Long-acting intramuscular ACTH stimulation test for the diagnosis of secondary adrenal insufficiency in children

A Comparison of Lower Doses of Porcine Sequence Corticotropin with Standard Dose in Testing the Hypothalamic Pituitary Adrenal Axis in Healthy Individuals

Context

Porcine sequence corticotropin (PSC) stimulation test (PSCST) is a reliable, cost-effective alternative to the short Synacthen test. Long-acting PSC is widely available as a 300 IU multidose vial (60 IU per 1 ml).

Aims

To compare the efficacy of lower doses of PSC that can be given directly from the multidose vial without reconstitution, with standard dose in assessing the hypothalamic pituitary adrenal (HPA) axis in healthy individuals.

Settings and Design

Prospective study comparing different doses of PSC.

Methods and Material

In 13 healthy volunteers, serum Cortisol was estimated at 30 and 60 minutes after intramuscular administration of 24IU/250 μg standard dose (0.4 ml) and lower doses of PSC (18 IU/0.3 ml/;12 IU/0.2 ml; and 6 IU/0.1 ml), with a gap of 4 weeks between each dose.

Statistical Analysis Used

Mean ± SD was used to express quantitative variables. ANOVA and paired T-test were used for statistical analysis.

Results

The mean ± SD of peak Cortisol levels after PSCST with all doses of PSC were >18 ug/dl. The means of peak Cortisol responses to different doses of PSC among subjects were comparable. In a subject, there was no significant dose effect and interaction (dose x time) effect indicating that the different doses were comparable (both at 30 and 60 minutes) (p = 0.735).

Conclusions

All tested lower doses of PSC obtained from the multidose vial without reconstitution, including the lowest dose (6 IU/62.5 μg) tested, were comparable in efficacy to the standard dose (24IU/250 μg) in assessing the adequacy of HPA axis in healthy individuals.

ACTH Stimulation Test for the Diagnosis of Secondary Adrenal Insufficiency: Light and Shadow

Secondary Adrenal Insufficiency (SAI) is a condition characterized by inappropriately low ACTH secretion due to a disease or injury to the hypothalamus or the pituitary. The evaluation when suspected is often challenging for the non-specific symptoms, the rarity of the disease, and the pitfalls associated with laboratory tests. A prompt and correct diagnosis of SAI is essential because although an adequate hormonal replacement therapy could be lifesaving, inappropriate life-long therapy with steroids can be harmful. The gold standard test for assessing the hypothalamus-pituitary-adrenal axis (HPA) is the insulin tolerance test (ITT), but due to safety issues is not widely used. Conversely, the ACTH stimulation test is a safer and well-tolerated tool for SAI diagnosis. However, data about its diagnostic accuracy show great variability due to both technical and interpretative aspects, such as dose, route of administration, the timing of the test, and assay used for cortisol measurements. Consequently, the clinical background of the patient and the pretest probability of HPA axis impairment become of paramount importance. We aimed to summarize the recent literature evidence in the conduction and interpretation of the ACTH stimulation test for the diagnosis of SAI to provide updated insights on its correct use in clinical practice.

Long-acting porcine ACTH stimulated salivary cortisol in the diagnosis of adrenal insufficiency

BACKGROUND

Synacthen stimulated salivary cortisol has been previously evaluated and found beneficial in the diagnosis of adrenal insufficiency (AI), especially in situations with altered cortisol-binding protein (CBG) levels. Unfortunately, Synacthen is not marketed in many parts of the world whereas porcine sequence corticotrophin (Acton Prolongatum) is readily available. This study aimed to find the diagnostic accuracy of Acton prolongatum stimulated salivary cortisol test (APSST) compared to the short synacthen test (SST).

METHODS

Consecutive outpatients with suspected AI underwent SST initially, followed by APSST after 3 days. For APSST, saliva was collected at 0, 60 and 120 minutes after administering 30 units Acton Prolongatum intramuscularly. Serum and salivary cortisol were estimated using electrochemiluminescence assay. (Cobas e 411, Elecsys Cortisol II kits) RESULTS: Sixty-seven patients with clinically suspected AI were enrolled for the study. Based on SST, 35 patients were classified as having AI [primary AI (n=19) and secondary AI (n=16)] whereas 32 had normal glucocorticoid reserve. The area under receiver operator curve of 0.99 and 0.98 was observed for salivary cortisol values at 60 and 120 minutes, respectively, for APSST. A cut-off value of 18.5 nmol/L (0.67 µg/dL) and 29.3 nmol/L (1.06 µg/dL) at 60 and 120 minutes, respectively, had a sensitivity as well as specificity of 93%-100% in diagnosing AI.

CONCLUSION

Salivary cortisol estimation following stimulation using intramuscular porcine ACTH (Adrenocorticotrophic hormone) (30 units) is an economical and accurate alternative to SST in the diagnosis of AI, m and its level of 30 nmol/L or more at 2 hours confirms adrenal sufficiency.

Intramuscular Short-term ACTH Test for the Determination of Adrenal Function in Children: Safe, Effective and Reliable

OBJECTIVE

Standard short adrenocorticotropic hormone (ACTH) stimulation test (SST) has traditionally been used for assessing adrenal gland fuction by intravenous (iv) application. However the iv form is not readily available in all countries, including Turkey. The aim of this study was to evaluate the effectiveness of the intramuscular (im) SST.

METHODS

Patients underwent im SST with suspected adrenal insufficiency (AI) and hyperandrogenism. The SSTs were done with 250 mcg ACTH (Synacthen Depot ampul, concentration 1 mg/mL). The cases were divided into two groups: suspected AI (group 1 n=87); and hyperandrogenism group (group 2 n=124). Definite AI was defined as peak cortisol <18 μg/dL, suspected AI as a peak cortisol of 18-21 μg/dL and normal result was defined as a peak cortisol ≥22 μg/dL.

RESULTS

The mean age of the patients was 11.7±5.2 years. In 164 patients (78%) all of the peak cortisol tests were normal (≥22 mcg/dL). The rates were 64% and 88% in group 1 and 2, respectively. Only 8.5% (n=18) of all cases had an inadequate peak cortisol response of <18 mcg/dL. On follow up, 15 patients whose peak cortisol was <18 mcg/dL needed cortisol therapy. Of all cases 3.3% (n=8) had 17-OHP ≥10 ng/dL. Clinical findings suggestive of non-classical congenital adrenal hyperplasia and/or mutation were found in six of these cases (75%). No local and systemic side effects or allergic reactions were observed in any patient.

CONCLUSION

IM ACTH SST is a safe, effective and reliable test in children with suspected AI. There were no local or systemic side effects, supporting the reliability of the im ACTH test.