Congenital Adrenal Hyperplasia😊

Congenital Adrenal Hyperplasia

Q. A 10-day-old baby is brought with severe dehydration. On examination, the baby has ambiguous genitalia and feeble peripheral pulses. On investigation, there is metabolic acidosis, serum sodium levels are 131meq/L and serum potassium level is 7.2meq/l. What is the probable diagnosis?
  • Ans: Congenital adrenal hyperplasia
Q. A male with hyperpigmentation, tanner stage 5, presents with hypertension and precocious puberty. The causative defect is:
  • A. 21 β-hydroxylase deficiency
  • B. 11 β-hydroxylase deficiency
  • C. 17 β-hydroxylase deficiency
  • D. 17 α-hydroxylase deficiency
      • Explanation:
      • B. 11 β-hydroxylase deficiency
      • 21 β-hydroxylase deficiency presents as salt wasting form.
      • 17 α-hydroxylase deficiency presents with male pseudohermaphroditism.
      21 α (Not β) OR 21 Hydroxylase deficiency
      21 α (Not β) OR 21 Hydroxylase deficiency
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      Enzyme Defect
      Clinical Features
      Effect in Females
      Effect in Males
      Cholesterol desmolase
      Death in utero
      —
      —
      3β hydroxy steroid dehydrogenase
      Salt wasting
      Female pseudo-hermaphroditism
      Hypospadias
      21 α (Not β) hydroxylase
      Salt wasting
      Female pseudo-hermaphroditism
      Male precocious pseudopuberty
      11β hydroxylase
      Hypertensive form
      Female pseudo-hermaphroditism
      Male precocious pseudopuberty
      17α hydroxylase
      Hypertensive form
      Female sexual infantilism
      Male pseudo-hermaphroditism
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  • Most Common Cause of:
    • Ambiguous genitalia in females.
    • Primary cause of female pseudohermaphroditism.

Enzyme Defects

  • Overall Most common: 21 α (Not β) hydroxylase.
  • Second most common overall: 11 β hydroxylase.

Clinical Presentation

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  • Mnemonic:
    • start with 1 → 11 and 17 → Hypertension
    • start with 2 or 3 → Salt wasting

Decreased Hormones:

  • Aldosterone ↓↓:
    • Hyponatremia
    • Hyperkalemia
    • hypotension.
    • salt-water wasting,
    • metabolic acidosis,
  • Cortisol ↓↓:
    • Hypoglycemia
    • Shock
  • Increased Hormones:
    • Androgen ↑↑:
      • Female - Ambiguous genitalia in females.
      • Males - Normal genitalia, Precocious puberty in males.
    • Occurs because:
      • ↓↓ cortisol → ↑↑ ACTH → stimulates adrenal → ↑↑ androgens.

Defects

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P450 Oxido-Reductase (OR) deficiency.

  • Associated with skeletal anomalies (Antley Bixler syndrome).

Q. A 2-month-old boy presented with ambiguous genitalia. His blood pressure is normal. The DHT value was low. The probable diagnosis is:

  • A. 21 β-hydroxylase deficiency
  • B. 11 β-hydroxylase deficiency
  • C. 17 α-hydroxylase deficiency
  • D. 3 β—hydroxy steroid dehydrogenase deficiency
      • ANS
      • C. 17 α-hydroxylase deficiency

Diagnostic

  • Screening:
    • 17-OH progesterone level is the screening test.
        • 17-OHP Level (ng/dL)
        Interpretation
        Action
        <200
        Rule out CAH
        ã…¤
        200–800
        Indeterminate
        Perform ACTH stimulation test
        ≥800
        Definitive
        ã…¤
  • Demonstrate mutation

Management:

  • Treatment should begin without waiting for karyotype results.
  • Drug of Choice (DOC): Corticosteroids.
  • Hydrocortisone (Life long replacement)
  • Fludrocortisone (Life long replacement)
  • Fluid and electrolyte imbalances must be corrected.

Antenatal diagnosis

  • If a mother has a baby with CAH,
  • DOC for antenatal Rx of CAH
    • Dexamethasone
    • to prevent virilization
    • Start as soon as detection of pregnancy
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