Archive for the ‘Tremor’
Parkinsonism is a movement disorder characterized by tremor, rigidity, bradykinesia, and postural instability.
Parkinsonism is a relatively common disorder that occurs in all ethnic groups, with an approximately equal sex distribution. The most common variety, idiopathic Parkinson’s disease (paralysis agitans), begins most often between 45 and 65 years of age.
Exposure to certain toxins (eg, manganese dust, carbon disulfide) and severe carbon monoxide poisoning may rarely lead to parkinsonism. Typical parkinsonism has occurred in individuals who have taken 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) for recreational purposes. This compound is converted in the body to a neurotoxin that selectively destroys dopaminergic neurons in the substantia nigra. Reversible parkinsonism may develop in patients receiving neuroleptic drugs and has also been caused by reserpine and metoclopramide. Only rarely is hemiparkinsonism the presenting feature of a brain tumor or some other progressive space-occupying lesion.
In idiopathic parkinsonism, dopamine depletion due to degeneration of the dopaminergic nigrostriatal system leads to an imbalance of dopamine and acetylcholine, which are neurotransmitters normally present in the corpus striatum. Treatment is directed at redressing this imbalance by blocking the effect of acetylcholine with anticholinergic drugs or by the administration of levodopa, the precursor of dopamine.
Tremor, rigidity, bradykinesia, and postural instability are the cardinal features of parkinsonism and may be present in any combination. There may also be a mild decline in intellectual function. The tremor of about four to six cycles per second is most conspicuous at rest, is enhanced by emotional stress, and is often less severe during voluntary activity. Although it may ultimately be present in all limbs, the tremor is commonly confined to one limb or to the limbs on one side for months or years before it becomes more generalized. In some patients, tremor is absent. Read the rest of this entry »
Tourette’s Syndrome is initially characterized by motor tics in 80% of cases, and these tics most commonly involve the face. In the remaining 20%, the initial symptoms are phonic tics; all patients ultimately develop a combination of different motor and phonic tics. These are noted first in childhood, generally between the ages of 2 and 15. Motor tics occur especially about the face, head, and shoulders (eg, sniffing, blinking, frowning, shoulder shrugging, head thrusting, etc).
Phonic tics commonly consist of grunts, barks, hisses, throat-clearing, coughs, etc, but sometimes also of verbal utterances including coprolalia (obscene speech). There may also be echolalia (repetition of the speech of others), echopraxia (imitation of others’ movements), and palilalia (repetition of words or phrases). Some tics may be self-mutilating in nature, such as nail-biting, hair-pulling, or biting of the lips or tongue. The disorder is chronic, but the course may be punctuated by relapses and remissions.
Obsessive-compulsive behaviors are commonly associated and may be more disabling than the tics themselves.
Examination usually reveals no abnormalities other than the tics. In addition to obsessive-compulsive behavior disorders, psychiatric disturbances may occur because of the associated cosmetic and social embarrassment. Electroencephalography may show minor nonspecific abnormalities of no diagnostic relevance. Read the rest of this entry »
The cause of benign essential tremor is uncertain, but it is sometimes inherited in an autosomal dominant manner. Tremor may begin at any age and is enhanced by emotional stress. The tremor usually involves one or both hands, the head, or the hands and head, while the legs tend to be spared. Examination reveals no other abnormalities. Ingestion of a small quantity of alcohol commonly provides remarkable but short-lived relief by an unknown mechanism.
Although the tremor may become more conspicuous with time, it generally leads to little disability, and treatment is often unnecessary. Occasionally, it interferes with manual skills and leads to impairment of handwriting. Speech may also be affected if the laryngeal muscles are involved. In such circumstances, propranolol may be helpful but will need to be continued indefinitely in daily doses of 60–240 mg. However, intermittent therapy is sometimes useful in patients whose tremor becomes exacerbated in specific predictable situations. Primidone may be helpful when propranolol is ineffective, but patients with essential tremor are often very sensitive to it. They are therefore started on 50 mg daily, and the daily dose is increased by 50 mg every 2 weeks depending on the response; a maintenance dose of 125 mg three times daily is commonly effective. Occasional patients fail to respond to these measures but are helped by alprazolam (up to 3 mg daily in divided doses).