Addison's disease

Addison’s disease, also known as primary adrenal insufficiency, is a rare but serious disorder in which the adrenal glands (located on top of the kidneys) fail to produce adequate amounts of essential steroid hormones, particularly cortisol and, in many cases, aldosterone. These hormones are vital for maintaining blood pressure, metabolism, immune function, and the body’s response to stress. Addison’s disease is potentially life-threatening if untreated, and it often requires lifelong management.

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Causes

1. Autoimmune destruction (most common)

   • The body’s immune system attacks the adrenal cortex, gradually reducing hormone production.

   • This accounts for up to 70–90% of cases in developed countries.

2. Infections

   • Tuberculosis remains a leading cause in developing regions.

   • Fungal infections (e.g., histoplasmosis), cytomegalovirus (CMV), and HIV can also damage the adrenal glands.

3. Metastatic cancer

   • Cancers, particularly from the lung, breast, or stomach, may spread to the adrenal glands.

4. Genetic and congenital causes

   • Adrenoleukodystrophy, congenital adrenal hypoplasia, and certain enzyme deficiencies.

5. Other causes

   • Adrenal hemorrhage (e.g., due to sepsis or anticoagulant use).

   • Surgical removal of adrenal glands.

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Symptoms

Symptoms usually develop slowly and may be mistaken for other conditions. However, during times of stress, illness, or injury, they can worsen suddenly (Addisonian crisis).

• Chronic symptoms:

  • Fatigue and weakness

  • Weight loss and loss of appetite

  • Low blood pressure (especially postural hypotension)

  • Hyperpigmentation (darkening of skin, particularly in creases and scars)

  • Nausea, vomiting, or abdominal pain

  • Salt craving (due to aldosterone deficiency)

  • Muscle and joint pains

  • Irritability, depression, or mood swings

• Acute adrenal crisis (life-threatening emergency):

  • Severe hypotension and shock

  • Sudden severe pain in lower back, abdomen, or legs

  • Vomiting and diarrhea leading to dehydration

  • Confusion, loss of consciousness

  • Low blood glucose (hypoglycemia)

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Diagnosis

1. Blood tests

   • Low cortisol levels

   • High ACTH (adrenocorticotropic hormone) in primary adrenal insufficiency

   • Low sodium (hyponatremia), high potassium (hyperkalemia), and sometimes low glucose

2. ACTH stimulation test (short Synacthen test)

   • Measures adrenal response to synthetic ACTH. Failure to produce cortisol confirms the diagnosis.

3. Imaging

   • CT scan of adrenal glands if tuberculosis, cancer, or hemorrhage is suspected.

   • MRI if pituitary or secondary causes are suspected.

4. Autoantibody tests

   • To confirm autoimmune adrenalitis (21-hydroxylase antibodies).

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Treatment

Treatment focuses on lifelong hormone replacement therapy and emergency management of adrenal crisis.

1. Glucocorticoid replacement (cortisol substitute)

• Hydrocortisone: usually 15–25 mg/day in divided doses (e.g., 10 mg morning, 5 mg afternoon, 5 mg evening).

• Alternative options:

  • Prednisolone: 3–5 mg/day once or twice daily.

  • Dexamethasone: rarely used due to long half-life.

2. Mineralocorticoid replacement (aldosterone substitute)

• Fludrocortisone: 0.05–0.2 mg/day, adjusted based on blood pressure, electrolytes, and plasma renin activity.

3. Stress dosing (important in illness or surgery)

• Patients need higher glucocorticoid doses during illness, trauma, or surgery to mimic the natural stress response.

• For minor illness: double usual oral hydrocortisone dose.

• For major illness/surgery: IV hydrocortisone 100 mg every 6–8 hours.

4. Treatment of adrenal crisis (medical emergency)

• Immediate IV hydrocortisone 100 mg followed by 50 mg every 6 hours or continuous infusion.

• IV fluids: rapid infusion of 0.9% saline with dextrose if hypoglycemia present.

• Treat underlying trigger (infection, trauma, stress).

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Lifestyle and Self-Management

• Medical alert identification: Patients should wear a bracelet or carry a card stating they have Addison’s disease.

• Emergency hydrocortisone injection kit: Patients and caregivers should be trained to administer an emergency injection during crisis.

• Regular monitoring: Electrolytes, blood pressure, and renin activity help adjust fludrocortisone.

• Healthy lifestyle: Adequate salt intake, balanced nutrition, and hydration.

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Complications

1. Addisonian crisis – if untreated, can lead to shock and death.

2. Associated autoimmune conditions – thyroid disease, type 1 diabetes, pernicious anemia (polyglandular autoimmune syndrome).

3. Long-term complications of steroid replacement – weight gain, osteoporosis, diabetes, if dosing is excessive.

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Prognosis

With proper lifelong replacement therapy and patient education, individuals with Addison’s disease can lead normal lives. Early recognition of symptoms and prompt treatment of adrenal crisis are crucial in preventing complications.