Biology of Disease

and salt losses and intravenous steroids to correct glucocorticoid and
mineralocorticoid deficiencies. The precipitating factors, such as bacterial
infections, require identification and appropriate treatment.

Cushing’s Syndrome

Adrenal hyperfunction can cause Cushing’s syndrome and arise from a
number of causes. The commonest cause is a pituitary lesion secreting high
levels of ACTH (referred to as Cushing’s disease). Other causes include ectopic
production of ACTH from a carcinoma of the lungs, or excessive production
of cortisol from an adrenal adenoma or carcinoma and iatrogenic causes,
such as corticosteroid or ACTH treatment. The major clinical features (Figure
7.31) include truncal obesity, thinning of skin, excessive bruising, poor wound
healing, purple striae on the abdomen and thighs, muscle weakness and
wasting,hirsutism, the development of increased body hair on the face, chest
upper back and abdomen in females (especially in adrenal carcinoma), hyper-
tension, amenorrhea and psychiatric disturbances. Excess of cortisol has a
mineralocorticoid effect leading to the retention of Na+ and water producing
hypertension. Hypokalemia may also occur because of an excessive loss of K+
(Chapter 8). Excess cortisol increases blood glucose levels and some of these
patients may have diabetes mellitus. The clinical features are due to increased
cortisol production and, partly, to excessive androgen release.

DISORDERS OF THE ADRENAL CORTEX

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Pigmentation of

hands and mouth

Nausea, vomiting and

dehydration

Abdominal pain

Anorexia (weight loss)

and lethargy

Swollen hump to

upper back

Acne

Moon face, with

swollen cheeks

Osteoporosis

Muscle weakness

Poor wound

healing

Easily bruised

Hypertension

Baldness

Increased abdominal fat

and striae

Figure 7.30 Schematic to show the clinical features
of Addison’s disease. Figure 7.31 Schematic to show the clinical features of Cushing’s syndrome.