Growth hormone testing Review of literature - PowerPoint Presentation

1. Growth hormone testingReview of literature

2.  Consensus guidelines for the diagnosis and treatment of growth hormone (GH) deficiency in childhood and adolescence: summary statement of the GH Research Society. GH Research Society. J Clin Endocrinol Metab. 2000;85(11):3990–3993. [PubMed] [Google Scholar]

3. Once other causes of short stature the initial screening laboratory tests include :circulating levels of IGF-I and IGFBP3 and a bone age determination The concentrations of IGF-1 and IGFBP3 likely reflect the integrated concentration of secreted GH and are stable during the day when compared to the pulsatile secretion of GH

4. literature suggests that IGF-I and IGFBP-3 are useful in the diagnosis of GHD. An obvious difficulty in determining the diagnostic performance of any test for GHD is the lack of a gold standard to determine true GHD. In general, however, both IGF-I and IGFBP-3 are reported to have good specificity but relatively poor sensitivity for GHD (*.**). Although these measures are not useful in isolation (**), they can be helpful when combined with other diagnostic measures with higher sensitivity. Cianfarani et al. combined IGF-I measurement with assessment of growth velocity (GV), which is sensitive but not highly specific for GHD, to achieve excellent specificity and sensitivity in those cases in which IGF-I and GV are concordant (i.e., both low or both normal) (*). Another advantage of IGF-I and IGFBP-3 is that they show superior reproducibility in comparison to stimulated GH levels (*)*. Cianfarani S, Tondinelli T, Spadoni GL, Scire G, Boemi S, Boscherini B. Height velocity and IGF-I assessment in the diagnosis of childhood onset GH insufficiency: do we still need a second GH stimulation test? Clin Endocrinol (Oxf) 2002;57(2):161–167. [PubMed] [Google Scholar]** Galluzzi F, Quaranta MR, Salti R, Saieva C, Nanni L, Seminara S. Are IGF-I and IGF-BP3 useful for diagnosing growth hormone deficiency in children of short stature? J Pediatr Endocrinol Metab. 2010;23(12):1273–1279. [PubMed] [Google Scholar]

5. IGF-1 levelsIGF-1 levels vary by age and should be interpreted relative to bone age rather than to chronologic age. IGF-1 levels are lowest in infancy and early childhood (< 5 years) and thus do not reliably discriminate between normal and subnormal in these age groups. At puberty, IGF-1 levels rise and normal levels help exclude GH deficiency. Low IGF-1 levels in older children suggest GH deficiency; however, IGF-1 levels are low in conditions other than GH deficiency (eg, psychosocial deprivation, undernutrition, celiac disease, hypothyroidism) and these disorders must be excluded

6. Measurement of IGFBP-3 IGFBP-3 may be acutely influenced by meal intakeHowever, IGFBP-3 levels, unlike IGF-1, are less affected by undernutrition and allow discrimination between normal and subnormal in younger children

7. one may interpret the results of this testing as follows:patients with clearly normal IGF-1 and IGFBP-3 (SD ≥0); i.e., in the upper half of the normal range), GH deficiency is extremely unlikely, and no further testing is requiredpatients with IGF-1 and IGFBP-3 (0>SD >-1); observe and follow clinically and reevaluate in 6 months patients with minimally low IGF-1 and IGFBP-3 (e.g., between-1 and −2 SD), perform provocative GH testingseverely reduced IGF-1 and IGFBP-3 (e.g.,<−2 SD) MRI is recommended and if abnormality is seen ,provocative GH testing is optional Consider genetic testing for GH –Igf1 axis

8. Home message if the growth faltering is severe, bone age is significantly delayed, and IGF-1 and IGFBP-3 are definitively low (e.g.,<−2 SD), and there are other anterior pituitary hormone deficits, it is reasonable to make the diagnosis of GHD without performing GH stimulation testing, especially in the setting of known hypothalamic-pituitary disease and/or its treatment (for example, brain surgery and/or radiation therapy).

