Endocrine Abstracts

Clinical Case: A 48-year old male presented with gradual onset of shortness of breath and atrial tachycardia requiring admission to intensive care unit. He was normally fit and well and did not have any history of thyroid/neck surgery. He was an ex-smoker who drank more than 40 units of alcohol per week.

Investigations: Laboratory tests revealed low serum calcium of 1.03 mmol/l (2.15–2.6 mmol/l), high serum phosphate of 2.77 mmol/l (0.9–1.50 mmol/l) and low serum magnesium of 0.53 mmol/l (0.65–1.05 mmol/l). His potassium, alkaline phosphatase and renal function were normal. Electrocardiogram at admission showed atrial tachycardiawith ventricular rate of 180 bpm, left ventricular hypertrophy, T wave depressions in leads V4-6 and prolonged QT interval. Chest x-ray showed cardiomegaly and features of pulmonary oedema. Urgent echocardiogram showed dilated and hypokinetic left ventricle with left ventricular ejection fraction of 27%. His parathyroid hormone was undetectable and he had normal thyroid function tests and vitamin D. He also underwent a coronary angiogram which was normal.

Treatment: Hypocalcaemia, hyperphosphataemia and undetectable parathyroid hormone is consistent with the diagnosis of primary hypoparathyroidism. He was initially treated with intravenous calcium gluconate and magnesium for several days until normalisation of serum calcium and serum magnesium. Following this, he was commenced on long term alfacalcidol and calcium supplementation. An echocardiogram done after three months of treatment showed improved left ventricular ejection fraction and normal left ventricular size. This patient is under long term follow-up with the cardiologist and the endocrinologists.

Conclusions: Dilated cardiomyopathy is a dangerous condition that can be associated with reversible conditions such as alcoholism, peripartum cardiomyopathy and various metabolic conditions. Hypoparathyroidism results in hypocalcaemia and hypomagnesaemia. Hypocalcaemia can cause prolongation of QT interval, ventricular arrhythmias and dilated cardiomyopathy. Calcium ion is important for the excitation of the myocardium and consequently its contractibility. Cardiomyopathy associated with hypoparathyroidism can be reversed when it is adequately treated with calcium and vitamin D supplementation. In these cases, recombinant parathyroid hormone is rarely required. It is important to identify hypocalcaemia as a treatable cause of cardiomyopathy as this can prevent the development of life threatening sequelae.