Progressive supranuclear palsy (PSP) is a degenerative brain disorder that mimics Parkinson disease. However, it is a more severe disorder that leads to difficulty with ambulation, balance, visual problems, severe dementia, alterations in behavior, difficulty with speech and swallowing. It occurs after the 5th decade of life and is underdiagnosed.
PSP presents gradually and is insidious. The age of presentation is usually between 55-70 years. Typical symptoms may include the following key features
Differential diagnosis of PSP:
Differentiating PSP from Parkinson disease
If PSP is suspected the following investigations are necessary:
Criteria have been established to help improve diagnostic accuracy of PSP and include the following :
Supportive features to help diagnosis include:
A Neurologist consultation is vital when evaluating a patient with PSP. The disorder is not easy to diagnose and can often be mistaken for Parkinson disease. The history should be obtained from the family or primary caregiver as it may reveal changes in behavior, daily functional activity and mobility.
So far there is no effective treatment of PSP . All treatments are supportive. Even though dopaminergic agents have been tried, they only work in mild cases and the symptom relief is short-lived. Only a few patients see benefit from these agents. Even though there is significant loss of cholinergic neurons in the brain of PSP patients, administration of cholinergic agents like physostigmine has not been helpful.
Other anecdotal reports indicate slight improvement after treatment with methysergide, trazodone, amitriptyline and idazoxan. However, the benefits are often short-lived and inconsistent.
Botulinum toxin has been used to treat levator inhibition and blepharospasm but the success rates are low. To prevent exposure keratopathy, artificial tears are recommended. In patients who have depression, have emotional apathy or pseudo bulbar crying episodes, antidepressants may help.
Supportive therapies include use of ambulatory devices like a wheelchair, communication aids and walker. Refer to occupation and physical therapies to help with posture and daily living activities. Speech therapist may help some patients with difficulty in swallowing.
PSP is progressive disorder without a cure. Eventually all patients become wheelchair bound and many require a feeding tube. The median survival time from symptom onset is about 5 years. Individuals who fall during the first year, have early dysphagia and incontinence with negative prognostic signs. In most cases aspiration pneumonia leads to death. The quality of life is very poor and the disorder can create stress in the family or caregiver.
The cause of PSP is not known and it is thought to be a sporadic disorder. Very few familial cases have been reported but the mode of inheritance is not well understood. It is believed that the disorder has an autosomal dominant inheritance with reduced penetrance .
The role of viruses and toxins as a cause is pure speculative since there is no study that has even shown such a link. Currently there are studies indicating that perhaps genes leading to formation of neurofibrillary tangles may play an important role .
PSP tends to occur after the 5th decade of life. Based on small series, the annual incidence of PSP is about 2- 5.3 new cases per 100,000 people every year. It is believed that these numbers are underestimated because many healthcare workers either have not heard about the disorder or fail to make the diagnosis. It is more likely that most of the patients are not diagnosed from the disorder and probably die from an unrelated disorder that is present at the same time. Review of the UK Parkinson Disease Society Brain Bank revealed that nearly 6% of patients diagnosed with Parkinson disease were found to have PSP at autopsy. The incidence of PSP is known to increase with age and overall the disorder affects more males than females.
Unlike Alzheimer dementia, PSP is not associated with amyloid plaques in the brain but is associated with abnormal accumulation of tau protein. Some experts have classified PSP as a Pick complex disorder. The major neurotransmitter subsystems involved in PSP are the GABAergic, dopaminergic nigrostriatal pathway, and cholinoceptive striatal neurons including the cholinergic brainstem and basal forebrain nuclei.
At autopsy the chief macroscopic abnormality seen in the brain is the significant loss of pigment in the substantia nigra and locus coerulus which are often shrunken and discolored. There is also significant degeneration of cholinergic nucleic and loss of choline acetyltransferase activity in many parts of the brain.
Degeneration may be seen in the subthalamus, substantia nigra and pallidum. There is also widespread distribution of neurofibrillary tangles in the hippocampus, subthalamus, putamen caudate, frontal cortex, red nucleus, dentate and inferior olive regions. The National Institute of Neurological Disorders and Stroke (NINDS) criteria for PSP requires high density of neurofibrillary tangles and neuropil threads in at least three of the following anatomical sites: subthalamic nuclei, pallidum, pons or substantia nigra or pons, mild to moderate density in at least three of the following sites: medulla, striatum, dentate nucleus and oculomotor complex.
Because the cause of PSP is not known prevention is not possible. However, it is important that healthcare providers understand the clinical presentation of PSP so that an early diagnosis can be made. The disorder is very disabling and of enormous stress to the caregiver, so an early diagnosis can mean prompt referral to physical, as well as speech and occupational therapy .
Progressive supranuclear palsy (PSP) also known as the Steel Richardson Olzewski syndrome is a neurodegenerative disorder very similar to Parkinson disease. The disorder occurs after the 5th decade of life and is progressive. Since the description of the disorder nearly 50 years ago, many small series have reported on the disorder. It is under-diagnosed not only by general physicians but also by neurologists. The cause of PSP is not known. Exposure to toxins and viruses has been proposed in the etiology of PSP without any concrete evidence. The features of PSP resemble those of Parkinson's disease and the two diseases are often confused. Despite certain common features with Parkinson's disease, PSP is a much aggressive disorder with many neuropsychiatric and motor abnormalities that it often leads to rapid decline and eventually to death.
Progressive supranuclear palsy (PSP), also known as Steele Richardson Olzewski syndrome, is a degenerative motor disorder very similar to Parkinson disease.
Initially most patients have difficulty with visual difficulties, walking and balance but as the disorder advances, cognitive and behaviour changes may also develop. Late in the course of PSP, walking and eye movements become very difficult . The cognitive impairment progresses to full blown dementia
Use of ambulatory aids may help during the early phase of the disease but the risk of fall is always present. Because of difficulty with chewing and swallowing, most patients can only take in liquid or pureed foods. Physical and occupational therapy may help with mobility in the early stages. When swallowing difficulty is severe, patients should have a feeding tube placed in the stomach. The risk of aspiration is always present.
As family members and caregivers of patients with PSP may develop feelings of anger, frustration and guilt, it is important for them to seek support for these difficulties.