Hypothalamo-pituitary-adrenal function in asthmatic patients receiving long-term corticosteroid therapy

Systemic glucocorticoid therapy and adrenal insufficiency in adults: A systematic review

OBJECTIVES

The aim of this systematic literature review was to summarize the current knowledge regarding the prevalence of, time to recovery from, and influence of glucocorticoid dose and duration on glucocorticoid-induced adrenal insufficiency (AI).

METHODS

Eligible studies were original research articles, which included adult patients with an indication for glucocorticoids and measured adrenal function following exposure to systemic glucocorticoids. Searches were performed in Web of Science and MEDLINE, with further articles identified from reference lists. Screening was performed in duplicate. Data were extracted for each group of glucocorticoid-exposed patients within eligible studies. The reported proportion of patients with AI was summarized as median and inter-quartile range. Results were then stratified by daily dose, cumulative dose, duration of exposure and time since last glucocorticoid use. The risk of bias within and across studies was considered: for randomised controlled trials risk of bias was assessed using the tool developed by the Cochrane Collaboration.

RESULTS

Overall, 73 eligible studies were identified out of 673 screened. The percentage of patients with AI ranged from 0% to 100% with a median (IQR) = 37.4% (13-63%). Studies were small-median (IQR) group size 16 (9-38)-and heterogeneous in methodology. AI persisted in 15% of patients retested 3 years after glucocorticoid withdrawal. Results remained widely distributed following stratification. AI was demonstrated at <5mg prednisolone equivalent dose/day, <4 weeks of exposure, cumulative dose <0.5g, and following tapered withdrawal.

CONCLUSIONS

The heterogeneity of studies and variability in results make it difficult to answer the research questions with confidence based on the current literature. There is evidence of AI following low doses and short durations of glucocorticoids. Hence, clinicians should be vigilant for adrenal insufficiency at all degrees of glucocorticoid exposure.

Pituitary adrenal recovery following short-term suppression with corticosteroids

To provide clinical guidelines for the use of high-dose short-term glucocorticoid therapy, we studied recovery of the hypothalamic-pituitary-adrenal axis in 10 normal men following the administration of suppressive doses of prednisone (25 mg twice daily for five days). Cortisol responses to insulin-induced hypoglycemia and synthetic ACTH before treatment were compared with responses two and five days after concluding the prednisone course when adrenal function was not influenced by the presence of exogenous steroid. Two days after prednisone therapy, peak cortisol responses to both hypoglycemia (11.0 +/- 0.9 microgram/dl mean +/- SEM) and synthetic ACTH (13.3 +/- 1.4 microgram/dl) were significantly reduced compared to pretreatment (20.6 +/- 1.6 and 27.3 +/- 2.5 microgram/dl, respectively, p less than 0.001). Five days after concluding the prednisone therapy, peak cortisol response to hypoglycemia had returned to near pretreatment levels although peak cortisol response in the adrenal gland to synthetic ACTH (22.3 +/- 1.1 microgram/dl) remained reduced (p less than 0.05). These data suggest that brief courses of high-dose prednisone therapy may limit the adrenal component of the hypothalamic-pituitary-adrenal response to stress for up to five days.

Adrenal suppression after short-term corticosteroid therapy

Adrenal function was evaluated in fourteen cancer patients receiving chemotherapy which included short-term high-dose courses of prednisone. 90 min corticotropin stimulation tests were performed before therapy and 1, 2, 4, and 7 days after steroids were discontinued. Responses were evaluated by standard criteria of adrenal function and by measurement of the intergrated cortisol response to corticotropin over 90 min. Thirteen of fourteen patients had suppressed adrenal function for at least 24 h. Although in most patients adrenal function had returned to normal between day 2 and 4, in five patients it remained suppressed for 7 days or more. Suppression did not correlate with either steroid dose or duration of therapy. Four of five patients receiving only 5 days' therapy showed evidence of adrenal suppression. Although overt clinical adrenal insufficiency after steroid administration is rare, these results indicate that adrenal function is suppressed more regularly after short-term high-dose steroid therapy than has been appreciated.

Recovery of hypothalamic-pituitary-adrenal function after intermittent high-dose prednisolone and cytotoxic chemotherapy

Hypothalamic/pituitary and adrenal (HPA) function was assessed in ten patients who received intermittent high-dose prednisolone and cytotoxic chemotherapy for 5-40 months. Standard insulin hypoglycaemia (IHT), thyrotrophin-releasing hormone and tetracosactrin tests were performed 36 hr after the last dose of prednisolone and subsequently 10 days--52 weeks after completion of all chemotherapy. In the first tests there was evidence of impaired hypothalamic-pituitary function judged by peak adrenocorticotrophic hormone (ACTH), growth hormone (GH) and thyrotrophin (TSH) responses, and corresponding plasma corticosteroid responses were sub-normal in five patients. In the final IHTs, seven patients had persistently subnormal ACTH responses but all the corresponding plasma corticosteroid responses returned to normal. Mean peak corticosteroid responses to insulin and tetracosactrin and peak GH responses were significantly greater than in the first tests. Such chemotherapy regimens may have prolonged effects on hypothalamic/pituitary function but the demonstration of normal corticosteroid responses to hypoglycaemia and tetracosactrin indicates that these patients' stress responses will be normal as early as 10 days after treatment is stopped.

