Long-Term Effect of Gabapentin in Stiff Limb Syndrome: A Case Report

Neurological examination revealed increased muscle tone in the left leg but was otherwise normal. Thyrotropin was slightly elevated. Other routine blood analyses, cerebrospinal fluid examination and magnetic resonance imaging of the brain and spinal cord were normal. Electromyography showed continuous and simultaneous motor unit firing in agonistic and antagonistic muscles. A diagnosis of SLS/SPS was confirmed by elevated antibodies against the 65-kD isoform of glutamic acid decarboxylase (GAD65) in serum (1,164 units, normal ! 100), and presence of antiGAD65 antibodies in cerebrospinal fluid. Both rigidity and spasms responded to treatment with 12 mg diazepam daily. She became able to walk without aid, but pronounced sedation prohibited car driving. Gabapentin was therefore introduced at 400 mg 3 times daily after 2 months and was immediately followed by further symptom relief and allowed reduction of diazepam to 5–7 mg daily. The condition remained stable for another half year. Gabapentin was then increased to 2,400 mg per day over a period of 1 week, with further improvement of rigidity and spasms. The condition has remained stable on this treatment for 7 years. She has not Dear Sir, Diagnosis and treatment of stiff person syndrome (SPS) and stiff limb syndrome (SLS) are often challenging [1] . Diazepam is widely used as first-line symptomatic treatment, but high doses, leading to sedation, are often needed. Alternative symptomatic treatment is therefore needed, and several other GABAergic drugs have been suggested [2] . However, clinical trials are hampered by the rarity of the disease, and actual reports on the effect of these drugs are scarce or lacking. This is the first case report on gabapentin in SPS and SLS, suggesting that gabapentin may have good and enduring effects combined with a favourable adverse effect profile in these conditions.