Progressive supranuclear palsy is a condition characterized by progressive gait disorder, postural instability, ophtalmoplegia, rigidity, dysarthria, dysphagia, and cognitive disturbance (frontal region). It usually affects elderly patients. The prevalence in US is around 1.9/100.000.
SIGNS & SYMPTOMS:
The clinical presentation involves:
Postural instability and falls (stiff gait with extended trunk and tendency to fall backwards)
Parkinsonism (asymmetric, may respond partially to levodopa)
Frontal cognitive dysfunction (impaired abstract thought, verbal fluency, motor perseveration, behavioral disturbances)
The disease usually progresses faster than Parkinson`s disease.
In clinical practice, diagnosis is mostly based on clinical features. Often the postural instability appears before the ophtalmoplegia (that may take years to develop). In such cases, a clinical test can be done during physical examination by pulling the patient by the shoulder from behind and seeing if the is able to maintain his posture or if he staggers backward.
The definitive diagnosis is confirmed only by histopathological evidence (neuronal loss, gliosis, presence of tau-positive inclusions on the basal ganglia), although this is not done in clinical practice. A probable diagnosis does not need histopathological evidence.
The criteria for probable diagnosis of progressive supranuclear palsy includes:
- Gradually progressive disorder
- Onset at age >= 40
- Vertical supranuclear palsy and prominent postural instability with falls in the first year of disease onset
- No evidence of other disease that could explain the foregoing features, as indicated by mandatory exclusion criteria (e.g. recent history of encephalitis, hallucinations or delusions, alien limb syndrome, Alzheimer dementia, cerebellar symptoms, dysautonomia, severe asymmetric parkinsonism, Whipple disease, structural abnormality).
Neuroimaging may show generalized atrophy most pronounced in the midbrain and brainstem. The prominent atrophy of the midbrain with a preserved pons create a hummingbird sign also known as penguin silhouette sign.
Differential diagnosis include Parkinson`s disease, frontotemporal dementia, Lewy bodies disease, corticobasal degeneration, vascular parkinsonism, among others.
There is no treatment for PSP that changes the disease`s progression.
Occupational therapy and physical therapy may provide relief and prevent falls in some patients.
Symptomatic treatments such as eyedrops for dry eyes and amantadine or botox injections for focal dystonia and drooling may be useful.
SOURCES & FURTHER READING:
- Rajput A, Rajput A. Progressive Supranuclear Palsy. Drugs Aging 2001; 18 (12): 913-925.
- Rehman HU. Progressive supranuclear palsy. Postgrad Med J 2000;76:333–336.
- Tawana K, Ramsden DB. Progressive supranuclear palsy. Mol Pathol. 2001 Dec; 54(6): 427–434.
- Litvan I. Progressive Supranuclear Palsy. Current Clinical Neurology: Atypical Parkinsonian Disorders Edited by: I. Litvan © Humana Press Inc., Totowa, NJ.