A reversible form of cardiomyopathy

Hypocalcemic cardiomyopathy-different mechanisms in adult and pediatric cases

BACKGROUND

Hypocalcemic cardiomyopathy (CMP) is a rare but potentially reversible cause of heart failure. However, the mechanism of hypocalcemia seems to differ between infants and adults. Although severe vitamin D deficiency alone is the usual cause of hypocalcemic CMP in infants, in adult patients significant cardiac dysfunction usually occurs as a result of hypoparathyroidism, either isolated or in combination with vitamin D deficiency. We present two cases of hypocalcemic CMP-one adult and one pediatric-to highlight these differences.

CASE PRESENTATION

The first patient was a 47-year-old female who presented with progressive dyspnea and fatigue and was found to have severe left ventricular (LV) systolic dysfunction (LV ejection fraction, 25%). Her serum calcium level was 3.5 mg/dL, serum phosphorus level was 5.7 mg/dL, and serum 25-hydroxyvitamin D level was 14.1 ng/mL, along with a serum PTH level of 11.8 pg/mL. Her LV ejection fraction normalized completely over 6 months with calcium and calcitriol treatment. In contrast, the second patient was an infant who had presented in cardiogenic shock. Investigations revealed serum calcium of 4.5 mg/dL, serum phosphorus of 11.9 mg/dL, 25-hydroxyvitamin D of 8.9 ng/mL, and serum PTH level of 670 pg/mL. Calcium and calcitriol supplementation resulted in rapid and complete clinical and hemodynamic recovery.

CONCLUSION

Hypocalcemia is a rare but treatable cause of dilated CMP. In infants, hypocalcemia is usually due to maternal vitamin D deficiency and is accompanied by compensatory hyperparathyroidism. In contrast, in adult patients, hypocalcemic CMP is usually a result of hypoparathyroidism, with or without concomitant vitamin D deficiency.

PTHrP-associated hypercalcemia of pregnancy resolved after delivery: a case report

A 35-year-old oriental woman, who was 32 weeks pregnant, was hospitalized with suspected preeclampsia. Subsequently, she developed stupor and lethargia. Biochemical assessment showed severe hypercalcemia (21 mg/dl) with undetectable parathyroid hormone (PTH) and markedly elevated PTH-related peptide (PTHrP) levels (26 pmol/l, normal values <1.1 pmol/l). The patient was treated with i.v. fluid administration, which resulted in an unsatisfactory reduction in serum calcium. Therefore, a cesarean section was performed to deliver the baby. Serum calcium levels promptly normalized after delivery with undetectable PTHrP levels. She delivered a healthy infant only presenting with transient mild jaundice and slightly prolonged QT interval with serum calcium level of 7.8-8.4 mg/dl (corrected for albumin levels). In the subsequent days, the patient developed a transient 'hungry bone' syndrome (calcium 6.7 mg/dl, phosphorous 2.1 mg/dl, and PTH 100.4 pg/ml). In conclusion, this pregnant patient presented with PTHrP-associated hypercalcemia, presumably of placental origin. Delivery resulted in prompt reduction of serum calcium levels and a transient 'hungry bone' syndrome.

Heparin-induced transient prolongation of the QT interval during endovascular embolisation of intracranial aneurysm

Prolonged QT interval and increased QT(C) dispersion have been described immediately following rupture of intracranial aneurysm, due to increased sympathetic activity. Here, we report a patient with transient prolongation of the QT interval, probably due to heparin-induced hypocalcaemia, which occurred during coiling of a right internal carotid aneurysm, 54 days after ictus. Correction of the hypocalcaemia led to resolution of the electrocardiogram and blood pressure abnormalities.