Prolonged QT Intervals in Isolated ACTH Deficiency

Isolated adrenocorticotropic hormone deficiency (IAD) is a rare disorder, characterized by secondary adrenal insufficiency with low or absent cortisol production, normal secretion of pituitary hormones except ACTH and the absence of structural pituitary defects. The clinical features include various symptoms such as vomiting, abdominal pain, myalgia, joint pain, severe hypotension, and hypovolemic shock due to glucocorticoid deficiency. Glucocorticoid replacement is required for the symptomatic patients. Since the reports in the 1950s, ECG abnormalities such as flat or inverted T waves, prolonged QT intervals are known to occur in adrenal insufficiency.

 There are six reports suggesting that sudden cardiac arrest occurs in IAD due to prolonged QT intervals. Although ECG abnormalities are modulated after hydrocortisone replacement, the mechanism by which hydrocortisone may affect ECG still remains unclear. Here we report a case of IAD whose ECG abnormalities were reversed with hydrocortisone replacement, suggesting a role played by glucocorticoids in the modulation of QT intervals. Also we show the characteristics of the six cases of IAD with QT prolonged intervals causing lethal arrhythmia.

Long QT syndrome is one of the symptoms of isolated ACTH deficiency. Long QT syndrome is known to be a risk factor for cardiovascular events, and prolonged QTs can be reversed by glucocorticoid replacement. We point out the possible mechanism whereby hydrocortisone may contribute to QT intervals.

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