What is the relationship between tremor and peripheral trauma?
The occurrence of tremor and other movement disorders, especially dystonia and myoclonus, after peripheral trauma is well established.
Typically, peripherally induced tremors have rest and action components. Some patients develop a typical picture of parkinsonism, with rest tremor, bradykinesia, hypomimia, and response to levodopa.
The physiopathology of this movement disorder is unknown.
Although conventional neurophysiologic studies show abnormalities of the peripheral nerves in less than one-half of patients, it is reasonable to speculate that damage to the peripheral nervous system causes sustained changes in the central nervous system connectivity and in motor unit-sensory reflex feedbacks, which account for the movement disorders.
The common association with reflex sympathetic dystrophy suggests that dysautonomia plays a role in the generation of posttraumatic movement disorders. About 60% of patients have predisposing factors such as personal and family history of ET and exposure to neuroleptics.
Treatment is difficult. Anticholinergic agents and antitremor medications, such as propranolol and primidone, are usually ineffective.
Clonazepam may provide moderate relief in some patients.
Some authors have successfully used injections of botulinum toxin into the affected musculature to control posttraumatic movement disorders.
Surgical treatment is another consideration when pharmacological treatment fails.
