Posterior reversible encephalopathy syndrome and parkinsonism as the first manifestation of primary hyperparathyroidism - a report of two cases

Primary hyperparathyroidism (PHPT) may be asymptomatic or present with renal calculi, secondary osteoporosis, fractures and neuropsychiatric manifestations. Posterior reversible encephalopathy syndrome (PRES) and parkinsonism are atypical manifestations that may be rarely associated with PHPT. We report two patients who presented with the conditions mentioned above.

The first patient involved a 38-year-old woman who presented with diminution of vision, seizures, altered behavior and hypertension over eight months. An MRI of the brain done had shown vasogenic edema involving the parieto-occipital regions, suggestive of PRES. A metabolic screen revealed PTH-dependent hypercalcemia that was localized to the left inferior parathyroid gland. Following focused parathyroidectomy, there was improvement in sensorium, vision and normalization of blood pressure. The second patient was of a 74-year-old man who presented with progressive extrapyramidal symptoms of gait abnormalities and rigidity since the past eight months. He was initiated on Selegeline and Levodopa for the same purpose, and subsequently reported minimal improvement in symptoms. Investigations revealed PHPT associated with a right inferior parathyroid adenoma. Within two weeks following surgery, there was an improvement in rigidity and gait and he was able to ambulate without support.

PRES has been reported to occur in the context of preeclampsia, hypertension, infection, sepsis and autoimmune conditions. PRES associated with hypercalcemia is rarely reported. While extra-pyramidally related manifestations are described in hypoparathyroidism, PHPT related parkinsonism is not commonly encountered. Identifying the underlying aetiology and initiation of corrective measures may lead to amelioration of patient symptomatology.

The occurrence of PRES and parkinsonism is rare in primary hyperparathyroidism; the two patients described above highlight the importance of screening for hypercalcemia in the setting of neurological manifestations.