AssessmentsBK virus (Hemorrhagic cystitis)
BK virus (Hemorrhagic cystitis)
BK virus, or BKV, is a mosquito borne virus that’s named after the initials of the patient in whom the virus was first identified.
BK virus typically infects the urinary system of immunocompromised individuals, or those with a weakened immune system, especially those receiving immunosuppressive medications following organ transplants.
Major clinical manifestations of BKV infection include hemorrhagic cystitis, which is inflammation of the urinary bladder associated with bloody urine, in bone marrow transplant recipients; ureteral stenosis, or narrowing, and nephropathy in kidney transplant recipients.
BK virus belongs to the polyomavirus family along with the JC virus. These contain a circular double-stranded DNA genome which is surrounded by an icosahedral capsid, which is a spherical protein shell made up of 20 equilateral triangular faces.
They are also called non-enveloped viruses since the capsid isn’t covered by a lipid membrane.
It turns out that the vast majority of the population is infected with BK virus during their childhood.
The virus is thought to be transmitted from person to person through respiratory droplets when someone coughs or sneezes and by ingesting contaminated food and water.
Once inside, the virus moves through the bloodstream and eventually reaches the kidneys, specifically the renal tubular epithelial cells, where it starts to replicate.
However, the sneaky little viruses are not eliminated, but instead they hit the snooze button, and go into a latent phase within the kidney epithelial cells.
In other words, they’re not dividing or causing disease.
But things can change if the immune system gets weaker.
BK virus infection is especially common in kidney and bone marrow transplant recipients.
In immunocompromised individuals, T-cells are affected, and without them, the BK virus in the epithelial cells starts multiplying one again, which results in tubular cell death by lysis, or the breakdown of the cell membrane, releasing the virus into the interstitial tissue.
This makes blood vessels in the infected area dilate and become more permeable, allowing more leukocytes and fluid to enter local tissue.
The end result are the four cardinal signs of inflammation: heat, pain, redness, and swelling.
The BK virus is a double-stranded DNA virus that infects the kidney epithelial cells, causing life-threatening hemorrhagic cystitis in immunocompromised people, especially in bone marrow transplant recipients. It can also cause nephropathy and ureteral stenosis in kidney transplant recipients. Symptoms include suprapubic pain, hematuria, symptoms of chronic kidney disease such as edema; fatigue, and breathlessness due to anemia.