Cryptosporidium

Background

Cryptosporidium is an protozoa that can cause diarrhea. Cryptosporidium is mostly commonly seen in HIV positive patients and is the most common cause of chronic diarrhea in HIV patients. Cryptosporidium oocysts are 4-6 µm in diameter and exhibit partial acid-fast staining.

Environmental exposures include: People who swim regularly in pools with insufficient sanitation, hikers who drink untreated water, people who handle infected cattle.

Clinical Presentation

Symptoms usually appear one week after infection which include:

• watery diarrhea
• dehydration
• stomach cramps/pain
• weight loss
• fever
• nausea/vomiting

Differential Diagnosis

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
  • Giardia lamblia
  • Cryptosporidium
  • Entamoeba histolytica
  • Cyclospora
  • Microsporidium
• Toxin
  • Staphylococcus aureus
  • Bacillus cereus

Noninfectious

• GI Bleed
• Appendicitis
• Mesenteric Ischemia
• Diverticulitis
• Adrenal Crisis
• Thyroid Storm
• Toxicologic exposures
• Antibiotic or drug-associated

Watery Diarrhea

• Enterotoxigenic E. coli (most common cause of watery diarrhea)
• 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

Diagnosis

• Stool acid-staining test
• Stool Culture

Management

• If patient non-sick appearing and not immunocompromised, medication often not needed
• Antiparasitics such as nitazoxanide for immunocompromised patients