[Hyperparathyroidism disclosed by forward sagging of the head].

An unusual clinical presentation of hyperparathyroidism is reported. The 73-year-old patient was unable to maintain her head upright after ten minutes of walking or standing. Parathyroid adenoma was diagnosed on the basis of ultrasound and pathological findings and parathyroid hormone assays. Following surgery the forward sagging of the head no longer occurred and serum levels of calcium and phosphorus returned to normal. Pathophysiological hypotheses are discussed. No similar cases with isolated weakness of the cervical and dorsal paravertebral muscles has been reported to date.