Normal left ventricular performance documented by Doppler echocardiography in patients with long-standing hypocalcemia

Evaluation of the left ventricular systolic strain in hypocalcemic infants with two-dimensional speckle tracking echocardiography

INTRODUCTION

Speckle tracking echocardiography (STE) is a new emerging method for evaluation of the cardiac systolic performance. We characterized left ventricular (LV) systolic functions of hypocalcemic infants, and assessed the effects of calcium and vitamin D supplementations on LV systolic functions using two-dimensional STE.

PATIENTS AND METHODS

A prospective controlled study was conducted in Mansoura University Children's Hospital, Egypt from 2015 to 2018 including 88 hypocalcemic infants (patient group) and 30 healthy controls. We subdivided the patient group into vitamin D deficiency group (n = 32) and normal vitamin D group (n = 56). All infants were investigated for serum phosphorus, alkaline phosphatase and 25-hydroxy vitamin D levels. Both patients and controls were initially evaluated for LV systolic functions using two-dimensional STE. After correction of hypocalcemia and vitamin D deficiency, reevaluation of LV systolic functions was done for the patient group.

RESULTS

LV systolic strains were lower in the patient group than controls (p < .001). After recovery of hypocalcemia of the patients, we reported significant improvement of strains and significant reductions of the end-diastolic and end-systolic volumes of the left ventricle (p < .001). Global longitudinal and circumferential strains were lower in patients with vitamin D deficiency than patients with normal vitamin D levels (p < .001). The LV systolic strain improved after correction of vitamin D deficiency and hypocalcemia (p < .001).

CONCLUSION

Two-dimensional STE could detect and follow up early LV systolic dysfunction in infants with hypocalcemia and vitamin D deficiency.

Manifestations of left ventricular dysfunction and arrhythmia in patients with chronic hypoparathyroidism and pseudohypoparathyroidism: a preliminary study

BACKGROUND

Cardiac damage triggered by severe hypocalcemia is well known. However, the role of chronic hypoparathyroidism (HP) and pseudohypoparathyroidism (PHP) in cardiac health is still unclear. We investigated the effect of chronic HP and PHP on cardiac structure and conductive function in patients compiling with treatment.

METHODS

The study included 18 patients with HP and eight with PHP aged 45.4 ± 15.4 and 22.1 ± 6.4 years, respectively with a previously regular follow-up. In addition, 26 age- and sex-matched healthy controls were included. General characteristics and biochemical indices were recorded. Cardiac function and structure were assessed by estimation of myocardial enzymes, B-type natriuretic peptide (BNP), and echocardiography. The 12-lead electrocardiogram and 24-h Holter electrocardiography were performed to evaluate the conductive function.

RESULTS

Levels of serum calcium in HP and PHP were 2.05 ± 0.16 mmol/L and 2.25 ± 0.19 mmol/L, respectively. The levels of myocardial enzyme and BNP were within the normal range. Adjusting for age at evaluation and body mass index, all M-mode measurements, left ventricular mass (LVM), LVM index (LVMI) and relative wall thickness (RWT) were comparable between patients and controls. Prolongation of corrected QT (QTc) intervals occurred in 52.6% (10/19) of patients, and 6.7% (1/15) of patients manifested more than 100 episodes of supraventricular and ventricular extrasystoles, as well as supraventricular tachycardia. None of the above arrhythmias was related to a severe clinical event.

CONCLUSIONS

From this pilot study, patients diagnosed with HP and PHP and well-controlled serum calcium levels manifested normal cardiac morphology and ventricular function, except for prolonged QTc intervals, and a small percentage of mild arrhythmias needing further investigation.

Clinical presentation and management of hypoparathyroidism

The clinical manifestations of hypoparathyroidism are variable and can involve almost any organ system. The main clinical features of the hypoparathyroidism are typically signs or symptoms due to neuromuscular irritability owing to low serum calcium level. In addition to hypocalcemia, hyperphosphatemia can contribute to long-term complications, including extra-skeletal calcifications. Bone turnover markers are generally decreased, and bone mass density is usually normal-increased compared to age- and gender-matched controls. It is still unclear whether or not these bone features could have an impact on the risk of fracture. Impaired renal function is a common complication described in patients treated for hypoparathyroidism. Other complications include premature cataracts, seizures, basal ganglia calcifications, and cardiac arrhythmias. Lastly, some clinical studies have also reported a reduced quality of life of patients with hypoparathyroidism. Increased awareness of the clinical manifestations of this disease is important to improve its clinical management.

Hypoparathyroidism

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.

