BK virus: Difference between revisions

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==Diagnosis==
==Diagnosis==
* Nephropathy: screening with urine or blood PCR followed by biopsy if concurrent renal dysfunction to confirm the 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
* Hemorrhagic cystitis: urine PCR is relatively non-specific, although a high viral load may be supportive
* Urine cytology may show decoy cells, though they are also seen in CMV and adenovirus
* Urine cytology may show decoy cells, though they are also seen in CMV and adenovirus



Revision as of 23:57, 23 May 2020

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

  • Nephropathy: screening with urine or blood PCR followed by biopsy if concurrent renal dysfunction to confirm the diagnosis
  • Hemorrhagic cystitis: urine PCR is relatively non-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