Rigidity, Spasticity, and Dystonia

Rigidity and spasticity tend to emerge later in the course of Huntington's disease, except in cases of childhood onset, in which they are often present from the beginning. They can impair gait, lead to falls, and necessitate the use of a wheelchair.

Dystonia may include twisting, tilting or turning of the neck (torticollis), involuntary arching of the back (opisthotonos) and arching of the feet. It may be a symptom of HD, or a side effect of neuroleptic therapy.

A variety of medications have been used to treat rigidity, spasticity, and dystonia, all with modest success at best.

• Benzodiazepines, such as clonazepam, or baclofen, starting at l0mg/day and increasing up to 60mg may relieve stiffness, but may also increase bradykinesia.
• Tizanidine, a clonidine like drug, is sometimes helpful for spasticity, beginning with 2mg qhs and increasing every 4-7 days to a maximum of 12-24mg in divided doses.
• Antiparkinsonian medicines such as amantadine 50-200mg/day, levodopa/carbidopa 25/100mg two to three times per day, or bromocriptine beginning at 1.25mg bid, increasing every few weeks, may be helpful with bradykinesia or rigidity, and some clinicians have tried trihexyphenidyl, 2-5mg, bid to tid.
• All of these medicines may cause delirium and may lose their efficacy after several months.

Consultation with a physical therapist or physiatrist to design a program to mobilize the patient and prevent contractures may be an important component to the management of rigidity and spasticity.

Botulinum toxin injections have been used rarely, but might be beneficial if severe rigidity of a small muscle or group of muscles is disturbing function.