Growth hormone status in adults treated for acute lymphoblastic leukaemia in childhood

OBJECTIVE

Growth hormone status was assessed in a cohort of 32 (16 male) adults who had received cranial irradiation (XRT) in childhood as part of their treatment for acute lymphoblastic leukaemia (ALL) and compared with 35 age matched young adults (18 male).

DESIGN

Height and weight were measured in all subjects and the heights of the patients at XRT were obtained from their case notes. Each patient and control underwent two provocative tests of growth hormone (GH) secretion using insulin (0.2 IU/kg body weight) and arginine (20 g/m2). Basal serum insulin like growth factor-1 (IGF-1) and IGFBP-3 (binding protein-3) concentrations were also measured.

RESULTS

The patient group had a significantly lower peak GH response to both provocative tests (P < 0.01), and lower IGF-1 and IGFBP-3 levels compared with the normal controls (P < 0.01). Nine of the patient group were severely GH deficient (peak GH response < 9 mU/l to both provocative agents) and a further 12 patients were GH insufficient (peak GH response < 20 mU/l to both tests with at least one peak GH response > 9 mU/l). Overall a significant median change in height from XRT to final height of -0.5 SDS was found which was even greater in the severely GH deficient group (median change in height of -2.1 SDS).

CONCLUSION

These data suggest that a significant proportion of adults treated with cranial XRT in childhood with irradiation doses between 18-25 Gy, as part of their treatment for ALL, are severely GH deficient now and should be considered for GH replacement. Changes in GH secretion evolve with time following irradiation-induced damage to the hypothalamic-pituitary axis; therefore long-term surveillance will be required in those remaining patients, in whom GH status is considered currently to be insufficient or even normal.

Cancer incidence in Karachi, Pakistan: first results from Karachi Cancer Registry

No cancer incidence data from Pakistan have been published in the 5 decades since independence. Incidence data for the period 1995-1997 from the population of the Karachi South district (1.7 million) are presented here. A total of 4,268 new cancer cases were registered during this period: 2,160 cases in males and 2,108 cases in females. Overall, 95.3% of the incident cases were microscopically verified. The incidence rates for all cancers combined were 80.5 per 100,000 (crude) and 136.7 per 100,000 (age- standardised rates [ASR]) for males and 91.8 (crude) and 163.2 per 100,000 (ASR) for females. In males, lung cancer (ASR 20.3) was the most frequently recorded malignancy followed by oral cavity (ASR 13.8) and larynx cancer (ASR 8.6). In females, breast was the most common site of cancer, accounting for one third of female cancers (ASR 51.7), followed by oral cavity (ASR 14.1) and ovarian cancer (ASR 10.2). Karachi reports the highest incidence of breast cancer for any Asian population, except Jews in Israel. Tobacco smoking is estimated to be responsible for 40% of cancers in males and tobacco chewing for a further substantial proportion of head and neck cancers.

The assessment of growth hormone status in normal young adult males using a variety of provocative agents

OBJECTIVE

In adults, there are few data regarding GH responses to provocative stimuli other than insulin-induced hypoglycaemia. We have compared the GH response to four different growth hormone secretagogues and placebo in normal healthy adult males.

DESIGN

This was a prospective, randomized, placebo-controlled study in 18 normal male subjects. After an overnight last, an intravenous cannula was inserted into the arm of each subject and a blood sample was taken for GH at -30, -15, and 0 minutes. Four provocative agents (intravenous insulin 0.2 IU/kg; intravenous arginine 20 g/m2 as an infusion over 30 minutes; oral clonidine, either 100 or 200 micrograms; intramuscular glucagon 1 mg) and placebo were administered to each subject in a randomized manner on different days. Further blood samples were taken at 15-minute intervals for 180 minutes for GH estimation.

RESULTS

The median (range) GH peak response for each agent was insulin 107.7 (28.1-200) mU/l; arginine 22.3 (3.1-72.9) mU/l; glucagon 42 (11.8-200) mU/l; 100 micrograms clonidine 7.2 (< 1-22.2) mU/l; 200 micrograms clonidine 8.2 (1.1- 88) mU/l and placebo 2.4 (< 1-30.2) mU/l. The peak GH response to insulin-induced hypoglycaemia (ITT) was significantly greater than for any other agent (P < 0.0001). The peak GH response to glucagon was significantly greater than for arginine (P < 0.05), clonidine at 100 and 200 micrograms (P < 0.01) and placebo (P < 0.01). The peak GH response following administration of arginine was significantly greater than for clonidine 100 and 200 micrograms (P < 0.05), and placebo (P < 0.01). The peak GH response following clonidine 200 micrograms was not significantly greater than following clonidine 100 micrograms (P = 0.38) or placebo. On an individual basis two, six and 15 of 18 subjects failed to achieve a peak GH level of > 20 mU/l to glucagon, arginine and clonidine respectively. In complete contrast only one subject achieved a peak response of less than 40 mU/l (28.1 mU/l) to ITT.

CONCLUSIONS

The most profound GH release is seen after insulin-induced hypoglycaemia. Glucagon appears to be more effective at inducing GH release than arginine. Clonidine at a dose of 100 or 200 micrograms is no more effective than placebo.

