Different impairment of muscle strength in adults with childhood-onset and acquired GH deficiency

Investigation of the Hypothalamo-pituitary-adrenal (HPA) axis: a contemporary synthesis

The hypothalamo-pituitary-adrenal (HPA) axis is one of the main components of the stress system. Maintenance of normal physiological events, which include stress responses to internal or external stimuli in the body, depends on appropriate HPA axis function. In the case of severe cortisol deficiency, especially when there is a triggering factor, the patient may develop a life-threatening adrenal crisis which may result in death unless early diagnosis and adequate treatment are carried out. The maintenance of normal physiology and survival depend upon a sufficient level of cortisol in the circulation. Life-long glucocorticoid replacement therapy, in most cases meeting but not exceeding the need of the patient, is essential for normal life expectancy and maintenance of the quality of life. To enable this, the initial step should be the correct diagnosis of adrenal insufficiency (AI) which requires careful evaluation of the HPA axis, a highly dynamic endocrine system. The diagnosis of AI in patients with frank manifestations is not challenging. These patients do not need dynamic tests, and basal cortisol is usually enough to give a correct diagnosis. However, most cases of secondary adrenal insufficiency (SAI) take place in a gray zone when clinical manifestations are mild. In this situation, more complicated methods that can simulate the response of the HPA axis to a major stress are required. Numerous studies in the assessment of HPA axis have been published in the world literature. In this review, the tests used in the diagnosis of secondary AI or in the investigation of suspected HPA axis insufficiency are discussed in detail, and in the light of this, various recommendations are made.

Performance of low-dose cosyntropin stimulation test handled via plastic tube

PURPOSE

Studies on 1 μg low-dose test showed that among 1 μg cosyntropin samples pushed through long IV plastic tubing, some adrenocorticotropic hormone dosage was not recovered, and in healthy volunteers it provided subnormal cortisol responses. The aim of the current study is to assess whether there is any loss in adrenocorticotropic hormone 1-24 concentration when pushed through a short plastic tube, and to assess serum and salivary cortisol responses in low-dose test among healthy volunteers, using a similar short plastic tube vs. direct intravenous consyntropin injection.

METHODS

We evaluated in vitro if adrenocorticotropic hormone was absorbed in a 2.5 cm plastic tube by measuring adrenocorticotropic hormone 1-24 concentration in a 1 μg/ml adrenocorticotropic hormone aliquot solution before and after being flushed through the plastic tube. For the in vivo study, we recruited 20 healthy adult volunteers. Each subject underwent low-dose test via 2.5 cm plastic tube via plastic tube and via direct intravenous injection by a metal syringe via direct intravenous injection, and cortisol responses were determined.

RESULTS

Mean adrenocorticotropic hormone 1-24 concentration did not differ significantly when flushed via plastic tube or measured in the aliquot solution (P = 0.25). In vivo, mean 30-min serum cortisol concentrations were 20.47 ± 2.87 and 21.62 ± 3.89 μg/dl in via plastic tube and in via direct intravenous injection tests, respectively, and did not show a significant difference (P = 0.16).

CONCLUSIONS

In low-dose test, using a 2.5 cm plastic tube ensures completeness of the intravenous adrenocorticotropic hormone injection dosage and provides equivalent cortisol responses.

Predictive factors of adrenal insufficiency in patients admitted to acute medical wards: a case control study

BACKGROUND

Adrenal insufficiency is a rare and potentially lethal disease if untreated. Several clinical signs and biological markers are associated with glucocorticoid failure but the importance of these factors for diagnosing adrenal insufficiency is not known. In this study, we aimed to assess the prevalence of and the factors associated with adrenal insufficiency among patients admitted to an acute internal medicine ward.

METHODS

Retrospective, case-control study including all patients with high-dose (250 μg) ACTH-stimulation tests for suspected adrenal insufficiency performed between 2008 and 2010 in an acute internal medicine ward (n = 281). Cortisol values <550 nmol/l upon ACTH-stimulation test were considered diagnostic for adrenal insufficiency. Area under the ROC curve (AROC), sensitivity, specificity, negative and positive predictive values for adrenal insufficiency were assessed for thirteen symptoms, signs and biological variables.

RESULTS

32 patients (11.4%) presented adrenal insufficiency; the others served as controls. Among all clinical and biological parameters studied, history of glucocorticoid withdrawal was the only independent factor significantly associated with patients with adrenal insufficiency (Odds Ratio: 6.71, 95% CI: 3.08 -14.62). Using a logistic regression, a model with four significant and independent variable was obtained, regrouping history of glucocorticoid withdrawal (OR 7.38, 95% CI [3.18 ; 17.11], p-value <0.001), nausea (OR 3.37, 95% CI [1.03 ; 11.00], p-value 0.044), eosinophilia (OR 17.6, 95% CI [1.02; 302.3], p-value 0.048) and hyperkalemia (OR 2.41, 95% CI [0.87; 6.69], p-value 0.092). The AROC (95% CI) was 0.75 (0.70; 0.80) for this model, with 6.3 (0.8 - 20.8) for sensitivity and 99.2 (97.1 - 99.9) for specificity.

CONCLUSIONS

11.4% of patients with suspected adrenal insufficient admitted to acute medical ward actually do present with adrenal insufficiency, defined by an abnormal response to high-dose (250 μg) ACTH-stimulation test. A history of glucocorticoid withdrawal was the strongest factor predicting the potential adrenal failure. The combination of a history of glucocorticoid withdrawal, nausea, eosinophilia and hyperkaliemia might be of interest to suspect adrenal insufficiency.

