Amebiasis: Difference between revisions
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==Background== | ==Background== | ||
*Fecal oral transmission of Entamoeba histolytica cyst | *Fecal oral transmission of Entamoeba histolytica cyst | ||
*Most infection asymptomatic | |||
*Excystation in intestinal lumen | *Excystation in intestinal lumen | ||
*Trophozoites adhere and colonizes large intestine forming new cysts or invade the intestinal mucosa to cause colitis or abscesses | *Trophozoites adhere and colonizes large intestine forming new cysts or invade the intestinal mucosa to cause colitis or abscesses | ||
Revision as of 04:25, 22 October 2018
Background
- Fecal oral transmission of Entamoeba histolytica cyst
- Most infection asymptomatic
- Excystation in intestinal lumen
- Trophozoites adhere and colonizes large intestine forming new cysts or invade the intestinal mucosa to cause colitis or abscesses
- Liver abscess - 10x more common in men
- Incubation period usually 2-4 weeks, but may range from a few days to years
Clinical Features
- Asymptomatic vs. dysentery vs. extraintestinal abscesses
- Intestinal- several weeks of crampy abdominal pain, weight loss, watery or bloody diarrhea
- Liver abscess-fever, cough, RUQ or epigastric pain, right-sided pleural pain or referred shoulder pain +/- GI upset
- Hepatomegaly with tenderness over the liver a typical finding
- Abscess rupture can involve associated peritoneum, pericardium, or pleural cavity
- Extrahepatic amebic abscesses in the lung, brain, and skin are rare
Differential Diagnosis
Dysentery
- Infectious- Shigella, Salmonella, Campylobacter, E.Coli.
- Noninfectious- Inflammatory bowel disease, ischemic colitis, diverticulitis, AV malformation.
Hepatic abscess
- Pyogenic abscess
- Aerobic: Escherichia coli, Klebsiella, Pseudomonas
- Anaerobic: Enterococcus, bacteroides, anaerobic streptococci
- Echinococcosis
- Amebiasis
- Benign cysts/malignancy
- Tuberculosis
- Mycosis
Fever in traveler
- Normal causes of acute fever!
- Malaria
- Dengue
- Leptospirosis
- Typhoid fever
- Typhus
- Viral hemorrhagic fevers
- Chikungunya
- Yellow fever
- Rift valley fever
- Q fever
- Amebiasis
- Zika virus
Acute diarrhea
Infectious
- Viral (e.g. rotavirus)
- Bacterial
- Campylobacter
- Shigella
- Salmonella (non-typhi)
- Escherichia coli
- E. coli 0157:H7
- Yersinia enterocolitica
- Vibrio cholerae
- Clostridium difficile
- Parasitic
- Toxin
Noninfectious
- GI Bleed
- Appendicitis
- Mesenteric Ischemia
- Diverticulitis
- Adrenal Crisis
- Thyroid Storm
- Toxicologic exposures
- Antibiotic or drug-associated
- Inflammatory bowel disease
Watery Diarrhea
- Enterotoxigenic E. coli (most common cause of watery diarrhea)[1]
- Norovirus (often has prominent vomiting)
- Campylobacter
- Non-typhoidal Salmonella
- Enteroaggregative E. coli (EAEC)
- Enterotoxigenic Bacteroides fragilis
Traveler's Diarrhea
- Giardia lamblia
- Cryptosporidiosis
- Entamoeba histolytica
- Cyclospora
- Clostridium perfringens
- Listeriosis
- Helminth infections
- Marine toxins
- Ciguatera
- Scombroid poisoning
- Paralytic shellfish poisoning
- Neurotoxic shellfish poisoning
- Diarrheal shellfish poisoning
Evaluation
- CBC
- Chem
- LFT
- Stool or abscess microscopy
- Stool, serum, or abscess fluid antigen
- Indirect hemagluttination (antibody)
- CT or ultrasound for suspected abscess
Management
Asymptomatic colonization
- Paromomycin or Diloxanide
Colitis
Liver abscess
- Flagyl, tinidazole, paromomycin, or diloxanide
- Consider drainage of abscess by IR if no response to antibiotics in 5 days, abscess > 5cm, or left lobe involvement
Disposition
- Home if no complications
References
- ↑ Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.