Primary Hyperparathyroidism Presenting as Posterior Reversible Encephalopathy Syndrome: A Report of Two Cases

Abstract

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological entity characterized by subcortical vasogenic edema presenting with acute neurological symptoms. Common precipitating causes include renal failure, pre-eclampsia/eclampsia, post-organ transplant, and cytotoxic drugs. Hypercalcemia is a rare cause of PRES; most cases occur in the setting of severe hypercalcemia secondary to malignancy or iatrogenic vitamin D/calcium overdose. Primary hyperparathyroidism (PHPT), as a cause of PRES, is an oddity. We report two cases of adolescent PHPT presenting with generalized tonic-clonic seizures and altered sensorium. On evaluation, both had hypertension, severe hypercalcemia (serum calcium 14.1 mg/dL and 14.5 mg/dL, respectively) and elevated parathyroid hormone levels. Magnetic resonance imaging (MRI) revealed T2/fluid-attenuated inversion recovery hyperintensities located predominantly in the parieto-occipital regions, suggestive of PRES. Identification and excision of parathyroid adenoma led to the restoration of normocalcemia. Neurological symptoms and MRI changes improved subsequently. An extensive literature search revealed only four cases of PHPTassociated PRES; none of them being in the pediatric/adolescent age group. The predominant clinical manifestations were seizures and altered sensorium. All had severe hypercalcemia; three had hypertension at presentation, while one was normotensive. Parathyroid adenomectomy led to normalization of serum calcium and resolution of neurological symptoms and radiological changes. Thus, severe hypercalcemia, although rare in PHPT, can lead to hypercalcemic crisis precipitating acute hypertension that can result in cerebral endothelial dysfunction with the breakdown of the blood-brain barrier, culminating in PRES. We therefore recommend that serum calcium levels should be checked in all patients with PRES and that PHPT be regarded as a differential diagnosis in those with underlying hypercalcemia.

A Novel Adult Case of Recurrent Acute Pancreatitis Caused by Hypercalcemia With Concurrent Manifestation of Posterior Reversible Encephalopathy Syndrome Revealing Undiagnosed Primary Hyperparathyroidism due to an Underlying Parathyroid Adenoma

“…The most similar case was a 12-yearold male who suffered one episode of bilateral tonic-clonic seizures followed by altered sensorium, arterial hypertension (unlike our case that had arterial hypotension), severe hypercalcemia (14.1 mg/dL) and high parathyroid hormone levels due to a left inferior parathyroid adenoma with clinicalradiological resolution following parathyroidectomy and correction of hypercalcemia. 1 Endothelial dysfunction is a critical factor in the underlying pathophysiology of PRES resulting from abrupt changes in blood pressure or direct toxic effects of cytokines that lead to the breakdown of the blood-brain barrier and brain edema. [1][2][3][4][5][6][9][10][11][12][13][14][15] PRES should be considered in patients with acute neurological symptoms, arterial hypertension, renal failure, autoimmune disease, immunosuppressive therapy or chemotherapy, preeclampsia/eclampsia, severe dysautonomia, and infections.…”

“…1 Endothelial dysfunction is a critical factor in the underlying pathophysiology of PRES resulting from abrupt changes in blood pressure or direct toxic effects of cytokines that lead to the breakdown of the blood-brain barrier and brain edema. [1][2][3][4][5][6][9][10][11][12][13][14][15] PRES should be considered in patients with acute neurological symptoms, arterial hypertension, renal failure, autoimmune disease, immunosuppressive therapy or chemotherapy, preeclampsia/eclampsia, severe dysautonomia, and infections. [1][2][3][4][5][6][9][10][11][12][13][14][15] It commonly appears with altered consciousness, seizures, headache, visual disturbances, and, rarely, focal neurological deficits.…”

“…[1][2][3][4][5][6][9][10][11][12][13][14][15] PRES should be considered in patients with acute neurological symptoms, arterial hypertension, renal failure, autoimmune disease, immunosuppressive therapy or chemotherapy, preeclampsia/eclampsia, severe dysautonomia, and infections. [1][2][3][4][5][6][9][10][11][12][13][14][15] It commonly appears with altered consciousness, seizures, headache, visual disturbances, and, rarely, focal neurological deficits. [1][2][3][4][5][6][9][10][11][12][13][14][15] Brain MRI can confirm the edema, which often involves, but is not solely restricted to, parieto-occipital cortical and subcortical structures that resolve within days or weeks.…”

“…Hypercalcemia is an infrequent cause of posterior reversible encephalopathy syndrome (PRES). 1,2 Most reported cases are secondary to iatrogenic vitamin D/ calcium overdose or malignancy. [2][3][4][5][6] Primary hyperparathyroidism is frequently associated with mild-moderate hypercalcemia and rarely leads to PRES.…”

“…[2][3][4][5][6] Primary hyperparathyroidism is frequently associated with mild-moderate hypercalcemia and rarely leads to PRES. 1 Hypercalcemia plays a significant role in the pathogenesis of acute and chronic pancreatitis and should be subjected to complementary tests for detecting endocrine or malignant causes. 7,8 We report a novel case of PRES following recurrent acute pancreatitis caused by hypercalcemia as a presenting manifestation of previously undiscovered primary hyperparathyroidism due to an underlying parathyroid adenoma.…”