Pituitary function in patients receiving intermittent cytotoxic and corticosteroid therapy for malignant lymphoma

Diurnal variation in plasma-cortisol was studied immediately before and after intermittent steroid therapy in seven patients receiving monthly courses of quadruple chemotherapy for Hodgkin's or non-Hodgkins lymphoma over a period of 6 months. The serum-thyroid-stimulating-hormone (T.S.H.) response to intravenous T.S.H.-releasing factor was also measured before and during the first course and before the second and fourth courses. The morning plasma-cortisol concentration fell significantly over 6 months when measured immediately before the start of each course. The mean evening cortisol concentration also fell over this period. In most patients the T.S.H. response showed a downward trend during treatment, although in two patients the response returned to normal whilst they were still undergoing therapy.

Hypothalamic/pituitary/adrenal function in patients treated with intermittent high-dose prednisolone and cytotoxic chemotherapy

Hypothalamic/pituitary/adrenal (H.P.A.) function was assessed in ten patients receiving intermittent high-dose prednisolone and cytotoxic chemotherapy for myeloma of lymphoma in order to predict their possible requirement for additional steroid therapy between and at the end of treatment courses. Standard insulin hypoglycaemia tests performed 36 hours after the last dose of prednisolone often demonstrated impairment of corticotrophin (adrenocorticotrophic hormone, A.C.T.H.) and growth-hormone responses, indicating hypothalamic/pituitary suppression; plasma-corticosteroid responses to endogenous A.C.T.H. and tetracosactrin were abnormal in two patients, indicating secondary adrenal suppression. Such hypothalamic/pituitary and adrenal suppression may make these patients susceptible to acute adrenal insufficiency in times of stress. H.P.A. function should be fully assessed on completion of chemotherapy.

Clinical and physiological assessment of asthmatic children treated with beclomethasone dipropionate

Forty-two perennial asthmatic children were selected for a 12-wk study using beclomethasone dipropionate. The groups included 21 steroid-dependent children (Group I) and 21 patients (Group II) whose disease was of sufficient severity that corticosteroid therapy was contemplated. All children received the drug in a dose of 100 mug 4 times daily. During the study, oral prednisone was withdrawn from the steroid-dependent children while other therapy was essentially unchanged. Group II children underwent a double-blind trial, receiving beclomethasone for 6 wk and placebo for 6 wk. Objective assessment of adrenal and pulmonary function was obtained at regular intervals. For the latter, total lung capacity and its subdivisions, airways resistance, maximum expiratory flow volume, and oxygen tension, were measured in both groups. In Group II static elastic recoil was measured also. For most tests the results were statistically significant. In both groups, 18 of 21 patients demonstrated an excellent clinical response, no evidence of adrenal suppression, and improvement in pulmonary function. Forty of 42 patients were followed for another 12 wk, and 19 of each group did well. After 20-24 wk of therapy, 16% of patients harbored monilia in their oropharynx, and 1 patient had clinical monilial stomatitis. Within the limits of the time of the study, beclomethasone dipropionate appeared to provide adequate clinical control in many chronic, severe, steroid-dependent and nonsteroid-dependent asthmatic children.

A controlled study of the effects of single doses of hydrocortisone on the resolution of acute attacks of asthma

To evaluate the effects of corticosteroids on the resolution of acute attacks of asthma, 38 young, acutely ill, asthmatic subjects were given a single intravenous injection of either 0.25, 0.50 or 1.0 g of hydrocortisone hemisuccinate or a placebo (sterile saline solution) in a random, double blind manner. Each was then treated with isoproterenol, at hourly intervals, for a minimum of six hours, and the serial changes in plethysmography, spirometry, lung volumes, subjective complaints and physical findings that occurred as the patients improved were observed. No statistical differences were found in any of the physiologic or clinical variables between those patients given any dose of steroids and their matched controls. From this it has been concluded that hydrocortisone, in the doses and route of administration employed, does not produce any immediate benefits in the treatment of acute asthma.

Endocrine response to substitution of corticotrophin for oral prednisolone in asthmatic children

The hypothalamo-pituitary-adrenal axis has been assessed in 17 asthmatic children before and after long-term prednisolone therapy was changed to daily corticotrophin. In 14 of the 17 children the plasma corticosteroid concentration exceeded 15 mug/100 ml within five days of starting corticotrophin. No exacerbation of asthmatic symptoms occurred during conversion. The plasma corticosteroid response to insulin-induced hypoglycaemia was normal in four children about six weeks after conversion to corticotrophin, took up to 36 months to become normal in nine, and remained abnormal in one child throughout the period of the trial.

Hypothalamic-pituitary-adrenal function in patients treated with long-term depot tetracosactrin

Four patients treated with depot tetracosactrin for 10 to 18 months maintained normal hypothalamic-pituitary-adrenal function assessed by the nyctohemeral variation of plasma corticosteroids and by the responses of plasma corticosteroids to insulin-induced hypoglycaemia, lysine-vasopressin, and depot tetracosactrin. The pituitary component of the response was analysed by measuring plasma immunoreactive ACTH levels. Three patients showed a nyctohemeral ACTH rhythm and normal ACTH responses to insulin-induced hypoglycaemia. Consistently undetectable morning plasma ACTH levels were found in the fourth patient, who also showed an unusually delayed rise in both ACTH and corticosteroid levels in response to insulin-induced hypoglycaemia, though the peak values attained were normal.The lack of suppression of hypothalamic-pituitary-adrenal function together with the good clinical response in these four patients suggests that treatment with depot tetracosactrin should be considered when long-term corticosteroid therapy is required.