The Growth Hormone Research Society consensus guidelines for the diagnosis and treatment of adult GH deficiency

Diagnosis and Management of Neuroendocrine Disorders of Survivors of Brain Tumors

Advances in the treatment of brain tumors have led to an increase in the number of survivors of this disease. Consequently, the long-term complications associated with past and current treatments are becoming more apparent. Of relevance to patients who receive treatment of brain tumors are the potential neuroendocrine complications that develop either acutely or several years following treatment. Presentation may differ between adults and children (e.g., short stature or adult growth hormone deficiency) but in both settings can complicate treatment and impact quality of life. The risk for the development of these complications depends on the location of the tumor (proximity to the pituitary/hypothalamus) and/or the treatment delivered (chemotherapy/surgery/radiation). Given the potential overlap in symptoms attributable to the underlying brain tumor and neuroendocrine dysfunction, a high level of suspicion, appropriate investigation, and administration of treatment may reduce morbidity and mortality for patients with brain tumors experiencing neuroendocrine dysfunction.

A review of guidelines for use of growth hormone in pediatric and transition patients

Growth hormone (GH) is approved by the US Food and Drug Administration (FDA) for use in pediatric patients with disorders of growth failure or short stature and in adults with growth hormone deficiency (GHD) and HIV/AIDS wasting and cachexia. For pediatric patients, guidelines for the use of GH have been developed by several organizations that have identified specific criteria for initiating GH therapy for each FDA-approved indication. Guidelines for adults have also been developed and include recommendations for transition (adolescent) patients with GHD. These patients are often treated with GH as children but may require continued treatment as young adults to attain full skeletal mineralization and improve cardiovascular risk factors. Adult and pediatric guidelines are supported by efficacy and safety studies, which show that, when started at an early age, GH treatment can increase growth velocity and that GH is safe and well-tolerated. We summarize the guidelines that are available for all FDA-approved indications among pediatric and transition patients. Adherence to these guidelines will help to ensure that patients with disorders of growth failure or short stature receive the necessary therapy to increase linear growth and transition smoothly to healthy adulthood.

Evaluation of coagulation and fibrinolytic parameters in adult onset GH deficiency and the effects of GH replacement therapy: a placebo controlled study

OBJECTIVE

Increased cardiovascular mortality/morbidity observed in patients with hypopituitarism is ascribed to growth hormone deficiency (GHD) because of its unfavorable cardiovascular risk profile. Abnormalities in the coagulation system may also contribute to increased cardiovascular morbidity/mortality. To get a better insight into the role of hemostasis in GHD we assessed several hemostatic markers at baseline and after 6 months of GH replacement therapy (GHRT). DESIGN-PATIENTS: Nineteen patients with adult onset GHD were enrolled (twelve patients into the treatment and seven patients into the placebo group) into the study. Platelet count, collagen/epinephrine closure time, collagen/ADP closure time, fibrinogen, prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III (AT III), protein C activity, protein S activity, lupus anticoagulant, antiphospholipid antibody immunoglobulin M, and antiphospholipid antibody immunoglobulin G were measured at baseline and 6 months after treatment.

RESULTS

The investigated parameters in the groups were similar at baseline except for low protein S (PS) activity. Protein S deficiency was observed in three of the patients in the GH treatment group at baseline, however the PS activity values normalized following GHRT. AT III and protein C activities decreased when compared to baseline values in the treatment group but not in the placebo group.

CONCLUSIONS

We observed protein S deficiency more frequent than seen in the general population and normalization of protein S activity and decreases, in other natural anticoagulants following GHRT. Further studies are required to understand the impact of these changes in cardiovascular morbidity and mortality in this patient population.

[Efficacy, safety and compliance of long-term growth hormone (GH) replacement therapy in adults with GH deficiency]

AIM

To study efficacy, safety and compliance of GH therapy for 4 years in 18 GH deficient (GHD) adults [12 women; mean age 50.5 yrs (25-66 yrs)].

METHODS

Clinical, biochemical and body composition (DXA) measurements were performed before and every year after GH therapy. Ecocardiography was performed at baseline and after 4 years. Dose of GH was 0.2 mg/day during the first year with subsequent titration to attain normal IGF-1 levels.

