Carl Swartling

Focal palmar hyperhidrosis can be effectively abolished by intradermal injections with botulinum toxin. Muscle weakness of finger grip has been reported as a reversible side-effect of this new treatment. The objective of this work was to measure muscular side-effects after treatment of palmar hyperhidrosis with botulinum toxin. As botulinum toxin has been used in the treatment of pain, we studied whether the toxin might influence afferent thin-fibre function by measuring temperature perception thresholds. Thirty-seven patients treated with botulinum toxin (Botox, Allergan Pharmaceuticals, Irvine, CA, USA) showed a decrease in compound muscle action potential (CMAP) for both abductor pollicis brevis (APB) and abductor digiti minimi (ADM) compared with pre-injection values on average by 64 and 36%, respectively, at 3 weeks which returned nearly to normal at 37 weeks. Muscle power for both finger abduction and finger opposition decreased to a lesser extent. Repetitive nerve stimulation and single fibre electromyography (EMG) showed a disturbed neuromuscular transmission. Thus, despite careful technique with small doses of botulinum toxin injected intradermally, the toxin diffuses to underlying muscles. With regard to the present results, one should be careful in using higher doses of Botox than 0.8 mU/cm(2) in the palmar skin above intrinsic muscles. No influence on thin-fibre function was seen.

The Essential Tremor Rating Assessment Scale was developed by the Tremor Research Group (www.tremorresearchgroup.org) to quantify essential tremor severity and its impact on activities of daily living. This scale requires only a pen and paper, and can be completed in about 10 minutes. Upper extremity action tremor is the main focus of this scale, but action tremor is also assessed in the head, face, voice, and lower limbs. The scale has excellent face validity, inter-and intra-rater reliability, and sensitivity to change. The activities of daily living section correlates strongly with the performance section, and this scale also correlates strongly with transducer measures of tremor and with the Fahn-Tolosa-Marn tremor rating scale. In the Fahn-Tolosa-Marn tremor rating scale, upper extremity tremor greater than 4 cm corresponds to a maximum rating of 4, while grade 4 tremor in the Essential Tremor Rating Assessment Scale corresponds to an amplitude greater than 20 cm. Therefore, the Essential Tremor Rating Assessment Scale is better suited for assessment of severe essential tremor.

Focal hyperhidrosis is a relatively common condition in which patients experience excessive sweating, usually of the palms, axillae, face or feet. Until recently, the only effective treatment option for this chronic condition was surgery. We aimed to evaluate the efficacy and tolerability of botulinum toxin type A (BTX‐A) in the treatment of patients with hyperhidrosis, establishing optimum dosages and methods of administration. One hundred and seventy patients with focal hyperhidrosis were referred for treatment, the majority with palmar and axillary hyperhidrosis. The iodine‐starch test was used to locate and show the extent of the hyperhidrotic area. Using a template to mark the injection sites, 2 U doses of BTX‐A were injected intradermally at regular intervals. Patients received either 0.5 or 0.8 U/cm 2 with regional anaesthesia if required. The iodine starch test and measurements of evaporation were used to assess efficacy. The majority of patients reported a marked reduction in sweating, About one‐third of the patients who received BTX‐A 0.5 U/cm 2 requested supplementary small injections into islands of skin where they experienced residual sweating. As a result, the standard dose was increased to BTX‐A 0.8 U/cm 2 . The median duration of treatment effect was 10 months (range, 3 to >14 months). The effectiveness of BTX‐A was not reduced by repeated use. BTX‐A treatment was well tolerated by all patients. In conclusion, chemical sudomotor denervation with BTX‐A should be recommended before surgical sympathectomy for the treatment of focal hyperhidrosis.