Reduced bone mineral density in young adults following cure of acute lymphoblastic leukaemia in childhood

Bone mineral density (BMD), serum osteocalcin and type I collagen C-telopeptide (ICTP) were assessed in a cohort of 31 (16 males) adults who had received cranial irradiation in childhood as part of their treatment for acute lymphoblastic leukaemia (ALL). Markers of bone turnover were compared with those of 35 age and body mass index (BMI) matched young adults (18 male). Growth hormone status had previously been determined using an insulin tolerance test and arginine stimulation test. Eight patients were classified as severe growth hormone deficiency (group 1), 12 patients as growth hormone insufficient (group 2) and 11 patients as normal (group 3). Vertebral trabecular BMD, lumbar spine and femoral neck integral BMD and forearm cortical bone mineral content (BMC) was measured 17.8 (6.8-28.6) years after cranial irradiation and was expressed as Z (standard deviation) scores. There was a significant reduction in vertebral trabecular BMD (median Z score -1.25, P < 0.001), in lumbar spine integral BMD (median Z score -0.74, P = 0.001), in forearm cortical BMC (median Z score -1.35, P < 0.001), and less so in femoral neck integral BMD (median Z score -0.43, P = 0.03). There was no difference among the growth hormone status groups for the following BMD measurements: vertebral trabecular BMD, lumbar spine integral BMD or femoral neck integral BMD (P = 0.8, P = 0.96 and P = 0.4 respectively). There was only a marginal significant difference for BMD at the wrist between growth hormone status groups (P = 0.04). There was no correlation between the BMD measurements with time since or age at diagnosis and no difference in markers of bone turnover between patients and controls; median serum osteocalcin 13.3 and 12.0 ng ml (P = 0.7), respectively, and for ICTP 5.0 and 4.9 microg L (P = 0.67) respectively. In conclusion, there is a highly significant reduction in BMD in young adults following treatment for ALL in childhood. The reduction in BMD affects both trabecular and cortical bone but did not seem to be related to time since diagnosis, age at diagnosis, or current growth hormone status. Possible explanations include a direct effect of chemotherapy, steroids or both on bone during childhood and hence an effect on the accretion of bone mass. In view of the risk of fractures in patients with osteopenia, adults treated for ALL in childhood may be at an increased risk of bone fractures later in life irrespective of the underlying cause of the osteopenia and thus intervention should be considered.

Hyperleptinaemia in young adults following cranial irradiation in childhood: growth hormone deficiency or leptin insensitivity?

OBJECTIVE

In order to explore the mechanism of obesity in long-term survivors of childhood leukaemia, fat mass, lean body mass and serum leptin were assessed in a cohort of 32 (17 males) adults who had received cranial irradiation (XRT) in childhood as part of their treatment for acute lymphobiastic leukaemia (ALL), and compared with 35 age and body mass index (BMI) matched young adults (18 male).

DESIGN

Thirty-one patients and 18 controls had fat mass and lean body mass assessed by dual x-ray absorptiometry (DEXA), using a lunar DPX-L scanner. Serum leptin concentrations were also measured in 27 patients and all controls. Growth hormone status had previously been determined using an insulin tolerance test and arginine stimulation test. Nine patients were classified as severe growth hormone (GH) deficient (group 1), 12 patients as GH insufficient (group 2) and 11 patients as normal (group 3).

RESULTS

BMI and absolute fat mass were not significantly different between the patients and controls regardless of their gender (P = 0.1 and P = 0.14 respectively). In contrast, absolute lean mass was significantly reduced (P < 0.01) and leptin concentrations were significantly increased (P < 0.001) in patients compared with controls. BMI, fat mass and leptin concentrations but not lean mass were significantly different between the three GH status groups (P < 0.01, P < 0.01, P = 0.004, and P = 0.67 respectively). When leptin concentrations were expressed per unit of fat mass, they were increased in the patients compared with the controls (P = 0.03) with significant differences between the GH status groups (P = 0.004), being significantly higher in the severe GH deficient group.

CONCLUSIONS

Young adults who receive cranial irradiation in childhood are prone to GH deficiency and hyperleptinaemia. The pathophysiological significance of the hyperleptinaemia remains to be established but it has occurred either as a consequence of radiation induced hypothalamic damage or GH deficiency.

The prevalence of severe growth hormone deficiency in adults who received growth hormone replacement in childhood [see comment]

OBJECTIVE

The few previous studies in which reassessment of GH status has been carried out in young adults treated with GH therapy for childhood GH deficiency concentrated on determining the incidence of 'transient GH deficiency'. As the benefits of GH replacement therapy in adults become increasingly appreciated, it is likely that GH therapy started in childhood for GH deficiency will be continued into adult life in many of those with severe GH deficiency. The aim of this study is to determine how many patients who received GH replacement therapy in childhood until completion of growth have GH deficiency severe enough to be considered for GH replacement therapy in adult life.

DESIGN

Retrospective analysis of the peak GH responses to provocative stimuli performed at the time of diagnosis of GH deficiency in childhood and at the completion of growth after GH replacement therapy had been stopped.

PATIENTS

Eighty-eight adults (49 male, 39 female) who had received GH therapy in childhood for a diagnosis of GH deficiency. The aetiology of the GH deficiency included craniopharyngioma, radiation induced associated with either a cerebral tumour or acute lymphoblastic leukaemia, histiocytosis-X and idiopathic.

MEASUREMENTS

In childhood the original diagnosis of GH deficiency was based biochemically on the failure of the peak GH response to reach 20 mU/l during two provocative tests in 59 of the 88 patients and to a single test in the remaining 29. A total of 147 tests were performed, the most common being an insulin tolerance test (ITT, n = 72) and an arginine stimulation test (AST, n = 53). At reassessment in young adult life 146 tests were performed (74 ITT, 64 AST). Severe GH deficiency was defined arbitrarily as a peak GH response of less than 9 mU/l to a single (n = 33) or to two (n = 55) pharmacological stimuli.

RESULTS

By definition all patients were considered GH deficient at the time of initial diagnosis. A peak GH response of less than 9 mU/l was seen in 64.8% at initial assessment and 60.2% at reassessment. Analysis in aetiological terms, however, showed that between assessments the incidence of severe GH deficiency increased in the group of radiation induced (48.8 vs. 55.8%) but decreased in the idiopathic group (78.1 vs. 53.1%). Out of the 55 patients who underwent two tests at reassessment, 47.3% of those with a GH peak less than 9 mU/l at one test had a GH peak greater than 9 mU/l at the second test. Fifteen of the 55 patients had additional pituitary hormone deficiencies and all 15 had a GH peak below 9 mU/l in both tests.

