Multiple System Atrophy (MSA) is a rare, progressive neurodegenerative disorder that emerges in adulthood, characterized by the gradual deterioration of nerve cells in several parts of the brain. This condition affects the autonomic nervous system, the part of the nervous system responsible for controlling involuntary functions like blood pressure. A defining characteristic of MSA is orthostatic hypotension, which is a significant drop in blood pressure that occurs when a person stands up from a sitting or lying position.
This abrupt change can lead to feelings of dizziness and lightheadedness. The dysfunction of the autonomic nervous system in MSA leads to this inability to properly regulate blood pressure.
The Neurological Link Between MSA and Blood Pressure
The autonomic nervous system is responsible for maintaining a stable blood pressure when you change your body’s position. When a person stands, gravity pulls blood downward, and the autonomic nervous system responds instantly. It signals blood vessels to narrow and the heart to beat slightly faster, ensuring that blood flow to the brain remains constant. This prevents a sudden drop in blood pressure.
In Multiple System Atrophy, this regulatory process is impaired. The disease is marked by the progressive degeneration of specific nerve cells in areas of the brainstem and spinal cord that are central to autonomic control. This neuronal loss disrupts the communication pathways that manage blood pressure. The body’s ability to release and respond to neurotransmitters like norepinephrine is diminished.
As a result, the blood vessels do not receive the proper signals to constrict upon standing. This failure leads to the pooling of blood in the lower extremities, a drop in blood pressure, and reduced blood flow to the brain.
Recognizing the Spectrum of Symptoms
The symptoms directly related to orthostatic hypotension are often the first to be noticed. These can include:
- A feeling of dizziness, lightheadedness, or fainting (syncope) after standing
- Blurred vision
- Weakness or a sensation of fatigue
- “Coat hanger pain,” an aching pain across the shoulders and neck caused by poor blood circulation
MSA also presents a wider range of symptoms beyond those related to blood pressure, grouped into two main types. The parkinsonian type (MSA-P) includes symptoms similar to Parkinson’s disease, such as slow movements (bradykinesia), muscle rigidity, and problems with posture and balance. A tremor may be present, but it is less common than in Parkinson’s disease.
The second type is the cerebellar type (MSA-C), which is characterized by ataxia. This manifests as poor coordination, an unsteady walk, and slurred speech (dysarthria). Many individuals eventually develop a combination of both parkinsonian and cerebellar symptoms as the disease progresses. Other autonomic problems are also common, including bladder control issues and constipation.
The Diagnostic Pathway
Diagnosing Multiple System Atrophy with orthostatic hypotension can be challenging, particularly in the early stages, because its symptoms overlap with other neurodegenerative conditions like Parkinson’s disease. There is no single test that can definitively confirm MSA. The diagnosis is clinical, based on a careful evaluation of the patient’s symptoms and a neurological examination.
To document orthostatic hypotension, autonomic function testing is performed. This often includes a tilt-table test, where the patient is strapped to a table that is tilted upwards to simulate standing, while their blood pressure and heart rate are monitored. A sustained drop in blood pressure during this test can confirm the presence of orthostatic hypotension.
Brain imaging, specifically a Magnetic Resonance Imaging (MRI) scan, is another diagnostic tool. While an MRI cannot definitively diagnose MSA, it can help rule out other conditions. In some cases of MSA, the MRI may reveal specific patterns of brain atrophy, such as the “hot cross bun” sign, which reflects degeneration in the pons.
Managing Orthostatic Hypotension in MSA
Management of orthostatic hypotension in MSA begins with non-pharmacological interventions. These strategies are considered the first line of defense. Patients are advised to:
- Increase their intake of fluids and salt to help expand blood volume.
- Wear compression stockings or an abdominal binder to prevent blood from pooling in the legs and abdomen.
- Perform physical counter-maneuvers, like crossing one’s legs or squatting, to raise blood pressure temporarily.
- Elevate the head of the bed at night to lessen the severity of morning orthostatic hypotension.
When lifestyle changes are not sufficient to control symptoms, pharmacological treatments are considered. Medications such as midodrine and fludrocortisone are commonly prescribed to help raise standing blood pressure. Midodrine works by causing blood vessels to constrict, while fludrocortisone helps the body retain more salt and water. Droxidopa is another medication that may be used.
A significant concern with these medications is the risk of developing supine hypertension, which is high blood pressure when lying down. This requires careful management, often involving blood pressure monitoring at home. The goal is to find a balance between controlling symptoms when standing and avoiding high blood pressure when at rest.
Disease Progression and Outlook
Multiple System Atrophy is a progressive condition, meaning its symptoms worsen over time. The rate at which the disease advances can vary significantly from one person to another. As the neurodegeneration continues, the symptoms of orthostatic hypotension, as well as the parkinsonian and cerebellar features, become more severe. This leads to increasing disability and a greater reliance on mobility aids.
Over time, complications can arise, such as difficulties with swallowing (dysphagia), which can increase the risk of aspiration pneumonia, and vocal cord paralysis, which can affect breathing and speech.
The life expectancy for individuals with MSA is around 10 years from the onset of symptoms, but this is an average, and the actual course can differ for each person. The cause of death is often related to complications of the disease, such as respiratory infections like bronchopneumonia.