SIR: Tan et al.1 previously reported successful treatment of three patients with bruxism associated with Huntington's disease (HD) using botulinum toxin-A (BTA). We are reporting effective treatment in another similar case.
A 50-year-old woman was admitted to our care with a diagnosis of HD, originally diagnosed at age 34. She complained of teeth grinding and severe jaw pain. We observed audible grinding of her teeth 100% of the time while awake.
Prescribed medications included paroxetine, haloperidol, and tamoxifen for previously diagnosed breast carcinoma. Haloperidol was started 2 months earlier for chorea, bruxism, and agitation. Chorea decreased at a dose of 2 mg/day, but bruxism did not improve. Bruxism worsened in spite of a dosage increase to 4 mg/day. Trials of baclofen and lorazepam did not improve bruxism.
We attempted treatment with BTA injections. First, we used BTA in a concentration of 5 units per 0.1 ml. Fifty units were divided among three injection sites in each masseter muscle for a total of 100 units.
We observed an immediate decrease in bruxism, with continued improvement over the first 3 days after treatment. Severe jaw pain also decreased after the first treatment and then resolved completely. Teeth grinding declined from 100% of time while awake to less than once in 10 minutes after 1 week, and then to less than once in 30 minutes 1 month after this treatment.
The second treatment was 1 month after the first. Bruxism had increased slightly near the end of this interval. A BTA concentration of 10 units per 0.1 ml was used for the second and for subsequent treatments. She has received a total of six treatments over 18 months.
For treatments two through six, both masseter and temporalis muscles were bilaterally injected. This combination gave more benefit than the masseter-only injections. All injections were administered with EMG guidance. The total BTA dose for each treatment was 100 units.
She continues to have an excellent result that variably lasts from 3 to 6 months. She remains free of jaw pain, and bruxism is minimal.
She has reported no adverse effects from this treatment, and we have observed none. Specifically, she has had no difficulty with mastication or deglutition. A swallowing evaluation done during this course of treatment was normal.
Bruxism involves jaw clenching and grinding of the teeth, commonly causes myofascial pain, and is often resistant to treatment. Other reports describe successful treatment with BTA of bruxism associated with traumatic brain injury.2—4
Bruxism has been reported in patients with HD,1,5 but it does not appear to be a common symptom. When present, it can be quite distressing. BTA injection is a therapeutic option. We recommend that BTA injections for this indication be given with EMG guidance. Our experience in treating our patient, and that previously reported by Tan et al.1 suggest that botulinum toxin type A is worthy of consideration for treatment of persons suffering from severe bruxism associated with Huntington's disease.