BK virus
From IDWiki
Background
Microbiology
- Double-stranded DNA virus in the Polyomaviridae family
Epidemiology
- Very high seroprevalence with asymptomatic infection ocurring in childhood
- Disease is seen in immunosuppressed patients, especially renal transplant recipients
- BKV nephropathy is seen in 1 to 10% of renal transplant recipients
- BKV ureteric stenosis is seen in about 3% of renal transplant recipients
- Hemorrhagic cystitis is seen in 10 to 25% of hematopoietic stem cell transplantation recipients
Clinical Presentation
Nephropathy
- Typically a cause of nephropathy in renal transplant patients
- Onset is 10 to 13 months post-transplant, with a wide range of 6 days to 5 years
- Presents with slowly increasing creatinine levels
- Occasional hematuria and fever
Ureteral stenosis
- Causes urinary obstruction and AKI in the donor kidney, usually without pain since it is not innervated
Hemorrhagic cystitis
- Complicates 10 to 25% of hematopoietic stem cell transplantations, most commonly in the context of GVHD
- Symptoms include hematuria, dysuria, urinary urgency and frequency, and suprapubic pain
- Clotting hematuria can cause urinary obstruction and renal failure
Other syndromes
- Very rarely causes encephalitis and pneumonitis
Diagnosis
- Positive urine PCR with renal failure in a renal transplant patient is diagnostic for nephropathy, especially with sustained viruria
- In hemorrhagic cystitis, urine PCR is less specific, although a high viral load may be supportive
- Urine cytology may show decoy cells, though they are also seen in CMV and adenovirus
Management
- There is no directed therapy
- Nephropathy is typically managed by decreasing immunosuppression, monitoring viremia for response
- Ureteral stenosis is similarly managed, but may require surgical intervention
- Hemorrhagic cystitis is managed supportively, with continuous bladder irrigation, analgesia, hydration, and transfusion of platelets or erythrocytes as needed
- Target for platelets is >50k
Prevention
- In renal transplant patients, monitor for viremia monthly after transplant, decreasing immunosuppression if positive
