Impact of growth hormone treatment on a 12-year-old female with newly diagnosed panhypopituitarism and distal arthrogryposis

Summary: Panhypopituitarism, characterized by multiple pituitary hormone deficiencies, is most often diagnosed in infancy or early childhood with adolescent presentation being uncommon. We present a 12-year-old female with late-onset panhypopituitarism presenting with short stature and concomitant bilateral distal arthrogryposis. Her height at presentation was 140.7 cm (6th percentile) with a growth velocity of 0.75 cm/year, Tanner stage 1, bone age consistent with chronological age, and predicted adult height of approximately 152.4 cm despite a mid-parental target near 167.6 cm. Laboratory testing supported growth hormone (GH) deficiency, central hypothyroidism, and adrenal insufficiency, with stimulation tests being subnormal. MRI showed hypoplasia of the anterior pituitary, an absent infundibulum, and an ectopic posterior pituitary, consistent with pituitary stalk interruption syndrome. Hydrocortisone (9 mg/m2/day) and levothyroxine (37.5 μg daily) were first initiated. Although GH was initially deferred due to concerns about worsening preexisting distal hand contractures, the family elected to begin weekly subcutaneous lonapegsomatropin-tcgd (Skytrofa, 7.6 mg, 0.24 mg/kg/week). At 3 months, the growth velocity increased to 8.7 cm/year with early breast development, and at 6 months, it reached 17.4 cm/year, bone age remained concordant with chronological age, and predicted adult height improved to approximately 162.6 cm. By 10 months, height percentile rose to the 12th percentile and Tanner stage 2 breast development was observed. Throughout treatment, there were no reported or observed changes in distal arthrogryposis hand contractures. This case report highlights that initiation of GH therapy may lead to a significant growth improvement without aggravating arthrogryposis-related contractures. Learning points: To report the rare co-occurrence of arthrogryposis and panhypopituitarism and discuss management. Distal arthrogryposis coexisting with GH deficiency did not worsen with GH therapy in this patient, supporting individualized risk-benefit analysis. Shared decision making is key when theoretical risks (e.g. joint symptoms) are weighed against the consequences of untreated GH deficiency.