CONCLUSIONS

Our study suggests that all children who have received GH replacement therapy in childhood should undergo reassessment of GH status in young adult life. Between 40 and 60% of such patients merit consideration for GH therapy in adult life depending on the definition of severe GH deficiency in use. Patients with isolated GH deficiency should undergo two provocative tests of GH secretion, but those with additional anterior pituitary hormone deficiencies require only one test at reassessment.

Influences on quality of life in GH deficient adults and their effect on response to treatment

OBJECTIVE

Studies of the effect of GH on quality of life (QOL) in growth hormone deficient (GHD) adults have reported conflicting results. Recently, however, we have demonstrated that by selecting only those patients with impaired QOL the efficacy of GH replacement on QOL can be greatly improved. The improvement in QOL was observed to correlate significantly with that recorded before commencing GH therapy. This study aims to assess if demographic variables affect QOL in untreated GHD adults or the improvement in QOL following GH therapy.

DESIGN

An open study of GH replacement, initiating treatment with a dose of 0.8 IU/day and titrating the dose by 0.4 IU increments to normalize the IGF-I SDS between - 2.0 and + 2.0 SD of the age related normal range.

PATIENTS

65 severely GHD patients (peak GH < 9 mU/l to provocative testing), mean age 38.7 (range 17-72) years. Inclusion criterion was that of subjectively poor quality of life on clinical interview.

MEASUREMENTS

Blood was taken for insulin-like growth factor 1 (IGF-I). The Psychological General Well-Being Schedule (PGWB) and Adult Growth Hormone Deficiency Assessment (AGHDA) self-rating questionnaires were used to assess quality of life at baseline, three and eight months after commencing GH.

RESULTS

The patients were subgrouped on the basis of gender, age of onset of GHD, pathology and presence of additional pituitary hormone deficits. The cohort consisted of 40 females and 25 males, 45 of adult-onset (AO) and 20 of childhood-onset (CO). GH deficiency resulted from a hypothalamo-pituitary pathology, or treatment thereof, in 36 patients and as a result of cranial irradiation for a primary brain tumour or prophylaxis in acute lymphoblastic leukaemia in 29 patients. Isolated GH deficiency (IGHD) was present in 25 patients, and 32 patients were demonstrated to have at least two additional pituitary hormone deficits (MPHD). No significant difference was detected between baseline PGWB scores of the subgroups. Multiple linear regression analysis revealed the age of onset of GHD to be a significant determinant of both the baseline PGWB (P = 0.05) and AGHDA (P = 0.025) scores, AO patients perceiving the greater distress. A significant improvement, from baseline, in both QOL scores was observed in all subgroups at three months, and in all subgroups at eight months except IGHD, where a trend towards improvement in the AGHDA score was observed but failed to reach significance. The mean improvement in the PGWB following GH therapy was not significantly different between subgroups. Multiple linear regression analysis confirmed baseline PGWB and AGHDA scores to be the most important variable in prediction of the level of improvement in respective scores following GH therapy. Age of onset was also observed to be a significant determinant of the PGWB scores following GH therapy (P = 0.02), the CO cohort experiencing the greater improvement. A similar relationship between age of onset and AGHDA scores was not observed (P = 0.22).

CONCLUSIONS

Baseline QOL as assessed by self-rating questionnaires is influenced by the age of onset of the GH deficiency, adult onset patients expressing the greater distress. Improvements in QOL scores are influenced by both baseline score and to a lesser extent the age of onset of GHD, the greater improvement being observed in childhood onset patients. The degree of improvement was observed to be independent of gender, pathology and number of pituitary hormone deficits. In a cohort selected by subjectively impaired QOL, we have demonstrated childhood onset GHD patients perceive themselves to have less impairment of QOL pretreatment. In contrast to previous data in unselected cohorts, however, we have shown that those childhood onset GHD patients in whom QOL is significantly reduced, show a capacity for improvement that is equal to, if not greater, than that seen in adult onset-GHD patients.

The prevalence of vitamin D abnormalities in South Asians with type 2 diabetes mellitus in the UK

BACKGROUND

The high prevalence of both hypovitaminosis D and type 2 diabetes (T2DM) in the Asian community is well recognised, but the impact of diabetes on vitamin D status and vice versa, has not been well reported.

AIMS

To determine the prevalence of hypovitaminosis D in Asian patients with T2DM and its impact on glycaemic control.

METHODS

A cross-sectional study was conducted in a tertiary referral centre in the UK. Two hundred and ten Asian patients aged more than 40 years were included (170 with and 40 without T2DM). Each had a standard bone profile (serum calcium, phosphate and alkaline phosphatase), serum parathyroid hormone and 25-hydroxycholecalciferol.

RESULTS

The prevalence of low serum 25-hydroxyvitamin D (< 50 nmol/l) was high in the group as a whole (> 80%) and more common in diabetics compared with controls (83% vs. 70%; p = 0.07). This was particularly so in men (82.5% vs. 57.9%; p = 0.02). HbA1c was higher in women with vitamin D deficiency (< 12.5 nmol/l) (8.11 +/- 1.11% vs. 7.33 +/- 1.32%, p = 0.046). In logistic regression analysis, T2DM was an independent predictor of hypovitaminosis D. In linear regression analysis, vitamin D deficiency was independently related to HbA1c in women with T2DM.

CONCLUSIONS

Hypovitaminosis D remains a major public health issue in the Asian population and is exaggerated in patients with T2DM. The fact that vitamin D deficient women had higher HbA1c levels raises the possibility that vitamin D replacement may improve glycaemic control.

