221- What are the acquired causes of hypogonadotropic hypogonadism?
Any patient with adult-onset hypogonadotropic hypogonadism should be investi-
gated for sellar–suprasellar pathology like tumor and infiltrative disorders. A his-
tory of head injury, cerebrovascular accident (e.g., subarachnoid hemorrhage),
snake bite, and postpartum lactational failure (pituitary apoplexy/necrosis) should
be actively sought as the cause for hypogonadotropic hypogonadism. In addition,
functional hypogonadotropic hypogonadism can be associated with any chronic
systemic illness.- What is congenital isolated hypogonadotropic hypogonadism?
Congenital isolated hypogonadotropic hypogonadism is defined as absence or
arrested puberty due to impaired GnRH and/or gonadotropin secretion without
structural abnormalities in hypothalamic–pituitary region or other pituitary hor-
mone deficiency. Approximately 30 % of individuals with congenital isolated
hypogonadotropic hypogonadism have identified genetic mutation as a cause of
hypogonadism, while the rest are idiopathic.- How to suspect congenital isolated hypogonadotropic hypogonadism during
early childhood?
The presence of micropenis, cryptorchidism, midline/skeletal defects, and
anosmia/hyposmia in a child, with or without family history of delayed puberty,
should raise a suspicion of IHH. - What are the clinical clues to differentiate between prepubertal and postpuber-
tal onset of hypogonadism in an adult male?
The presence of micropenis, cryptorchidism/small testicular volume (testicular
volume <4 ml), scant pubic and axillary hair, eunuchoidal habitus (due to
delayed epiphyseal closure), and high-pitched voice suggests the prepubertal
onset of hypogonadism. Postpubertal onset of hypogonadism is suggested by
the presence of normal body proportions, normal- or small-sized testes with
soft consistency, regression of pubic and axillary hair, and reduced shaving
frequency (Fig. 7.5).
7 Delayed Puberty