RESULTS

There was a significant reduction of total body fat (mean 2.8 kg), truncal fat (mean 1.9 kg) and an increase of lean body mass (mean 0.8 kg) and bone mineral density (BMD) on lumbar spine and femur, particularly in sites with T-score<-1,0 at baseline. Insulin levels and HOMA index worsened in the first year, but at the end no changes were noted on glucose, insulin, HOMA index and glycosylated hemoglobin. Two patients with altered glucose tolerance at baseline developed type 2 diabetes during follow-up. Total and LDL-cholesterol were significantly lower after therapy, with changes directly associated with baseline values. Cardiac parameters did not change. Side effects were mild and disappeared spontaneously. Tumor recurrence was not observed. Low compliance (estimated by low IGF-1 levels) was observed in 4 (22%), 2 (11%) and 6 (33%) patients at the end of second, third and fourth year, respectively.

CONCLUSIONS

Four years of GH therapy in GHD adults had a positive impact on body composition, BMD and lipid profile, with no effects on insulin sensitivity and heart. Glucose tolerance should be monitored carefully during long-term GH therapy.

Sleep architecture in Sheehan's syndrome before and 6 months after growth hormone replacement therapy

OBJECTIVE

To characterize the sleep parameters in patients with growth hormone (GH) deficiency in Sheehan's syndrome adults and to assess the effects of 6-month GH replacement therapy (GHRT).

METHODS

Twenty-two women with Sheehan's syndrome, (mean age; 49.1+/-2.2 years), and 12 women with similar age (mean age; 51.3+/-3.8 years) and body mass index as control subjects were included in the study. Under baseline conditions, women received adequate hormone replacement therapy for all hormonal deficiencies other than GH. Twelve patients received recombinant GH (Genotropin; Pfizer Stockholm, Sweden) (treatment group) and eight patients received placebo (placebo group) for 6 months. Two patients had only baseline evaluation and were not followed up prospectively. Two polysomnography (PSG) recordings were performed on the patients group, one in the baseline period and the other at the sixth month of treatment (either GH or placebo). Control group had only baseline PSG.

RESULTS

GH deficient females with Sheehan's syndrome have more NREM (95.9+/-1.5% and 88.6+/-0.9%, respectively; p<0.05), particularly in stage 4 sleep (11.4+/-1.9% and 4.9+/-1.6, respectively; p<0.05), less REM sleep (4.2+/-1.5% and 11.4+/-0.9, respectively; p<0.05) and also less sleep efficiency (69.7+/-3.4% and 81.1+/-2.8%, respectively; p<0.05) when compared to healthy controls. After 6 months of GHRT there was no significant difference in sleep parameters.

CONCLUSION

GH deficiency has sleep disturbing effects on Sheehan's syndrome patients under baseline conditions.

The influence of growth hormone status on physical impairments, functional limitations, and health-related quality of life in adults

The availability of recombinant human GH and somatostatin analogs has resulted in widespread treatment for adults with GH deficiency (GHD) and those with GH excess (acromegaly). Despite being at opposite ends of the spectrum in terms of their GH/IGF-I axis, both of these populations experience overlapping somatic impairments. Adults with untreated GHD have low circulating levels of IGF-I that manifest as altered body composition with increased fat and reduced lean body and skeletal muscle mass. At the other end of the spectrum, adults with GH excess, who have elevated levels of IGF-I, also have altered body composition. Impairments that result from disorders of either GHD or GH excess are both associated with increased functional limitations, such as reduced ability to walk quickly for prolonged periods, and poorer health-related quality of life (HR-QoL). Adults with untreated GHD and GH excess both commonly complain of excessive fatigue that seems to be associated more with impaired aerobic than muscular performance. Several studies have documented that administration of GH or somatostatin analogs to adults with GHD or GH excess, respectively, ameliorates abnormal biochemical profile and the associated somatic impairments. However, whether these improvements translate into improved physical function in adults with GHD or GH excess remains largely unknown, and their impact on HR-QoL controversial. Review of placebo-controlled trials to date suggests that GH and somatostatin analogs have greater effects on gas exchange and aerobic performance than as anabolic agents on skeletal muscle mass and function. Future investigations should include dose-response studies to establish the optimal combination of pharmacological agents plus exercise required to improve not only biochemical markers but also physical function and HR-QoL in adults with GHD or GH excess.

Adult growth hormone replacement therapy and neuroimaging surveillance in brain tumour survivors

OBJECTIVE

Systematic collections of neuroimaging data are nonexistent in brain tumour survivors treated with adult growth hormone replacement therapy (AGHRT). We present our surveillance data.

DESIGN

In 1993, our unit implemented a policy of performing brain scans on every brain tumour survivor before starting AGHRT, with repeat neuroimaging at least once after 12-18 months' treatment. Reports for baseline scans and most recent scans were analysed for this retrospective study.

PATIENTS

All brain tumour survivors who received AGHRT (60 patients) were included in the analysis.

MEASUREMENTS

Evidence and extent of residual tumour, tumour progression, tumour recurrence, and secondary neoplasms (SN) on baseline scan and latest follow-up scan.

