We read with interest the recent communication on this subject(1). Triple A syndrome is characterized by selective defect in glucocorticoid production. Therefore, plasma cortisol is low and it does not rise after stimulation with ACTH. Plasma ACTH levels are elevated suggesting a primary unresponsive- ness of adrenal cortex to ACTH(2).

In the case described by the authors, low serum cortisol was consistent with the diagnosis of isolated glucocorticoid deficiency. However, normalization of serum cortisol following replacement with prednisolone as reported by the authors(1) is not explainable. One would expect serum cortisol to remain low or even become lower during prednisolone therapy because of adrenocorticoid suppression induced by exogenous prednisolone. In other words, because of feedback inhibition of ACTH production from pituitary by exogenous prednisolone, the production of endogenous cortisol which is already low despite maximum stimulation of adrenal cortex by ACTH, would fall further. Moreover, monitoring plasma cortisol levels is not areliable indicator of adequate glucocorticoid replacement therapy in adrenocorticoid hypofunction. In such cases adequacy of replacement therapy is 'better judged by clinical parameters(2,3).
 

Ratna Pori,
Jatinder S. Goraya,
Department of Pediatrics,
Government Medical College and Hospital,
 Sector 32, Chandigarh 160047.
India.
 

References:

1. Shivananda, Premalatha R, Raheela, Gayathri P. Triple-A syndrome. Indian Pediatr 1998; 35: 1131-1135.

2. Forest MG. Adrenal steroid deficiency states. In: Clinical Pediatric Endocrinology, 3rd edn.

3. Ed Brooke CGD. London, Blackwell Science, 1995; pp 453-498.

4. Findling JW, Aron JC, Tyrrell JB. Glucocorticoids and adrenal androgens. In: Basic and Clinical Endocrinology,. 5th edn. Eds. Greenspan FS, Strewler GJ. London, Prentice- Hall International Inc, 1997; pp 317 -358.