Hypoparathyroidism - disease update and emerging treatments

Parathyroid hormone (PTH) is the primary regulator of blood calcium levels and bone metabolism. Insufficient levels of PTH lead to hypoparathyroidism, characterized by low serum calcium and elevated serum phosphate levels. It is most commonly caused by the inadvertent damage to the parathyroid glands during thyroid surgery. Patients with hypoparathyroidism are currently being treated with oral calcium and active vitamin D, and to avoid worsening hypercalciuria, target serum calcium levels are within the lower end of normal. With current treatment, patients may suffer from large swings in serum calcium and are at a substantial risk of chronic renal failure, nephrocalcinosis, and kidney stones. The recent FDA approval of recombinant human (rh) PTH(1-84) for the treatment of hypoparathyroidism adds PTH replacement therapy to the endocrinologist's armamentarium to treat this chronic disease.

Hypocalcemic Heart Failure in Thalassemic Patients

Hypocalcemic cardiomyopathy in primary or secondary hypoparathyroidism is usually refractory to conventional treatment of cardiac failure. We report the case of a thalassemic patient with severe cardiac failure that might have been attributed to several factors, such as hemosiderosis, hypomagnesemia, and hypocalcemia, refractory to conventional cardiac therapy. Cardiac echocardiography showed impaired biventricular performance, and laboratory analyses revealed hypoparathyroidism due to hemosiderosis. When concomitant treatment of heart failure and calcium supplementation was initiated, correction of hypocalcemia resulted in clinical and laboratory improvement, providing strong evidence in support of our hypothesis about hypocalcemic myocardiopathy.

A novel mutation (E767K) in the second extracellular loop of the calcium sensing receptor in a family with autosomal dominant hypocalcemia

Autosomal dominant hypocalcemia resulting from gain-of-function mutations of the calcium sensing receptor (CASR) is a rare familial disorder that can become evident at any age. We report a novel mutation (E767K) of the CASR in a family with autosomal dominant hypocalcemia. Ten members of the family had a history of hypocalcemia. The index case exhibited marked hypocalcemia and seizures in the newborn period, while her father who also has hypocalcemia, was largely asymptomatic except for a myocardial infarction-like event at 21 years of age, a new presentation of the disorder. The E767K mutation, which resides in the second extracellular loop adjacent to the fifth transmembrane domain, co-segregated with hypocalcemia in these two individuals. Both subjects are heterozygous for the mutation. The proband is also heterozygous for the previously reported CASR polymorphism of G990R in the intracellular domain, while her father is homozygous. The co-segregation of this naturally occurring mutation with autosomal dominant hypocalcemia supports the previously reported experimental model in which it was proposed that the three acidic residues (767, 758, and 759) in exo-loop 2 in CASR help maintain an inactive conformation of the receptor.

Assessment and management of patients with abnormal calcium

Calcium is essential for homeostasis, and normocalcemia should be maintained strictly during the perioperative period. The biochemistry of calcium equilibrium results from the calcium-sensing receptors on the parathyroid glands, which detect changes in calcium concentrations and initiate the proper response. Asymptomatic hypercalcemia is a common metabolic derangement that is often discovered on routine serum screening. The most common etiologies are primary hyperparathyroidism and cancer. Increasingly, parathyroidectomy is the preferred therapy for primary hyperparathyroidism. Severe hypercalcemia ("hypercalcemic crisis") should be managed aggressively with a combination of intravenous fluids, steroids, bisphosphonates, and calcitonin. Some of these patients may require an urgent parathyroidectomy for calcium control. Hypocalcemia needs to be verified, as many cases of hypocalcemia are the artifact of hypoalbuminemia. Severe hypocalcemia occurs after subtotal or total parathyroidectomy with auto transplantation as well as after massive resuscitation or blood transfusion. Strategies aimed at correcting calcium concentrations depend on the severity of symptomatology. If symptoms are mild, oral calcium supplementation can be given; otherwise, intravenous calcium should be administered.

ECG changes in a 25-year-old woman with hypocalcemia due to hypoparathyroidism. Hypocalcemia mimicking acute myocardial infarction

The case of a 25-year-old woman presenting with chest pain, ECG changes, and laboratory findings suggestive of myocardial infarction is reported. Cardiac catheterization showed impaired left ventricular performance but otherwise normal coronary arteries. Laboratory analyses revealed primary hypoparathyroidism, and supplementation with calcium and vitamin D(3) was initiated. There was subsequent improvement in laboratory findings as well as echocardiographically determined left ventricular performance. Thereafter, the patient remained asymptomatic. Apart from some persisting ECG repolarization disturbances, there was complete normalization of the initial changes. This case demonstrates a combination of clinical, blood biochemical, and ECG findings mimicking acute myocardial infarction.