Amoebiasis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Serge Korjian M.D.

Overview

Amoebiasis must be differentiated from other causes of abdominal pain, bloating, acute or chronic diarrhea, and weight loss, such as other infectious causes of gastroenteritis, including bacterial, viral, fungal, and parasitic pathogens, in addition to non-infectious causes, including acute pancreatitis, appendicitis, bowel obstruction, diverticulitis, drug reaction, hyperthyroidism, inflammatory bowel disease, celiac disease, lactose intolerance, Whipple disease, tropical sprue, and lymphoma.

Differentiating Amoebiasis from other Diseases

Amoebiasis must be differentiated from other causes of acute or chronic diarrhea, bloating, abdominal pain, and fever (less common).
Differential diagnosis of amoebiasis includes the following:

Infectious Differential Diagnoses

Bacterial infections (e.g. E. coli infection, shigellosis, salmonellosis, C. jejuni infection)
Viral infections (e.g. norovirus, rotavirus, astrovirus, HIV)
Fungal infections (e.g. Candida spp.)
Parasites (Giardia, Cryptosporidium spp., Cyclospora)

Non-infectious Differential Diagnoses

The following are the non-infectious differential diagnoses of E. coli enteritis:

Acute pancreatitis
Adrenal insufficiency and Waterhouse-Friedrichsen syndrome
Allergy (e.g. insect bite allergy or anaphylaxis)
Appendicitis
Bowel obstruction
Celiac disease
Diverticulitis
Drug reaction (e.g. antimicrobial agents, antihypertensive therapy, chemotherapy, anticonvulsants)
Endometriosis
Familial Mediterranean fever
Gastrointestinal perforation
Hyperthyroidism
Ileus
Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
Intussusception
Ischemic colitis
Ketoacidosis
Lactose intolerance
Lymphoma
Mesenteric ischemia
Necrotizing enterocolitis
Ogilvie syndrome
Peritonitis
Pneumonia
Poisoning and toxicity (e.g. carbon monoxide poisoning, organophosphate poisoning, digitoxin toxicity)
Ruptured abdominal aortic aneurysm
Spider bite
Tropical sprue
Volvulus
Urinary tract infection
Whipple disease

To view a comprehensive list of abdominal pain differential diagnoses, click here.
To view a comprehensive list of diarrhea differential diagnoses, click here.

The table below summarizes the findings that differentiate inflammatory causes of chronic diarrhea^[1]^[2]^[3]^[4]^[4]

Cause	History	Laboratory findings	Diagnosis	Treatment
Diverticulitis	Bloody diarrhea Left lower quadrant abdominal pain Abdominal tenderness on physical examination Low grade fever	Leukocytosis Elevated serum amylase and lipase Sterile pyuria on urinalysis	Abdominal CT scan with oral and intravenous (IV) contrast	bowel rest, IV fluid resuscitation, and broad-spectrum antimicrobial therapy which covers anaerobic bacteria and gram-negative rods
Ulcerative colitis	Diarrhea mixed with blood and mucus, of gradual onset. Signs of weight loss Rectal urgency Tenesmus Blood is often noticed on underwear Different degrees of abdominal pain	Anemia Thrombocytosis A high platelet count Elevated ESR (>30mm/hr) Low albumin	Endoscopy	Induction of remission with mesalamine and corticosteroids followed by the administration of sulfasalazine and 6-Mercaptopurine depending on the severity of the disease.
Entamoeba histolytica	Abdominal cramps Diarrhea Passage of 3 – 8 semiformed stools per day Passage of soft stools with mucus and occasional blood Fatigue Intestinal gas (excessive flatus) Rectal pain while having a bowel movement (tenesmus) Unintentional weight loss	cysts shed with the stool	detects ameba DNA in feces	Amebic dysentery Metronidazole 500-750mg three times a day for 5-10 days Tinidazole 2g once a day for 3 days is an alternative to metronidazole Luminal amebicides for E. histolytica in the colon: Paromomycin 500mg three times a day for 10 days Diloxanide furoate 500mg three times a day for 10 days Iodoquinol 650mg three times a day for 20 days For amebic liver abscess: Metronidazole 400mg three times a day for 10 days Tinidazole 2g once a day for 6 days is an alternative to metronidazole Diloxanide furoate 500mg three times a day for 10 days must always be given afterwards.

References

↑ Konvolinka CW (1994). “Acute diverticulitis under age forty”. Am J Surg. 167 (6): 562–5. PMID 8209928.
↑ Silverberg MS, Satsangi J, Ahmad T, Arnott ID, Bernstein CN, Brant SR; et al. (2005). “Toward an integrated clinical, molecular and serological classification of inflammatory bowel disease: report of a Working Party of the 2005 Montreal World Congress of Gastroenterology”. Can J Gastroenterol. 19 Suppl A: 5A–36A. PMID 16151544.
↑ Satsangi J, Silverberg MS, Vermeire S, Colombel JF (2006). “The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications”. Gut. 55 (6): 749–53. doi:10.1136/gut.2005.082909. PMC 1856208. PMID 16698746.
↑ ^4.0 ^4.1 Haque R, Huston CD, Hughes M, Houpt E, Petri WA (2003). “Amebiasis”. N Engl J Med. 348 (16): 1565–73. doi:10.1056/NEJMra022710. PMID 12700377.

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[pmid8209928-1] Konvolinka CW (1994). “Acute diverticulitis under age forty”. Am J Surg. 167 (6): 562–5. PMID 8209928.

[pmid16151544-2] Silverberg MS, Satsangi J, Ahmad T, Arnott ID, Bernstein CN, Brant SR; et al. (2005). “Toward an integrated clinical, molecular and serological classification of inflammatory bowel disease: report of a Working Party of the 2005 Montreal World Congress of Gastroenterology”. Can J Gastroenterol. 19 Suppl A: 5A–36A. PMID 16151544.

[pmid16698746-3] Satsangi J, Silverberg MS, Vermeire S, Colombel JF (2006). “The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications”. Gut. 55 (6): 749–53. doi:10.1136/gut.2005.082909. PMC 1856208. PMID 16698746.

[pmid12700377-4] 4.0 ^4.1 Haque R, Huston CD, Hughes M, Houpt E, Petri WA (2003). “Amebiasis”. N Engl J Med. 348 (16): 1565–73. doi:10.1056/NEJMra022710. PMID 12700377.

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