Pediatric Endocrinology and Metabolism
Core concepts
Understand growth hormone physiology and the workup of short stature (bone age, IGF-1, provocative testing). Know thyroid disorders: congenital hypothyroidism (screening, jaundice, constipation, hypotonia) and acquired hypothyroidism/hyperthyroidism. Master type 1 diabetes presentation (polyuria, polydipsia, weight loss, ketoacidosis) and management principles (insulin, monitoring, sick-day rules, DKA fluid and insulin protocols). Understand puberty disorders: precocious puberty (central vs peripheral, GnRH stimulation) and delayed puberty (constitutional vs pathologic). Know adrenal disorders: congenital adrenal hyperplasia (virilization, salt wasting, 17-hydroxyprogesterone), Addison disease, and Cushing syndrome. Recognize rickets (vitamin D deficiency, bowing, widened wrists, low phosphate, elevated alkaline phosphatase) and hypoglycemia inborn errors of metabolism (avoid fasting, consider metabolic screen).
Traps
- Missing DKA in a child with vomiting and abdominal pain - check glucose and ketones.
- Treating DKA with bicarbonate routinely or giving insulin before fluids - follow protocol.
- Confusing central precocious puberty (GnRH-dependent, treat with GnRH agonist) with peripheral causes (tumors, exogenous hormones).
- Missing congenital hypothyroidism because the infant looks well; rely on newborn screening.
- Forgetting that rickets can present with seizures from hypocalcemia.
Worked example / rule of thumb
A 9-year-old with polyuria, weight loss, and vomiting: check glucose and ketones; if DKA, start isotonic fluid resuscitation, then insulin infusion, and monitor potassium closely (insulin drives potassium intracellularly). Rule of thumb: polyuria + polydipsia + weight loss = diabetes until proven otherwise; check glucose and ketones early.