Growth Hormone Deficiency In Children

(Pituitary dwarfism)

Growth hormone deficiency is the most common pituitary hormone deficiency in children and can be isolated or occur together with the lack of other pituitary hormones. Growth hormone deficiency typically results in growth retardation and short stature with normal proportions. The diagnosis includes the measurement of pituitary hormone levels and MRI for the detection of structural abnormalities of the pituitary or of brain tumors. Treatment is usually for some hormone replacement and removal of any causal tumors.

Patients with growth hormone deficiency associated with generalized hypopituitarism, also have a deficiency of one or more other pituitary hormones (eg. As follicle stimulating hormone, luteinizing hormone, adrenocorticotropic hormone [ACTH], thyroid-stimulating hormone, antidiuretic hormone [ADH]).

Growth hormone deficiency is the most common pituitary hormone deficiency in children and can be isolated or occur together with the lack of other pituitary hormones. Growth hormone deficiency typically results in growth retardation and short stature with normal proportions. The diagnosis includes the measurement of pituitary hormone levels and MRI for the detection of structural abnormalities of the pituitary or of brain tumors. Treatment is usually for some hormone replacement and removal of any causal tumors. Patients with growth hormone deficiency associated with generalized hypopituitarism, also have a deficiency of one or more other pituitary hormones (eg. As follicle stimulating hormone, luteinizing hormone, adrenocorticotropic hormone [ACTH], thyroid-stimulating hormone, antidiuretic hormone [ADH]). Etiology growth hormone deficiency may occur alone or in conjunction with a generalized hypopituitarism. In both cases the growth hormone deficiency can be acquired or congenital (including hereditary genetic causes). In rare cases, there is no shortage in the growth hormone, but the growth hormone receptors do not function normally (growth hormone insensitivity). Isolated GH deficiency is estimated to be at 1 / 4,000 to 1 / 10,000 children. It is usually idiopathic, but about 25% of patients have an identifiable cause. Among the congenital causes include abnormalities of the growth hormone-releasing hormone receptor and the GH1 gene and certain CNS malformations. Among the acquired causes include a therapeutic irradiation of the CNS (high-dose radiation can cause a generalized hypopituitarism), meningitis, histiocytosis, and brain injury. Irradiation of the spine, prophylactically or therapeutically, can affect the future growth of the spine and thus endanger the growth in length. A generalized hypopituitarism may have genetic causes include hereditary or sporadic mutations affect the cells of the pituitary gland. In such cases, abnormalities of other organ systems may be present, in particular center line defects such as cleft palate or septo-optic dysplasia (which is pellucidum by a lack of the septum, an atrophy of the optic nerve and a hypopituitarism in). A generalized hypopituitarism can also be purchased through many types of lesions that affect the hypothalamus or the pituitary gland; examples thereof include tumors (z. B. most craniopharyngioma), infections (eg. as tuberculosis, toxoplasmosis, meningitis), and infiltrative diseases. The combination of lytic defects of bone and skull and diabetes insipidus has a histiocytosis (Langerhans cell histiocytosis) of the Langerhans cells. Symptoms and complaints The manifestations depend on the age of the patient, the etiology underlying and the specific hormone deficiencies from. Growth hormone deficiency manifests itself usually as a growth disorder that is sometimes accompanied by a delay of tooth development. The size is below the 3rd percentile, and the growth rate is <6 cm / year before the age of 4, <5 cm / year at the age of 4-8 years and <4 cm / year before puberty. Although small in stature, preserving the normal proportions between the upper and lower body segment in a child with hypopituitarism. The skeletal maturity, determined by determination of bone age is> 2 years behind the chronological age. Other abnormalities may be present depending on the underlying defect and the child may have a delayed or absent puberty. The weight gain may be disproportionate to the size and growth, which can lead to a relative overweight. have newborns, congenital defects of the pituitary or hypothalamus, may have hypoglycemia (which may also occur in older children), midline defects (z. B. cleft palate) or a micro penis as well as manifestations of other endocrine deficiencies. Diagnosis Clinical evaluation, including growth criteria and other medical history Imaging