2. OBJECTIVES
• Acute
– Indications for testing and treatment
– Infectious associations
• Chronic
– Categories and characteristics
– Stool osmolar gap
–Common medications
• Illness script (a little about microscopic colitis)
3. ACUTE DIARRHEA
• Indications for testing:
– Diarrhea >1wk
– Bloody
– Severe symptoms
– Known IBD
– HIV
– Pregnancy
– Antibiotics or Hospitalized >3 days in past 3 months
• Indications for antibiotic treatment:
• Severe symptoms with bloody diarrhea
• No blood, but fever, >6 stools/d, age >70, serious comorbidity, volume depletion,
requiring hospitalization, severe pain
6. STOOL OSMOLAR GAP
290 – 2 x (stool Na + stool K)
• Used when watery diarrhea persists >4 weeks
• Helps to distinguish between osmolar and secretory
• Measured stool osmolality
– If concern for water added to stool
• Stool Magnesium of phosphate
– May be measured if surreptitious laxative use is a concern
10. A 23 year old male presents with chronic diarrhea for 2-3 years that
has become more severe in the last 6 months with 6 BMs per day.
Stools are mushy, malodourous and associated with crampy
abdominal pain. He has lost 5lbs in the past 6 months despite eating
more calories. No fever, blood in the stool, foreign travel.
Most appropriate first test?
A. Anti-Saccharomyces cerevisae antibodies
B. Flexible sigmoidoscopy
C. Tissue transglutaminase antibody
D. Anti-gliadin antibody
Acute diarrhea
- testing: stool culture, ova and parasites parasites
- stool culture positive in 80% of severe)
- treatment:
Exception? Stable, then rule out EHEC/Shiga toxin production first
Choice of agent: azithromycin (better for dysentery), ciprofloxacin/levofloxacin
Loperamide – how to dose?
4 mg now x2, the 2 mg after each loose stool for max 16mg
Avoid with dysentery or c diff
Celiac: total IgA levels are performed to rule out IgA deficiency, tTG-IgG can be collected if defeicent
- weakly positive serology may be negative 3 weeks after gluten free diet, by 6 months 80% will have negative serology
- others – more costly
- anti-antigliadin antibodies
- antibodies to deaminated gliadin peptite
- anti-endomysial antibodies
iron deficiency anemia, elevated LFTs, B12 deficiency
Microscopic colitis: upregulated interferon gamma, IL-15, TNF
Of note, uptodate lists EGD with biopsies as test to be performed WITH serologies (given high pretest probability), but MKSAP states serologies first.
