A Complicated Case of Posterior Reversible Encephalopathy Syndrome (PRES) Secondary to Severe Hypercalcemia

Background:PRES is a rare but severe condition with highly variable neurologic manifestations ranging from headaches to seizures, coma and radiologic findings of focal vasogenic edema(1). It is commonly caused by hypertension, chronic renal failure, preeclampsia / eclampsia and immunosuppressants. We are reporting a rare presentation of PRES caused by severe hypercalcemia. Clinical Case: A 29- year old female presented with frontal headaches, visual disturbance, emesis and confusion. Her medical history was relevant for hyperthyroidism treated with partial thyroidectomy (on methimazole) and complicated by iatrogenic hypoparathyroidism. The resulting hypocalcemia was managed with calcitriol and calcium supplementation. On presentation, the patient was awake but disoriented. Physical examination was remarkable for right-sided hemianopsia. Admission blood pressure (BP) was 192/127 suggestive of hypertensive emergency. Initial laboratory tests revealed severe hypercalcemia (calcium: 18.7 mg/dL, ionized: 2.1 mmol/L), acute kidney injury (creatinine of 2.5 mg/dL, (baseline = <1), elevated 1, 25-dihydoxy vitamin D: 65.1 pg/mL, PTH <1 pg/mL, and negative urine toxicology. Head CT without contrast revealed symmetric bilateral parieto-occipital parenchymal hypoattenuation and MRI confirmed the aforementioned findings to be consistent with PRES. The patient was admitted to the ICU and started on Nicardipine intravenous (IV) infusion, IV fluids and calcitonin. Other causes of severe hypercalcemia such as multiple myeloma and hypercalcemia of malignancy were ruled out. Home calcium and calcitriol supplements were discontinued due to suspicion of intoxication. After correction of serum calcium levels her encephalopathy, hypertension and AKI resolved. She was subsequently transferred to the medical floor in stable condition. Calcium supplementation was resumed when serum calcium level normalized and calcitriol was held until further follow up of calcium levels as outpatient. Conclusion: Severe hypercalcemia is a rare cause of PRES secondary its effect on vascular smooth muscle vasoconstriction and increased vascular resistance leading to severe hypertension. Thus, it is imperative to establish a prompt diagnosis and rule out hypercalcemia in all patients presenting with PRES to prevent its devastating neurologic complications. Reference: Fugate JE, Rabinstein AA. Posterior reversible encephalopathy syndrome: clinical and radiological manifestations, pathophysiology, and outstanding questions. Lancet Neurol. 2015 Sep;14(9):914–925. doi: 10.1016/S1474-4422(15)00111-8. Epub 2015 Jul 13. Erratum in: Lancet Neurol. 2015 Sep;14(9):874. PMID: 26184985.