Presenting History
In infants presenting with suspected Congenital Adrenal Hyperplasia (CAH), elicit the timing of genital ambiguity, failure to thrive, persistent vomiting, lethargy, dehydration crises, and neonatal sibling deaths.
- External Genital Ambiguity (46,XX Females):
- Was genital ambiguity (enlarged clitoris, fused labia, single perineal opening) recognized at birth?
- What was the initial sex assignment or advice given?
- Adrenal Salt-Wasting Crisis (Day 7 to 21 of Life):
- Did the infant begin vomiting persistently (projectile or non-projectile, non-bilious) at 1 to 3 weeks of age?
- Is there severe failure to regain birth weight or rapid weight loss ($>10-15\%$ of birth weight)?
- Has the infant become profoundly lethargic, limp, somnolent, cold to touch, or oliguric ($<1$ wet diaper/day)?
- Skin Hyperpigmentation:
- Is there noticeable darkening / hyperpigmentation of the skin, especially over the areolae, axillae, scrotum/labioscrotal folds, and genital creases?
Negative History (3C 1D Framework)
| Category | Pertinent Negative Question | Rationale / Significance |
|---|---|---|
| Causes | Maternal Virilization: No history of maternal voice deepening, severe acne, or hirsutism during pregnancy. Exogenous Hormones: No maternal intake of progestins or androgens during first trimester. | Maternal virilization points to placental aromatase deficiency or maternal androgen-secreting luteoma. Exogenous steroids can cause transient female pseudohermaphroditism without adrenal crisis. |
| Complaints (Differentiating) | Pyloric Stenosis: No palpable epigastric olive mass; vomiting is not associated with hypochloremic alkalosis. Surgical Abdomen: No bilious (green) vomiting, abdominal distension, or bloody stools. | Congenital hypertrophic pyloric stenosis features hypokalemic metabolic alkalosis; CAH features hyperkalemic acidosis! Green vomiting indicates malrotation with volvulus. |
| Complications | Hypoglycemia: No seizures, severe tremors, or apnea. Hypovolemic Shock: Assess for weak thready pulses, cyanosis, cold clammy extremities, and delayed CRT. Cardiac Arrhythmias: No sudden collapse or irregular heart rhythm (from severe hyperkalemia). | Cortisol deficiency impairs gluconeogenesis causing fatal hypoglycemia. Aldosterone deficiency causes massive renal sodium wasting and vasodilatory shock. Potassium $>7.5\text{ mEq/L}$ causes peaked T waves, conduction block, and ventricular fibrillation. |
| Differentials | Complete Androgen Insensitivity (CAIS): Normal female external genitalia in a 46,XY infant with non-palpable uterus. Mixed Gonadal Dysgenesis (45,X/46,XY): Features asymmetrical genitalia with a unilateral palpable gonad. | CAIS does not virilize and has no adrenal salt-wasting crisis. In classic 21-OHD, gonads are bilaterally non-palpable in the 46,XX female. |
Other Relevant History
- Family History & Pedigree (The Critical CAH Clue):
- Meticulously document consanguinity (autosomal recessive inheritance).
- Inquire strictly about unexplained neonatal deaths in prior siblings, especially male infants dying at 1 to 3 weeks of age from "sudden collapse", "dehydration", or "sepsis" (unrecognized male salt-wasting CAH).
- Birth Weight vs Current Weight: Exact gram weight loss since delivery.
History Summary
"Baby `Patient Name`, a `Age in days/weeks` old infant, genetically `46,XX / 46,XY`, `Birth Order` born of a `consanguineous/non-consanguineous` marriage from `City, State`, presented with ambiguous genitalia noted since birth, failure to regain birth weight with severe weight loss (`Weight loss in %`), recurrent non-bilious vomiting, hyperpigmentation, and severe lethargy progressing to circulatory shock at `Day of life` of life, with a family history of `Early sibling death / Consanguinity`, in the absence of bilious vomiting or fever.
In view of the ambiguous genitalia, severe salt-wasting dehydration, shock, and hyperpigmentation, I would like to consider a provisional diagnosis of Classic Congenital Adrenal Hyperplasia (21-Hydroxylase Deficiency, Salt-Wasting form), presenting in acute life-threatening Adrenal Crisis, requiring emergency fluid and stress-dose hydrocortisone resuscitation."
General & Head-to-Toe Examination
- Behavioral State: Obtunded, lethargic, weak whimpering cry.
- Vitals:
- Heart Rate: Marked tachycardia (HR $>160-180\text{ bpm}$) with feeble, thready peripheral pulses.
- Blood Pressure: Hypotension / Circulatory Shock (e.g., $<60/35\text{ mmHg}$).
- Temperature: Hypothermia (axillary $<36.0^\circ\text{C}$).
- Capillary Refill Time (CRT): Severely prolonged ($>3-4\text{ seconds}$).
- Anthropometry: Current weight vs birth weight (calculate percentage weight loss); length, head circumference.
- General Physical Findings:
- Dehydration: Sunken fontanelle, sunken eyes, dry oral mucosa, skin tenting $>3\text{ seconds}$ (Severe $>10\%$ dehydration).
- Hyperpigmentation: Striking dark pigmentation over areolae, axillae, umbilicus, and corrugated genital skin.
- External Genitalia Examination (Prader Staging):
- Phallus / Clitoris: Measure stretched length and width; calculate Clitoral Index ($>35\text{ mm}^2$ diagnostic of clitoromegaly).
- Labioscrotal Folds: Assess degree of posterior fusion, corrugation, and hyperpigmentation.
- Urogenital Orifice: Single perineal opening (urogenital sinus) vs separate urethral and vaginal orifices.
- Gonadal Palpation: Check rigorously for palpable gonads in scrotum, labia, and inguinal canals. (Absence of palpable gonads in a virilized infant is classic 21-OHD 46,XX until proven otherwise!).
Systemic Examination
- Cardiovascular System: Marked tachycardia, distant heart sounds, absence of murmurs.
- Abdomen: Soft, scaphoid, non-tender, no organomegaly or pyloric olive mass.
- CNS: Lethargic, generalized hypotonia, sluggish primitive reflexes.
Final Summary & Diagnosis
"A `Age in days/weeks` old 46,XX infant presenting with Prader stage `Stage I to V` ambiguous genitalia without palpable gonads, hyperpigmentation, severe weight loss (`% loss`), recurrent non-bilious vomiting, and decompensated hypovolemic shock (BP `BP in mmHg`, CRT `CRT in sec`), with family history of early neonatal sibling death and parental consanguinity.
My final diagnosis is Classic Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency (Salt-Wasting form), presenting in acute life-threatening Adrenal Crisis with severe hypovolemic shock, hyponatremia, and hyperkalemia, requiring emergent normal saline bolus, IV hydrocortisone, and hyperkalemia management."