High-dose treatment with botulinum toxin A in cervical dystoniain

Injections with botulinum toxin A (BTX A)are considered as the treatment of choice in cervical dystonia. However, high dose treatment and short injections intervals are thought to be risk factors for the development of side effects and BTX A antibodies.

In the following we report on the treatment of 3 patients with cervical dystonia unresponsive to commonly used doses of BTX A. All patients were clear of BTX antibodies. The first patient a 35-year old man attended our clinic with a severe spasmodic torticollis. His head turned to the right side and he showed a mild no-no tremor. He rated his pain with 85 on a visual analogue scale ranging from 0–100. The TWSTRS accounted to 71 points. Accuracy of the injections was checked by ultrasound and EMG guidance. The stepwise increase of the dose from 150 to 460 MU BTX A (BOTOX)resulted in a complete remission of the symptoms. The second patient, a 60–year old man first noticed a tremor of his head at work. He felt pain of the right side of his neck and the head was pulled to the left side (TWSTRS=70; pain scale=90). After failure of 1200 Units of BTX A (Dysport), the patient was switched to treatment with BTX B. While the first injection with 10000 MU of BTX B resulted in some pain relief the following injections up to 25000 MU did not lead to a further improvement of pain or head position. The MRI scan showed marked hypertrophy of the left splenius muscle and the right sternocleidomastoid muscle. The clinical test of BTX senitivity by injecting 1000 MU BTX B into the abductor minimi muscle was negative while 100 MU BOTOX led to a paralysis. Therefore, the patient was commenced on another trial with BTX A and the dose was increased up to 530 MU BTX A.

The third patient a 19-year old Turkish man was referred to our clinic by the paediatric service. His dystonic symptoms started at the age of 12 and he developed a complicated cervical dystonia. The first injections of BTX A were started with a total amount of 320 MU.The dose was increased to 580 MU(BOTOX)resulting in a marked improvement of his head position. In summary, there are some patients who seem to be primary non-responders to BTX treatment but show good treatment results on high doses of BTX A. Misplaced injections could be excluded as reason for treatment failure on lower doses. Remarkably,the effect of BTX A injections occurred suddenly as crossing a threshold. In conclusion high dose treatment with BOTOX was safe and might be indicated in some patients.