tests levels of insulin-like growth factor 1 (IGF-1) and IGF-binding protein type 3 (IGFBP-3) As a rule, confirmed by provocation tests evaluation of other pituitary hormones and other causes of poor growth Current consensus guidelines for the diagnosis of growth hormone deficiency require the integration of growth criteria, medical history, laboratory findings and results of imaging techniques. The size is assessed. The measurement results for the size and weight should be entered on a card growth in all children (growth assessment). (For children aged 0-2 years, s. WHO Growth Charts for children 2 years and older s. CDC Growth Charts). Measurement of the IGF-1 and IGFBP-3 levels starts the evaluation of GH / IGF-1 axis. During the middle to late childhood, the IGF-1 levels that reflect the GH activity are measured. GH levels themselves vary greatly and are difficult to interpret. Because IGF-1 levels increase at puberty, they should be interpreted relative in relation to the bone age rather than chronological age. Normal IGF-1 levels make a GH deficiency unlikely. Nevertheless, it also comes in circumstances other than GH deficiency at low IGF-1 levels such. As at psychosocial neglect, malnutrition and hypothyroidism. In infancy and early childhood, the IGF-1 levels are normally low and therefore they do not reliably distinguish between normal and subnormal in these age groups. However, the IGFBP-3 levels (the main carrier of IGF-peptides), in contrast to IGF-1 less affected by malnutrition and allow distinction between normal and subnormal in younger children. In children with low IGF-1 and IGFBP-3 levels of GH deficiency is usually confirmed by determining the GH levels itself. Since GH basal is typically low or not measurable (except shortly after falling asleep), random GH levels are unusable and is required for GH determination of a challenge test (growth hormone deficiency in children: Provocative tests). Unfortunately provocation tests are non-physiological, subject to determination errors and are difficult to reproduce. In addition, the definition of a normal reaction varies with age, gender and test center and is based on limited evidence. Imaging studies are performed when growth is abnormal. Bone age should be determined using a conventional X-ray of the left hand. In a GH deficiency skeletal maturity is impaired to the same extent as the longitudinal growth. An evaluation of the pituitary and of the sella turcica by CT or MRI better is indicated in a GH deficiency and for the exclusion of calcifications tumors; the sella is unusually small in 10-20% of patients. Laboratory testing for screening be performed to look for other possible causes of poor growth, including hypothyroidism (z. B. thyroid stimulating hormone, thyroxine) Kidney Diseases (electrolytes, creatinine levels) Inflammatory and immune disorders (eg., Tissue transglutaminase antibodies, ESR) hematologic disorders (eg blood count with differential blood count) genetic testing for certain syndromes (eg, Turner’s syndrome, Turner’s syndrome.. diagnosis) may be indicated by physical findings or if the growth pattern significantly from the family different. When a high suspicion for a GH deficiency, additional testing the pituitary function be performed (for. Example, ACTH, cortisol levels in the serum at 8am, luteinizing hormone, follicle-stimulating hormone and prolactin). Tips and risks Unlike many endocrine deficiencies in which hormone levels are diagnostically, have random GH levels of little use in the diagnosis of GH deficiency. Provocative tests Since the GH secretion in patients typically runs abnormally with reduced function of the thyroid gland and the adrenal glands, a provocation testing should be performed only after adequate hormone substitution here. The insulin tolerance test is the best provocation test to stimulate the release of GH, but is rarely performed because it is risky. Other provocation tests are less dangerous, but also less reliable. These include tests using arginine infusion (500 mg / kg given intravenously over 30 minutes), clonidine (0.15 mg / m2 po [a maximum of 0.25 mg]), levodopa (10 mg / kg po for children; 500 mg po (for adults) and glucagon 0.03 mg / kg iv [a maximum of 1 mg]). GH levels are measured after administration of the drug, depending on the drug at various time points. Since no single test is 100% reliable in determining the GH release, two GH provocation tests are performed (typically the same day). GH levels usually indicate 30-90 min after the administration of insulin or the start of arginine infusion, 30-120 min after the administration of levodopa, 60-90 min after a Clonidingabe and 120-180 min for a glucagon peaks. The GH response that is considered normal, is