Congenital Adrenal Hyperplasia: Model Clinical Case and Viva Q&A

Clinical Case of Congenital Adrenal Hyperplasia

Case Presentation

A 2-week-old female newborn is brought to the emergency department with poor feeding, vomiting, and lethargy. The parents report that the baby has been increasingly difficult to wake for feedings over the past 24 hours.

Physical Examination

• Weight: 2.8 kg (birth weight was 3.2 kg)
• Temperature: 38.2°C
• Heart rate: 180 bpm
• Respiratory rate: 60 breaths/min
• Blood pressure: 65/40 mmHg
• Skin: Hyperpigmentation noted, especially in the genital area and nipples
• Genitalia: Ambiguous with clitoromegaly

Laboratory Findings

• Serum sodium: 124 mEq/L (low)
• Serum potassium: 6.8 mEq/L (high)
• Blood glucose: 48 mg/dL (low)
• 17-hydroxyprogesterone: 22,000 ng/dL (markedly elevated)

Diagnosis and Management

Based on the clinical presentation, physical examination, and laboratory findings, a diagnosis of salt-wasting congenital adrenal hyperplasia is made. The patient is immediately started on intravenous hydrocortisone and fludrocortisone, along with fluid resuscitation and glucose administration. Genetic testing confirms a mutation in the CYP21A2 gene, consistent with 21-hydroxylase deficiency.

Clinical Presentations of Congenital Adrenal Hyperplasia

Varieties of Clinical Presentations

1. Classic Salt-Wasting CAH

   • Severe aldosterone deficiency
   • Presents in early infancy with salt-wasting crisis
   • Hyponatremia, hyperkalemia, metabolic acidosis
   • Dehydration, shock, and potentially death if untreated
   • Ambiguous genitalia in females, normal-appearing male genitalia with hyperpigmentation

2. Classic Simple Virilizing CAH

   • Sufficient aldosterone production to prevent salt-wasting
   • Prenatal virilization of female genitalia
   • Rapid postnatal growth and pseudoprecocious puberty in both sexes
   • Advanced bone age

3. Non-classic CAH (Late-onset CAH)

   • Milder enzyme deficiency
   • Symptoms may appear in late childhood, adolescence, or adulthood
   • Premature pubarche, hirsutism, acne, menstrual irregularities
   • Infertility or subfertility

4. CAH-X Syndrome

   • CAH with a contiguous gene deletion affecting CYP21A2 and TNXB genes
   • Features of CAH plus connective tissue abnormalities (joint hypermobility, skin hyperextensibility)

5. Prenatal-onset Growth Restriction

   • Rare presentation in severe cases
   • Intrauterine growth restriction due to cortisol deficiency
   • Can be associated with salt-wasting crisis after birth

6. Asymptomatic CAH

   • Detected through newborn screening
   • No clinical signs at birth
   • May develop symptoms later if untreated

7. CAH with Atypical Genital Development in Males

   • Varying degrees of undervirilization in genetically male infants
   • Can include cryptorchidism, hypospadias, or micropenis

Knowledge Check: Question and Answers for Medical Students & Professionals

This interactive quiz component covers essential viva questions and answers. It includes 30 high-yield viva questions with detailed answers.

Question 1 of 30

Disclaimer

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