspepsia, vomiting, heartburn, wt loss, steatorrhea, systemic sxs of HA, joint pain, fatigue, rosacea

Question 14

PEs of SIBO?

Answer 14

scar? abd distention? succussion splash?

Question 15

Labs of SIBO?

Answer 15

CBC may show macrocytic or microscopic anemia, low ferritin
glucose breath hydrogen analysis
14C-d-xylose breath test
jejunal aspirate during endoscopy