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should also be done as it may help in differentiating between CDGP and hypo-

gonadotropic hypogonadism. Further evaluation is guided by the results of hor-

monal tests and include karyotype, MRI brain/sella, inhibin B, LH response to

GnRH, and testosterone response to hCG (Fig. 7.10).

Delayed puberty

Tanner stage B 1 , and >13 years

Testicular size <3 ml, > 14 years

Exclude systemic illness

LH, FSH, T/E 2

↓/Normal LH,FSH and ↓T/E 2

CDGP

Hypogonadotropic hypogonadism Hypergonadotropichypogonadism

↑LH, FSH and ↓T/E 2

Fig. 7.10 Approach to a child with delayed puberty

35. Should all patients with hypogonadotropic hypogonadism undergo MRI brain?

The need for MR brain imaging in patients with hypogonadotropic hypogonad-

ism should be individualized. MRI brain should be performed in a patient with

hypogonadotropic hypogonadism, if associated with anosmia/hyposmia, mul-

tiple pituitary hormone deficiency, hyperprolactinemia, or symptoms of mass

effect.

36. What are the neuroimaging characteristics of Kallmann syndrome?

Hypoplasia/agenesis of olfactory bulb and/or olfactory sulci and non-

visualization of olfactory tracts are the characteristic neuroimaging

abnormalities in patients with Kallmann syndrome. In addition, corpus callo-

sum agenesis and cerebellar abnormalities have also been described. Olfactory

bulbs and tracts are best visualized by coronal images, whereas olfactory sulci

in axial images (Fig. 7.11).

7 Delayed Puberty