West Nile & Dialysis, a Medical Mystery
Aug 20, 2004 -- This modern medical mystery story
occurred last year in Georgia. Three patients who all received dialysis on the
same machine -- one after another -- were infected with the West Nile virus. Did they become
infected at the dialysis center or somewhere else? Two lived in the same
neighborhood and the third lived about a mile away. While there definitely was a
high potential for mosquito exposure where they lived, no West Nile-positive
mosquitoes were found.
Comments
This cluster of dialysis patients with West Nile
infections suggests possible transmission of the virus in the dialysis center. West Nile virus transmission
through blood transfusion, organ transplantation, in utero and possibly through
breast milk has been described. But in this situation where the dialysis center
was a common denominator, the epidemiologic investigation looked at possible
cross-contamination of supplies, equipment, medications and procedures. No
source or explanation for the three cases of West Nile Virus has been found. It
remains on the books as a modern medical mystery.
Barbara K. Hecht,
Ph.D.
Frederick Hecht, M.D.
Medical Editors, MedicineNet.com
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Possible Dialysis-Related West Nile Virus Transmission --- Georgia, 2003
In October 2003, the Georgia Division of Public Health
(DPH) was notified of two patients from the same county with confirmed West Nile
virus (WNV) disease
who had received hemodialysis on the same day and on the same dialysis machine.
The two dialysis patients (patients A and C) had the only confirmed cases of
human WNV disease reported in their county in 2003. Review of the dialysis
center's records indicated that another patient (patient B) had received
dialysis on the same machine between these two patients on the same day. This
report summarizes results of the epidemiologic investigation, which suggested
that WNV might have been transmitted at the dialysis center. Hemodialysis
centers should adhere strictly to established infection-control procedures to
avoid WNV transmission through dialysis.
Patient A. The first patient, who received dialysis on the machine
(machine A) in late August, was a man aged 77 years with a history of
hypertension and end-stage renal disease (ESRD). Eight days after dialysis,
patient A was hospitalized with a 48-hour history of fever, chills, confusion,
and anorexia. Blood cultures were negative. Serologic testing of serum revealed
IgM and IgG antibodies to WNV by enzyme-linked immunosorbent assay
(ELISA) and a
higher neutralizing antibody titer to WNV (1:1,280) than to St.
Louis encephalitis virus (SLEV) (1:320). Patient A had not received a blood
transfusion <30 days before symptom onset. After a 9-day hospitalization, he
was afebrile at discharge.
Patient B. The second
patient, who received dialysis on machine A between patients A and C, was a
woman aged 71 years with a history of type 2 diabetes, ESRD, and hypertension.
Dialysis center and hospital records and
patient interview revealed no symptoms of illness during late August or early
September, and patient B had not received a blood transfusion in July, August,
or September. In addition, she had never received a flavivirus vaccination
(which might elicit cross-reactive antibody to serologic tests for WNV) or
traveled outside the United States. A serum sample obtained 42 days after
dialysis was uninterpretable for IgM antibody to WNV (i.e., because of high
background reactivity), negative for IgM to SLEV, and positive for IgG to both
WNV and SLEV by ELISA; the neutralizing antibody titers were 1:160 to WNV and
1:10 to SLEV. A second specimen taken from this patient 84 days after dialysis
was negative for IgM antibody to WNV and SLEV by ELISA, positive for IgG to both
WNV and SLEV by ELISA, and had neutralizing antibody titers of 1:320 to WNV and
1:20 to SLEV.
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.
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