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Q1: What is the underlying condition, which can explain his thick tongue and cranial computed tomogram abnormalities?
Chronic hypocalcaemia can explain his symptom and sign of a thick tongue, and cranial computed tomography finding of bilateral basal ganglia calcification. His thick tongue was a manifestation of Schultze's sign of latent tetany: a mechanical stimulation of the tongue is followed by local muscle contraction.1 2
Clinically Chvostek's and Trousseau's signs were positive. The electrocardiogram revealed sinus tachycardia, and a corrected QT interval of 0.56 seconds (normal 0.36–0.43). Serum calcium was 1.03 mmol/l (2.12–2.62), phosphorus 3.48 mmol/l (0.8–1.4), vitamin D3 concentration 23 pmol/l (36–144), and serum parathyroid hormone concentration 1.2 pmol/l (10–65). The blood counts and concentrations of serum sodium, potassium, magnesium, and creatinine were normal. The serum alkaline phosphatase was 168 U/l (40–125), lactate dehydrogenase 2860 U/l (230–460), and creatine phosphokinase 674 U/l (30–200). The low parathyroid concentration with severe hypocalcaemia indicated hypoparathyroidism, most probably idiopathic hypoparathyroidism.
Box 1: Other cardiovascular manifestations of hypocalcaemia
Prolongation of QT interval.6
Refractory life threatening hypotension (secondary to vasodilatation and diminished aldosterone secretion).7
QRS and ST changes on electrocardiography simulating acute myocardial infarction or conduction abnormalities.8
Raised plasma creatine phosphokinase (of skeletal muscle origin).7
Improvement in cardiac output, peak velocity of blood flow, and exercise tolerance in asymptomatic hypocalcaemic patients on calcium replacement.10
Q2: What is the pathophysiology of his cardiac failure?
The pathophysiology of his cardiac failure is chronic hypocalcaemia leading to hypocalcaemic dilated cardiomyopathy and cardiac failure. Hypocalcaemia leads to decreased myocardial contractility, clinically this may translate into congestive heart failure. The congestive cardiac failure in hypocalcaemia is refractory to diuretics and digitalis but rapidly responds to restoration of calcium concentrations to normal.3 Calcium infusion increases both cardiac output and blood pressure in hypoparathyroid patients suggesting a subclinical direct cardiac dysfunction due to hypocalcaemia,4 but hypomagnesaemia and reduced circulating parathyroid hormone may also be involved in causing dilated cardiomyopathy in hypoparathyroidism.5
Q3: What are the other cardiovascular manifestations of this condition?
For other cardiovascular manifestations of this condition see box 1.
Echocardiography showed enlarged left and right ventricles, and mitral and tricuspid regurgitation. Hypocalcaemic cardiomyopathy with congestive cardiac failure and tetany were diagnosed, both secondary to idiopathic hypoparathyroidism of long duration. He was managed with intravenous calcium chloride, oral calcitriol, and oral calcium carbonate. The attacks of thick tongue did not recur, and cardiac failure rapidly subsided. He became normocalcaemic over a period of four days with a QTc of 0.41 s. Over a follow up period of six months his echocardiogram reverted to normal, and he is doing well.
Suspect hypocalcaemic cardiomyopathy in a patient presenting with thick tongue (or other manifestations of tetany) and unexplained cardiac failure.
Lack of awareness of this condition may lead to inappropriate therapy of cardiac failure with loop diuretics, leading to a worsening of hypocalcaemia and its possible acute life threatening manifestations (laryngeal spasm, prolonged QTc, ventricular arrhythmias, and refractory hypotension), by increasing renal excretion of calcium.
Hypoparathyroidism presenting with hypocalcaemic cardiomyopathy and lingual tetany.