BK virus infection
BK virus infection is caused by the BK virus, a member of the Polyomavirus family, and commonly occurs in childhood, often presenting with mild respiratory symptoms. Once acquired, the virus can remain dormant in the body, potentially leading to urinary tract and kidney complications later in life, particularly in individuals with weakened immune systems. Transmission is thought to occur through person-to-person contact, possibly via saliva, air, or bodily fluids, rather than from animals. Risk factors for reactivation of the virus include older age, male gender, and injuries to the kidneys, with approximately 80% of the population carrying a latent form of the virus without experiencing symptoms.
In immunocompromised individuals, such as organ transplant patients, the infection can lead to severe health issues, including interstitial nephritis and hemorrhagic cystitis. Diagnosis typically involves blood and urine tests, while treatment options vary based on the severity of the infection. Mild cases may resolve without intervention, whereas more severe cases may require adjustments in immunosuppression therapy and additional supportive treatments. Preventative measures, including screening high-risk individuals, are crucial for early detection and management of BK virus infection.
BK virus infection
- ANATOMY OR SYSTEM AFFECTED: Kidneys, lungs, respiratory system, urinary system
Definition: an infection is caused by the BK virus
BK virus infection is caused by the BK virus, a member of the Polyomavirus family. Initial infection with the BK virus is common in childhood and may produce mild respiratory symptoms. However, the virus can remain latent, causing urinary tract and kidney complications for certain populations later in life. The BK virus was first isolated in 1971 from a kidney transplant patient with the initials “B. K.”
Causes
It is not known exactly how the BK virus is transmitted. It is known, however, that the virus is spread from person to personnot from an animal sourcepossibly through saliva, air, cough, blood, needles, blood transfusions, sexual contact, pregnancy, or organ transplant.
Risk Factors
Older people are generally at higher risk of having BK infection. Males are also at higher risk. Injuries to the kidney may also cause the BK virus to become active.
Most people have unknowingly been infected with the BK virus at some point in their lives. It is likely they had the infection but had symptoms that were similar to a cold or upper respiratory infection. The virus typically remains in a latent form and does not cause disease. It is thought that nearly 80 percent of the population contains a latent form of the BK virus. However, the virus can be reactivated if the immune system is compromised or weakened. A long-term illness, such as diabetes or acquired immunodeficiency syndrome, may weaken the immune system. Anti-rejection medications taken by organ transplant patients may also weaken the immune system.
Symptoms
If symptoms do appear, they are generally mild in the form of a respiratory infection or fever. However, in immunocompromised persons, symptoms can be severe and include a variety of issues. Some of these issues include interstitial nephritis and narrowed ureters following kidney transplant, hemorrhagic cystitis following bone marrow transplant, increased risk of bladder cancer,encephalitis, retinitis, and pneumonitis. Signs of BK virus infection also include stomach problems, blurry vision, brown or reddish-colored urine, burning pain or trouble when passing urine, or passing more urine than usual, cough, colds, or trouble breathing, muscle pain or weakness, and seizures.
Screening and Diagnosis
Diagnosis is made by blood and urine testing or biopsy. Polymerase chain reaction techniques are often used to identify the virus.
Treatment and Therapy
A mild BK infection may go away without treatment. In the severe cases seen in immunocompromised persons, decreasing immunosuppression therapy is the principal treatment. Leflunomide is sometimes used because it has both immunosuppressive and antiviral properties. Intravenous immunoglobulin is also used. Additional treatments, such as pain medication, bladder irrigation, or hyperhydration, may be necessary. Virus-specific T cell therapy is an emerging treament that shows promise.
Prevention and Outcomes
Screening persons at high risk for BK virus infection, such as kidney transplant recipients, allows for early detection and prevention of symptomatic BK infection.
Bibliography
"BK Virus: What Transplant Patients Need to Know.” National Kidney Foundation, www.kidney.org/kidney-topics/bk-virus-what-transplant-patients-need-to-know. Accessed 12 Nov. 2024.
Blanckaert, K., and A. S. De Vriese. “Current Recommendations for Diagnosis and Management of Polyoma BK Virus Nephropathy in Renal Transplant Recipients.” Nephrology Dialysis Transplant, vol. 21, 2006, pp. 3364-67.
Egli, A., et al. “Prevalence of Polyomavirus BK and JC Infection and Replication in Four Hundred Healthy Blood Donors.” Journal of Infectious Diseases, vol. 199, 2009, pp. 837-46.
Gorriceta, June H., et al. "BK Viral Infection: A Review of Management and Treatment." World Journal of Transplantation, vol. 13, no. 6, 2023, p. 309, doi:10.5500/wjt.v13.i6.309. Accessed 12 Nov. 2024.
Grady, D. Deadly Invaders: Virus Outbreaks Around the World, from Marburg Fever to Avian Flu. Kingfisher, 2006.
Lamarche, Caroline, et al. "BK Polyomavirus and the Transplanted Kidney: Immunopathology and Therapeutic Approaches." Transplantation, vol. 100, no. 11, 2016, p. 2276, doi:10.1097/TP.0000000000001333. Accessed 12 Nov. 2024.