9. provocative testingIn children with low levels of IGF-1 and IGFBP-3, GH deficiency is usually confirmed by measuring GH levels. Because basal GH levels are typically low or undetectable (except after the onset of sleep), random GH levels are not useful and assessment of GH levels requires provocative testing. However, provocative testing is nonphysiologic, subject to laboratory error, and poorly reproducible. Also, the definition of a normal response varies by age, sex, and testing center and is based on limited evidence.

10. Given the numerous concerns with provocative GH testing, some have suggested that provocative testing should not play a role in diagnosis (*), or that it should not be obligatory for cases in which the diagnosis is clear based on growth measures (**). At minimum, discussion and attempt at consensus are needed regarding optimal provocative stimuli, appropriate cut-off levels specific to GH assay and other factors such as BMI and pubertal status, utility of sex steroid priming, and standardization of testing protocols to minimize risk and discomfort while maximizing diagnostic sensitivity and specificity. In addition, use of other diagnostic tests, including IGF-I, IGFBP-3, cranial MRI and genetic testing, should be explored further for their potential to supplement or supplant provocative GH testing.*. Gandrud LM, Wilson DM. Is growth hormone stimulation testing in children still appropriate? Growth Horm IGF Res. 2004;14(3):185–194. [PubMed] [Google Scholar]**. Rosenfeld RG, Albertsson-Wikland K, Cassorla F, Frasier SD, Hasegawa Y, Hintz RL, et al. Diagnostic controversy: the diagnosis of childhood growth hormone deficiency revisited. J Clin Endocrinol Metab. 1995;80(5):1532–1540. [PubMed] [Google Scholar]

11. Multiple studies have also demonstrated that provocative GH tests are poorly reproducible. Lee et al. recently reported correlations between peak GH to various stimuli (clonidine, insulin, dopamine) in children with idiopathic short stature (ISS) who underwent identical stimulation testing on two occasions separated by a month (*). They report that peak GH on the first and second occasions were not significantly correlated with each other for any of the stimuli (*) Loche et al. report similarly poor reproducibility, as 28 of 33 (85%) children who had initially failed two provocative GH tests passed a third test performed 1–6 months later (**). Given this lack of reproducibility over a short-term period, it is not surprising that, upon re-testing in early adulthood, approximately half of individuals who were treated for iGHD during childhood no longer demonstrate GHD (***)*. Lee HS, Hwang JS. Influence of body mass index on growth hormone responses to classic provocative tests in children with short stature. Neuroendocrinology. 2011;93(4):259–264. [PubMed] [Google Scholar]. Uses data from a relatively large sample of 187 children to demonstrate the association between increased BMI and decreased peak GH and to illustrate the poor reproducibility of provocative GH tests in comparison to IGF-I and IGFBP-3.**. Loche S, Bizzarri C, Maghnie M, Faedda A, Tzialla C, Autelli M, et al. Results of early reevaluation of growth hormone secretion in short children with apparent growth hormone deficiency. J Pediatr. 2002;140(4):445–449. [PubMed] [Google Scholar]*** Juul A, Kastrup KW, Pedersen SA, Skakkebaek NE. Growth hormone (GH) provocative retesting of 108 young adults with childhood-onset GH deficiency and the diagnostic value of insulin-like growth factor I (IGF-I) and IGF-binding protein-3. J Clin Endocrinol Metab. 1997;82(4):1195–1201. [PubMed] [Google Scholar]

12. Provocative GH testing remains the subject of much controversy, and there are significant issues concerning the validity and reproducibility of GH testing. A peak stimulated GH of less than 7mcg/L is the usual cut-off for GH deficiency in children in the United StatesAlthough it is well-established that peak GH may vary according to the stimulus given and the assay employed for measurement ,a uniform cut-off value is generally used regardless of stimulus or assay.

13. Variety of growth hormone stimulation testsVariety of growth hormone stimulation testsThere are many pharmachological stimulants that have been used tostimulate growth hormone secretion, the most commonly used in clinical practice are: arginine, clonidine, glucagon and insulin.

