Management of Infant with Panhypopituitarism
Corticosteroid replacement must be initiated immediately (Option A) in any infant with documented panhypopituitarism and low cortisol, as adrenal insufficiency is life-threatening and treatment should never be delayed. 1, 2, 3
Critical First Step: Immediate Glucocorticoid Replacement
Start hydrocortisone immediately at physiological replacement doses of 15-20 mg/m²/day divided into 2-3 doses (typically 5-7 mg/m² in morning, 2.5-3.5 mg/m² in early afternoon, and optional smaller evening dose if using three-dose regimen). 1, 4
Treatment of adrenal insufficiency must never be delayed for any diagnostic procedures or to initiate other hormone replacements, as acute adrenal crisis carries high mortality if untreated. 1, 2, 3
In infants with confirmed panhypopituitarism and documented low cortisol with low ACTH (secondary adrenal insufficiency), no further dynamic testing is required before starting treatment. 2, 5
Critical Sequencing: Why Corticosteroids Must Come First
The most dangerous pitfall is starting thyroid hormone replacement before or simultaneously with glucocorticoid replacement. 2
Initiating levothyroxine in an infant with untreated adrenal insufficiency can precipitate acute adrenal crisis by increasing cortisol metabolism and metabolic demands. 2
Corticosteroids must be started several days before thyroid hormone replacement to prevent this life-threatening complication. 2
This sequencing rule is absolute and non-negotiable in panhypopituitarism management. 2
Subsequent Hormone Replacement (After Glucocorticoid Stabilization)
Thyroid Hormone Replacement (Second Priority)
After 3-7 days of stable glucocorticoid replacement, initiate levothyroxine for documented secondary hypothyroidism (low TSH with low free T4). 5
Starting dose typically 10-15 mcg/kg/day in infants, with monitoring of free T4 levels. 5
Growth Hormone Replacement (Third Priority - Delayed)
GH replacement should be deferred for 3-6 months (Option C is correct for GH timing, but only after addressing the acute issues). 1, 5
In neonates and young infants with panhypopituitarism, GH deficiency diagnosis is based on auxology, MRI findings, and low IGF-1 levels rather than dynamic testing, as GH stimulation tests cannot be reliably performed in the neonatal period. 5
GH therapy initiation requires baseline polysomnography before starting treatment due to risks of adenotonsillar hypertrophy and obstructive sleep apnea. 1
The delay allows for stabilization on glucocorticoid and thyroid replacement, assessment of growth velocity, and proper safety evaluation before GH initiation. 5
Monitoring and Safety Considerations
Glucocorticoid Monitoring
Avoid supraphysiological dosing that can suppress growth - conventional twice-daily hydrocortisone creates unphysiological peaks 2 hours post-dose and prolonged nadirs before the next dose. 4
Monitor for signs of both under-replacement (hypoglycemia, poor feeding, failure to thrive) and over-replacement (excessive weight gain, growth suppression, Cushingoid features). 4
Emergency Education
Families must receive immediate education on stress-dosing (doubling or tripling maintenance dose during illness), recognition of adrenal crisis symptoms, and when to seek emergency care. 1, 2, 6
Provide emergency injectable hydrocortisone and medical alert identification. 1, 2
Why Option B (TSH Reassessment) is Incorrect
Simply reassessing TSH without addressing the cortisol deficiency first is dangerous and potentially fatal. 2
The low TSH is expected in panhypopituitarism (secondary hypothyroidism) and does not require reassessment before treatment - it requires treatment, but only after glucocorticoid replacement is established. 2, 5