What Causes Renal Diseases in Multiple Sclerosis Patients?
Kidney problems in people with multiple sclerosis (MS) can happen because of strong medicines and other health factors.
Here’s what can cause kidney problems in MS patients:
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Bladder dysfunction: People with MS can have bladder problems because the nerves that control the bladder don’t work correctly. This is called a neurogenic bladder. When this happens, urine can remain in the bladder for too long, which can lead to urinary tract infections (UTIs). If UTIs are not treated, they can turn into kidney infections or kidney stones. Sometimes, it may also lead to urosepsis (infection spreads into the blood).
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Medication side effects: Some medications used to treat MS can also harm the kidneys. These include disease-modifying therapies (DMTs), monoclonal antibodies, antibiotics, and chemotherapy.
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Chronic inflammation: People with MS experience chronic inflammation, which means their body remains inflamed for an extended period. Over time, this can cause kidney damage, leading to glomerulonephritis (the tiny filters in the kidneys become damaged).
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Autoimmune kidney involvement: In rare cases, individuals with multiple sclerosis may develop kidney problems due to their immune system's autoimmune reaction, which causes it to start attacking the body's own tissues. It can lead to conditions like glomerulonephritis or interstitial nephritis. Managing MS with autoimmune kidney involvement requires careful balancing of medicines.
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Others: Some people with MS have high blood pressure (BP), which can increase the risk of kidney disease. Also, a person’s genes can sometimes make them more likely to have kidney problems if they have MS.
What Are the Renal Effects of Multiple Sclerosis?
The renal effects induced by multiple sclerosis are
1. Glomerular filtration rate:
The glomerular filtration rate (GFR) is affected in patients with multiple sclerosis, indicating renal damage. Such patients may develop renal failure attributed to the neurogenic bladder (bladder malfunction), acute tubular necrosis (death of tubular epithelial cells), iatrogenic reduction in renal perfusion, or allergic interstitial nephritis. Many drugs that treat multiple sclerosis have the potential to induce infections. Hence, antibiotic therapy is needed.
2. Urinary tract infection:
Nervous system lesions in multiple sclerosis patients can cause urine retention and sphincter dysfunction. Urinary incontinence is a regular feature in patients, and they need to use catheters to empty their bladders. On their own, urine retention and sphincter dysfunction can cause the development of infection, but with catheter use, the risk of developing and spreading infections is even higher.
The urine retained in the bladder allows bacteria to grow, leading to bladder infections. Urinary tract infections can further spread to the kidneys, which could result in severe complications like kidney failure. Urinary tract infections tend to occur if bladder emptying problems are untreated. The risk of developing urinary tract infection was two-fold higher in patients with multiple sclerosis. There is also a risk of mortality.
Renal disorders further complicate multiple sclerosis. When a viral infection-induced urinary tract infection spreads to the kidneys, it can cause viral disease within the kidney. The body recognizes them as viral infections and initiates reactions, inducing flare-ups of multiple sclerosis.
The symptoms of a urinary tract infection include the urge to urinate, frequent urination, a burning sensation during urination, lower abdominal or back pain, fever, and unusual-smelling, dark urine. Multiple sclerosis patients must seek treatment for urinary tract or kidney infections to prevent unpleasant complications.
3. Renal stones:
Multiple sclerosis and kidney stones may not have a direct causal relationship, but multiple sclerosis patients commonly develop calcium phosphate and struvite stones and are less likely to develop calcium oxalate monohydrate stones. Renal stones or urinary tract infections primarily cause kidney pain in individuals with MS. The method of bladder emptying was associated with the risk of kidney stone development.
Individuals using intermittent straight catheterization (insertion or removal of a catheter several times) are 3.5 times more likely to get stone disease, and those using indwelling catheters (collect urine in drainage bags) are ten times more likely to get kidney stones. Multiple sclerosis patients are likely to have had surgery to remove renal stones or percutaneous nephrolithotomy (a minimally invasive procedure for kidney stone removal).
4. Bladder storage issues:
Dysfunction in bladder storage is a sign of an overactive bladder. The bladder tends to contract more than usual due to nerve damage. The contraction increases the urge in the affected individual to urinate more frequently. They may have to wake up several times at night to urinate.
5. Bladder emptying problem:
The urinary bladder may not empty when the individual urinates. Nerve damage may cause interruption to the signals that help evacuate the bladder. This causes the bladder to remain full, resulting in overfill. Such individuals may have a weak urinary stream, incontinence, or urinary tract infections. The patients feel the urge to urinate but are hesitant when trying to urinate.