RESULTS

All patients had baseline scans performed. Follow-up scans were available in 41/45 (91%) patients who received AGHRT for more than 1 year (mean duration +/- SD of GHRT was 6.7 +/- 3.6 years). Sixteen patients had residual tumours, and SNs (all meningiomas) were demonstrated in three patients on baseline scans. Appearances remained stable in 34 (83%) patients during follow-up (extending to 17.4 +/- 8.3 years after tumour diagnosis). Of the 16 residual primary tumours, an incurable ependymoma continued to grow, and one meningioma progressed slightly in size over 7.7 years. Follow-up scans also revealed continued growth of the SNs detected at baseline, and five additional meningiomas (two in patients with a previous SN, confirming an excess risk in this subgroup, P = 0.02). All SNs occurred on average 22.8 (range 17-37) years after radiotherapy.

CONCLUSIONS

Our data do not suggest an increased rate of recurrence or progression of childhood brain tumours during AGHRT. Nonetheless, vigilance and long-term surveillance are needed in these patients in order to detect and monitor SNs, in particular in patients with a previous history of a SN. We endorse a proactive neuroimaging policy, preferably as part of a larger, controlled trial in the future.

Insulin-like growth factor I (IGF-I) and IGF-binding protein 3 as diagnostic markers of growth hormone deficiency in infancy

BACKGROUND

The diagnosis of growth hormone deficiency (GHD) in infancy is difficult, and no specific cutoff value during GH provocative testing is recommended in early life.

METHODS

Serum insulin-like growth factor I (IGF-I) and serum IGF-binding protein 3 (IGFBP-3) levels were evaluated as diagnostic markers of GHD. Measurements of IGF-I and IGFBP-3 during the 1st year of life were analyzed in 11 patients clinically suspected of having GHD (neonatal hypoglycemia, micropenis, or evidence of other pituitary hormone deficiencies), in whom the diagnosis was later verified. A prospective cohort of 51 healthy infants served as controls.

RESULTS

The sensitivity of IGF-I as a diagnostic marker of GHD was 90% (10 out of 11 patients) with a cutoff value of -2 standard deviations (SD), and the sensitivity of IGFBP-3 measurements was 81% (9 out of 11 patients) with a cutoff value below -2 SD. One patient had serial measurements before initiation of GH treatment where the IGF-I was fluctuating (3 of 6 slightly above -2 SD), whereas all IGFBP-3 measurements were below -2 SD.

CONCLUSIONS

The IGF-I had a high sensitivity in detecting infants with GHD. The combination of IGF-I and IGFBP-3 increased the diagnostic sensitivity. We speculate that assessment of IGF-I and IGFBP-3 may add diagnostic value in infants suspected of having GHD and furthermore that values below -2 SD are highly suggestive of GHD.

Occurrence of Pituitary Dysfunction following Traumatic Brain Injury

Traumatic brain injury (TBI) may be associated with impairment of pituitary hormone secretion, which may contribute to long-term physical, cognitive, and psychological disability. We studied the occurrence and risk factors of pituitary dysfunction, including growth hormone deficiency (GHD) in 50 patients (mean age 37.6 +/- 2.4 years; 40 males, age 20-60 years; 10 females, age 23-87 years) with TBI over 5 years. Cranial or facial fractures were documented in 12 patients, and neurosurgery was performed in 14. According to the Glasgow Coma Scale (GCS), 16 patients had suffered from mild, 7 moderate, and 27 severe TBI. Glasgow Outcome Scale (GOS) indicated severe disability in 5, moderate disability in 11, and good recovery in 34 cases. Basal pituitary hormone evaluation, performed once at times variable from 12 to 64 months after TBI, showed hypogonadotrophic hypogonadism in 7 (14%), central hypothyroidism in 5 (10%), low prolactin (PRL) levels in 4 (8%), and high PRL levels in 4 (8%) cases. All subjects had normal corticotrophic and posterior pituitary function. Seven patients showed low insulin-like growth factor-I (IGF-I) levels for age and sex. Results of GHRH plus arginine testing indicated partial GHD in 10 (20%) and severe GHD in 4 (8%) cases. Patients with GHD were older (p <0.05) than patients with normal GH secretion. Magnetic resonance imaging demonstrated pituitary abnormalities in 2 patients; altogether pituitary dysfunction was observed in 27 (54%) patients. Six patients (12%) showed a combination of multiple abnormalities. Occurrence of pituitary dysfunction was 37.5%, 57.1%, and 59.3% in the patients with mild, moderate, and severe TBI, respectively. GCS scores were significantly (p <0.02) lower in patients with pituitary dysfunction compared to those with normal pituitary function (8.3 +/- 0.5 vs. 10.2 +/- 0.6). No relationship was detected between pituitary dysfunction and years since TBI, type of injury, and outcome from TBI. In conclusion, subjects with a history of TBI frequently develop pituitary dysfunction, especially GHD. Therefore, evaluation of pituitary hormone secretion, including GH, should be included in the long-term follow-up of all TBI patients so that adequate hormone replacement therapy may be administered.