Dose titration and patient selection increases the efficacy of GH replacement in severely GH deficient adults

OBJECTIVE

Previous studies of GH replacement in adults have used unselected cohorts of GH deficient (GHD) adults and weight-based dosing regimens resulting in supraphysiological serum IGF-I levels and a high frequency of side-effects and withdrawal from these studies. By choosing patients with a high level of morbidity at baseline and using a low dose GH titration regimen we aimed to avoid over-replacement and increase the efficacy of treatment.

DESIGN

An open study of GH replacement, initiating treatment with a dose of 0. 8 U/day and titrating the dose by 0.4 U increments to normalize the IGF-I SDS between - 2.0 and + 2.0 SD of the age-related normal range.

PATIENTS

65 severely GHD patients (peak GH < 9 mU/l to provocative testing), 25 males, of mixed adult and childhood-onset and mean age 38.7 (range 17-72) years. Inclusion criterion was that of subjectively poor quality of life on clinical interview.

MEASUREMENTS

Height, weight, waist and hip circumference were measured to allow calculation of body mass index (BMI) and waist-hip ratio (WHR). Bone mineral density (BMD) was measured by dual X-ray absorptiometry (DEXA). Serum haemoglobin A1C (HbA1C), lipid profile and insulin like growth factor 1 (IGF-I) were measured. The Psychological General Well-Being Schedule (PGWB) and Adult Growth Hormone Deficiency Assessment (AGHDA) self-rating questionnaires (SRQ) were used to assess quality of life.

RESULTS

Baseline characteristics were consistent with those previously described in severely GHD adults; mean IGF-I SDS - 2.4 (+/- 2.7), BMI 28.8 (+/- 5. 4) kg/m2, total cholesterol 6.17 (+/- 1.2) mmol/l, reduced BMD z-scores at the lumbar spine (- 0.8 +/- 1.2) and femoral neck (- 0. 44 +/- 1.4), and SRQ scores considerably lower than reported in previous studies of GH deficient adults and normal controls. Following initiation of GH serum IGF-I SDS was increased significantly from baseline to a mean level of 0.15 +/- 2.7 (P < 0. 001) and 0.31 +/- 2.0 (P < 0.001) at three and eight months, respectively. The mean PGWB score increased from 59.7 +/- 19.9 to 75. 8 +/- 15.0 (P < 0.001) and 73.7 +/- 19.5 (P = 0.001) at three and eight months, respectively. An increase of 14 points represents the largest improvement in quality of life, using this index, that has been reported in GHD adults. The mean AGHDA score also demonstrated considerable improvement, falling from 15.3 +/- 6.0 to 10.4 +/- 6.2 (P < 0.001) and 9.8 +/- 6.5 (P < 0.001) at three and eight months, respectively. The changes observed in both the PGWB and AGHDA scores between baseline and at both three and eight months were shown to correlate significantly with the respective baseline score. A significantly greater improvement was observed in the PGWB following GH replacement in those with a baseline PGWB score of < 60 than in those with a score > 60. This observation was significant at both three (27.1 vs 6.7, P = 0.0001) and eight (25.6 vs 3.3, P = 0.0003) months. All PGWB subscales showed significant improvement though that of vitality was of greatest magnitude. A strong correlation was observed between the generic and disease-specific SRQ (r = - 0.73, P < 0.001).

CONCLUSIONS

The observed improvement in quality of life in GH deficient adults is proportional to the degree of impairment before commencing therapy. The use of low-dose titration and selection of a population with greater morbidity reduces the occurrence of over-replacement and increases the efficacy of treatment. This allows direction of resources to those in greatest need.

Long-term change in the bone mineral density of adults with adult onset growth hormone (GH) deficiency in response to short or long-term GH replacement therapy

OBJECTIVE

Only two previous studies have assessed the effects of long-term GH replacement therapy on bone mineral density (BMD) in patients with adult onset GH deficiency. To date no study has looked at the long-term impact on BMD after a short course (6-12 months) of GH replacement. In two groups of patients with adult onset GH deficiency we have studied BMD either (a) after 3 years of continuous GH replacement or (b) 2 years after completion of a short course of GH.

DESIGN

An open GH therapeutic study in which patients were recruited from a previous double-blind placebo-controlled study. The BMD status of all patients was unknown to the physician and patient at the time of recruitment.

PATIENTS

Group A (n = 7, three females) all received GH replacement continuously for 3 years. Group B (n = 8, five females) included six patients who received GH replacement for 6 months and two who received GH replacement for 12 months with BMD being measured at 6-monthly intervals.

METHODS

Single photon absorptiometry (SPA) and later single X-ray absorptiometry (SXA) were used to measure forearm cortical BMD. Dual-energy X-ray absorptiometry (DXA) was used to measure lumbar spine, trochanteric, femoral neck and Ward's area BMD.

RESULTS

In group A lumbar spine and trochanter BMD had increased significantly from baseline by 3.7% (DXA: median change = 0.045 g/cm2; P = 0.028) and 4.0% (DXA: median change = 0.031 g/cm2; P = 0.046), respectively. There were non-significant decreases in femoral neck (1.9%) (DXA: median change = -0.02 g/cm2; P = 0.39), Ward's area (6.5%) (DXA: median change = -0.06 g/cm2; P = 0.09) and forearm (2.6%) (SPA/SXA: median change = -0.013 g/cm2; P = 0.18). In group B, compared with baseline, only trochanter BMD changed significantly, increasing by 5.9% (DXA: median change = 0.0485 g/cm2; P = 0.049). Lumbar spine (DXA: median change = -0.001 g/cm2) Ward's area (DXA: median change = 0.0135 g/cm2), femoral neck (DXA: median change = -0.005 g/cm2) and forearm cortical (SPA/SXA; median change = -0.01 g/cm2) BMD did not change significantly (P = 0.67, P = 0.57, P = 0.86 and P = 0.31, respectively). Median percentage changes compared with baseline were -0.1%, 1.8%, -0.5% and -2.1%, respectively. From the time of completion of GH therapy however, BMD increased significantly at lumbar spine, (median change = 0.023 g/cm2), Ward's area (median change = 0.03 g/cm2) and trochanter (median change = 0.056 g/cm2) (P = 0.036, P = 0.049 and P = 0.012, respectively) but not at the femoral neck (median change = 0.017 g/cm2; P = 0.31) or forearm (median change = 0 g/cm2; P = 0.75).

