Polyomavirus-associated nephropathy

Polyomavirus-associated nephropathy (PVAN) is a viral complication that affects renal transplant recipients.

• Prevalence: PVAN occurs in 1-10% of renal transplant patients, with a significant impact on graft survival rates [1][2].
• Graft loss: The disease can lead to loss of the transplanted organ in up to 80% of cases [3][8].
• Etiology: The main cause of PVAN is attributed to polyomavirus infection, which establishes a lifelong presence in the renal tubular cells [4].

Symptoms and diagnosis

• Interstitial inflammation: The presence of interstitial inflammation, tubular atrophy, and interstitial fibrosis are key diagnostic features of PVAN [5].
• Histologic findings: Histological examination of kidney tissue is essential for differentiating viral nephropathy from acute rejection [7].

References:

[1] C Costa · 2012 - Polyomavirus-associated nephropathy (PVAN) is one of the most common viral complications in renal transplant recipients and is an increasingly recognized cause of graft loss.

[2] HH Hirsch · 2013 - Polyomavirus-associated nephropathy (PVAN) is an emerging disease in renal transplant patients with variable prevalence of 1-10% and graft loss up to 80%.

[3] AP Limaye - BK polyomavirus (BKPyV) is a small double-stranded DNA virus that establishes lifelong infection in the renal tubular and...

[4] DRJ Kuypers · 2012 - Polyomavirus-associated nephropathy (PVAN) remains an important infectious complication after renal transplantation, affecting 1–10% of recipients and causing...

[5] XT Chen · 2020 - The diagnosis of polyomavirus-associated nephropathy (PyVAN) was established by the presence of interstitial inflammation, tubular atrophy, interstitial...

[6] CL Shen · 2021 - BK polyomavirus nephropathy (BKVN) and allograft rejection are two closely-associated diseases on opposite ends of the immune scale in kidney transplant...

[7] CC Nast - This article reviews the diagnosis, histologic findings, and classifications of PVN, and discusses how to differentiate viral nephropathy from acute rejection.

[8] C Costa · 2012 - PVAN may occur in 1%-10% of renal transplant patients with loss of the transplanted organ in 30% up to 80% of the cases. Etiology of PVAN is mainly attributable...

[9] D Yang · 2022 - BK polyomavirus–associated nephropathy (BKPyVAN) is one of the main complications after kidney transplant, with 2-year graft survival rates of...

Polyomavirus-associated nephropathy (PVAN) can manifest in various ways, affecting kidney transplant patients.

Some common signs and symptoms of PVAN include:

• Changes in the color of urine, which may appear brown or red due to the presence of blood [1].
• Pain when urinating, also known as dysuria [1].
• Difficulty urinating, which can be a sign of urinary tract obstruction [1].
• Needing to urinate more than usual, indicating an increase in urine production [1].

In addition to these symptoms, PVAN can also cause systemic signs of infection, although this is relatively rare. These may include:

• Fever
• Muscle pain or weakness
• Seizures

It's essential to note that some patients with PVAN may be asymptomatic, and the virus may only be detected through urine cytology smears [8]. In such cases, the presence of viral inclusion-bearing cells (decoy cells) in the urine can indicate elevated polyomavirus replication.

Early detection and diagnosis are crucial for managing PVAN.

References:

[1] Changes in the colour of urine (urine that is brown or red in colour) · Pain when urinating · Difficulty urinating · Needing to urinate more than usual. [8] The appearance of viral inclusion bearing cells, so‐called 'decoy cells', in urine cytology

Diagnostic Tests for Polyomavirus-associated Nephropathy

Polyomavirus-associated nephropathy (PVAN) is a serious complication in kidney transplant recipients, caused by the BK polyomavirus (BKPyV). Accurate diagnosis is crucial to prevent further damage to the transplanted kidney. Several diagnostic tests are used to detect PVAN:

• Kidney Allograft Biopsy: Considered the gold-standard diagnostic test for PVAN, showing distinct intra-nuclear viral inclusions and SV40 large T antigen staining [5].
• Quantitative Polymerase Chain Reaction (PCR): Used to detect BKPyV DNA in urine and plasma, with high sensitivity and specificity [3].
• Urine Cytology: A commonly used screening test for PVAN, which can show viral inclusions in the urine [8][9].
• High-Frequency Ultrasound (US): Valuable for diagnosing PVAN and distinguishing it from rejection in kidney transplant recipients [6].

Additional Diagnostic Methods

Other diagnostic methods include:

• Plasma Quantitative PCR: Used to detect BKPyV DNA in plasma, which can be a useful screening tool [4].
• Urine Quantitative PCR: Similar to plasma quantitative PCR, used to detect BKPyV DNA in urine.
• Histologic Findings: Several histologic changes are associated

Treatment Options for Polyomavirus-associated Nephropathy

Polyomavirus-associated nephropathy (PVAN) is a serious complication that can occur in kidney transplant recipients, caused by the reactivation of polyomavirus. While there are no specific antiviral treatments available, several drug therapies have been explored to manage PVAN.

Reduction of Immunosuppression

The mainstay

Polyomavirus-associated nephropathy (PVAN) can be challenging to diagnose, and it requires a differential diagnosis approach to rule out other conditions that may present with similar symptoms.

Key differences from acute rejection:

• PVAN is often associated with interstitial inflammation, tubular atrophy, and interstitial fibrosis [5].
• Histological findings in PVAN include the presence of polyomavirus-infected cells, which can be identified by electron microscopy (EM) or immunohistochemical staining [9].

Distinguishing features from other conditions:

• PVAN is distinct from acute rejection due to its association with interstitial inflammation and tubular atrophy [5].
• The presence of polyomavirus-infected cells in the kidney tissue is a hallmark of PVAN, which can be confirmed by EM or immunohistochemical staining [9].
• In contrast to other conditions such as BKPyV-associated nephropathy (BKPyVAN), PVAN is often associated with a more severe clinical course and higher risk of graft loss [3].

Clinical presentation:

• Patients with PVAN may present with symptoms such as changes in urine color, pain when urinating, difficulty urinating, and increased frequency of urination [7].
• These symptoms can be similar to those seen in other conditions such as BKPyVAN or acute rejection.

Diagnostic methods:

• The primary method for detecting BKPyV infection is quantitative polymerase chain reaction (PCR) to detect BKPyV DNA in urine and plasma [8].
• Biopsy of the affected organ and demonstration of the presence of polyomavirus in the tissue via EM or by immunohistochemical staining are also essential for diagnosis [9].

References:

[1] Costa, C. (2012). PVAN may consist in interstitial nephritis and/or ureteric stenosis with ureteric obstruction, hydronephrosis, and sometimes associated urinary tract infections... [1]

[3] Hirsch, H. H. (2013). Polyomavirus-associated nephropathy (PVAN) is an emerging disease in renal transplant patients with variable prevalence of 1-10% and graft loss up to 80%. [3]

[5] Chen, X. T. (2020). The diagnosis of polyomavirus-associated nephropathy (PyVAN) was established by the presence of interstitial inflammation, tubular atrophy, interstitial... [5]

[7] Yang, D. (2022). High-frequency US characteristics are valuable for diagnosing BK polyomavirus–associated nephropathy (BKPyVAN) and distinguishing BKPyVAN from rejection in... [7]

[8] Wen, J. (2022). The primary method for detecting BKPyV infection is quantitative polymerase chain reaction (PCR) to detect BKPyV DNA in urine and plasma. [8]

[9] Snydman, D. R. (2002). Diagnosis usually requires biopsy of the affected organ and demonstration of the presence of polyomavirus in the tissue via EM or by immunohistochemical... [9]

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