What is Addison’s Disease?

Addison’s disease is a rare, chronic endocrine system disorder that occurs when the adrenal glands do not produce adequate steroid hormones.

The endocrine system refers to the collection of glands that secrete hormones in the body. When these hormone levels become too high or too low, problems occur such as diabetes, thyroid disease, growth disorders, or sexual dysfunction, among others.

The adrenal glands, located above the kidneys, are part of the endocrine system that produce a variety of hormones, including cortisol, aldosterone, & DHEA. Cortisol & aldosterone play key roles in the functioning of the human body, including regulation of BP, metabolism, & the body’s response to stress. The body uses DHEA to make androgens & estrogens (the male & female sex hormones).

Addison’s disease may also be called:

• primary hypoadrenalism
• primary adrenal insufficiency
• chronic adrenal insufficiency
• hypocortisolism

The disease is named after Thomas Addison, who first described the condition in 1849.

Causes

Addison’s disease is caused by problems with the adrenal gland – primary adrenal insufficiency – and can be caused by an autoimmune disorder, certain infections, or various other rare causes.

Adrenal insufficiency or cortisol deficiency results from alteration in any step in the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is a complex set of direct influences & interactions between three endocrine glands (the hypothalamus, pituitary gland, & adrenal glands). These interactions control reactions to stress & regulate body processes including the immune system, digestion, mood & emotions, sexuality, & energy storage & use. This dysfunction may be temporary or permanent.

There are 4 possible ways through which the adrenal glands produce insufficient cortisol:

1. Most commonly, primary adrenal insufficiency is a result of autoimmune destruction of the adrenal glands. It is common for these patients to have other autoimmune diseases as well.
2. Infections, such as tuberculosis, can destroy the adrenal glands, as well as cytomegalovirus, meningitis, & some fungal infections can also lead to Addison’s disease.
3. Adrenal dysgenesis, in which the gland has not formed adequately during development, is genetic, and very rare.
4. Impaired steroidogenesis occurs when the gland is present but biochemically unable to produce cortisol, sometimes caused by certain medication interference.

Signs & symptoms of adrenal insufficiency include:

• Hyperpigmentation (darkening of the skin) – most visible on scars,
  skin folds, pressure points, lips, & lining of the cheek.
• Chronic fatigue
• Orthostatic hypotension (lightheadedness when standing)
• Muscle weakness
• Loss of appetite
• Weight loss
• Abdominal pain
• Nausea/vomiting/diarrhea
• Headache
• Anxiety / Mood changes
• Sweating
• Craving salty foods

*The slowly progressing symptoms are often ignored until a stressful event, such as surgery, an illness, a severe injury, or pregnancy, causes them to worsen.

Addisonian crisis is a collection of symptoms that indicates severe adrenal insufficiency. It is a medical emergency & if not treated, can cause death.

Characteristic symptoms include:

• Profound physical weakness
• Sudden, severe pain in lower back, abdomen, or legs
• Severe vomiting & diarrhea, resulting in dehydration
• Low blood pressure
• Loss of consciousness
• Fever
• Convulsions
• Peripheral vascular collapse
• Renal shutdown

The diagnosis of Addison’s disease involves several tests:

Blood work may reveal the following:

• Hyponatremia (low sodium) – due to loss of aldosterone production
• Hyperkalemia (high potassium) – also due to loss of aldosterone production
• Hypercalcemia (high calcium)
• Hypoglycemia (low glucose)
• Low Cortisol

ACTH (Adrenocorticotropic hormone) stimulation test measures the level of cortisol in the blood before & after an injection of synthetic ACTH. ACTH signals the adrenal glands to produce cortisol, and if adrenal glands are damaged, the output of cortisol is limited or nonexistent.

Ultrasound or CT scan of the abdomen – can show abnormalities in the adrenal glands.

Antibody blood tests – can detect antibodies associated with autoimmune Addison’s disease.

Treatment for Addison’s disease involves:

• Lifelong hormone replacement therapy to correct the levels of steroid hormones – usually given orally, but injections can be given if the patient is vomiting.
• Hydrocortisone or prednisone – to replace cortisol
• Fludrocortisone – to replace aldosterone
• Patient needs plenty of sodium intake, especially during heavy exercise, hot weather, diarrhea, or a stressful situation, such as an infection or operation.

As a nurse, it is important to remind the patient with Addison’s disease to:

• Wear a medical alert bracelet that reads ‘adrenal insufficiency’ at all times.
• Keep extra medication handy – missing just one day of therapy may be dangerous, so it’s important to have an extra supply with them, as well as keeping an injectable form of corticosteroids on hand in case of an emergency.
• Stay in contact with their doctor – to make sure the replacement hormones are adequate but not excessive – adjustments in the doses or timing may need to be made.

Review

Addison’s disease is an endocrine, or hormonal, disorder that occurs when the adrenal glands are damaged and cannot produce enough of the adrenal hormone cortisol. The adrenal hormone aldosterone may be lacking also.

Typical symptoms include weakness, fatigue, & hyperpigmentation.

If not treated, an adrenal crisis can lead to death.

Diagnosis is confirmed through hormonal blood tests & possibly imaging studies.

Treatment involves replacing the hormones that the adrenal glands are not making.