CONCLUSION

Long-term GH replacement therapy for three years appears to have beneficial effects on bone in patients with adult onset GH deficiency particularly at the lumbar spine and trochanter; the effects on femoral neck and forearm cortical BMD, however, are less impressive. A short course (6-12 months) of GH replacement therapy results in an increase in trochanter BMD several years later, and after an initial decline in BMD whilst on GH replacement, lumbar spine and Ward's area BMD return towards their baseline values. These results emphasize that not all types of bone and skeletal sites respond to GH therapy identically. Furthermore a short course of GH replacement over 6-12 months may result in significant changes in BMD several years later.

Rahim AA, Eliana F, Shrestha HK, Chaudhary S, Ngugi N, Mbanya JC, Aye TT, Latt TS, Akanov ZA, Syed AR, Tandon N, Unnikrishnan AG, Madhu SV, Jawa A, Chowdhury S, Bajaj S, Das AK. Consensus Recommendations on Sulfonylurea and Sulfonylurea Combinations in the Management of Type 2 Diabetes Mellitus - International Task Force

For decades, sulfonylureas (SUs) have been important drugs in the antidiabetic therapeutic armamentarium. They have been used as monotherapy as well as combination therapy. Focus on newer drugs and concerns about the risk of severe hypoglycemia and weight gain with some SUs have led to discussion on their safety and utility. It has to be borne in mind that the adverse events associated with SUs should not be ascribed to the whole class, as many modern SUs, such as glimepiride and gliclazide modified release, are associated with better safety profiles. Furthermore, individualization of treatment, using SUs in combination with other drugs, backed with careful monitoring and patient education, ensures maximum benefits with minimal side effects. The current guidelines, developed by experts from Africa, Asia, and the Middle East, promote the safe and smart use of SUs in combination with other glucose-lowering drugs.

How many tests are required to diagnose growth hormone (GH) deficiency in adults?

OBJECTIVE

The diagnosis of GH deficiency in adults relies on the results of GH provocative testing. Whilst in some patients the testing strategy is clear, this is not the case in all patients. The objective of this study was to further examine the concordance between the GH responses to two different provocative stimuli, to correlate this with the number of additional pituitary hormone deficits, and to produce guidelines as to which patients require two GH provocative tests and which require only one.

STUDY DESIGN AND PATIENTS

The results of GH provocative tests were reviewed in 103 patients (mean age 28 years, 48 male), with documented or potential hypothalamic-pituitary disease and 35 normal volunteers (mean age 21 years, 18 male). All patients and normal volunteers underwent an insulin tolerance test (ITT) and an arginine stimulation test (AST). Severe GH deficiency was defined as a GH response to an ITT of < 5 mU/l and a GH response to an AST of < 2 mU/l, utilizing data from previous studies in this unit. Patients were divided into four groups according to the number of anterior pituitary hormone deficits present other than possible GH deficiency: no other pituitary hormone deficits (GHD0) or one, two or three other hormone deficits (GHD1, GHD2 or GHD3).

RESULTS

The 103 patients were divided between the four groups as follows: 69 (67%) in GHD0, 15 (14. 6%) in GHD1, six (5.8%) in GHD2, and 13 (12.6%) in GHD3. There was a significant decline in the median GH peak to both the ITT and the AST with increasing numbers of other pituitary hormone deficits (P < 0.0001). If the magnitude of the difference between each individual's GH response to the ITT and AST is plotted against the mean GH value a clear trend is seen (Spearmans rank correlation = 0. 88, P < 0.0001) indicating that the magnitude of the difference between the GH responses to an ITT and AST increases with the underlying mean GH value. These data allow the estimation of the median ITT/AST ratio as 1.17 (CI 0.98, 1.39). None of the control subjects and 14.1% (10), 26.7% (four), 83% (five) and 92.3% (12) of groups GHD0, 1, 2 and 3, respectively, had severe GHD. The concordance between the AST and ITT (percent of patients in whom both tests confirmed or refuted the biochemical diagnosis of severe GHD) was 100%, 76.8%, 66.6%, 83.3%, and 92.3% in the controls, GHD0, 1, 2, and 3, respectively. Thus, 16/69 GHD0, 5/15 GHD1, 1/6 GHD2 and 1/13 GHD3 patients were misclassified by one or other test.

CONCLUSION

We have demonstrated that a constant ratio links the GH response to an ITT and AST in an individual, rather than a constant difference, and that the difference between the GH responses to two provocative stimuli is greater in those patients with milder degrees of GH deficiency or insufficiency. These patients tend to have one or no additional pituitary hormone deficits and may be misclassified if a single GH provocative test is performed. We suggest that whilst a single GH provocative test can be used with confidence in patients with two or three additional pituitary hormone deficits, in patients with suspected isolated GH deficiency or with only one additional pituitary hormone deficit, two GH provocative tests should be performed.

