Adrenal cortex disorders

Corticosteroids are hormones secreted from the adrenal cortex. These hormones arise from the cortex of the adrenal gland and are made from the crystalline steroid alcohol cholesterol. Synthetic forms of the natural adrenal cortical hormones are available The potent antiinflammatory action of the corticosteroids makes these drugs useful in the treatment of many types of musculoskeletal disorders. The corticosteroids are discussed in Chapter 50. 

Modified, with permission, from Williams GH, Dluhy RG. Disorders of the adrenal cortex. In Kasper DL, Braunwald E, Fauci A, et al, (eds.) Harrison s Principles of Internal Medicine. New York McGraw-Hill 2005 2127-2148. 

The HPA axis has been hypothesised to be of aetiological importance in depressive illnesses (McAllister-Williams Young, 1998 McAllister-Williams et al., 1998). Severely depressed patients (Sachar et al., 1973) and bipolar disorder patients (Linkowski et al., 1985) have signihcantly raised cortisol concentrations compared to controls. Imaging studies show an enlargement of the adrenal cortex in depressed patients compared to healthy subjects (Nemeroff... 

Ang II exerts important actions at vascular smooth muscle, adrenal cortex, kidney, heart, and brain. Through these actions, the renin-angiotensin system plays a key role in the regulation of fluid and electrolyte balance and arterial blood pressure. Excessive activity of the renin-angiotensin system can result in hypertension and disorders of fluid and electrolyte homeostasis. 

The natural adrenocortical hormones are steroid molecules produced and released by the adrenal cortex. Both natural and synthetic corticosteroids are used for the diagnosis and treatment of disorders of adrenal function. They are also used—more often and in much larger doses—for treatment of a variety of inflammatory and immunologic disorders. 

Bondy PhK. Disorders of the adrenal cortex. In Wilson JD, Foster DW, editors. Williams Textbook of Endocrinology. 7th edn.. Philadelphia Saunders, 1985 816. 

The adrenal cortex synthesizes corticosteroids (glucocorticoids and mineralocor-ticoids), which differ in activities. In humans, cortisol is the main glucocorticoid, and aldosterone is a main mineralocorticoid. Steroid therapy causes severe potential side effects, hence a careful consideration is always exercised before starting therapy. These are used in variety of disorders such as rheumatic disorder, renal disease, allergic manifestation, bronchial asthma, skin diseases, infectious diseases, malignancy, and hepatic diseases. 

Several relatively common disorders result in aldosterone secretion abnormalities and aberrations of electrolyte status. In Addison s disease, the adrenal cortex is often destroyed through autoimmune processes. One of the effects is a lack of aldosterone secretion and decreased Na+ retention by the patient. In a typical Addison s disease patient, serum [Na+] and [CL] are 128 and 96 meq/L, respectively (see Table 16.2 for normal values). Potassium levels are elevated, 6 meq/L or higher, because the Na+ reabsorption system of the kidney, which is under aldosterone control, moves K+ into the urine just as it moves Na+ back into plasma. Thus, if more Na+ is excreted, more K+ is reabsorbed. Bicarbonate remains relatively normal. The opposite situation prevails in Cushing s disease, however, in which an overproduction of adrenocorticosteroids, especially cortisol, is present. Glucocorticoids have mild mineralocorticoid activities, but ACTH also increases aldosterone secretion. This may be caused by an oversecretion of ACTH by a tumor or by adrenal hyperplasia or tumors. Serum sodium in Cushing s disease is slightly elevated, [K+] is below normal (hypokalemia), and metabolic alkalosis is present. The patient is usually hypertensive. A more severe electrolyte abnormality is seen in Conn s syndrome or primary aldosteronism, usually caused by an adrenal tumor. Increased blood aldosterone levels result in the urinary loss of K+ and H+, retention of Na+ (hypernatremia), alkalosis, and profound hypertension. 

Bondy PK Disorders of the adrenal cortex, in Wilson JD, Foster DW (eds) Textbook of Endocrinology. Saunders, New York, 1985, pp. 816-890. Carroll MC, Campbell RD, Porter RR Mapping of steroid 21-hydroxylase genes adjacent to complement component C4 genes in HLA, the major histocompatibility complex in man. Proc Natl AcadSci USA 82 521-525,1985. 

The disorder is due to a deficiency in the cholesterol side chain-splitting enzyme responsible for converting cholesterol to pregnenolone (P14). The adrenal cortex is hyperplastic and yellow due to accumulated cholesterol. Adrenal insufficiency is indicated clinically and incomplete masculiniza-tion of male fetuses is due to the inadequacy of testosterone production by the testes in early fetal life. A mild form of the disorder has been described by Camacho et al. (C2). 

ACTH( adrenocorticotrophic hormone) acts specifically on the adrenal cortex to elicit secretion of cortisol. Disorders of the hypothalamic-pituitary -adrcnal axis are described in detail on pages 86-91. 

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