Paraneoplastic PRES from lymphoma induced hypercalcemia: Case report and review of the literature

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

BACKGROUND/OBJECTIVE

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.

CASE REPORT

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.

DISCUSSION

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.

CONCLUSION

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.

Malignant Hypercalcemia: A Rare Etiology of Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a rare and severe neurotoxic encephalopathic state characterized by variable neurologic manifestations ranging from headache and confusion to seizures, coma, and reversible subcortical vasogenic edema on imaging. PRES is commonly induced by chronic renal failure, hypertension, chemotherapeutic drugs, and eclampsia. PRES induced by hypercalcemia is uncommon and not widely underlined in the literature. We underline a case of a 61-year-old female diagnosed with advanced breast carcinoma presented with altered sensorium and generalized limb weakness. She was found to have malignant hypercalcemia, and brain imaging demonstrated subcortical vasogenic edema in the occipital and frontal lobe, suggestive of PRES. Her condition gradually improved after the treatment of hypercalcemia.

Vitamin D deficiency attenuates endothelial function by reducing antioxidant activity and vascular eNOS expression in the rat microcirculation

This study examined the effects of vitamin D deficiency on vascular function and tissue oxidative status in the microcirculation; and whether or not these effects can be ameliorated with calcitriol, the active vitamin D metabolite. Three groups (n = 10 each) of male Sprague Dawley rats were fed for 10 weeks with control diet (CR), vitamin D-deficient diet without (DR), or with oral calcitriol supplementation (0.15 μg/kg) for the last four weeks (DSR). After 10 weeks, rats were sacrificed; mesenteric arterial rings were studied using wire myograph. Oxidative stress biomarkers malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were measured in the mesenteric arterial tissue. Vascular protein expression of endothelial nitric oxide synthase (eNOS) was determined by Western blotting. Acetylcholine-induced endothelium-dependent relaxation of DR was lower than CR. eNOS expression and SOD activity were lower in mesenteric arterial tissue of DR compared to CR. Calcitriol supplementation to DSR did not ameliorate the above parameters; in fact, augmented endothelium-dependent contraction was observed. Serum calcium was higher in DSR compared to CR and DR. In conclusion, vitamin D deficiency impaired microvascular vasodilation, associated with eNOS downregulation and reduced antioxidant activity. Calcitriol supplementation to vitamin D-deficient rats at the dosage used augmented endothelium-dependent contraction, possibly due to hypercalcaemia.

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

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 39 year-old woman with milk-alkali syndrome complicated by posterior reversible encephalopathy syndrome

Milk-alkali syndrome (MAS) is characterized by the triad of hypercalcemia, metabolic alkalosis, and acute kidney injury. Once thought to be a rare condition, there has been a resurgence of cases due to the consumption of calcium-containing supplements for osteoporosis prevention and dyspepsia in the general population. We describe the case of a female who presented with acute encephalopathy, hypercalcemia, and new-onset seizure. An extensive hypercalcemia workup and ruling out of other causes led to the diagnosis of MAS from excessive intake of calcium carbonate. Brain magnetic resonance imaging revealed signal abnormalities in the occipital and posterior parietal lobes that were indicative of posterior reversible encephalopathy syndrome. The patient's encephalopathy resolved after treatment of her hypercalcemia with fluid resuscitation and cessation of her calcium supplements. We present our case to highlight this unusual presentation of MAS, challenges in diagnosis, and briefly discuss the pathophysiology underlying hypercalcemia-induced encephalopathy.