Abnormal diurnal pattern of cortisol secretion in patients after aneurysmal subarachnoid hemorrhage

Substantial evidence suggests that impairment of the hypothalamus?pituitary system can occur following an aneurysmal subarachnoid hemorrhage (aSAH). Given that the diurnal cortisol rhythm is primarily controlled by the hypothalamus?pituitary system, this study examined whether changes in diurnal cortisol rhythm occurred after aSAH. Cortisol concentrations were measured in the saliva samples collected from patients after aSAH and other types of cerebral hemorrhage (non-aSAH) in the post-awakening period and at night (21:00?h), and the cortisol awakening response (CAR) and diurnal cortisol decline were determined. The area under the cortisol curve from immediately after to 45?min after awakening (CARauc) in the aSAH patient group was comparable to that in the non-aSAH or healthy control groups. However, an obvious cortisol peak was not found after the awakening period, and the morning/nighttime cortisol ratio in the aSAH patient group was significantly lower than that in other examined groups due to higher nighttime cortisol concentrations. In aSAH patients, the CARauc and nighttime cortisol concentrations were negatively correlated with the Fisher CT grade. These results indicate that the diurnal cortisol rhythm is not regulated normally after aSAH, and cortisol secretory activity decreases as the volume of subarachnoid bleeding increases. Our findings will be helpful to understand altered hypothalamus?pituitary?adrenal axis function after aSAH.

Impaired hypothalamo-pituitary-adrenal axis in patients with ankylosing spondylitis

BACKGROUND

To investigate the hypothalamic-pituitary- adrenal (HPA) axis in patients with ankylosing spondylitis (AS) and healthy controls.

METHODS

Forty-nine AS patients and 20 healthy controls were included. Lowdose ACTH test (LDST) was used to assess the HPA axis. Basal cortisol, stimulated peak cortisol levels, and acutephase reactants [C-reactive protein (CRP), erythrocyte sedimentation rate, and fibrinogen] were studied. Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Bath Ankylosing Spondylitis Metrology Index were also evaluated.

RESULTS

Patient and control groups were not different regarding age, sex, body mass index and waist circumference (WC). Basal cortisol levels did not show a significant difference between groups. However, cortisol increment after low-dose ACTH was significantly impaired in AS subjects with respect to controls (20.0+/-4.4 vs 24+/-2.2 microg/dl, p<0.001). Eleven AS patients had impaired cortisol peak after LDST when a cortisol cut-off is accepted as 500 nmol/l (18 microg/dl) and none of the controls exhibited a peak cortisol responses to LDST<500 nmol/l. Comparison of AS subjects who were receiving anti-tumor necrosis factor (TNF) (no.=23), and conventional therapy (no.=26) yielded similar basal and peak cortisol concentrations. Peak cortisol concentrations were associated with basal cortisol, impaired cortisol response, CRP, and fibrinogen. Impaired cortisol response (subjects with peak cortisol levels <18 microg/dl) was significantly correlated with basal and peak cortisol concentrations and BASDAI.

CONCLUSION

Our results indicate an increased prevalence of subclinical glucocorticoid deficiency in AS patients. Anti-TNF treatment seems not to have effect on HPA axis.

Isolated corticotrophin deficiency

Isolated ACTH deficiency (IAD) is a rare disorder, characterized by secondary adrenal insufficiency (AI) with low or absent cortisol production, normal secretion of pituitary hormones other than ACTH and the absence of structural pituitary defects. In adults, IAD may appear after a traumatic injury or a lymphocytic hypophysitis, the latter possibly due to autoimmune etiology. Conversely, a genetic origin may come into play in neonatal or childhood IAD. Patients with IAD usually fare relatively well during unstressed periods until intervening events spark off an acute adrenal crisis presenting with non specific symptoms, such as asthenia, anorexia, unintentional weight loss and tendency towards hypoglycemia. Blood chemistry may reveal mild hypoglycemia, hyponatremia and normal-high potassium levels, mild anemia, lymphocytosis and eosinophilia. Morning serum cortisol below 3 microg/dl are virtually diagnostic for adrenal insufficiency. whereas cortisol values comprised between 5-18 microg/dl require additional investigations: insulin tolerance test (ITT) is considered the gold standard but-when contraindicated-high or low dose-ACTH stimulation test with serum cortisol determination provides a viable alternative. Plasma ACTH concentration and prolonged ACTH infusion test are useful in differential diagnosis between primary and secondary adrenal insufficiency. For some patients with mild, near-to-asymptomatic disease, glucocorticoid replacement therapy may not be required except during stressful events; for symptomatic patients, replacement doses i.e., mean daily dose 20 mg (0.30 mg/kg) hydrocortisone or 25 mg (0.35 mg/kg) cortisone acetate, are usually sufficient. Administration of mineralocorticoids is generally not necessary as their production is maintained.

Measures of hypothalamic-pituitary-adrenal function in patients with asthma treated with inhaled glucocorticoids: clinical and research implications

In asthmatic patients treated with inhaled glucocorticoids there may be a risk of suppression of hypothalamic-pituitary-adrenal (HPA) function. The aim of the present study was to review peer-refereed data on HPA function in asthmatic patients taking inhaled glucocorticoids, and to discuss the value of HPA function measures in clinical practice and research. There is no evidence that inhaled glucocorticoids in recommended doses cause clinically significant HPA insufficiency. If sensitive measures of basal adrenal activity are used, however, dose-related suppressive effects with specific drugs and application systems can be detected. In adults, fluticasone propionate appears to be more potent than budesonide or triamcinolone acetonide in suppressing measures of basal adrenal activity. Measures of basal adrenal activity are useful in clinical trials that assess and compare systemic activity of specific drugs, application devices, and administration regimens, but have no place in the management of asthma.