Cryptosporidiosis

Key Features

Essentials of Diagnosis

IN IMMUNOCOMPETENT PATIENTS

• Watery diarrhea

• Abdominal pain and cramps

• Nausea and vomiting

• Fever

• Mild illnesses and asymptomatic infection may also be common

IN IMMUNOCOMPROMISED PATIENTS

• Chronic diarrhea with frequent foul smelling stools

• Malabsorption, weight loss

• Severe, life-threatening watery diarrhea may be seen

• Extraintestinal disease

General Considerations

• Causes of coccidiosis

  • Cryptosporidium spp (eg, C parvum and C hominis)

  • Isospora belli

  • Cyclospora cayetanensis

  • Sarcocystis species

• Oocysts (coccidiosis) or spores (microsporidiosis) are transmitted

  • From person to person

  • By contaminated drinking or swimming water or food

• Ingested oocysts release sporozoites that invade and multiply in enterocytes, primarily in the small bowel

• Coccidian oocysts and microsporidian cysts can remain viable in the environment for years

• Coccidia and microsporidians are generally missed on routine evaluations of stool for ova and parasites because special staining techniques are required for identification

• Leading cause of recreational water-associated outbreaks of gastroenteritis

Demographics

• These infections occur worldwide, particularly in the tropics and in regions where hygiene is poor

• In developing countries, infection seen primarily in children younger than 5 years

• In developed countries, most patients are adults

• Clustering occurs in households, day care centers, and among sexual partners

• Outbreaks are of particular concern, as exemplified by the 1993 epidemic in Milwaukee in which 400,000 persons became ill

Clinical Findings

Symptoms and Signs

IN IMMUNOCOMPETENT PATIENTS

• Incubation period appears to be 1–14 days

• Symptoms resolve rapidly, but can persist for 2 weeks or more

• Diarrhea is usually watery, with accompanying abdominal pain and cramps, nausea, vomiting, and fever

• Relapses may follow initial resolution of symptoms

• Mild illnesses and asymptomatic infection are also common

IN IMMUNODEFICIENT PATIENTS

• Chronic diarrhea with frequent foul smelling stools

• Malabsorption

• Weight loss

• Severe, life-threatening watery diarrhea may be seen

• Also causes extraintestinal disease, including

  • Pulmonary infiltrates with dyspnea

  • Biliary tract infection with sclerosing cholangitis and AIDS cholangiopathy

Differential Diagnosis

• Infection with I belli, C cayetanensis, and S bovihominis

• Giardiasis

• Viral gastroenteritis, eg, rotavirus

• Other traveler's diarrhea, eg, Escherichia coli

• Cholera

• Other cause of diarrhea in AIDS, eg, cytomegalovirus colitis

Diagnosis

• Typically, stool is without blood or leukocytes

• Diagnosis is made by detecting the organism in stool using a modified acid-fast stain

  • This technique is relatively insensitive

  • Multiple specimens should be evaluated before ruling out the diagnosis

• Routine evaluation for ova and parasites typically does not include a modified acid-fast stain, so this must be specifically requested in many laboratories

  ...