Sub-acute Posterior Reversible Encephalopathy Associated with Extrapyramidal Signs Induced by Primary Hyperparathyroidism: A Case Report and a Revision of Literature

Aims: We present the case of a subacute psycho-motor deterioration in the context of a hypercalcemic state due to primary hyperparathyroidism inducing a posterior reversible encephalopathy.

Presentation of Case: a 78 year-old man, affected by parkinsonism, developed a subacute psycho-motor deterioration in the course of a month and presented to our attention with generalized seizures. Biochemical analysis revealed hypercalcemia due to primary hyperparathyroidism. After the surgical removal of a hyperfunctioning parathyroid gland, we assisted to a dramatic improvement. Alongside with characteristic MRI findings, the picture was compatible with a posterior reversible encephalopathy syndrome (PRES).

Discussion: To date, this is the third reported case of PRES caused by primary hyperparathyroidism. Our case appears peculiar because of the subacute onset of the syndrome, and of the accompanying progressive worsening of a pre-existing extrapyramidal syndrome. Also, the specific setting of radiologic findings and hormonal anomalies points to a prominent role of endothelial dysfunction in the still debated pathogenesis of PRES.

Conclusion: Our case presents a rare combination of hyperparathyroidism, PRES and parkinsonism. We propose that the Blood-Brain barrier plays a central role in this setting.