cryptosporidiosis is a parasitic disease that causes diarrhea lasting for about 1 - 2 weeks among the immunocompetent and becoming a more severe life - threatening illness among immunocompromised individuals . it constitutes 24% of human immunodeficiency virus ( hiv ) positive patients with diarrhea compared with 6.1% in the immunocompetent individuals . association of cryptosporidiosis with malignancies is not as robust as acquired immunodeficiency syndrome ( aids ) . here , we report a case of cryptosporidiosis causing severe persistent diarrhea in a patient with multiple myeloma . the case we present here is the patient was a 64-year - old female who had been diagnosed to have multiple myeloma , stage iii b , type igg kappa 17 years ago in 1993 . she was being treated with oral lenalidomide ( 25 mg for 21 days ) and dexamethasone ( 40 mg on days 1 , 8 and 15 ) of 28 days cycle for the current progression of myeloma . the baseline serum m band prior to the start of this regimen was 3.4 g / dl . she presented on day 17 of the 2 cycle with the complaints of profuse watery diarrhea , 10 - 12 times / day for the previous 15 days . the diarrheal product was non - bloody , without any mucus and not foul smelling . this was associated with nausea , mild crampy abdominal pain and a sense of fecal urgency without any fever . there was anemia ( hemoglobin of 9.7 g / dl ) and leucopenia ( white blood cells count 2800/mm ) but the absolute neutrophil count ( 1700/mm ) and platelets were normal . the liver and renal function tests were within normal limits but serum potassium was low ( 2.2 meq / l ) . the routine blood culture was sterile and the polymerase chain reaction test in peripheral blood for cytomegalovirus deoxyribonucleic acid was negative . stool examination showed 2 - 3 polymorphonuclear leucocytes per high power field with mucus but no visible or occult blood . colonoscopy was performed , which suggested colonic mucosal inflammation likely to be infective in origin [ figure 1 ] . at this point , a diagnosis of cryptosporidial infection was suspected and the stool was submitted for examination with the modified kinyoun acid - fast stain . the patient was then started on oral nitazoxanide 500 mg 12 hourly for 10 days . the diarrheal frequency decreased after 5 days and it resolved completely by the 10 day of this drug . the patient was able to resume treatment with lenalidomide and dexamethasone later without any complications . colonic mucosal inflammation on colonoscopy of the patient oocysts of cryptosporidium parvum in modified kinyoun acid - fast stain cryptosporidiosis is a protozoal intestinal infection caused by many species of the genus cryptosporidium that are either obligate human or human and bovine parasites . the first association with human diarrheal disease was reported in 1976 , one case in an otherwise healthy child and one in an immunosuppressed adult . the infection is acquired by ingesting parasites in water or food contaminated by human or animal feces or by having contact with soil , a person , or an item that has been contaminated with the parasite . the diagnosis is established by demonstration of oocysts in the stool by the modified acid - fast kinyoun stain . since the initial reports four clinical syndromes of cryptosporidial infection have been described in hiv positive patients : chronic diarrhea ( affecting 36% of patients ) , cholera - like disease ( 33% ) , transient diarrhea ( 15% ) and relapsing illness ( 15% ) . the severity of illness is related to the cd4 count in these patients . in immunocompetent patients , usually children < 5 years of age the clinical presentation in our patient with severe diarrhea of 2 weeks duration that resulted in dehydration and dyselectrolytemia was more consistent with an underlying immunodeficiency which is expected in a patient with long standing multiply treated myeloma . although uncommon , cryptosporidial diarrhea has been described in patients with malignancy . in one study , the incidence of cryptosporidiosis was 1.3% in the 560 cancer patients presenting with symptoms of diarrhea out of which 71% had hematolymphoid malignancy . in other studies it was found that the risk of severe disease is largely limited to children with acute leukemia and lymphoma . interestingly , bone marrow transplantation does not seem to confer any additional risk over that of the underlying disease . cryptosporidial diarrhea should be included in the differential diagnosis of any patient with persistent severe diarrhea , especially in patients with hematological malignancies . diagnosis can be established by stool examination and administration of nitazoxanide is effective in controlling the infection .
cryptosporidiosis is a protozoal infection that leads to self - limited diarrheal disease in immunocompetent individuals and a more severe illness in immunocompromised patients especially those infected with the human immunodeficiency virus . 
 although patients with hematolymphoid malignancies can develop this infection , it is an uncommon cause of diarrhea in these patients . 
 the patient was a 64-year - old woman , a known case of multiple myeloma for 17 years , who had been treated with multiple lines of chemotherapy earlier . 
 she was being treated with lenalidomide plus dexamethasone for active myeloma at the time of this episode . 
 she presented with profuse watery diarrhea of 15 days duration that was proven to be due to cryptosporidium parvum on stool examination . the diarrheal illness resolved after treatment with nitazoxanide . 
 although uncommon , cryptosporidial infection should be suspected in patients with hematological malignancies who have persistent diarrhea . 
 stool examination with the modified acid - fast kenyoun stain establishes the diagnosis in the majority of cases . 
 antiparasitic treatment is effective in controlling the infection .