Ulcers produced by ligation of individual gastric mucosal arteries in the guinea pig

It is not known whether or not individual gastric mucosal arteries are end-arteries. We therefore occluded single mucosal guinea pig arteries, resulting in necrosis of the whole thickness of mucosa in the area supplied by the artery in 25 of 33 cases (76%). However, there were no cases of necrosis in 33 control sham ligations performed in the same animals (p less than 0.001). In another group, ligation of two or three adjacent mucosal arteries resulted in necrosis in 10 of 11 cases (p less than 0.0001), against 0 necrosis in 11 sham ligations. Killing the animals at varying intervals showed that after 1 day the mucosa was necrotic, after 2 days it was shed, and later it might perforate. We conclude that many mucosal arteries in the guinea pig may behave as functional end-arteries. How these findings may pertain to ulceration is discussed in relation to (a) the existence of atypical mucosal arteries found in the ulcer-bearing areas in humans and (b) the role of the muscularis mucosae on arterioles perforating it in both humans and other species.

Appendicitis risk prediction models in children presenting with right iliac fossa pain (RIFT study): a prospective, multicentre validation study

BACKGROUND

Acute appendicitis is the most common surgical emergency in children. Differentiation of acute appendicitis from conditions that do not require operative management can be challenging in children. This study aimed to identify the optimum risk prediction model to stratify acute appendicitis risk in children.

METHODS

We did a rapid review to identify acute appendicitis risk prediction models. A prospective, multicentre cohort study was then done to evaluate performance of these models. Children (aged 5-15 years) presenting with acute right iliac fossa pain in the UK and Ireland were included. For each model, score cutoff thresholds were systematically varied to identify the best achievable specificity while maintaining a failure rate (ie, proportion of patients identified as low risk who had acute appendicitis) less than 5%. The normal appendicectomy rate was the proportion of resected appendixes found to be normal on histopathological examination.

FINDINGS

15 risk prediction models were identified that could be assessed. The cohort study enrolled 1827 children from 139 centres, of whom 630 (34·5%) underwent appendicectomy. The normal appendicectomy rate was 15·9% (100 of 630 patients). The Shera score was the best performing model, with an area under the curve of 0·84 (95% CI 0·82-0·86). Applying score cutoffs of 3 points or lower for children aged 5-10 years and girls aged 11-15 years, and 2 points or lower for boys aged 11-15 years, the failure rate was 3·3% (95% CI 2·0-5·2; 18 of 539 patients), specificity was 44·3% (95% CI 41·4-47·2; 521 of 1176), and positive predictive value was 41·4% (38·5-44·4; 463 of 1118). Positive predictive value for the Shera score with a cutoff of 6 points or lower (72·6%, 67·4-77·4) was similar to that of ultrasound scan (75·0%, 65·3-83·1).

INTERPRETATION

The Shera score has the potential to identify a large group of children at low risk of acute appendicitis who could be considered for early discharge. Risk scoring does not identify children who should proceed directly to surgery. Medium-risk and high-risk children should undergo routine preoperative ultrasound imaging by operators trained to assess for acute appendicitis, and MRI or low-dose CT if uncertainty remains.

FUNDING

None.

The diagnosis of growth hormone deficiency (GHD) in successfully treated acromegalic patients

Due to persistent qualitative abnormalities in GH secretion following treatment, and lack of a sensitive marker of GHD in mid-adult life it is extremely difficult to diagnose GHD in treated acromegalic patients. The diagnosis of GHD in patients with pituitary disease relies on provocative tests of GH reserve. Arginine releases GH by reducing somatostatin inhibition of GH release, whereas GH secretagogues (GHS) affect GH release by direct stimulation of the GHS receptor, though an intact GH releasing hormone (GHRH) axis is a prerequisite. The peak GH response to insulin-induced hypoglycaemia and arginine in acromegalic patients, in whom basal serum GH levels of less than 5 mU/l have been achieved, is greatly diminished in those treated by hypothalamo-pituitary irradiation. We aimed to study the response of successfully treated acromegalic patients to the growth hormone secretagogue hexarelin in view of its different putative mechanism of action, and in addition, to determine whether it has any value in the diagnosis of GH deficiency in this subset of patients. Nineteen acromegalic patients, in whom mean serum GH levels below 5 mU/l have been achieved through treatment, were recruited. Eight of the patients had been treated by surgery alone (Group A) and 11 had received primary or postoperative irradiation (Group B). All patients underwent 20 min blood sampling to provide a 24-h GH profile. Serum IGF-I was measured from a sample drawn between 0900 h and 1000 h. On a second visit arginine 20 g/m2 was infused over 30 min, blood samples were taken before commencing the infusion and at 30-min intervals thereafter for 180 min. At the final visit hexarelin 1.5 mcg/kg was administered as an intravenous bolus at t = 0. Blood was drawn at 15-min intervals from - 30 to 180 min. All patients in group A showed an increment in serum GH following hexarelin (DeltaGHHEX) > 20 mU/l, a normal response to arginine, and a mean 24-h GH > 0.5 mU/l. In group B only 4/11 achieved a DeltaGHHEX > 20 mU/l, 5/11 producing a response of < 2 mU/l. Four of the five patients with a DeltaGHHEX < 2 mU/l were also demonstrated to have a mean 24-h GH of < 0.5 mU/l and serum IGF-I SDS < + 0.5. All four patients in Group B who achieved a DeltaGHHEX > 20 mU/l, were observed to show an absent or minimal GH response to arginine. Despite loss of the GH response to arginine, the DeltaGHHEX is retained in a proportion of those patients in whom "safe" GH levels were achieved following irradiation. From the putative mechanisms of action of these provocative agents a plausible explanation would be that the GHRH axis is more resilient than endogenous somatostatin-secreting neurones to radiation-induced damage. Furthermore, GH secretagogues may have a role, in combination with serum IGF-I levels, in the diagnosis of GH deficiency in treated acromegaly.

