Congenital Adrenal Hyperplasia (Adrenogenital syndromes)

What is Congenital Adrenal Hyperplasia?

Congenital Adrenal Hyperplasia and adrenogenital syndromes are diseases of the Adrenal glands.The adrenal cortex is divided into three zones which synthesise three different types of hormones:

Glucocorticoids (cortisol): glucose metabolism and immune functions

Mineralocorticoids (aldosterone): blood pressure and salt regulation

Sex steroids: effects on sex organ differentiation, bone and soft tissues.The adrenogenital syndromes and CAH result from a defect in the synthesis of the above hormones, with a block in the cortisol synthesis pathway causing increased sex steroid synthesis (due to greater substrate for synthesis).

Statistics on Congenital Adrenal Hyperplasia?

21-hydroxylase deficiency presents in 1 in 15000 births and accounts for 90% of cases of congenital adrenal hyperplasia. 11-hydroxylase deficiency occurs in 1 in 200000 births and 17-hydroxylase, 3-hyroxysteroid dehydrogenase and 20,22 desmolase deficiencies are rare. All adrenogential syndromes are autosomal recessive.

Risk Factors for Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia results from a deficiency of an enzyme in the cortisol synthetic pathways. This results in increased ACTH to maintain adequate cortisol leading to diversion of the steroid precursors to the androgenic steroid pathways. Thus 17-hydroxyprogesterone, androstenedione and testosterone levels are increased.

Adrenogenital syndrome may also be caused by androgen secreting adrenal cortex neoplasms.

Progression of Congenital Adrenal Hyperplasia

Severely affected infants will die if the disorder is not treated. Other patients may present with milder disease later in life. With early diagnosis and proper management patients can lead a normal life in terms of sexual development and fertility. Final stature is often decreased because of difficulty in optimizing gluococorticoid therapy.

How is Congenital Adrenal Hyperplasia Diagnosed?

Urea and electrolytes - show effects of mineralocorticoid deficiency (low sodium, high potassium and sometimes metabolic acidosis) and mineralocorticoid excess (low potassium, metabolic alkalosis and sometimes mildly raised sodium).

Prognosis of Congenital Adrenal Hyperplasia

The outcome is usually associated with good health, but short stature may result even with treatment. Males have normal fertility. Females may have a smaller opening of the vagina and lower fertility.Medication to treat this disorder must be continued for life.

How is Congenital Adrenal Hyperplasia Treated?

Treatment involves replacement of glucocorticoid activity and mineralocorticoid activity if deficient. Correct dosage in children should ensure normal 17-hydroxyprogesterone levels while allowing normal growth.

Congenital Adrenal Hyperplasia References

[1] Braunwald, Fauci, Kasper, Hauser, Longo, Jameson. Harrison's Principles of Internal Medicine. 15th Edition. McGraw-Hill. 2001[2] Cotran, Kumar, Collins 6th edition. Robbins Pathologic Basis of Disease. WB Saunders Company. 1999.[3] Hurst JW (Editor-in-chief). Medicine for the practicing physician. 4th edition Appleton and Lange 1996.[4] Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002 Pg 427-430.[5] Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001