Multiple Sclerosis (MS) is a chronic disease that affects the central nervous system, disrupting communication pathways between the brain and the body. Hematuria, the presence of blood in the urine, may be visible (gross hematuria) or only detectable under a microscope (microscopic hematuria). While MS itself does not directly cause bleeding from the urinary tract, the disease-related complications arising from neurological dysfunction frequently lead to conditions that do cause blood to appear in the urine. Any instance of hematuria in a person with MS should be treated seriously and prompts a medical investigation.
How MS Affects Urinary Control
The primary link between MS and urinary problems is the development of a condition known as neurogenic bladder dysfunction. MS lesions, which are areas of demyelination and damage in the brain and spinal cord, interrupt the nerve signals controlling the bladder. These signals govern the coordinated action between the detrusor muscle, which contracts to empty the bladder, and the sphincter muscles, which control the flow of urine.
When these nerve messages are disrupted, it leads to two main patterns of dysfunction: impaired storage and impaired emptying. Impaired storage results in an overactive bladder, causing frequent, urgent, and sometimes uncontrolled urination. Impaired emptying occurs when the bladder cannot fully contract or the sphincter muscles fail to relax completely, leaving residual urine behind. This incomplete voiding is a significant risk factor for subsequent health issues within the urinary tract.
Urinary Complications That Cause Bleeding
The inability to empty the bladder fully, a common consequence of neurogenic bladder, creates an environment where complications that cause bleeding can thrive. The most frequent cause of hematuria in this population is a Urinary Tract Infection (UTI). Urinary stasis, where residual urine remains in the bladder, provides a warm, nutrient-rich breeding ground for bacteria, leading to frequent infections. Severe or upper-tract UTIs, such as pyelonephritis, often result in inflammation and irritation of the urinary tract lining, which causes red blood cells to leak into the urine.
Another complication is the formation of bladder stones, also known as calculi. Chronic urine retention and a change in urine chemistry due to infections can accelerate the crystallization of minerals into stones. These stones cause irritation and damage to the bladder wall as they rub against the lining, leading to bleeding. In addition, people who manage their bladder dysfunction with intermittent or indwelling catheters may experience hematuria due to mechanical trauma. The presence of the catheter itself can cause minor irritation or injury to the urethral and bladder lining, resulting in visible or microscopic blood loss.
Why Hematuria Requires Immediate Investigation
Even when a person has MS and a known history of bladder issues, hematuria is a symptom that must always be investigated by a physician. The symptom acts as a red flag for several serious conditions unrelated to MS, which require rapid diagnosis and treatment. Most concerning is the possibility of urological cancers, such as bladder or kidney cancer, for which hematuria is often the earliest and most recognizable sign.
Prompt diagnostic testing is necessary to rule out these malignancies, especially since certain risk factors, like long-term indwelling catheter use or past treatment with specific immunosuppressive drugs, may increase the risk of bladder cancer. Hematuria can also signal issues originating in the kidneys, including kidney stones, infections, or inflammatory conditions like glomerulonephritis. Furthermore, some common medications, such as blood thinners or certain pain relievers, can cause or worsen urinary bleeding, and this must be identified and managed by a doctor.
When to Consult a Specialist
Any instance of visible blood in the urine (gross hematuria) or a finding of microscopic hematuria on a routine lab test warrants an immediate consultation with a primary care provider. This initial visit will typically include a thorough analysis of the urine to confirm the presence of blood and check for signs of infection. If an infection is not the cause, or if the bleeding is recurrent, the patient will likely be referred to a specialist.
The correct specialist is a Urologist, a physician who specializes in the diseases of the urinary tract. The urologist will conduct a comprehensive evaluation, which may include imaging tests such as a kidney and bladder ultrasound or a CT scan. A cystoscopy, where a small camera is used to look directly inside the bladder, is often performed to identify the exact source of the bleeding.