14. Provocative Growth Hormone TestingRightly or not, provocative GH testing continues to play a primary role in the diagnosis of GHD. Provocative tests are invasive, are typically 2–4 hours in length, and have potential risks and side effects. The most common provocative agents include insulin, glucagon, clonidine, arginine, and L-dopaThe use of GHRP-2 ( is a synthetic agonist of ghrelin, the newly-discovered gut peptide which binds to the growth hormone (GH) secretagogue receptor) as a novel provocative agent with minimal side effects has recently been explored (*), but extensive additional testing would be needed before clinical use.* Asakura Y, Toyota Y, Muroya K, Adachi M. Growth hormone response to GH-releasing peptide-2 in children. J Pediatr Endocrinol Metab. 2010;23(5):473–480. [PubMed] [Google Scholar]

15. Because no single test is 100% effective in eliciting GH release, two GH provocation tests are done (typically on the same day). GH levels generally peak 30 to 90 minutes after administration of insulin or the onset of arginine infusion, 30 to 120 minutes after levodopa, 60 to 90 minutes after clonidine, and 120 to 180 minutes after glucagon.

16. Clonidine stimulation testClonidine is an alpha 2-adrenergic agonist that increases the growth hormone releasing hormone secretion, and inhibits somatostatin release.The patient should receive nothing by mouth for at least four to 6 h prior to the test and is generally off all other medications. After the baseline blood sample is obtained, clonidine is administered at a dose of 5 μg/kg, to a maximum of 250 μg. Samples for GH assay should be obtained at 0, 30, 60 and 90. Clonidine is an agent used to lower blood pressure; consequently, blood pressure should be monitored at 0, 30,60, and 90 min after clonidine administration. In young children, clonidine frequently causes drowsiness, which may last for several hours. Patients should have a place to lie down and may be allowed to sleep throughout the procedure. Drowsiness may prolong fasting period and may cause hypoglycemia.Subjects must be encouraged to eat or drink after the test is finished. Water may be frequently offered to the patient throughout the test .

17. Arginine stimulation testThe arginine stimulant works by inhibiting somatostatin release andconsequently increasing GH secretion Prior to the administration of the pharmacological stimulus, the patient should be fasting after midnight or following bedtime snack. After the baseline serum sample is obtained, arginine HCL (0.5 g/kg to a maximum of 40 g) is administered IV over a 30-min period. The maximum GH peak is expected 60 min after starting the arginine infusion. blood pressure sample be collected at 0, 15,30,45,60, and 90 ,120 min after administrationFrequent side effects with this protocol are nausea and vomitingReferencesAlatzoglou KS, Dattani MT. Growth hormone deficiency in children. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 23.Guber HA, Farag AF. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 24.Patterson BC, Felner EI. Hypopituitarism. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 573

18. How the Test is Performed ?Blood is drawn several times. Blood samples are taken through an intravenous (IV) line instead of reinserting the needle each time. The test takes between 2 hours.An IV is usually placed in a vein, most often the inside of the elbow or the back of the hand. The site is first cleaned with germ-killing medicine (antiseptic).The first sample is drawn early in the morning.Medicine is given through the vein. This medicine stimulates the pituitary gland to release GH.Additional blood samples are drawn over the next few hours.After the last sample is taken, the IV line is removed. Pressure is applied to stop any bleeding.

19. RisksThere is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.Other risks associated with having blood drawn are slight, but may include:Excessive bleedingMultiple punctures to locate veinsFainting or feeling lightheadedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)

20. Glucagon stimulation testThis test is a very good option for small children and infants.Glucagon induces GH secretion by stimulating endogenous insulin secretion to compensate for elevated serum glucose levels It is a good substitute for the insulin tolerance test that may be risky in newborns and small children.After an overnight fast, glucagon is administered intramuscularly or subcutaneously at a dose of 0.03 mg/kg to a maximum of 1 mg. Serum samples should be drawn at 0, 1,2, 2.5 and 3 h after administration of glucagon The maximal GH peak occurs in most patients between 2 and 3 h after the stimulus. Young children may develop nausea and vomit during the course of this test.I. Georeli, P. Triantafyllou, M. Dimitriadou, et al., Timing of GH peak in bothglucagon and clonidine tests is of major clinical importance, Endocr. Praact. 25(2019) 800–809.

