Diarrhea: Acute, Sub acute, & Chronic
Study guide:
Definition:
-
It is the passage of loose\watery stool at least 3 times per 24 hours (>200 ml).
-
Classification based on duration:
-
Acute: <2 weeks
-
Sub-acute: 2-4 weeks
-
Chronic: >4 weeks
-
-
Classification based on etiology: mainly for acute
-
Community acquired
-
Nosocomial/ Hospital-acquired
-
Acute:
-
Community acquired:
-
Viral:
-
Rotavirus
-
Norovirus
-
-
Bacterial:
-
SEVERE WATERY DIARRHEA:
-
Mechanism:
-
Fluid loss from the proximal small intestine without cellular injury.
-
-
Course:
-
Acute, brief 1-3 days
-
Self limited.
-
-
Common microorganisms:
-
-
-
-
DYSENTERY (BLOODY) DIARRHEA:
-
Primary site for colonization: colon.
-
Characteristics:
-
Diarrhea in smaller volume than in watery diarrhea BUT lasts longer.
-
Diarrhea with BLOOD + PUS.
-
Inflammation and/or distinctive changes in the colonic mucosa.
-
-
Presents as: fever, abdominal pain and cramps, & tenesmus.
-
Most cases resolve spontaneously in 2-7 days.
-
-
Common pathogens:
-
Note: CHESS commonly cause bloody stool: Campylobacter, Hemorrhagic E.coli, E.histolytica, Salmonella, Shigella.
-
ENTERIC FEVER (TYPHOID FEVER):
-
Salmonella enterica serovar typhi.
-
Presents as: gradual onset of a systemic infection with fever and abdominal pain"(diarrhea is not a constant feature!)
-
-
DIARRHEAL DISEASE WITH VOMITING AS A PROMINENT FEATURE:
-
Nosocomial/ Hospital-acquired:
-
Infants:
-
Rotavirus -> winter time, breakouts.
-
Enteropathogenic E.coli (EPEC): infantile diarrhea.
-
-
Adults:
-
Antibiotic associated diarrhea:
-
S\E of antibiotics (erythromycin, augmentin, cephalexin, Clindamycin)
-
C.difficile overgrowth (takes 3 days).
-
-
Non- antibiotic associated diarrhea:
-
CT contrast.
-
Laxatives, magnesium, and sorbitol.
-
Tube feed diarrhea
-
-
-
Sub-acute:
-
Travelers’ diarrhea: ingestion of fecally contaminated food, water, or ice.
-
Causes:
-
80% is bacterial cause.
-
50% of all cases: Enterotoxigenic E.coli.
-
10%-20% of cases: Shigella.
-
Other: campylobacter jejuni.
-
-
Diagnosis of Acute & Subacute Diarrhea:
-
Exclude infection (stool study) GOLD STANDARD for acute diarrhea.
-
Checking for: mucus, blood (RBCs), WBCs.
-
If negative go for Endoscopy.
-
-
Management of Acute & Subacute Diarrhea:
Chronic:
-
Classified according to the characteristic of stool:
-
SECRETORY:
-
Mechanism:
-
Derangement of electrolyte and fluid transport across the intestinal epithelium.
-
(Special channels in the walls are disturbed).
-
-
Etiology:
-
Medication: ethanol, stimulant laxatives.
-
Anatomical defects (bowel resection) and Congenital (chloridorrhea, mucosal defect…).
-
Toxins (e.g. vibrio cholera).
-
Hormones & neuroendocrine tumors (e.g. VIPoma, gastrinoma…).
-
-
NOT affected by FASTING!
-
-
OSMOTIC:
-
Mechanism:
-
Osmotically active solute: driving water into the lumen.
-
-
Etiology:
-
Osmotic laxatives (poorly absorbed ions: Mg++, SO4+).
-
Non-absorbable sugars (artificial sweeteners, lactose intolerance).
-
-
Gets better with FASTING!
-
-
FATTY
-
Characteristics: malodourous, bulky stool, difficult to flush
-
Floating is due to gas not fat.
-
-
Mechanism:
-
Mal-absorption:
-
Mucosal diseases (celiac disease)
-
Short bowel syndrome (after surgery)
-
-
Mal- digestion:
-
Pancreatic insufficiency (chronic pancreatitis)
-
Cholecystectomy:
-
Mechanism: bile will drain directly into small intestine -> exceed the terminal ilium absorptive capacity -> too much bile reaching the colon -> diarrhea
-
-
-
Post-mucosal lymphatic obstruction.
-
-
-
INFLAMMATORY
-
Presents as: pain, fever, cramps, and bloody diarrhea.
-
Etiology:
-
Inflammatory bowel disease (IBD) -> crohn’s disease, and ulcerative colitis.
-
Infections (C. diff colitis, Yersinia, TB)
-
Always exclude infection in inflammatory (bloody) diarrhea, even if you are sure of your diagnosis.
-
-
Osmotic Gap 50-100 mosm \ Kg

> 100 Osmotic Diarrhea
normal pH: 7-7.5
pH high
pH low
Ions
Sugar
<50
Secretory Diarrhea
-
MOTILITY DISORDER
-
Etiology:
-
Diabetic neuropathy à disturbance in symp. / parasymp.
-
Hyperthyroidism à bowels hyper-motile
-
Addison’s disease
-
Irritable Bowel Syndrome (IBS):
-
-
A. Mechanism: stress -> hyperactive colon.
B. More in females.
C. Presentation: chronic lower abdominal PAIN+ changes in the bowel habits (diarrhea, constipation, or both).
D. Dx.: Manning and Rome criteria.
-
Diagnosis of Chronic Diarrhea:
-
CBC: looking for leukocytosis.
-
Chemistry: looking for electrolyte disturbances.
-
Stool: occult blood.
-
Fecal leukocyte: suggestive of infections.
-
Biopsy for inflammatory bowel disease.
-
-
Management of Chronic Diarrhea:
-
Treat the underlying cause
-
Symptomatic
-
References:
-
Kumar P, Clark M. Kumar & Clark's clinical medicine.
-
Le T, Krause K. First aid for the basic sciences. New York: McGraw-Hill Medical; 2012.
-
Le T, Bhushan V, Singh Bagga H. First aid for the USMLE step 2 CK. New York: McGraw-Hill Medical; 2010.
-
Bergin J. Medicine recall. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2008.
-
Collins P, Fox C. Gastroenterology. Edinburgh: Mosby; 2008.
-
Fischer C. Master the boards.
-
Agabegi S, Agabegi E, Ring A. Step-up to medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2013.
Written by: Haifa Al-Issa
Reviewed by: Roaa Amer
Haneen Al-Farhan
Format Editor: Roaa Amer
Website publisher: Salman Alahmed
Bayan Alzomaili