What is HIV Nephropathy?
The human immunodeficiency virus (HIV) is an ever-changing virus that is often linked with kidney disease. In the early days of the HIV epidemic, it often led to a specific type of kidney disease known as ‘collapsing focal segmental glomerulosclerosis’. However, kidney disease caused by HIV can also show up as ‘HIV-immune-complex kidney disease’ and ‘thrombotic microangiopathy’. These medical terms refer to different ways that the kidneys can be damaged by the disease.
In recent years, thanks to a combination of antiretroviral therapy and the wide availability of these medications, people with HIV are living longer lives without showing typical signs of the disease. Today, it seems more common for patients to experience kidney problems due to the side-effects of certain HIV therapies, as well as other non-infectious conditions such as diabetes or high blood pressure.
Despite these developments, kidney disease remains a major cause of death in patients infected with HIV. In fact, there’s a six-fold increase in death for those suffering from acute kidney injury (a sudden episode of kidney failure or damage) and chronic kidney disease (long-term kidney damage).
Furthermore, because HIV can infect and multiply within the cells of the kidney, fully treating the virus may only be possible with the total elimination of the virus within the kidney. This is because the virus in the kidney seems to behave independently from the virus in the blood.
What Causes HIV Nephropathy?
People living with HIV (PLWHIV) can experience a variety of kidney issues. These can be due to the effects of HIV within the kidney, other illnesses, drug side effects, and a malfunctioning immune system. Kidney disease related to HIV generally affects a part of the kidney called the glomerulus, which is responsible for cleaning the blood.
This disease can be divided into two main types: podocytopathies and immune complex-mediated disease. Podocytopathies involve damage to a specific cell in the kidney (the podocyte). The main types seen with HIV are called HIV-associated nephropathy (HIVAN), focal segmental glomerulosclerosis, a less common variant of the disease called minimal change disease, and diffuse mesangial hypercellularity. These diseases can cause problems with the filtering function of the kidneys leading to protein in the urine. This is due to the HIV virus infecting kidney cells, the virus instructing kidney cells to behave abnormally, and disruption in the normal functioning of host genes.
For cases associated with immune complex-mediated diseases, it isn’t entirely clear how these are related to HIV, and other secondary causes should be explored. These diseases include post-infectious glomerulonephritis, lupus-like nephritis, IgA nephropathy, membranous nephropathy, and membranoproliferative glomerulonephritis. These terms refer to different ways the immune system can mistakenly damage the kidneys.
Risk Factors and Frequency for HIV Nephropathy
In the mid-1990s, the occurrence of kidney disease related to HIV, known as HIV-associated nephropathy, reached its peak. It was found in around 3.5% to 10% of people with HIV in the United States. This primarily affected individuals of African descent. However, the rate has been going down due to the widespread use of combined anti-retroviral treatments.
Signs and Symptoms of HIV Nephropathy
People with HIV-associated nephropathy often have a rapid drop in their GFR (a measure of kidney function) and surprisingly high levels of protein in their urine. Swelling in the lower leg areas and high blood pressure aren’t usually seen in these individuals. Since people in this group often have other ongoing health conditions or infections, it’s crucial to rule out other causes of their health problems.
Testing for HIV Nephropathy
According to the HIV Medicine Association’s guidelines, people living with HIV should regularly be screened for kidney problems, specifically a condition known as HIV nephropathy. These screenings should include blood tests for creatinine (a waste product that healthy kidneys remove), estimated glomerular filtration rate (which measures kidney function), as well as urine tests in order to detect any significant amount of protein. These tests are especially important when starting or changing antiretroviral therapy (the treatment for HIV), and should be done at least twice a year for patients whose condition is stable.
For better assessment, an ultrasound of the kidneys can also be useful. This test evaluates the echo patterns from the kidneys, which can help to predict HIV nephropathy. If the echo score is high, it may indicate HIV nephropathy, while a low score can exclude it. However, this method is not always definitive, since most people with HIV nephropathy have echo scores that fall in between these two extremes. For a definitive diagnosis, a biopsy would be necessary. In a biopsy, a small piece of kidney tissue is removed and examined to confirm the diagnosis. The decision to perform a biopsy should be based on the patient’s symptoms, the likelihood of any other diseases, potential treatment options, and the associated risks.
