Chapter 3-The Physicians Guide To The Management of HD
Myodonus, Tics and Epilepsy
Myoclonus, sudden brief jerks involving groups of muscles, is more common in juvenile-onset HD, where it may be mistaken for a seizure. Like chorea, myoclonus may not be disabling or particularly distressing, but may respond to treatment with clonazepam or divalproex sodium if treatment is necessary.
Tics are brief, intermittent stereotyped movements such as blinking, nose twitching, head jerking, or transient abnormal postures. Ties which involve the respiratory and vocal apparatus may result in sounds including sniffs, snorts, grunts, coughs, and sucking sounds.
Patients may be unaware of vocal tics, but family members may find the incessant noises grating. They should be helped to understand that the tics are not under voluntary control. Tics generally do not by themselves require treatment, but may respond to neuroleptics, benzodiazepines, or SSRIs.
Epilepsy is uncommon, though not unheard of, in adults with HD, but is said to be present in 30% of individuals with juvenile-onset HD.
A first seizure in an HD patient should not be attributed to HD without further evaluation as it may be indicative of an additional neurologic problem, such as a subdural hematoma sustained in a fall.
The workup of a first seizure should include a complete exam, laboratory studies to rule out an infection or metabolic disturbance, an EEG, and a brain imaging study. The treatment of a seizure disorder in a person with HD depends on the nature of the seizures.
In the juvenile HD patient, myoclonic epilepsy or other generalized seizures may suggest divalproex sodium as a first treatment choice.
Although seizure management in HD is not usually difficult, for the occasional patient seizure control is quite difficult to achieve, requiring multiple medications or specialized referral.