Young adult survivors of childhood acute lymphoblastic leukemia: spontaneous GH secretion in relation to CNS radiation

BACKGROUND

Young adults who are long-term survivors of acute lymphoblastic leukaemia (ALL) in early childhood usually do well and do not have to go to regular medical checkups. Many of these survivors did receive prophylactic cranial radiotherapy during their oncological treatment. The effect of cranial irradiation on the hypothalamus is considered to be progressive. Therefore, late effects, such as reduced growth hormone (GH) secretion, may remain undetected until adulthood.

PROCEDURE

Records from all patients treated for ALL before the onset of puberty in the region of West Sweden, between 1 January 1973 and 31 December 1985 were included, provided they were in first remission with a minimum follow-up time of 15 years, and a minimum age of 20. These criteria were met by 47 young adults aged 20-32 years, of whom 35 agreed to participate. We studied spontaneous GH secretion over 24 hr, IGF-I and IGFBP-3, final height and BMI. The patients had been treated according to three consecutive Swedish childhood leukaemia group protocols. The median follow-up time was 20 years, and 19 of the patients had been treated with cranial irradiation (CRT+), 16 had not (CRT-).

RESULTS

CRT+ patients had significantly lower maximal peaks of GH than CRT- patients. Fifty percent of the CRT+ patients had a GH(max) below the cut-off level (3.3 microg/l), for GH treatment. CRT- patients all had GH(max) levels considered within the normal range. Final height of all the patients, except one CRT+ women, was in the range of expected midparental height, the median loss in final height in the CRT+ patients was 0.8 standard deviation (SD). No patient in this study was obese by definition (BMI <30 kg/m(2)). IGF-I and IGFBP-3 concentrations did not correlate to variations in spontaneous GH secretion in these patients.

CONCLUSIONS

In spite of the little effect on final height, we found impaired spontaneous GH secretion in 79% of young adults 20-32 years of age, and GH deficiency (GHD) in 47% after low-dose cranial irradiation in early childhood. The consequences of this low-GH secretion need to be investigated.

The use of the hypoglycaemic clamp in the assessment of pituitary function

OBJECTIVE

The standard dynamic test used to diagnose hypopituitarism is the insulin tolerance test (ITT), in which insulin-induced secretion of ACTH, GH and cortisol is measured. However, because of differences in insulin sensitivity some patients fail achieve sufficient hypoglycaemia to assess pituitary function and colleagues experience severe hypoglycaemia and are at risk for cardiac dysrhythmia, seizure or coma. This risk may be particularly pertinent in the evaluation of older adults. We hypothesized that the hypoglycaemic clamp may be useful in assessing pituitary function in some patients.

PATIENTS AND MEASUREMENTS

Twenty-one normal subjects (14 old [50-76 years] and 7 young [18-36 years]) and 7 hypopituitary subjects were studied. A clamp study was performed in which insulin infusion was given at 2 mU/kg/min and increased to 4 mU/kg/min if the target glucose concentration was not reached after 40 min. Dextrose was infused as needed to clamp the plasma glucose concentration at 2.2 mmol/l for 30 min. On a separate day, 7 young controls also underwent an ITT in which 0.15 U/kg insulin was administered as a bolus intravenous injection at time 0. In both studies, baseline values were taken at - 10, - 5 and 0 min. Samples were then collected every 5 min for plasma glucose and every 10 min for insulin, ACTH, cortisol and GH.

RESULTS

ACTH and GH secretion during each test were similar in younger controls (P = NS) but cortisol secretion was lower during ITT (P < 0.01 vs. clamp). Hypopituitary subjects had significantly less ACTH, cortisol and GH secretion than controls of all ages (P < 0.001 for all). Peak GH secretion was significantly lower in the old controls than in young controls (22 +/- 12 vs. 48 +/- 26 mU/l, respectively; P < 0.01) but significantly higher than the hypopituitary subjects (2 +/- 2 mu/l; P < 0.001).

CONCLUSION

These data demonstrate that the hypoglycaemic clamp can be used in the assessment of pituitary function and suggest that this technique may be particularly beneficial in the evaluation of GH deficiency in older adults who may not tolerate the ITT.