Bilateral Basal Ganglia Calcification; An Unusual Initial Presentation of Pseudohypoparathyroidism

Physiological intracranial calcification occurs in about 0.3–1.5% of cases. Hypoparathyroidism and pseudohypoparathyroidism are the most common causes of pathological basal ganglia calcification. A 21-year-old female who was initially evaluated by neurology team for headache and diplopia, underwent MRI of brain which revealed Calcifications involving the bilateral basal ganglia, thalami, dentate nuclei as well as juxtacortical frontal lobes. She reported Fatigue and muscle pain, usually in her arms especially after playing sports which had been going on for many years. She had no history of fractures, seizures, psychiatric disorders, developmental delay or obvious cognitive impairments. She denied any family history of calcium disorders or autoimmune diseases. As she had been generally healthy in her whole life, she never had any lab testing done. On examination, Height 5’1”, Chvostek’s sign was positive. Fundoscopy was normal. she had no dysmorphic features or shortened 4th metacarpal. Investigations revealed serum calcium less than 5.0 mg (N 8.3 - 10.1 mg/dl), PTH 205.1 pg/ml (N 18.4 - 80.1 pg/ml), phosphate 7.1 mg (N 2.5 - 5 mg), Vitamin-D 36.2 ng/ml (N 30.0 - 100.0 pg/ml),magnesium 2.0 m (N 1.6 - 2.6 mg/dl) with normal albumin, alkaline phosphatase and renal function test. She was diagnosed with pseudohypoparathyroidism and started on calcium and active vitamin D supplement and was referred for genetic testing study. She reported significant improvement in myalgia after a few weeks of starting calcium and active vitamin D supplementations and repeat lab testing showed improved hypocalcemia and hyperphosphatemia. This case illustrates unusual presentation of PTH resistance with basal ganglia calcification as initial presentation prompting further workup. She likely has pseudohypoparathyroidism type 1b. Since adequate treatment of hypoparathyroidism may lead to marked clinical improvement, determination of serum calcium, phosphorus, and parathyroid hormone is mandatory in all individuals with calcification of the basal ganglia to rule out hypoparathyroidism.