An unusual cause of older adult falls: Stiff Leg Syndrome

Mr. B. was hospitalized for repeated falls and a painful syndrome of his right leg evolving since several weeks. The symptoms began with paroxysmal painful contractures in the lower back and in the right leg. Progressively, a hypertonia of the lower limb has settled, leading to falls, loss of independence and use of a rolling chair. On the clinical examination, we noticed a global contraction of the right leg, with an ankle in equinovarus and a quasi-irreducible flexion at 20 degrees of the knee. Muscle spasms were very painful, triggered by muscle contractions and by emotion. An electrophysiological study was performed. The needle electromyography objectived abnormal muscular activities at rest with a continue muscle activity on the right adductor, quadriceps, anterior tibialis and on muscles of the feet (Fig. 1). Motor and sensory nerve conduction variables, including: motor nerve conduction velocities, distal latencies and amplitudes were within normal. Analysis of the cerebro-spinal fluid was normal. On the immunological findings, anti-nuclear antibodies, anti-neutrophil cytoplasmic antibodies and onco-neural antibodies were negative. Glutamic Acid Decarboxylase antibodies (GAD) were positive at 111 U/ml (N: 0–1). The clinical examination, electrophysiological and immunological findings led to the diagnosis of a limited form of Stiff-man syndrome: a Stiff-leg syndrome.