The “Eyes” Have It. Ophthalmological Findings of Bilateral Cataract in a Boy with Hypoparathyroidism

Abstract

Background: Hypoparathyroidism is a relatively rare pediatric endocrine disorder in which parathyroid hormone (PTH) production is low or absent, resulting in low serum calcium and high phosphorus. In children, hypoparathyroidism is either congenital or acquired and is often associated with a genetic syndrome. Clinical manifestations include neuromuscular hyperexcitability, tetany, cardiac arrhythmias, and seizure. Radiographic findings include basal ganglia calcifications. In adult literature, ophthalmological findings of lenticular opacities and cataract have also been reported in hypoparathyroidism. Due to the rarity of this condition, there is a paucity of ophthalmological findings in children. We report a pediatric case with severe hypocalcemia, recurrent generalize seizures, intracranial calcifications and bilaterally cataracts secondary to hypoparathyroidism. Case: A 7-year-old boy, from a remote area in China, presented to a local hospital with one-year history of paresthesia in hands and feet. Initial lab evaluation revealed hypocalcemia with serum calcium of 1.76 mmol/L (2.03-2.68). Oral calcium supplement was started but symptoms progressively worsened. He was transferred to a tertiary hospital for further evaluation. On admission, physical exam was significant for positive Chvostek and Trousseau signs and lab evaluation showed serum calcium: 1.28 mmol/L (2.15-2.57), phosphorus: 4.2 mmol/L (0.95-1.75), magnesium: 0.97 mmol/L (0.73-1.06), PTH: 2.2 pg/mL (8.7-79), and 25(OH)Vit D: 97.1 mmol/L (36-126). Multiple symmetrical calcifications were found in the frontal lobe and basal ganglia. Ophthalmology consultation revealed bilateral cataracts with impaired vision. Trio whole exome sequencing with copy number variation testing reveled no pathogenic or likely pathogenic copy number and sequence level variants. He was diagnosed with idiopathic acquired hypoparathyroidism. The seizure disorder, intracranial calcification, and bilateral cataracts were attributed to severe and prolonged hypocalcemia secondary to hypoparathyroidism. He had a second episode of seizure after he was admitted, and seizure resolved after treated with midazolam and IV calcium gluconate. He was started on 1,25 (OH)2 vitamin D. Clinical symptoms resolved and he became biochemically eucalcemic with titrated therapy. Summary: Although lenticular changes have been observed in adults with hypoparathyroidism since the 1950’s, hypoparathyroidism and resulting cataract formations are relatively rare. Proposed mechanism of cataract formation in hypoparathyroidism is prolonged hypocalcemia resulting in membrane damage in the aqueous humor and subsequent sodium content increase in the lens. To our knowledge there are no prior pediatric reports of cataracts associated with hypoparathyroidism and signifies the importance of ophthalmologic referral and evaluation.