Primary adrenal insufficiency

Primary Adrenal Insufficiency

Primary adrenal insufficiency, also known as Addison's disease, is a rare endocrine disorder characterized by the inadequate production of steroid hormones by the adrenal glands. This condition results from the destruction or dysfunction of the adrenal cortex, leading to a deficiency in glucocorticoids, mineralocorticoids, and adrenal androgens.

Etiology

The most common cause of primary adrenal insufficiency is autoimmune adrenalitis, where the body's immune system mistakenly attacks the adrenal glands. Other causes include:

• Infections: Tuberculosis, fungal infections, and HIV can lead to adrenal gland damage.
• Genetic Disorders: Congenital adrenal hyperplasia and adrenoleukodystrophy.
• Metastatic Cancer: Cancer that spreads to the adrenal glands.
• Hemorrhage: Adrenal hemorrhage due to trauma or anticoagulant therapy.

Pathophysiology

In primary adrenal insufficiency, the adrenal cortex is unable to produce sufficient amounts of cortisol and aldosterone. Cortisol is crucial for stress response, metabolism, and immune function, while aldosterone regulates sodium and potassium balance. The lack of these hormones leads to:

• Hyponatremia: Low sodium levels due to aldosterone deficiency.
• Hyperkalemia: High potassium levels.
• Hypoglycemia: Low blood sugar due to cortisol deficiency.
• Hypotension: Low blood pressure.

Clinical Presentation

Patients with primary adrenal insufficiency may present with:

• Fatigue and Weakness
• Weight Loss and Anorexia
• Hyperpigmentation: Darkening of the skin, especially in areas exposed to friction.
• Hypotension: Particularly orthostatic hypotension.
• Salt Craving
• Nausea, Vomiting, and Abdominal Pain

Diagnosis

Diagnosis of primary adrenal insufficiency involves:

• Serum Electrolytes: Checking for hyponatremia and hyperkalemia.
• ACTH Stimulation Test: Measures the adrenal glands' response to adrenocorticotropic hormone (ACTH).
• Plasma Cortisol Levels: Low levels indicate adrenal insufficiency.
• Autoantibody Testing: To detect autoimmune adrenalitis.

Management

Treatment of primary adrenal insufficiency involves hormone replacement therapy:

• Glucocorticoids: Such as hydrocortisone or prednisone to replace cortisol.
• Mineralocorticoids: Such as fludrocortisone to replace aldosterone.
• Patient Education: On stress dosing and emergency management.

Prognosis

With appropriate treatment, individuals with primary adrenal insufficiency can lead normal lives. However, they must be vigilant about stress dosing and recognizing signs of adrenal crisis, a life-threatening condition requiring immediate medical attention.

Also see

• Adrenal gland
• Cushing's syndrome
• Congenital adrenal hyperplasia
• Endocrinology