21. Insulin hypoglycemia test the mechanism of stimulation is the counter-regulatory response to insulin-induced hypoglycemia Patient should be fasting after midnight. Strict surveillance by an experienced nurse and/ or physician is mandatory. Calibrated glucose monitor at bedside, an IV line with saline solution and 25 ml syringes filled with 10%-glucose solution should be prepared prior to the initiation of the test. In children over 4 years of age, to start the protocol, 0.1 unit/kg of regular Insulin should be administered IV. For younger children, a dose of 0.05 unit/kg is usually sufficient.Blood samples for GH analysis should be obtained at 0, 15, 30, 45, 60, and 90 min after insulin administration. Serum glucose levels must be evaluated at the bedside at each time point during the protocol. For the test to be valid, the blood glucose level must decrease by 50% of the initial value or to<40 mg/dl (2.2 mmol/L). However more severe hypoglycemia must be voided because it can lead to seizures, coma or death

22. Clinical symptoms such as sweating, tremor, tachycardia, and nervousness are indicative that adequate hypoglycemia has occurred and those symptoms usually abate by the next scheduled blood sample if the symptoms progress and the patient shows lethargy, loss of consciousness or seizure; the test is interrupted and terminated by the immediate IV administration of glucose from the previously prepared syringes (dose of 3cc /kg dw10%). If this occurs, do not stop collecting serum samples according to the protocol. Upon completion of the test, a meal high in carbohydrate is offered to the patient. The patient must be monitored until serum glucose levels return to normal. The GH peak occurs approximately 20 min after the glucose nadir.In some patients the GH peak is delayed, thus, a 90 min blood sample is recommended. Children with GH deficiency frequently have enhanced response to insulin and are more likely to have an episode of sever hypoglycemia

23. Priming with sex steroidsSince sex steroids cause the increase in GH secretion during puberty For priming boys, one commonly used protocol is the administration of 100 mg depot testosterone between 7 and 10 days before the actual GH stimulation test [29]. Forgirls , some endocrinologists prime with ethinyl-estradiol, oneprotocol is as follows: 0.02 mg for children with<23 kg and 0.05 mg for those over 23 kg; given orally 18, 12, and 1 h prior to starting the test. G. Marin, H.M. Domene, K.M. Barnes, B.J. Blackwell, F.D. Cassorla, G.B. Cutler Jr.,The effects of estrogen priming and puberty on the growth hormone response tostandardized treadmill exercise and arginine-insulin in normal girls and boys, J.Clin. Endocrinol. Metab. 79 (1994) 537–541.

24.

25. CASE 1An eight-year, two -month-old girl in view of short stature is discussed hear she was referred when she was 2y,10m for slowed growth. She had been born at term weighing 3.1 kg , BH=51 by a normal spontaneous vaginal delivery . Her mother is 160cm tall, and Her father is 170cm tall. After ruling out systemic illness, she was evaluated for growth hormone deficiency (GHD) by stimulation tests.Review of systems was negative for systemic disorder . On first examination the child had not dysmorphic face , or skeletal abnormality ,height was 82.5 centimeters 4·5 SDbelow the third percentile for chronological age. Her weight was 9 kilograms. serum insulin-like growth factor 1 (IGF-1) level was low (7.91ng/mL,)<-2SD subsequent clonidine test was done showing a GH deficiency with serum GH: 0.29ng/mL, 0.36 , 0.43, 0.42 In 0, 30, 60, 90 and 120 min (indicative of GH deficiency)Provocative arginine-GH stimulation testing demonstrated a peak GH level of 0.42  ng/mLCranial MRI revealed no masses or lesions.  Confirmatory genetic testing revealed XX female

