Monitoring Growth Hormone Treatment

Abstract

The use of growth hormone (GH) has expanded from the treatment of short stature due to GH deficiency (GHD) in children with open epiphyses to include growth failure due to chronic renal insufficiency (CRI) and Turner's syndrome (TS) as well as adults with GHD. The safety considerations in using GH differ somewhat in these diagnostic groups, and the physician caring for these patients will need to keep this in mind when monitoring patients receiving GH. Peripheral edema and carpal tunnel syndrome have been reported as side effects more frequently in adults than in children treated with GH. Idiopathic intracranial hypertension has been reported most frequently in children with CRI (31.1 cases per 1000 patient-years [pt-yrs]), although children with GHD and TS also have an increased incidence (1.6 and 3.7 cases per 1000 pt-yrs, respectively). The greatest risk is at the beginning of treatment, and complaints of headache or visual disturbance at this time should prompt careful neurologic and ophthalmologic examination. The risk of leukemia and nonleukemic extracranial neoplasms in children treated with GH seems to be confined to those with identifiable risk factors. Although numerous studies have failed to show an increased risk of brain tumor recurrence associated with GH treatment, children with a history of such tumors should have completed tumor therapy and have brain imaging studies before beginning GH. Children with CRI, GHD, and TS have an increased risk of developing slipped capital femoral epiphysis. Complaints of limping or hip or knee pain need to be evaluated with radiographic studies if there is limited hip movement. Although there is no evidence that treatment with GH causes scoliosis, children with pre-existing scoliosis should be observed for rapid progression after starting GH treatment. Most studies of the effect of GH on carbohydrate metabolism show only transient changes in insulin sensitivity. Nevertheless, patients with an increased risk of diabetes should be encouraged to modify their diet and exercise habits. Gynecomastia is a common side effect in adults receiving GH, and self-limited gynecomastia has been reported in prepubertal boys during GH treatment. Older preparations of pituitary GH contained GH oligomers and were frequently associated with high titers of GH antibodies and growth deceleration. Except for patients with GH gene deletions, antibodies are rarely a cause of poor response to GH. Other causes of poor growth should be investigated in a child who fails to respond to prescribed GH as expected. Specific recommendations for managing patients in different diagnostic categories who are treated with GH are reviewed.