Pediatric Endocrinology and Metabolism
Core concepts
Master growth hormone deficiency versus constitutional delay versus familial short stature, using bone age and growth velocity. Understand thyroid disease (congenital hypothyroidism screening, acquired hypothyroidism, Graves disease), adrenal disorders (congenital adrenal hyperplasia, Addison disease, Cushing syndrome), and disorders of sexual development. Know the approach to hypoglycemia in the older child and the recognition of diabetic ketoacidosis and its management. Understand pubertal timing - precocious versus delayed puberty.
Traps
Questions test the distinction between central and peripheral precocious puberty and the use of GnRH stimulation. Another trap is misinterpreting a low free T4 with an elevated TSH in a sick child (nonthyroidal illness). Do not forget that DKA management requires fluid resuscitation, insulin infusion, and monitoring for cerebral edema.
Worked example
An 8-year-old girl with breast development and pubic hair, advanced bone age, and a pubertal LH response to GnRH stimulation has central precocious puberty; treatment is a GnRH agonist. A peripheral cause (adrenal or ovarian tumor) would show suppressed gonadotropins. The trap is treating without confirming the central versus peripheral origin.
Rule of thumb
For short stature, calculate growth velocity and bone age before ordering hormone tests; a normal velocity with a bone age matching height age suggests familial or constitutional patterns.