Address of Corresponding Author

Horm Res 2004;62:84-87 (DOI: 10.1159/000079539)

  Key Words

• Ventricular flutter
• Catecholaminergic polymorphic ventricular tachycardia
• Hypokalaemia
• Growth hormone deficiency
• Growth hormone stimulation test

  Abstract

We report the observation and analysis of a new adverse event during the insulin tolerance test (ITT) and propose additional safety procedures. An 8-year-old girl with growth hormone insufficiency had a cardiac arrest due to ventricular flutter when she was tested for growth hormone deficiency by the ITT. Severe hypokalaemia (K⁺ 2.6 mmol/l) was observed after resuscitation. Ergometry ECG revealed catecholaminergic polymorphic ventricular tachycardia, a hereditary arrhythmogenic disease. Consecutive measurements of serum potassium during ITT in 29 short children (21 boys) with growth failure revealed a mean decrease of serum potassium by 1.1 ± 0.4 mmol/l with the nadir at 30 min after the insulin bolus. Hypokalaemia (serum potassium <3.5 mmol/l) occurred in all but one child; severe hypokalaemia (serum potassium <2.9 mmol/l) was measured in every third child. This observation indicates that acute hypokalaemia which is induced by insulin and catecholamine excess occurs frequently in ITT. The case shows that the combination of acute hypokalaemia and the adrenergic counterregulation in ITT is a strong trigger of cardiac arrhythmias, which can become life-threatening if the child has an arrhythmogenic disease. Therefore, we recommend ECG monitoring during ITT to enhance the detection of cardiac arrhythmias. In addition, in the case of a comatose child during ITT the determination of the glucose and potassium level as well as adequate treatment are necessary.

Copyright © 2004 S. Karger AG, Basel

  Author Contacts

PD Dr. Gerhard Binder
University Children's Hospital
Hoppe-Seyler-Strasse 1
DE-72076 Tübingen (Germany)
Tel. +49 7071 29 83781, Fax +49 7071 29 4157, E-Mail gdbinder@med.uni-tuebingen.de

  Article Information

Received: November 5, 2003
Accepted: April 20, 2004
Published online: July 5, 2004
Number of Print Pages : 4
Number of Figures : 3, Number of Tables : 0, Number of References : 19