Dementia as presenting symptom of primary hyperparathyroidism: favourable outcome after surgery.

The case of a 76-year-old female patient is presented with a two-year history of progressive dementia, apathy and gait impairment. Initially, Alzheimer's disease was diagnosed and she was given donepezil for one year with no significant improvement. An extensive blood and biochemical control revealed high serum calcium and parathormone levels, and normal thyroid hormones and anti-thyroid antibodies. Ultrasound of thyroid and parathyroid glands revealed an adenoma of the right parathyroid. The detailed investigation for causes of secondary hyperparathyroidism was negative. Due to the absence of clinical hyperparathyroidism she was initially treated conservatively. At referral, the neurological picture consisted of: mild signs of parkinsonism, moderate dementia (MMSE=15) and severe behavioural disturbances. Because of the continuous aggravation of the cognitive deficit, parathyroidectomy was decided although there were no clinical or laboratory signs of involvement from other organs. Three weeks after the operation the neurological picture showed dramatical improvement. Parkinsonism and behavioural disorders were remarkably reduced and the MMSE score raised to 25. In summary we report an exceptional case of primary hyperparathyroidism (PHPT) presenting as dementia and treated successfully by parathyroidectomy.