Tertiary adrenal insufficiency

Secondary adrenal insufficiency occurs as a result of a pituitary gland dysfunction whereby decreased production and secretion of ACTH leads to a decrease in cortisol synthesis. Tertiary adrenal insufficiency is a disorder of the hypothalamus that results in decreased production and release of CRH, which, in turn, decreases pituitary ACTH production and release. In contrast to Addison s disease (i.e., primary adrenal insufficiency), aldosterone production is unaffected in the secondary and tertiary forms of the disease. Chronic adrenal insufficiency often has a good prognosis if diagnosed early and treated appropriately. 

Tests to Determine Diagnosis of Primary, Secondary, and Tertiary Adrenal Insufficiency ... 

Secondary or tertiary adrenal insufficiency plasma ACTH low or ... 

Once diagnosis is confirmed, perform further testing to differentiate between primary, secondary, and tertiary adrenal insufficiency. 

Determine the duration of treatment for patients with secondary and tertiary adrenal insufficiency. 

Interpretation Serum cortisol values more than 20ixg/dL exclude primary adrenal insufficiency. Glucocorticoid withdrawal would be required before assessing secondary or tertiary adrenal insufficiency in such cases. Little or no increase in cortisol secretion is seen in primary adrenal failure even over-successive days. A progressive staircase rise is seen over 2 to 3 days in adrenal insufficiency caused by pituitary or hypothalamic disease or steroid concentration suppression. Little or no response is also seen in congenital adrenal hyperplasia (CAH) caused by 21- and 17-hydroxylase deficiencies. 

Adrenal insufficiency is a rare disorder with a prevalence of only 4 to 11 cases per 100,000 population if untreated it is fatal. The disorder is classified as primary,secondary, or tertiary. Primary adrenal insujficiency, also known as... 

In secondary and tertiary adrenal insufficiency (Table 51-5), inadequate cortisol production may be due to destructive processes in the hypothalamic-pituitary that result in a decreased ability to secrete ACTH (secondary) or CRH (tertiary).However, the most common cause of tertiary insufficiency is chronic pharmacological administration of glucocorticoids that vsuppress CRH synthesis. This leads to a decrease in both ACTH release and cortisol secre-... 

The CRH stimulation test (see Box 51-3) can be used to differentiate tertiary from secondary adrenal insufficiency. Those with tertiary disease show an elevation in ACTH with CRH administration, whereas those with secondary disease show only minima changes in ACTH concentrations. 

Although subnormal basal plasma concentrations of DHEA-S occur in primary, secondary, and tertiary forms of adrenal insufficiency, measurement is of little value in the diagnosis of adrenal insufficiency low concentrations of adrenal androgens are normally observed in children and in the elderly. Patients with human immunodeficiency virus (HIV) infection have been shown to have reduced concentrations of DHEA-S. DHEA-S concentrations are usually determined in the management of women with hirsutism or in patients suspected of having adrenal tumors. ... 

Replacement therapy for secondary or tertiary adrenocortical insufficiency These deficiencies are caused by a defect either in CRF production by the hypothalamus or corticotropin production by the pituitary (see p. 247). [Note Under these conditions, the adrenal cortex synthesis of mineralocorticoids is less impaired than that of glucocorticoids.] The adrenal cortex responds to corticotropin administration by synthesizing and releasing the adrenal corticosteroids. Hydrocortisone is also used for these deficiencies. 

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