Diagnosing Growth Hormone Deficiency After Aneurysmal Subarachnoid Hemorrhage

Abstract

To the Editor: We read with interest the article by Dimopoulou1 on hypopituitarism after aneurysmal subarachnoid hemorrhage (SAH). Although this topic deserves the attention of the neurological community treating these patients, especially those readers who, from the scope of the journal cannot be expected to be familiar with diagnostic criteria for endocrine disorders, deserve to be assured about the soundness of the proposed definitions of neuroendocrine dysfunction and the conclusions derived thereof. In the case of the authors’ definition of growth hormone deficiency (GHD) in SAH patients, this should be questioned for several reasons. The authors assume inadequate growth hormone secretion indicative of GHD in their patients if IGF-I levels are <2 standard deviations for the appropriate age range, quoting an article by Aimaretti et al.2 However, insulin-like growth factor (IGF)-I levels do not only reflect growth hormone (GH) secretory status but also are influenced by several other factors. Therefore, low IGF-I levels can only be considered a parameter of impaired GH secretion if malnutrition, liver failure, poorly controlled diabetes mellitus, and uremia are ruled out.3 It is well-known that the IGF-I levels observed in hypopituitary patients and the normal range of IGF-I levels progressively overlap with advancing age of the patients. Along these …