1. INTRODUCTION
Postoperative permanent hypoparathyroidism is characterized by
hypocalcemia, hyperphosphatemia, and low to inappropriately normal
parathyroid hormone levels, which persist more than six months after
surgery.1 It occurs in 0.3% to 5.1% of individuals
who undergo thyroid surgery for thyroid cancer.2-4Severe hypocalcemia can present with carpopedal spasms, tetany,
seizures, and cardiac dysrhythmias. Longstanding postoperative
hypoparathyroidism is characterized by intracranial calcifications of
basal ganglia and cerebellum; calcifications beyond these areas are
rare.1,5 We report the case of a 56-year-old lady who
presented with carpopedal spasms, tetany, generalized tonic-clonic
seizure, and extensive bilateral brain calcifications due to
postoperative permanent hypoparathyroidism.
2. CASE REPORT
A normotensive, nondiabetic 56-year-old lady, who had undergone
near-total thyroidectomy for papillary carcinoma of thyroid 20 years
ago, presented in the emergency department with history of spasms in her
hands and calves, followed by sustained contraction of hand muscles.
Then she had an episode of tonic-clonic generalized abnormal body
movements with uprolling of eyes and frothing from mouth, which lasted
about 30-35 seconds; it was followed by a brief period of confusion and
amnesia. She had been taking calcium, vitamin D, and hormonal
supplements for hypothyroidism after the surgery until five months ago
when she stopped taking them due to her general good condition. Four
months ago, she experienced episodes of calf spasms, which lasted about
five minutes and were severe enough to limit walking. On seeking medical
care, the episodes were attributed to calcium deficiency, and she was
prescribed calcium and cholecalciferol. She had undergone cataract
surgery eight years ago. She had no history of fever, headache,
vomiting, palpitation, or chest pain.
On examination, the patient
had positive trousseau’s sign on tourniquet test, which manifested as
carpopedal spasm: flexion of the wrist and metacarpophalangeal joints,
extension of the interphalangeal joints, and adduction of the thumb. She
had an old, transverse post-surgical scar on her neck. Ophthalmological
evaluation revealed an intraocular lens implant in each eye. There was
no pallor, icterus, clubbing, or lymphadenopathy. Her respiratory,
cardiovascular, abdominal, and neurological examinations were
unremarkable.
Laboratory investigations revealed the following findings: corrected
serum total calcium, 1.25 mmol/L (normal range, 2.1-2.6); serum
phosphorus, 2.19 mmol/L (normal range, 0.8-1.54); Intact Parathyroid
Hormone (IPTH), 5.2 ng/L (normal range, 7.5-53.5); 25-hydroxyvitamin D,
112.07 nmol/L (normal range, 74.88-249.6); magnesium, 0.53 mmol/L
(normal range, 0.69-1.02); serum albumin, 39 g/L (normal range, 38-49);
Alkaline Phosphatase (ALP), 221 U/L (normal range, 90-306); free T3,
3.05 pmol/L (normal range, 4.26-8.1); free T4, 28.3 pmol/L (normal
range, 10.2-28.2); Thyroid Stimulating Hormone (TSH), 0.31 mU/L (normal
range, 0.46-4.68); serum sodium, 138 meq/L (normal range, 135-145); and
potassium, 5.1 meq/L (normal range 3.5-5). Her ECG showed normal sinus
rhythm with no QT interval prolongation.
Computed tomography of the brain revealed extensive bilateral
calcifications involving basal ganglia, thalami, periventricular region,
subcortical fronto-pareito-occipital region, and cerebellum (Figure 1).
The patient was treated with intravenous calcium gluconate, calcitriol,
and magnesium. Serum calcium and magnesium levels were checked daily.
After four days of intravenous calcium treatment, total calcium rose to
2.1 mmol/L. Her spasms subsided, and seizure did not recur. On the fifth
day, intravenous calcium was replaced by oral calcium. She was
discharged on 1500 mg of oral calcium and 1 mcg of oral calcitriol
daily.
The patient was explained about the appropriate supplements and advised
to follow up every three months. She followed up on the third month of
discharge. She had strictly adhered to the treatment regimen and had not
experienced seizure or spasm again; her total calcium level was 2.15
mmol/L (normal range, 2.1-2.6).