26. The patient has been followed up at endocrinology clinic for over years.After that The patient was treated with GH at a dosage of 25 micg daily in 6/2/93 for over the past 7m of follow- up,Hight became 89cm equel to 5%

27. CASE 2A 16.5-year-old girl referred for evaluation of short stature. The patient had 141 cm height and 37 kg weight. Hieght was-4SD below the mean. She was conscious and alert girl who was drinking more than usual without complaints of headache, vomiting and diminution of vision. Early examination was characterized that she was suffering from delayed puberty, her breasts were undeveloped and had stopped growing, and her menses wasn’t started at this age. The neurologic examinations were normal; the optic disc was pale but she had not papilloedema. Other general physical examination was normal.IGF1 and IGFBP3 Were less than -2SD The biochemistry tests revealed that she had hypogonadotrop hypogonadism. Bone age equaled to 14yCraniopharyngioma presenting with delay to puberty: a case report S NoorianIRANIAN JOURNAL OF PEDIATRICS 23 (1), 12-12

28. DiagnosisMagnetic resonance imaging (MRI) demonstrated a suprasellar multiloculated mixed cystic-solid mass (48.27. 45 mm) suggestive of a craniopharyngioma

29. A 6.5-year-old boy who was born of non-consanguineous marriage   Patient was born on 37 weeks of gestation, by caesarian section.  Birth weight was 1600 g (<5th weight for gestational age percentile and birth height was 42 cm (-4sd) (IUGR)In exam weight of 11.5 kg ,a height of 98.5 cm (SDS = −4), head circumference of 50 cm (within normal range for age and gender)The patient suffered from failure to thrive with sparing of her head circumferenceExamination of the hand revealed clinodactyly of fifth finger In accordance to Tanner staging score, testis development and, pubic hair were Tanner stages one.CASE 3 hormonal analysis which revealed a normal thyroid profileand normal serum level of IGF-1=170.9 ng/ml (52-297 ng/ml) and basal growth hormone (GH) (2.8 μiu/ml). No defects were detected on MRI of the sella. growth hormone stimulation test with Clonidine was performed which confirmed complete GH deficiency (at 30 min=1.8 μiu/ml, 60 min=45 μIU/ml), and 120min=66.3 μIU/mlOther laboratory tests TTGAb, BUN/Cr, TFT and ABG ,ca p .Na K. were in Normal range

30. physical examination revealed a boy with a weight of 11.5 kg ,a height of 98.5 cm (SDS = −4), head circumference of 50 cm (within normal range for age and gender)Birth weight was 1600 g (<5th weight for gestational age percentile) and birth height was 42 cm (-4sd)

31. broad forehead ,small jaw,and Thin upper lip triangulafacies crowded teeth(tooth malalignment and malposition)RSS ( RUSSELL SIVER SYNDROM) fifth-finger clinodactyly

32. Case 4A 4-year-old boy from unrelated parents , who was refered for evaluation of poor weight gain and short stature . Physical examination revealed a flat and broad nasal root, with a sign of repaired cleft lip palate and micropenis, it was discovered that the child was severely growth retarded for age ,bellow the third percentile for height, approximately(- 4SDS) .Low FT4 level with normal TSH level were demonstrated in the serum and Basal GH and IGF1 level were also low .After treatment of central hypothyroidism with levothyroxin ,GH stimulating test , show no adequate response, consistent with growth hormone deficiency ,the other hormones (LH/FSH, prolactin) levels were normal.Measurement of ACTH and cortisol required dynamic testing, so ACTH Depot test was done and normal response was seen. MRI imaging revealed Arnold chiary malformation type 1. Both the radiographic and lab data findings were consistent with rare MPHD syndrome

33. LHX4 (LIM Homeobox 4) is a Protein Coding gene. Diseases associated with LHX4 include Pituitary Hormone Deficiency, Combined, 4 and Pituitary Stalk Interruption Syndrome.Diagnosis

34.