West Nile & Dialysis, a Medical Mystery (cont.)

Patient C. The third and last patient to receive dialysis on machine A on the same day in late August was a man aged 60 years with a history of type 2 diabetes, hypertension, alcoholism, recent onset of ESRD, and prostate cancer. Nineteen days after his dialysis procedure, patient C was admitted to a local hospital with fever, chills, altered mental status, and cachexia. After admission, he had seizures and was intubated and placed on a ventilator. Analysis of cerebrospinal fluid (CSF) indicated a mild pleocytosis (67 white blood cells [62% polynuclear cells, 38% mononuclear cells] and five red blood cells/mm3) and an elevated protein level (122 mg/dL). Computerized tomography scans of the patient's brain on the second and tenth days of hospitalization revealed bilateral lacunar infarcts, white matter changes, and cortical and subcortical atrophy. Serologic tests of serum were positive for IgM and IgG antibodies to WNV by ELISA. The neutralizing antibody titer was higher to WNV (1:1,280) than to SLEV (1:20). Patient C had not received a blood transfusion <30 days before symptom onset. Twenty days after admission, he had a high fever and respiratory failure and died.

DPH and the local health department investigated practices and procedures at the dialysis center. No breakdowns in disinfection procedures for the dialysis machine or dialyzers and no breaches in infection-control practices were revealed. All bloodline attachments to the dialysis machine were disposable and discarded after each dialysis session. Patient blood samples were withdrawn from the bloodline for testing on a monthly basis, unless otherwise directed by the physician. Medications were bottled in multiple-dose units but were drawn by using a needle in a separate medication room and injected into the patients' bloodlines with a syringe. Both the needle and syringe were then discarded. No single medication was administered to all three patients on the day of their dialyses. However, patients A and B had received a common medication, and patients A and C also had received a common medication, although most likely from separate vials. Blood samples from three other patients who had received dialysis on machine A on the previous day and on the following day were all negative for IgM and IgG antibodies to WNV.

Patients A and C resided in the same neighborhood, 0.2 miles apart, and patient B resided approximately 1 mile away from this neighborhood. An environmental assessment around the homes of patients A and C and in the neighborhood where they resided revealed a high potential for mosquito exposure, including lack of window screens, barrels of stagnant water, and wooded areas between homes. Mosquito surveillance of the area in mid-October indicated that Culex quinquefasciatus mosquitoes were the most abundant mosquito species; however, no WNV-positive mosquitoes were identified, as would be expected from mosquito collections obtained so late in the transmission season. Pesticide spraying to kill adult mosquitoes in the neighborhood was conducted two days after surveillance. Three neighbors of patients A and C submitted blood samples for testing for WNV; all samples were negative for IgM and IgG antibodies to WNV.

Reported by: CE Smith, MD, JM Jenkins, D Staib, PJ Newell, MD, KJ Mertz, MD, S Lance-Parker, DVM, RM Kelly, PhD, KA Bryant, MPH, Georgia Div of Public Health; EB Hayes, MD, GL Campbell, MD, Div of Vector-Borne Infectious Diseases, National Center for Infectious Diseases; A Srinivasan, MD, D Jernigan, MD, M Arduino, MD, Div of Healthcare Quality Promotion; K Abe, PhD, EIS Officer, CDC.

Source: Morbidity and Mortality Weekly Report, published by the CDC, August 20, 2004 / Vol. 53 / No. 32.

Last Editorial Review: 8/20/2004