Abstract #1014122: COVID-19 Associated Hypercalcemia , A Rare Yet Interesting Case

Abstract

1004352 Uremic Leontiasis Ossea Causing Acute Monocular Blindness Author Block: Azeen Anjum, MD primary author, Internal Medicine, Texas Health Presbyterian Hospital of Dallas Introduction: Uremic leontiasis ossea (ULO) is a form of renal osteodystrophy characterized by overgrowth of facial and cranial bones. This condition can sometimes lead to compression of nerves, vessels, or the upper airway. This is a rare case of ULO causing compressive optic neuropathy leading to acute monocular blindness. Case Description: A 36 year-old man with end stage renal disease (ESRD) due to post-streptococcal glomerulonephritis on hemodialysis (HD) for 15 years presented with acute left-sided monocular vision loss. Physical exam was significant for facial deformity with bilateral mandibular enlargement. Laboratory analysis revealed parathyroid hormone (PTH) level of 2,309 pg/mL (8.7-77.1), calcium of 8.1 mg/dl (8.6-10.0), vitamin D 25-hydroxy of 16.8 ng/ml (30-80), inorganic phosphorus of 3.2 mg/dl (2.4-4.4), and serum alkaline phosphatase of 837 U/L (40-150). CT Head showed diffuse osseous expansion of the calvarium and facial bones with significant stenosis of the bilateral orbital apices and optic canals. Fundoscopic exam demonstrated a left-sided pale optic nerve with diffuse nerve edema, consistent with optic nerve compression. High-dose steroids were started with partial improvement in light perception in the left eye. He was discharged with follow-up with oculoplastic surgery for surgical decompression evaluation. Discussion: ULO is seen in poorly-managed ESRD patients who have chronic uncontrolled secondary hyperparathyroidism, like our patient. Treatment for renal osteodystrophy is primarily prevention with dietary modification, medical management, and regular HD. Unfortunately our patient had not been compliant with his diet, S105 medications, or HD, which likely lead to his ULO. There are only two other reported cases of ULO causing optic nerve compression. There is no standardized treatment for complications of ULO but parathyroidectomy and steroids followed by surgical decompression have been successful. This case highlights the importance early recognition and treatment of secondary hyperparathyroidism. It is important to consider ULO on the differential for acute cranial nerve palsy in a patient with uncontrolled hyperparathyroidism due to ESRD. https://doi.org/10.1016/j.eprac.2021.04.691