Multiple system atrophy

Multiple system atrophy (MSA) is a progressive, usually sporadic neurodegenerative disorder. It combines autonomic failure with parkinsonism, cerebellar impairment, or both. MSA-P and MSA-C describe the predominant motor pattern, not separate diseases. Speech, swallowing, sleep, breathing, movement, and cognition can also be affected, with substantial variation between people.1

Urgent safety

New noisy or high-pitched breathing, breathing pauses, shortness of breath, choking, inability to clear secretions, fainting, or a fall with injury requires urgent medical assessment. Stridor may occur during sleep or while awake and is clinically important in MSA.2

Orthostatic hypotension and other autonomic problems can cause marked blood-pressure changes. Treatment decisions must account for competing risks, including worsening supine hypertension. Do not change blood-pressure, bladder, movement, sleep, or other medication without the responsible clinician.2

Clinical pattern and diagnosis

Possible features include:

• orthostatic hypotension, urinary dysfunction, erectile dysfunction, constipation, and sweating or temperature-regulation changes;
• bradykinesia, rigidity, postural instability, gait difficulty, or tremor;
• ataxia, impaired coordination, and scanning or slurred speech;
• dysphagia, weak or strained voice, sleep-disordered breathing, and stridor;
• sleep, mood, executive, or other cognitive changes.

Diagnosis is clinical and requires specialist evaluation. The Movement Disorder Society criteria distinguish clinically established, clinically probable, and possible prodromal MSA. MRI findings are required for the clinically established category, while autonomic testing, urologic assessment, sleep or respiratory assessment, and other tests may support the diagnosis or exclude alternatives. No single test definitively confirms MSA during life.1

Treatment and follow-up

There is no proven disease-modifying treatment. Care is symptom-directed and may involve movement-disorder neurology, autonomic or urologic care, respiratory or sleep medicine, rehabilitation, nutrition, and palliative care according to the person's goals.2

Medication response and adverse effects vary. Mobility equipment, seating, home changes, and exercise plans require direct assessment because ataxia, postural instability, orthostatic symptoms, fatigue, and blood-pressure changes alter what is safe.

Swallowing, voice, and communication

Report coughing or choking, wet or changed voice, unexplained fever or chest infection, weight loss, dehydration, prolonged meals, or difficulty managing saliva. Speech-language and swallowing assessment should address current respiratory status and mealtime performance. Diet texture, posture, pacing, and swallowing strategies must come from direct assessment rather than the diagnosis alone.2

MSA can cause dysarthria, reduced loudness, strained voice, fatigue, and motor-access changes. It does not justify assuming loss of language, literacy, competence, or a specific access method. Communication assessment should consider speech, hearing, vision, eye movement, coordination, upper-limb control, posture, fatigue, cognition, and the settings in which communication matters.

Useful options may include writing, alphabet or word boards, stored messages, text-to-speech, or speech-generating AAC. Trial direct touch, an adapted pointer, switches, partner-assisted scanning, or eye gaze from actual performance. Establish a reliable yes/no response and urgent messages, provide partner training, and keep a low-tech backup. Plan early enough to learn and personalize the system, then reassess as needs change.5 For evaluation, trials, funding, and implementation, use the AAC device acquisition guide.

Coding

• ICD-10-CM G90.3: Multi-system degeneration of the autonomic nervous system.

This descriptor is used for MSA in ICD-10-CM, but coding should follow the documented diagnosis, phenotype, associated conditions, encounter purpose, and current local rules.6

Sources

1. Wenning et al. Movement Disorder Society criteria for the diagnosis of multiple system atrophy — current diagnostic categories and MRI requirements (2022; PMID 35445419).
2. Batla et al. Multiple system atrophy — practical clinical recognition and multidisciplinary symptom management (2023; PMID 36927875).
3. Cortelli et al. Stridor in multiple system atrophy: consensus statement — recognition, evaluation, and clinical importance of stridor (2019; PMID 31570638).
4. Fanciulli et al. Current symptomatic and disease-modifying treatments in multiple system atrophy — treatment evidence and absence of an established disease-modifying therapy (2020; PMID 32316335).
5. American Speech-Language-Hearing Association: Augmentative and Alternative Communication — individualized, multimodal AAC assessment without cognitive prerequisites.
6. Centers for Medicare & Medicaid Services: FY2026 ICD-10-CM definitions — G90.3 descriptor.

Review boundary

This page cannot diagnose MSA or remotely determine respiratory, swallowing, fall, or autonomic risk. Urgent symptoms require immediate clinical assessment. Medication, diet, exercise, mobility, respiratory, and communication decisions require direct evaluation and coordination with the treating team.