eMedicine Specialties > Infectious Diseases > Parasitic Infections
Isosporiasis: Differential Diagnoses & Workup
Updated: Oct 24, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Workup
Laboratory Studies
- The diagnosis of isosporiasis is based on a combination of clinical, epidemiological, and diagnostic tests.
- Routine laboratory tests are not diagnostic, but peripheral eosinophilia is an important clue.
- Stool specimen features include the following:
- Large oocysts of I belli are observed on modified acid-fast stains of stool specimens (see Image 1).
- Multiple specimens or specimen concentration increases diagnostic yield.
- Charcot-Leyden crystals are observed in stool specimens.
- Polymorphonuclear leukocytes (PMNs) are not observed in fecal specimens.
- Serologic tests for isosporiasis are not available.
Imaging Studies
- Nonspecific radiographic findings (eg, prominent mucosal folds, thickening of intestinal wall) may be observed.
- If performed as a part of workup for malabsorption, I belli may be observed with electron microscopy of tissue specimens.
Other Tests
- Auramine-rhodamine fluorescent stain
- Modified Kinyoun acid-fast stain
- Ultraviolet autofluorescence microscopy - A simple rapid test to identify I belli
- Zinc sulfate or sugar flotation - The most sensitive stool concentration technique
- Real-time polymerase chain reaction (PCR) test (promising in recent studies)4
Procedures
- Examination of duodenal aspirate or string test may aid in the diagnosis of isosporiasis.
- A small-bowel biopsy is not a routine test for diagnosis of isosporiasis.
Histologic Findings
Nonspecific findings of isosporiasis observed in small-bowel biopsy specimens include mucosal atrophy, shortened villi, hypertrophic crypts, and lamina propria infiltrated with eosinophils. I belli may be observed in the cytoplasm of enterocytes with electron microscopy.
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Differential Diagnoses & Workup: Isosporiasis |
| Treatment & Medication: Isosporiasis |
| Follow-up: Isosporiasis |
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Further Reading
Keywords
isosporiasis, Isospora belli, I belli, Isospora belli infection, I belli infection, extraintestinal isosporiasis, disseminated isosporiasis, intestinal parasitic infections, Isospora belli enteritis, I belli enteritis, Cryptosporidium, Cyclospora, Toxoplasma
Differential Diagnoses & Workup: Isosporiasis