Currently, there is another kidney problem that can occur in people with HIV, which is much more common than HIV nephropathy. This condition is known as combination antiretroviral therapy (cART) induced nephropathy. It’s important to tell the difference between these two kidney problems, as the treatments for both conditions are different. Some key differences include the patient’s CD4 count (a measure of immune system health), viral load (the amount of HIV in the blood), protein levels in the urine, the rate of kidney function decline, and the appearance of the kidneys on ultrasound. These factors can help your doctor determine whether you have HIV nephropathy or cART induced nephropathy.
Treatment Options for HIV Nephropathy
HIV-associated nephropathy (HIVAN) can quickly lead to a severe kidney condition called end-stage renal disease (ESRD), which can increase the risk of death. For that reason, it’s crucial not to delay treatment for HIVAN.
At the moment, the primary treatment is something called combined antiretroviral therapy. This is a type of treatment that uses a combination of medicines to manage HIV. The good news is that this treatment can significantly reduce the likelihood of HIVAN progressing into ESRD.
In addition to combined antiretroviral therapy, another important component of HIVAN treatment is something called the Renin-angiotensin-aldosterone system (RAAS) blockade. This involves the use of specific drugs known as angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) which can aid in kidney survival. While these are typically used together with the antiretroviral therapy, in some cases, steroids may also be added, especially where the kidney function fails to improve. However, it’s important to remember that the benefits of using steroids for this purpose aren’t very strong, and steroids also come with a broad range of potential side effects.
While the antiretroviral therapy is crucial, it’s also important to adjust it to the patient’s kidney function because some of these medicines can directly affect the kidneys. For instance, medicines such as tenofovir, atazanavir, and indinavir can impact kidney function.
If a patient’s HIVAN advances to ESRD, the primary way of managing it is through renal replacement therapy, a treatment that filters waste and extra water from your blood, similar to the job that healthy kidneys do. Additionally, a kidney transplant is another viable option and has been demonstrated to be effective in patients with controlled HIV.
What else can HIV Nephropathy be?
There are several kidney diseases associated with HIV. These may include:
- HIV-associated immune complex kidney disease
- Membranoproliferative glomerulonephritis (often related to hepatitis C infection)
- Amyloidosis
- Minimal change disease
- Postinfectious glomerulonephritis
- Thrombotic microangiopathy
- Diabetic nephropathy
- Immunoglobulin A nephropathy
- Membranous glomerulopathy
What to expect with HIV Nephropathy
Before the introduction of combined antiretroviral therapy, HIV associated nephropathy (HIVAN), a type of kidney disease linked to HIV, would quickly advance to the final stage of kidney disease within 2-4 months. Today, with modern treatment, patients can expect a more positive outcome. However, it’s important to note that patients with HIVAN still face greater challenges compared to those with kidney diseases caused by other factors.
Possible Complications When Diagnosed with HIV Nephropathy
The key issue that occurs with HIVAN is the disease’s progression towards CKD, which is a chronic kidney disease. This can eventually lead to ESRD, or an end-stage renal disease, which necessitates renal replacement therapy or kidney treatment. Less commonly, complications like hypertension and swelling in the lower limbs (edema) can also occur.
Here’s what you need to know:
- Progression to chronic kidney disease (CKD)
- The development of end-stage renal disease (ESRD), requiring kidney treatment
- Less common complications like high blood pressure (hypertension)
- Possibility of swelling in the lower extremities (edema)
Preventing HIV Nephropathy
HIV-related kidney disease is a severe condition that if left untreated, can lead to final-stage kidney disease. Patients need to be encouraged to take their HIV medications regularly and strictly adhere to their treatment regimen. They should also consistently see their regular doctor and kidney specialist. This will help to manage their disease and prevent it from progressing to a more serious stage.
