Multiple Sclerosis (MS) is a chronic autoimmune disorder targeting the central nervous system, including the brain and spinal cord. The immune system attacks the myelin sheath, the protective covering around nerve fibers, disrupting communication between the brain and the rest of the body. Hypertension, or high blood pressure, is a common condition where the long-term force of blood against artery walls is consistently too high. Research confirms a significant association between MS and hypertension, suggesting that the neurological damage caused by MS can directly and indirectly influence the body’s mechanisms for regulating blood pressure. Understanding this relationship is necessary for comprehensive care and management of individuals living with MS.
Understanding the Link Between MS and Hypertension
Population-level data consistently demonstrates a higher prevalence of hypertension in people with MS. The co-occurrence of two chronic conditions is known as comorbidity, and hypertension is one of the most frequently observed comorbidities alongside MS. One extensive study analyzing millions of electronic health records found that high blood pressure was 25% more common in individuals with MS compared to the general population.
This increased risk is observed across different ages, sexes, and racial groups, suggesting a connection that is not simply due to shared environmental factors. The presence of hypertension alongside MS is also relevant to the overall course of the neurological disease. Having elevated blood pressure has been linked to greater overall disability in MS patients, highlighting that vascular health and neurological health are intertwined. Establishing this epidemiological link sets the stage for investigating the underlying biological and behavioral mechanisms.
Autonomic Dysfunction as a Primary Mechanism
The most direct biological path connecting MS to altered blood pressure regulation involves the Autonomic Nervous System (ANS). The ANS controls involuntary functions like heart rate, breathing, and blood vessel constriction. MS-related damage, specifically demyelination and lesion formation in regions of the brainstem and spinal cord, can lead to a condition known as dysautonomia, or ANS malfunction. These CNS areas are the control centers responsible for maintaining cardiovascular homeostasis and stable blood pressure.
When these signaling pathways are disrupted, the body loses its ability to correctly manage blood pressure in response to changes, such as standing up. This damage to the regulatory centers can lead to sustained or labile hypertension because the central control mechanisms for keeping blood pressure within a narrow, healthy range are compromised. While dysautonomia often manifests as orthostatic hypotension (a drop in pressure upon standing), the same underlying damage contributes to high blood pressure. The severity of this cardiovascular dysautonomia is tied more closely to the duration of the disease than to the overall physical disability score. The resulting imbalance between the sympathetic and parasympathetic branches of the ANS creates chronic, unstable blood pressure regulation, contributing to the higher observed rates of hypertension.
Secondary Factors Increasing Hypertension Risk
Beyond the direct neurological damage to the ANS, several secondary factors related to living with MS contribute significantly to the increased risk of developing high blood pressure. Chronic systemic inflammation, a hallmark of the MS disease process, can negatively impact the cardiovascular system. The inflammatory state can damage the endothelium, which is the delicate inner lining of blood vessels, contributing to arterial stiffness and functional changes that raise blood pressure.
Physical inactivity is another significant contributor, as MS symptoms like fatigue, mobility issues, and pain often lead to a sedentary lifestyle. Lack of regular physical activity is a well-established independent risk factor for hypertension in the general population. Research has found that individuals with MS may spend approximately 7.5 hours per day sitting, which directly correlates with higher blood pressure outcomes.
Certain medications used to manage MS or its symptoms can also directly affect blood pressure as a side effect. For example, high-dose intravenous methylprednisolone, a corticosteroid frequently used to treat MS relapses, can cause transient hypertension. Furthermore, some disease-modifying therapies, such as glatiramer acetate, teriflunomide, and alemtuzumab, have been reported in clinical trials and post-marketing surveillance to be associated with an increased incidence of hypertension.
Treatment Considerations for Co-occurring Conditions
The presence of both MS and hypertension requires a specialized and coordinated approach to medical management. Healthcare professionals must recognize the high comorbidity rate and prioritize aggressive screening and management of high blood pressure. Treating hypertension is necessary not only for reducing the risk of stroke and heart attack but also for potentially limiting MS disease progression.
Selecting appropriate antihypertensive medications must be done with careful consideration of the underlying ANS dysfunction and potential drug interactions. Standard blood pressure drugs must be chosen to avoid exacerbating common MS symptoms like fatigue or orthostatic hypotension, which is a frequent manifestation of dysautonomia. Additionally, prescribers must be aware of the cardiovascular side effects of MS disease-modifying therapies, as new-onset hypertension could be a sign of an adverse drug event.
Lifestyle modifications, a cornerstone of hypertension management, also need to be tailored to the individual’s level of disability and fatigue. Customized, low-impact exercise plans and dietary changes are necessary to address the sedentary tendencies caused by the neurological symptoms without triggering an MS relapse or overwhelming the patient.