6. Combined urinary emptying and storage problems:
Multiple sclerosis patients can have both bladder emptying and storage issues simultaneously. The condition occurs when the bladder muscle and urinary sphincter fail to function in coordination. The condition can also lead to kidney damage.
7. Glomerulonephritis:
Glomerulonephritis in multiple sclerosis patients is attributed to immunomodulatory therapies like interferon beta. The therapy is a first-line treatment in patients with relapsing and remitting multiple sclerosis. There are reports of minimal change in disease and membranous glomerulonephritis in patients taking interferon beta for multiple sclerosis. The kidney damage induced by interferon beta can be direct or indirect.
What Are the Factors Contributing to Renal Disease in MS?
The factors contributing to renal disease in MS are:
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Medication side effects: Medicines like interferons and monoclonal antibodies can exert negative effects on the kidneys. Additionally, antibiotics that are used in treating MS-related infections can cause acute interstitial nephritis (swelling and inflammation of the kidney interstitium affecting kidney function).
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Immune dysfunction: The immune system affected by MS causes chronic inflammation of the kidneys, which can eventually lead to kidney damage.
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Neurogenic Bladder Dysfunction: This is a common complication of multiple sclerosis that causes bladder control issues. This complication can further cause renal stones and urinary tract infections. The risk of renal failure due to this factor is high among MS patients.
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Chemotherapy: MS patients receiving hematopoietic stem cell transplantations (HSCTs) may experience kidney damage because these are nephrotoxic.
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Genetic susceptibilities: According to studies, several genetic factors may contribute to the development of renal diseases in individuals with MS.
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High blood pressure: MS patients with high blood pressure are more prone to develop kidney diseases.
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Others: Apart from the above-mentioned factors, smoking, using tobacco, being obese, the presence of other co-morbidities, and reduced mobility can all affect the function of the kidneys.
All the above factors can cause high creatinine levels (a sign that the kidneys aren’t working well). That’s why it’s very important for MS patients to have regular kidney check-ups and take good care of their bladders.
What Is the Prevalence of Renal Disease in MS?
According to the research, the prevalence of renal disease in multiple sclerosis patients is estimated to be around 0.74 to 2.49 percent. This means that patients with multiple sclerosis experience a minimal risk of developing kidney problems. Therefore, kidney complications among MS individuals are not very common, but certain factors, like uncontrolled hypertension (requires regular monitoring) and medication side effects, can increase the risk.
What Are the Measures to Overcome Renal Diseases in Multiple Sclerosis?
Measures to overcome renal diseases in multiple sclerosis are:
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Lifestyle changes, such as limiting fluid intake at night, exercises to strengthen the pelvic floor, and bladder training, may help manage renal manifestations in multiple sclerosis patients. If the renal symptoms do not resolve with lifestyle changes, the doctor may prescribe medications that control bladder contraction and decrease urine sensation.
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Multiple sclerosis patients must schedule bathroom breaks throughout the day.
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Avoid bladder irritants like cigarettes, caffeine, artificial sweeteners, and alcohol.
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Bladder emptying dysfunctions are treated with catheters to enable complete bladder emptying.
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Urinary tract infections in patients with multiple sclerosis should be treated promptly. The first line of treatment for urinary infections is antibiotics.
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Patients with small renal stones are typically given medications to help them pass through the urine. Surgical options with catheter placement are advised if the renal stones do not clear. Using intermittent straight catheters, suprapubic tubes, or Foley catheters should be delayed wherever possible.
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The kidney excretes drugs used to treat multiple sclerosis through glomerular filtration and tubular secretion. GFR helps eliminate non-protein-bound molecules, whereas proximal tubules excrete protein-bound molecules. Multiple sclerosis patients are known to have impaired renal function. Therefore, the doses of Cyclophosphamide drugs are adjusted to minimize renal damage.
Conclusion:
Therefore, studies report that there is a link between multiple sclerosis and kidney disease. Although the prevalence is low, MS can affect renal health. The renal diseases that develop in multiple sclerosis patients include urinary tract infections, renal stones, bladder problems, and glomerulonephritis. Timely diagnosis and management of renal disease can prevent disease progression.
Key Takeaways:
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Multiple sclerosis can also affect other organs, like the kidneys and the liver, even though MS doesn’t attack them directly.
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Many people with MS have urinary problems, and in some cases, about 3 out of 100 people, these problems can lead to kidney damage over time.
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If you have MS and are having kidney problems, kindly talk to our iCliniq nephrologist. They can help create a plan to care for your kidneys and maintain your health.
