Hematuria, the presence of blood in the urine, is a symptom that always warrants medical attention. The human immunodeficiency virus (HIV) itself does not directly cause red blood cells to appear in the urine. However, the chronic effects of the infection and the weakened immune system it creates can lead to several specific conditions that result in hematuria. Understanding this distinction is important for individuals managing HIV, as it points toward complications that require targeted diagnosis and treatment.
The Impact of HIV on Kidney Structure
Prolonged or uncontrolled HIV infection can directly damage the filtering units of the kidney, a condition known as HIV-Associated Nephropathy (HIVAN). HIVAN is a structural disease where the kidney’s filtering system, the glomeruli, becomes scarred and collapses (collapsing focal segmental glomerulosclerosis). This damage is a consequence of the virus infecting the kidney’s epithelial cells, including the podocytes and tubular cells, which are part of the filtration barrier.
The expression of HIV viral genes within these renal cells contributes to their proliferation, dedifferentiation, and eventual death. The resulting structural failure of the glomeruli allows large proteins and red blood cells to leak into the urine, causing hematuria. HIVAN is more common in individuals with advanced HIV disease and is strongly associated with specific genetic risk factors, particularly variants in the APOL1 gene found in people of African descent.
This form of chronic kidney injury often presents with significant proteinuria, or protein in the urine, alongside the hematuria. The introduction of effective Antiretroviral Therapy (ART) has dramatically reduced the incidence of HIVAN by suppressing viral replication throughout the body, including within the kidney tissue. For individuals diagnosed with HIVAN, starting or optimizing ART is a primary part of the treatment plan to slow the rapid progression to end-stage kidney disease.
Specific Infection and Cancer Causes of Hematuria
Hematuria can also signal an opportunistic infection or malignancy that takes advantage of a suppressed immune system. HIV infection compromises the body’s ability to fight off pathogens, increasing the risk of severe bacterial urinary tract infections (UTIs) that can cause inflammation and bleeding in the bladder or kidneys.
Specific infections, such as tuberculosis, can spread beyond the lungs to affect the kidneys and urinary tract, causing bloody urine. Cytomegalovirus (CMV) can cause CMV cystitis, resulting in inflammation and hematuria, particularly when the immune system is severely weakened. Inflammation of the prostate gland, known as prostatitis, is also more likely in HIV-positive men and can manifest with bloody urine and painful urination.
Certain HIV-associated cancers can also cause hematuria by invading urinary tract tissues. Kaposi sarcoma (KS), a malignancy that forms lesions in blood vessel walls, can affect the bladder or urethra, leading to visible blood in the urine. Similarly, some high-grade non-Hodgkin lymphomas (NHL) are more common in people with advanced HIV and can potentially infiltrate the urinary or reproductive organs.
Common Causes of Hematuria Unrelated to HIV Status
Many causes of hematuria are prevalent in the general population, regardless of HIV status. The most frequent causes are often benign or easily treatable, and they should be considered before attributing the symptom to HIV-related complications. General urinary tract infections (UTIs) caused by common bacteria are a frequent source of blood in the urine.
Kidney or bladder stones are mineral deposits that can cause irritation and bleeding as they pass through the narrow urinary tract. In men over the age of 50, benign prostatic hyperplasia (BPH), or an enlarged prostate, is a frequent cause of microscopic hematuria. Even strenuous physical activity, such as long-distance running, can cause temporary irritation and blood in the urine.
Less frequent but serious causes include bladder, kidney, or prostate cancer, especially in older individuals. Certain medications, including blood thinners and high-dose pain relievers, can also predispose any individual to bleeding in the urinary tract. A thorough medical history is necessary to distinguish these common issues from HIV-specific complications.
Medical Evaluation and Diagnostic Procedures
Any instance of blood in the urine, whether visible or microscopic, requires prompt medical evaluation to determine the underlying cause. The initial diagnostic step is typically a urinalysis, which confirms the presence of red blood cells and checks for other indicators like protein or red blood cell casts, which suggest kidney (glomerular) damage. A urine culture is usually performed to rule out a bacterial infection as the source of bleeding.
Blood tests are used to assess overall kidney function by measuring levels of waste products like creatinine, which helps determine if kidney disease is present. If a structural cause is suspected, imaging studies such as an ultrasound or a Computed Tomography (CT) scan of the abdomen and pelvis may be ordered to visualize the kidneys, ureters, and bladder for masses or stones.
If the cause remains unclear, a cystoscopy may be performed to directly examine the bladder lining. For suspected HIVAN or other kidney diseases, a kidney biopsy may be necessary to obtain a definitive diagnosis of the tissue damage. The medical team must always consider the patient’s HIV status, current CD4 count, and any use of Antiretroviral Therapy when interpreting results and formulating a treatment plan.