Pediatrics · Year 3 · from Pediatrics
Case 3: Growth Hormone Deficiency
Patient Demographics
- Age: 8-year-old male
- Sex: Male
Chief Complaint
"Our son has been falling off his growth curve for the past two years."
History of Present Illness
An 8-year-old boy presents with his parents who report progressive decline in his growth percentiles over the past 2 years. He was previously tracking at the 50th percentile for height but has now fallen to below the 3rd percentile. Parents report he seems to have more body fat around his abdomen despite not overeating. He was born via breech delivery with mild birth asphyxia but had normal development otherwise. He has had no recent illnesses, takes no medications, and has a good appetite. He fatigues more easily than his peers during physical activity.
Growth Parameters
- Height: 112 cm (<3rd percentile, -2.8 SD)
- Weight: 24 kg (25th percentile)
- BMI: 19.1 kg/m2 (85th percentile - relatively overweight for height)
- Growth velocity: 3.2 cm/year (severely diminished; normal is 5-6 cm/year prepubertally)
- Previous height at age 6: 108 cm (50th percentile)
Physical Examination
- General: Short stature, appears younger than stated age, slightly overweight
- HEENT: Frontal bossing, midface hypoplasia, depressed nasal bridge
- Eyes: Normal visual fields
- Cardiovascular: Normal
- Abdomen: Truncal adiposity, no organomegaly
- Genitourinary: Small phallus for age, prepubertal testes
- Extremities: Short limbs proportionate to trunk, small hands and feet
- Skin: Fine, thin skin
- Neurologic: Normal
Workup
- Bone age: 5 years (delayed 3 years)
- IGF-1: 45 ng/mL (low for age)
- IGFBP-3: 1.2 mg/L (low)
- GH stimulation test (arginine-insulin): Peak GH 3.2 ng/mL (deficient; normal >10 ng/mL)
- TSH: 2.8 mIU/L (normal)
- Free T4: 1.0 ng/dL (normal)
- Morning cortisol: 12 mcg/dL (normal)
- CBC, CMP: Normal
- Brain MRI: Small anterior pituitary, ectopic posterior pituitary bright spot, absent pituitary stalk
Diagnosis
Growth hormone deficiency secondary to pituitary stalk interruption syndrome
Clinical Reasoning
The declining growth velocity, falling percentiles, markedly delayed bone age, low IGF-1/IGFBP-3, and failed GH stimulation test confirm growth hormone deficiency. The characteristic MRI findings of pituitary stalk interruption syndrome explain the etiology, likely related to perinatal insult from breech delivery. The truncal adiposity and micropenis are consistent with GH deficiency. Evaluation for additional pituitary hormone deficiencies is warranted.
Management
- Growth hormone replacement: Recombinant human GH 0.024-0.034 mg/kg/day subcutaneously at bedtime
- Monitoring: Height velocity (target >8 cm/year in first year), IGF-1 levels every 6 months, bone age annually
- Screen for additional pituitary deficiencies: ACTH stimulation test, thyroid function monitoring, prolactin
- Long-term follow-up: Monitor for development of additional hormone deficiencies, especially at puberty
- Treatment duration: Continue until growth plates fuse or height velocity <2 cm/year with bone age >14 years
Clinical Image
Image Description: Sagittal MRI of the brain demonstrating pituitary stalk interruption syndrome with absent pituitary stalk and ectopic posterior pituitary.
Source: Radiopaedia URL: https://radiopaedia.org/cases/pituitary-stalk-interruption-syndrome-1 License: CC BY-NC-SA 3.0