Growth hormone status during long-term hexarelin therapy

Hexarelin, a powerful GH-releasing peptide, is capable of causing profound GH release in normal subjects after oral, intranasal, i.v., and s.c. administration. The effect of long-term administration on GH levels in adults is unknown. We have, therefore, assessed the effects of 16 weeks of twice-daily s.c. hexarelin therapy (1.5 micrograms/kg BW) on the GH response to a single injection of hexarelin, and also the GH response to hexarelin 4 weeks after cessation of hexarelin therapy. We have also assessed the effects of chronic hexarelin therapy on serum insulin-like growth factor (IGF)-I, IGF binding protein-3, markers of bone formation (osteocalcin, procollagen-type-III-N-terminal-peptide, and C-terminal propeptide of type I collagen), and resorption (urinary deoxypyridinoline and pyridinoline), body composition, and bone mineral density. The mean (+/- SEM) area under the GH curve (AUCGH) at weeks 0, 1, 4, 16, and 20 were 19.1 +/- 2.4 micrograms/L.h, 13.1 +/- 2.3 micrograms/L.h, 12.3 +/- 2.4 micrograms/L.h, 10.5 +/- 1.8 micrograms/L.h, and 19.4 +/- 3.7 micrograms/L.h, respectively. There was a significant change in AUCGH over the study period (P = 0.0003). Further analysis showed that, compared with baseline, the decrease in AUCGH at week 4 and week 16 were significant (P < 0.05 and P < 0.01, respectively). Four weeks after completion of hexarelin therapy, the AUCGH increased significantly, compared with AUCGH at week 16 (P < 0.05), and was not significantly different from that at week 0. Serum IGF-I and IGF binding protein-3 did not change significantly over the 20-week period (P = 0.24 and P = 0.74, respectively). Of the bone markers measured, only serum C-terminal propeptide of type I collagen changed significantly and was higher at week 16, compared with baseline (P = 0.019). Total body fat, lean body mass, and bone mineral density had not changed significantly at week 16, compared with baseline (P = 0.6, P = 0.3, and P = 0.3, respectively). In summary, we have demonstrated that chronic hexarelin therapy results in a partial and reversible attenuation of the GH response to hexarelin. In the present study, the biological impact of this hexarelin schedule on the GH-IGF-I axis seems to be minimal. The therapeutic potential of chronic hexarelin requires further investigation.

Survivors of childhood cancer: long-term endocrine and metabolic problems dwarf the growth disturbance

The long-term effects of radiotherapy and chemotherapy are becoming increasingly recognized as the cure rates of certain childhood malignancies improve. The endocrine system is particularly sensitive to cancer therapies. Long-term survivors of childhood cancer who received cranial irradiation have been shown to have lower than predicted height, an increased prevalence of obesity and reductions in strength, exercise tolerance, bone mineral density, quality of life and academic achievement. Growth hormone deficiency (GHD) is the most frequent endocrine deficiency observed following cranial irradiation. Adults with GHD resulting from primary hypothalamic-pituitary disease during childhood have been shown to exhibit a clinical picture similar to that described in long-term survivors of childhood cancer: increased fat mass and reduced lean mass, strength, exercise tolerance, bone mineral density and quality of life. This review considers the possible contribution of GHD to the adverse sequelae observed in long-term survivors of childhood malignancy and includes our preliminary experience in treating 14 adults with GHD resulting from the treatment of childhood malignancies.

Normalization of impaired response of platelets to prostaglandin E1/I2 and synthesis of prostacyclin by insulin in unstable angina pectoris and in acute myocardial infarction

The minimal inhibitory concentration of prostaglandin E1 (used as a probe for prostacyclin [PGI2]) needed to inhibit platelet aggregation (36 +/- 16 nM) in normal volunteers (n = 40) increased (64 +/- 30 nM) in patients (n = 46) with acute coronary artery disease. Bolus injection of insulin in 20 patients, 0.1 U/kg body weight 4 times a day (every 6 hours) for 7 days decreased the minimal inhibitory concentration of prostaglandin E1 from 64 +/- 30 to 26 +/- 12 nM (p less than 0.001). Twenty other patients who received only saline solution had no decrease in minimal inhibitory concentration of the prostanoid. The bolus injection of insulin also increased the plasma level of PGI2 (9 +/- 2 pM) two-fold in these patients (28 +/- 10 pM). Administration of aspirin inhibited the insulin-induced increase of plasma prostanoid level. Patients in the placebo group had no increase in plasma PGI2 level. The bolus injection of insulin administered only once to another group of patients (n = 6) demonstrated that the hormonal effects were maximally increased within an hour of insulin administration, and were directly related to the increased insulin level in plasma. These results indicated the feasibility of using physiologic quantities of insulin for controlling of platelet aggregation through resensitization of platelet response to prostaglandin and increased synthesis of PGI2 in vivo in acute coronary artery disease.

Neonatal polycythemia

461 consecutive inborn babies, delivered during the period September 1993-March 1994 were subjected to a microhematocrit assessment at 6 hours of age to determine the incidence of polycythemia. 47 babies (inborn and out born), admitted to the neonatal unit with confirmed polycythemia were studied for clinical and laboratory abnormalities. These 47 babies were then randomly assigned to receive partial exchange transfusion with either normal saline or fresh plasma. The incidence of polycythemia was 27 of 461 (5.8%). 23 of 27 (85.1%) were term babies and 15 of 27 (55.5%) were small for gestational age. 14 of 27 (51.1%) babies had mothers who had pregnancy induced hypertension. Feeding problems (16/47) and lethargy (25/47) were the commonest symptoms (34% and 51% respectively). 25 of 47 (51%) babies had hypoglycemia and 5 of 47 (10.6%) had hypocalcemia. Thrombocytopenia was seen in 13/47 (27.65%) of cases. 24 babies received normal saline and 23 received fresh plasma for partial exchange transfusion. The immediate post-exchange fall in hematocrit was significant in both groups and this was well sustained over the following 48 hours. However, improvement in clinical and laboratory parameters was more remarkable with fresh plasma. Polycythemia appears to be a real clinical entity in neonates in India and babies with known risk factors should be actively screened for this condition. Once diagnosis is established special attempts should be made to rule out hypoglycemia. For treatment of polycythemia fresh plasma is preferable for partial exchange transfusion but normal saline appears to be an adequate substitute.

