Pathogenesis insulinlike growth factor 1(IGF-1)is secreted and acts locally at the site of growing bone GF-1 binds to one of several IGF-binding proteins (IGFBPs)and circulates almost entirely (99%)in the bound state IGFBP-3 accounts for the majority of IGF-I binding and this binding proteins activity depends directly on GH
• insulinlike growth factor 1 (IGF-1) is secreted and acts locally at the site of growing bone • IGF-1 binds to one of several IGF-binding proteins (IGFBPs) and circulates almost entirely (>99%) in the bound state • IGFBP-3 accounts for the majority of IGF-I binding and this binding protein’s activity depends directly on GH Pathogenesis
Etiology Most causes of ghd are idiopathic Secondary causes Brain tumors most commonl craniopharyngioma CNS surgery · CNS radiation Anatomical abnormalities(eg, septooptic dysplasia, empty sella syndrome) ° Genetic ghd
• Most causes of GHD are idiopathic • Secondary causes • Brain tumors, most commonly craniopharyngioma • CNS surgery • CNS radiation • Anatomical abnormalities (eg, septooptic dysplasia, empty sella syndrome) • Genetic GHD Etiology
Clinical Presentation Short stature Low growth velocity for age and pubertal stage Increased amount of adipose tissue around the waist The child may look younger Delayed tooth development Delayed onset of puberty Episodes of hypoglycemia
• Short stature • Low growth velocity for age and pubertal stage • Increased amount of adipose tissue around the waist • The child may look younger • Delayed tooth development • Delayed onset of puberty • Episodes of hypoglycemia Clinical Presentation
Laboratory studies 1. GH stimulation test Provocative stimuli include insulin, arginine, levodopa (I-dopa), clonidine and glucagon GH response to insulin is the most reliable test for GHD GH response( GH level <10 ng/m)after given 2 provocative stimuli diagnoses gh deficiency
1. GH stimulation test • Provocative stimuli include insulin, arginine, levodopa (l-dopa), clonidine and glucagon • GH response to insulin is the most reliable test for GHD. • GH response ( GH level <10 ng/ml) after given 2 provocative stimuli diagnoses GH deficiency Laboratory Studies