Addison's disease

Question 1

What is Addison’s disease?

Answer 1

abrupt destruction of the adrenal gland (acute adrenal insufficiency; e.g., due to massive adrenal hemorrhage) or by its gradual progressive destruction or atrophy (chronic adrenal insufficiency; e.g., due to autoimmune conditions, infection).

Question 2

What are the causes of Addison’s disease?

Answer 2

(Autoimmune adrenalitis)
(Infectious adrenalitis) Tuberculosis, CMV
(Adrenal hemorrhage) i.e. Sepsis, Disseminated intravascular coagulation (DIC)

Question 3

What is the pathophysiology in primary adrenal insufficiency?

Answer 3

(Hypoandrogenism) Loss of libido
Impaired spermatogenesis
(Hypocortisolism) ↑ ACTH → ↑ production of POMC (in order to increase ACTH production) → ↑ melanocyte-stimulating hormone (MSH) → hyperpigmentation of the skin (bronze skin)
(Hypoaldosteronism) hypotension (hypotonic hyponatremia and volume contraction), hyperkalemia, metabolic acidosis

Question 4

What are the clinical features of Addison’s disease?

Answer 4

(Hypoaldosteronism) Hypotension
Salt craving
(Hypercortisolism) Weight loss, anorexia
Fatigue, lethargy, depression
Muscle aches
Weakness
Gastrointestinal complaints (e.g., nausea, vomiting, diarrhea)
Sugar cravings
(Orthostatic) hypotension
(Hypoandrogenism) Loss of libido
Loss of axillary and pubic hair

Question 5

How is Addison’s disease diagnosed?

Answer 5

(Serum electrolytes) Hyponatremia, Hyperkalemia, Normal anion gap metabolic acidosis, hypoglycemia
(Definitive investigation) ACTH stimulation test (short Synacthen test), Plasma cortisol is measured before and 30 minutes after giving Synacthen 250ug IM

Question 6

What is the treatment for Addison’s disease?

Answer 6

(glucocorticoid and mineralocorticoid replacement therapy) Hydrocortisone + fludrocortisone respectively