De-cryptifying Cryptosporidium

The good Dr. Grovenburg presented a case of a young woman who presented with five days of acute watery diarrhea, generalized abdominal pain and high fevers. Her labs were notable for leukocytosis, acute kidney injury, and negative HIV. Her GI pathogen panel was negative, but stool PCR was positive for cryptosporidium.

A Refresher on Cryptosporidium-

* Most common parasitic cause of secretory diarrhea in humans (along with Giardia). 
* Affects both immunocompetent hosts (self-limited diarrhea) & immunocompromised hosts (chronic, life-threatening illness).  
* Fecal-oral transmission, often via contaminated water. Oocysts are resistant to chlorine treatment. 
* Diagnosis is made by microscopic identification of oocysts, PCR testing, or enzyme immunoassay of stool samples. 
* Treatment: Supportive care PLUS
        o    Immunocompetent host: Nitozoxanide if sx>14d
        o    Immunocompromised host: 
            -    HIV: Nitozoxanide + HAART
            -    Chronic immunosuppression: Nitozoxanide + dose reduced immunosuppressants

Antibiotics for acute diarrhea?

* If severe features: >6 BMs/daily; T > 38.5; hypovolemia; immunocompromised host:  benefits likely outweigh theoretical risk
* If bloody diarrhea in stable patient:  defer ABX pending stool C&S
* If non-bloody diarrhea without severe features: supportive care only