Associated Diseases
Disorders associated with Mineralcorticoid production (specifically Aldosterone)
Hypoaldosteronism
This condition is associated with a decrease in Zona Glomerulosa activity, usually as a direct consequence of reduced renin production at the kidneys.
Symptoms include excessive loss of water and sodium causing dehydration and hypotension. Changes in electrolyte potentials are apparent, particularly Hyperkalemia, affecting electrophysiology in both neurons and muscle.
Common treatments include the use of Fludrocortisone, which mimics aldosterone, combined with liberal salt intake.
(Hyper)aldosteronism
This is a result of excessive aldosterone production and secretion from the Zona Glomerulosa. It is often a secondary consequence of invasion of the adrenal cortex by an adenoma, whose cells themselves act as glands, or cause enhanced activity of the endogenous cells. The kidneys continue to reabsorb sodium and at the same time excrete large quantities of potassium, leading to hypertension and hypokalemia. Low intracellular potassium levels which will eventually disrupt cardiac, renal and neuronal function.
Spironolactone is the most popular choice of drug for treatment of aldosteronism. It acts as an aldosterone antagonist and is often combined with the administration of diuretics to promote secretion of sodium and water.
Disorders associated with Glucocorticoid production
Addison’s disease
Addison’s disease is related to decreased activity of the Zona Fasiculata and an inadequate production of Glucocorticoids, particularly Cortisol. It can be a result of auto-immune disorders against ACTH or its receptors at the cortex, or bacterial infection (including the tuberculosis bacterium). Symptoms include weight loss, weakness, nausea, lethargy, poor reactions to stresses such as injury, and often a darkening of the skin. Unfortunately, these often don’t become apparent until most of the adrenal cortex has already been destroyed.
Treatments include the replacement of Glucocorticoids, usually via administration of hydrocortisone tablets.
Cushing’s disease
This is in some ways, the opposite of Addison’s disease, and is associated with an overactive Zona Fasiculata causing excess Cortisol secretion. This is often associated with a tumour of the pituitary gland which results in hypersecretion of ACTH. However, it is just as common for this to be a result of hyperactivity of the adrenal cortex independent of ACTH.
It presents with symptoms such as excess subcutaneous fat deposition over the torso, and muscle wastage on the arms and legs. For these reasons, the appearance of affected patients is often described as a lemon on a matchstick! In addition, patients suffer hyperglycaemia, water retention, muscle weakness, hypertension and an enhanced vulnerability to infection.
For a full list and illustration of symptoms click here
Treatment could involve a range of options from surgery to long-term use of cortisol-inhibiting drugs.
Disorders associated with Androgens
Androgenital syndrome (aka Congenital Adrenal Hyperplasia)
Often accompanied by Addison’s disease, Androgenital syndrome is caused by adrenal androgen hypersecretion. It is a genetic disease associated with the loss of 21-hydroxylase; the enzyme needed by the adrenal glands to make cortisol and aldosterone. Without these hormones, more androgens are synthesised. It affects both girls and boys, but symptoms appear earlier in girls. Children will have enlarged external genitalia, which in extreme cases will result in gender confusion at birth. It can have a masculinising effect in girls such as a deepened voice and excessive hair growth.
Girls may have success with combined oral contraceptives or anti-androgens. Topical cosmetic therapies such as hair removal are useful for helping manage the symptoms. Additional Cortisol is commonly prescribed in an attempt to normalise hormone levels, but it is important to get the balance right! (Click here to see why).