Congenital adrenal hyperplasia

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Background

Steroidogenesis: The enzymes affected in CAH are represented by one red and four green bars on the top half of the diagram (for example, "21α-hydroxylase" is visible near the top center. "17α-hydroxylase" and "17,20 lyase" are carried out by a single enzyme).Depending upon which enzyme is unavailable, production of androgens (lower left) or mineralocorticoids (upper right) is reduced. This, in turn, can lead to increased production of other molecules, due to a buildup of precursors.
  • 95% of cases due to deficiency of 21-hydroxylase
    • Leads to cortisol deficiency, aldosterone deficiency, virilization
  • Patients present during 2nd-5th week of life in crisis
  • Although congenital adrenal hyperplasia is part of the normal neonatal screening, results might not be available for 3 to 4 weeks.

Clinical Features

Clitoromegaly (with normal labia and introitus) in a female child with CAH.
  • Patient presents in 2nd week of life in crisis
  • Salt-wasting
  • Virilization: The development of male-pattern physical traits in females
  • Brown hue skin color
  • Partial CAH may present later and less dramatically with irregular menses in adolescence

Differential Diagnosis

  • Adrenal salt-wasting crisis

Sick Neonate

THE MISFITS [1]

Adrenal crisis

Evaluation

Work-Up

Diagnosis

Management

  • NS 10-20mL/kg bolus 0.9% saline solution or 5% dextrose in normal saline
    • Hypotonic saline or 5% dextrose without addition of NS should not be used as can worsen hyponatremia
  • Steroid replacement
    • Neonates: Hydrocortisone 25mg IV/IO
    • Obtain blood sample for steroid hormone measurement
      • Most importantly 17-OHP (17-hydroxyprogesterone) to evaluate for 21-hydroxylase deficiency prior to administering hydrocortisone
  • Hypoglycemia
    • If significant hypoglycemia, given IV bolus 5-10mL/kg of 10% dextrose (0.5-1.0 g/kg) or 2-4mL/kg of 25% dextrose (D25) infused slowly at rate of 2-3 mL/min
  • Hyperkalemia
    • Typically improves promptly after hydrocortisone
    • Rare occasionally for severe and symptomatic hyperkalemia, administration of glucose and insulin is needed to manage hyperkalemia

Disposition

  • Admit

See Also

References

  1. Brousseau T, Sharieff GQ. Newborn emergencies: the first 30 days of life. Pediatr Clin North Am. 2006 Feb;53(1):69-84, vi.