Multiple system atrophy
1 . General outline
Multiple system atrophy (MSA) with postural hypotension, also called Shy-Drager
syndrome, is a progressive disorder of the central and sympathetic nervous
systems. The disorder is characterized by postural (or orthostatic) hypotension—an
excessive drop in blood pressure when the patient stands up, which causes
dizziness or momentary blackouts. MSA has been classified clinically into
three types, olivopontocerebellar atrophy (OPCA), which primarily affects
balance, coordination, and speech; a parkinsonian form (striatonigral degeneration),
which can resemble Parkinson's disease because of slow movement and stiff
muscles; and a mixed cerebellar and parkinsonian form. In all three forms
of MSA, the patient can have orthostatic hypotension.
Parkinsoninan-like mild cognitive impairment can be observed, but no dementia.
2) Synonyms: Shy-Drager syndrome, olivopontocerebellar atrophy, striatonigral degeneration
3 . Course :
Orthostatic hypotension and symptoms of autonomic failure such as constipation,
impotence in men, and urinary incontinence usually predominate early in the
course of the disease. Constipation may be unrelenting and hard to manage.
Shy-Drager syndrome may be difficult to diagnose in the early stages. For
the majority of patients, blood pressure is low when the patients stand up
and high when the patients lie down. Other symptoms that may develop include
impaired speech, difficulties with breathing and swallowing, and inability
3. CAUSES AND RISK FACTORS :
Neurodegeneration in subcortical nuclei is mainly affecting oligodendrocytes.
A simultaneous synucleopathy and tauopathy is observed.
4. EPIDEMILOGICAL DATA :
Argyrophilic intracytoplasmic inclusions in oligodendrocytes (AGCIs) are
widespread, not only in the olivopontocerebellar and striatonigral systems
but also among fibers connecting their affecting lesions of MSA.
6. TREATMENT :
Orthostatic hypotension in Shy-Drager syndrome is treatable, but there is
not known effective treatment for the progression central nervous system
degeneration. The general treatment course is aimed at controlling symptoms.
Antiparkinsonian medication, such as L-dopa, may be helpful. To relieve low
blood pressure while standing, dietary increases of salt and fluid may be
beneficial. Medications to elevate blood pressure, such as salt-retaining
steroids, are often necessary, but they can cause side effects and should
be carefully monitored by a physician. Alpha-adrenergic medications, non-steroidal
anti-inflammatory drugs, and sympathomimetic amines are sometimes used. Sleeping
in a head-up position at night reduces morning orthostatic hypotension. An
artificial feeding tube or breathing tube may be surgically inserted for
management of swallowing and breathing difficulties.
What is the prognosis?
Shy-Drager syndrome usually ends in the patient’s death by 7 to 10 years
after diagnosis. Breathing problems such as aspiration, stridor (high-pitched
breathing sounds due to airway obstruction), or cardiopulmonary arrest are
common causes of death.
10. Further reading
Gilman et al, J.Neurol.Sci, 1999, 163:94-98