Multiple Sclerosis (MS) is a chronic, inflammatory disease where the immune system mistakenly attacks the myelin sheath, the protective covering of nerve fibers in the central nervous system. This process disrupts communication between the brain and the rest of the body. A stroke is an acute neurological event, often referred to as a “brain attack,” which occurs when blood flow to a part of the brain is interrupted. Understanding the relationship between these two conditions is important as research explores the heightened risk of stroke in people living with MS.
The Core Question: Is There a Direct Link?
Multiple Sclerosis does not directly cause a stroke in the same way that a condition like severe hypertension might. However, medical research confirms a significant statistical association between having MS and an increased risk of experiencing a stroke, both ischemic and hemorrhagic types. Studies indicate that individuals with MS face a risk of stroke that is approximately 2.5 times higher compared to the general population.
This elevated susceptibility is observed for both ischemic strokes, caused by a blood clot blocking flow, and hemorrhagic strokes, involving bleeding in the brain. Specifically, the risk for an acute ischemic stroke is reported to be about 2.79 times greater, while the risk for an intracerebral hemorrhage is about 2.31 times greater.
Underlying Mechanisms Increasing Stroke Risk
The connection between MS and stroke is rooted in several shared biological and physiological processes. Chronic systemic inflammation, a defining feature of MS, plays a central role in damaging the vascular system. This ongoing inflammatory state can lead to endothelial dysfunction, the impaired function of the cells lining the blood vessels, promoting atherosclerosis and increasing the likelihood of clotting.
People with MS also frequently share traditional cardiovascular risk factors. These include higher rates of dyslipidemia (abnormal cholesterol levels) and hypertension, which may be due to the disease itself or related to lifestyle adjustments and medication side effects. Platelet activation markers are also found at higher levels in MS patients, suggesting a greater tendency for clot formation.
Furthermore, MS-related physical disability often results in reduced mobility and a more sedentary lifestyle. This lack of physical activity contributes to slower blood flow, or venous stasis, particularly in the lower extremities. Venous stasis increases the risk of deep vein thrombosis (DVT). If this clot breaks free, it can travel to the brain and cause an embolic stroke.
Recognizing and Differentiating Symptoms
Differentiating between an acute stroke and a Multiple Sclerosis pseudo-exacerbation can be challenging because the symptoms often overlap. Both conditions can manifest as acute weakness, numbness on one side of the body, vision changes, or difficulty with walking and coordination. A pseudo-exacerbation is a temporary worsening of existing MS symptoms, often triggered by factors like infection or fever, and does not involve new central nervous system damage.
The key distinguishing factor is the speed of onset for the symptoms. Stroke symptoms typically appear very suddenly, often within minutes, and are severe. In contrast, symptoms of an MS relapse usually develop more gradually over the course of hours or days. Symptoms like a complete loss of vision in one eye or profound difficulty speaking are more characteristic of a stroke.
If any sudden, focal neurological symptoms occur, seek immediate medical help, as successful stroke treatment is highly time-dependent. Though MS-related symptoms can mimic a stroke, medical professionals can use advanced imaging like an MRI to distinguish between a new stroke and an MS lesion.
Mitigating Stroke Risk Factors
Managing established cardiovascular risk factors is a primary strategy for MS patients to lower their stroke risk. This involves monitoring and treating conditions such as high blood pressure, high cholesterol, and diabetes to keep them within healthy target ranges. A healthcare team may recommend specific medications, such as statins or antihypertensives, to manage these factors.
Maintaining physical activity is strongly encouraged to combat the effects of immobility. Even limited mobility exercises can help improve blood circulation and reduce the risk of clot formation. Lifestyle modifications, including avoiding smoking and adopting a heart-healthy diet, provide additional protection for the vascular system.
The use of disease-modifying therapies (DMTs) for MS has been associated with a decreased likelihood of ischemic stroke, suggesting that controlling the underlying inflammatory disease activity may offer vascular protection. Patients should discuss their individual risk profile and potential preventative treatments, such as antiplatelet or anticoagulant therapy, with their neurologist.