Reduced toxicity of F-deficient Sendai virus vector in the mouse fetus

Current concerns over insertional mutagenesis by retroviral vectors mitigate investigations into alternative, potentially persistent gene therapy vector systems not dependent on genomic integration, such as Sendai virus vectors (SeVV). Prenatal gene therapy requires efficient gene delivery to several tissues, which may not be achievable by somatic gene transfer to the adult. Initially, to test the potential and tropism of the SeVV for gene delivery to fetal tissues, first-generation (replication- and propagation-competent) recombinant SeVV, expressing beta-galactosidase was introduced into late gestation immunocompetent mice via the amniotic and peritoneal cavities and the yolk sac vessels. At 2 days, this resulted in very high levels of expression particularly in the airway epithelium, mesothelium and vascular endothelium, respectively. However, as expected, substantial vector toxicity was observed. The efficiency of gene transfer and the level of gene expression were then examined using a second-generation SeVV. The second generation was developed to be still capable of cytoplasmic RNA replication and therefore high-level gene expression, but incapable of vector spread due to lack of the gene for viral F-protein. Vector was introduced into the fetal amniotic and peritoneal cavities, intravascularly, intramuscularly and intraspinally; at 2 days, expression was observed in the airway epithelia, peritoneal mesothelia, unidentified cells in the gut wall, locally at the site of muscle injection and in the dorsal root ganglia, respectively. Mortality was dramatically diminished compared with the first-generation vector.

The effect of chronic hexarelin administration on the pituitary-adrenal axis and prolactin

OBJECTIVE

With the development of growth hormone (GH) releasing agents and their use in human subjects, it is clear that these agents are not specific for GH release. More recent studies in humans have demonstrated acute increases in adrenocorticotrophic hormone (ACTH), cortisol and prolactin (PRL) after boluses of intravenous or subcutaneous GHRPs. The potential adverse effects of repeated episodes of transient hyperprolactinaemia and hypercortisolaemia during long-term therapy with growth hormone releasing peptides (GHRPs) and similar agents have raised concern. We have therefore assessed the impact of chronic hexarelin administration on the pituitary-adrenal axis and serum prolactin levels.

DESIGN

Each subject received twice-daily subcutaneous hexarelin therapy (1.5 micrograms/kg body weight) for 16 weeks. The ACTH, cortisol and PRL responses to the morning subcutaneous injection of hexarelin were assessed. Hexarelin was administered at time 0 and blood samples were taken at -10, 0, 10, 20, 30, 40, 50, 60, 90, 120, 170 and 180 min. The ACTH and PRL responses were assessed at baseline and after 16 weeks of therapy. The cortisol response was assessed at baseline, 16 weeks and also 4 weeks after completion of hexarelin therapy. Basal levels of cortisol binding globulin (CBG), 24-h urinary free cortisol (UFC) estimations, thyroid stimulating hormone (TSH) and total thyroxine (TT4) were performed at baseline, weeks 16 and 20.

RESULTS

The mean (+/- SEM) area under the cortisol curve (AUCCORT) at baseline, week 16 and week 20 were 1506 (+/- 77) nmol/l/h, 1222 (+/- 92) nmol/l/h and 1586 (+/- 58) nmol/l/h, respectively. There was a significant change in AUCCORT over the study period (P = 0.008). Compared with baseline, AUCCOPRT had decreased significantly (P < 0.05) after 16 weeks of hexarelin therapy. Four weeks after completion of hexarelin therapy, the AUCCORT increased significantly compared with AUCCORT at week 16 (P < 0.01) and was no longer significantly different from baseline values. There were no significant changes in UFC (P = 0.3), basal cortisol measurements (P = 0.19), area under the ACTH curve (AUCACTH) (P = 0.24) or CBG (P = 0.6) over the study period. The mean (+/- SEM) area under the PRL curve (AUCPRL) at the baseline and week 16 were 624 (+/- 82) mU/l/h and 641 (+/- 83) mU/l/h, respectively. There was no significant change in AUCPRL over the study period (P = 0.35).

CONCLUSION

The present study demonstrates clearly that in this hexarelin dosage regimen, over-stimulation of the pituitary adrenal axis and prolactin secretion do not occur. In fact the impact of chronic hexarelin therapy on the pituitary-adrenal axis, i.e. decreased AUCCORT, contradict the findings reported after acute hexarelin administration and cannot be explained by changes in CBG. The lack of change in UFC, however, suggests that these changes are unlikely to be of clinical significance although the underlying mechanism requires further study.

Echocardiographic observations regarding pericardial effusions associated with cardiac disease

Cardiac disease associated with congestive heart failure was found to be the most common cause (22 of 76) of pericardial effusion in patients referred for echocardiography. Parameters of left heart function were markedly abnormal in these patients with congestive heart failure and pericardial effusion, but were not significantly different from a group of patients with congestive heart failure without pericardial effusion. Clinical findings consistent with cardiac decompensation also failed to discern between these two groups. Nonetheless, patients with congestive heart failure with pericardial effusion had significantly larger right ventricular internal dimensions than those without effusion. Patients with pericardial effusion related to congestive heart failure (P < .01), heart disease without congestive heart failure (P < 0.001) and those patients post recent myocardial infarction (P < 0.05) had significantly larger right ventricular internal dimensions in diastole than normal subjects. Patients with pericardial effusions related to recent open heart surgery, idiopathic pericarditis or of miscellaneous causes had normal right ventricular internal dimensions. It is likely that right ventricular dilation indicates abnormal volume/pressure relationships of the right heart and that this abnormality, through alterations in venous and lymphatic drainage, underlies the accumulation of pericardial effusion in these patients with heart disease with or without congestive heart failure.