Idiopathic hypoparathyroidism and systemic sclerosis: An association likely missed
A 59-year-old man with episodic generalized tonic-clonic seizures, instability of gait, and recurrent falls since six months was referred from the neurology clinic for endocrine evaluation for low serum calcium level detected during investigation for seizures. There was no history of tingling, numbness, or tetany of hands or feet. He complained of decreased hearing for the past several years. Examination was significant for dry coarse skin and skin thickening and tightening over the legs, thighs, forearms, and hands [], which was noticed by the patient two years ago but was not interfering with his routine activities. There was no history of skin rash or Raynaud's phenomenon. He complained of intermittent arthritis mainly involving the small joints of the hand and feet along with elbow, shoulder, and knees, with a history of morning stiffness, which was not severe enough to impair his day-to-day activities or take nonsteroidal anti-inflammatory drugs. Trousseau sign was positive at one minute. Chvostek sign was absent. He had slurring of speech, a wide-spaced gait, impaired tandem walking, and positive cerebellar signs. Pure tone audiometry revealed bilateral moderate sensorineural hearing loss. Biochemical evaluation was significant for persistent hypocalcemia, hyperphosphatemia, normal serum magnesium, 25-hydroxyvitamin D, and low intact parathyroid hormone []. Antinuclear antibody (ANA) was positive (titer >1:320) with centromere pattern (indirect immunofluorescence, Hep-2 cells). Anti-topoisomerase-1 (Sci-70) antibody was strongly positive (BlueDOT ENA®, Belgium); anti-U1RNP antibody (RNP: ribonucleoprotein) and rheumatoid factor were negative. Anti-thyroid peroxidase (TPO) antibody was strongly positive []. Parathyroid glands could not be visualized on high-resolution ultrasonography and magnetic resonance imaging (MRI) of the neck. Computed tomography (CT) of the brain revealed diffuse symmetric calcification in the basal ganglia and cerebellum []. Skin biopsy from the right thigh revealed hyperkeratosis and increased pigmentation of the basal cell layer, increased collagen in the dermis, and perivascular lymphomononuclear cell infiltration with atrophy of skin appendages compatible with scleroderma [].\nA diagnosis of idiopathic hypoparathyroidism with systemic sclerosis was made in a gentleman who had presented with recurrent seizures and cerebellar ataxia and had diffuse skin tightening of all four limbs with arthritis. Calcium carbonate was started at 2 g/day in divided doses increased to 3 g/day over eight weeks. Calcitriol was started at 0.5 μg/day and increased to 1 μg/day over eight weeks. Phenytoin 300 mg/day was changed to sodium valproate 750 mg/day for seizure prophylaxis. Last evaluated 10 months after the initial diagnosis, his ataxia had improved and he was seizure-free with negative Trousseau sign. Serum calcium was being maintained at low-normal levels and serum phosphorus had normalized.