somewhat arbitrary. Each stimulated GH levels> 10 ng / ml is generally sufficient to preclude a GH deficiency. GH deficiency can at answers <10 ng / ml (some centers use a lower cutoff, z. B. 7 ng / ml) are drawn on two pharmacological stimuli into consideration, but the results must be interpreted in the context of auxological data. Because GH levels rise during puberty, many children who do not pass the provocative GH stimulation test before puberty may, after puberty or when they are geprimet with gonadal steroids, have normal results. By provocation tests may slight disturbances in the regulation of GH secretion can not be detected. In children, for example, the short stature due to GH secretion, the results of provocation tests to show in terms of GH secretion often to normal levels. However, measurements of GH levels over 12-24 h pathologically low total amounts of secretion over 12 to 24 h. However, this test is expensive and unpleasant and thus is not the test of choice for GH deficiency. If a reduced GH secretion is confirmed secretory tests of other pituitary hormones and (if abnormal) are carried out of the hormones their peripheral endocrine glands goal with pituitary imaging studies if it is not already. Must Therapy with recombinant GH substitution Sometimes substitution of other pituitary hormones, the administration of recombinant GH is indicated for all children with short stature and documented GH deficiency. The dose is usually from 0.03-0.05 mg / kg s.c. once a day. During therapy, the rate of height growth accelerates often to values ??of 10 to 12 cm / year in the first year. Although height growth then slows down again, but it remains above the levels prior to treatment. The therapy is continued until an acceptable size has been reached or the growth rate falls to values ??below 2.5 cm / year. The rate of side effects of GH therapy is low, but includes idiopathic intracranial hypertension (pseudotumor cerebri- idiopathic intracranial hypertension), slippage of the epiphysis the femoral head (Epiphysiolysis femoris (Slipped capital femoral epiphysis, SCFE)) and transient peripheral edema mild. Prior to the application of recombinant GH GH was used which was extracted from pituitary. This has resulted in rare cases, the occurrence of Creutzfeldt-Jakob disease 20-40 years after treatment (Creutzfeldt-Jakob disease (CJD)). From pituitary extracted GH was last used in the 1980s. It is controversial whether short stature children should be treated with the clinical signs of GH deficiency but with normal GH secretion and normal levels of IGF-1 with GH. Many experts recommend a GH therapy for 6-12 months, which will only continue if the growth rate doubled during treatment or more than 3 cm / year above the rate before treatment. Others reject this approach from because it is experimental, can cause side effects, pathologised actually normal children and also ethical and psychosocial concerns of "megalomania" causes. If other Hypophysenhormonmängel accompany the GH deficiency, an additional hormone replacement is required. Cortisol (Addison's disease: treatment) and thyroid hormones (hypothyroidism: therapy) should be replaced during childhood, adolescence and adulthood, when the blood levels of these hormones are low. Diabetes insipidus requires life-long treatment with desmopressin in tablet form or intranasally (Central diabetes insipidus: therapy) usually. When puberty is abnormal, treatment is indicated with sex hormones (Male hypogonadism in children: treatment) when the length growth has reached satisfactory levels. GH therapy in children whose short stature resulting from therapeutic irradiation of the pituitary gland in the context of a cancer that has at least theoretical risk of causing a relapse. However, studies have shown no unexpected high incidence of the emergence of new tumors or recurrences. A GH replacement is likely to be classified at least 1 year after successful completion of an antitumor therapy as safe. Important points Growth hormone deficiency (GH) deficiency can occur in isolation or in conjunction with a generalized hypopituitarism. The causes include congenital (including genetic) diseases and a number of acquired disorders of the hypothalamus and / or pituitary gland. GH deficiency causes dwarfism; numerous other manifestations may be present depending on the cause. Diagnosis is based on a combination of clinical findings, imaging studies and laboratory tests, usually including provocative tests of GH release. Children with short stature and a documented GH deficiency should receive recombinant GH; other manifestations of hypopituitarism be treated as needed.

Health Life Media Team

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