HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) is a progressive kidney disease characterized by damage to the filters in the kidneys that are responsible for removing waste from the blood. It is one of the most severe complications of HIV infection, primarily affecting individuals with advanced HIV disease. The condition is marked by proteinuria, which is the presence of excessive protein in the urine, and by a rapid decline in kidney function, leading to chronic kidney disease (CKD) and potentially end-stage renal disease (ESRD). HIVAN is considered a form of focal segmental glomerulosclerosis (FSGS), specifically associated with HIV infection.

Etiology and Pathogenesis

The exact mechanism by which HIV causes nephropathy is not fully understood, but it is believed to involve direct infection of renal epithelial cells by the virus. This leads to a cascade of events including podocyte proliferation, dedifferentiation, and ultimately, the collapse of the glomerular architecture. Genetic factors, such as susceptibility genes in certain populations, particularly African Americans, also play a significant role in the development of HIVAN.

Clinical Presentation

Patients with HIVAN typically present with signs of nephrotic syndrome, which include heavy proteinuria, hypoalbuminemia (low levels of albumin in the blood), and edema. The disease often progresses rapidly, with many patients developing renal insufficiency and ESRD within months of diagnosis. High blood pressure and hematuria (blood in the urine) may also be present.

Diagnosis

Diagnosis of HIVAN is based on a combination of clinical presentation, laboratory findings, and renal biopsy. Renal biopsy, showing collapsing FSGS, is the gold standard for diagnosis. However, in patients with advanced HIV and typical features of HIVAN, a biopsy may not always be necessary. Serological tests to confirm HIV infection and assess viral load, along with renal function tests, are also key components of the diagnostic process.

Treatment

The primary treatment for HIVAN is antiretroviral therapy (ART) to control HIV replication. This has been shown to improve kidney function and slow the progression of the disease. In addition to ART, treatment may include medications to reduce proteinuria and manage blood pressure, such as angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensin receptor blockers (ARBs). In cases of advanced kidney disease, dialysis or kidney transplantation may be necessary.

Prognosis

The introduction of effective ART has significantly improved the prognosis for patients with HIVAN. With early diagnosis and treatment, the progression to ESRD can often be delayed, and some patients may experience partial recovery of kidney function. However, the prognosis remains poor for patients who develop ESRD, with high morbidity and mortality rates.

Prevention

Prevention of HIVAN primarily involves the early detection and treatment of HIV infection. Regular monitoring of kidney function in individuals with HIV, especially those with risk factors for kidney disease, is crucial for early identification and management of HIVAN.