What is Adrenal Insufficiency?
Adrenal insufficiency is a condition where the adrenal glands fail to produce sufficient amount of steroid hormones, which are chemicals that help in regulating the organ function. Adrenal glands are located above the kidneys. Steroid hormones comprise primarily of cortisol, but can also include impaired aldosterone production which helps in regulating sodium, potassium and water retention. Patient craves for salt or salty foods due to loss of sodium through urine.
Some conditions like Addison's disease and congenital adrenal hyperplasia manifest as adrenal insufficiency. If adrenal insufficiency is not treated promptly, it may cause severe abdominal pain, vomiting, severe muscle weakness and fatigue, depression, hypotension, weight loss, mood and personality changes, kidney failure, and shock (adrenal crisis). Adrenal crisis is a condition which usually occurs when the body undergoes extreme stress, such as an injury, accident, severe infection or surgery; all this may be followed by death.
If hypothalamus or the pituitary gland (located at the base of the skull), do not produce sufficient amount of hormones which help to regulate adrenal function, then this may also cause adrenal insufficiency known as secondary adrenal insufficiency.
Classification and Types of Adrenal Insufficiency
Adrenal insufficiency is classified into three major types:
- Primary adrenal insufficiency: This occurs due to impairment of the adrenal glands.
- Idiopathic adrenal insufficiency occurs due to unknown cause and is a sub type.
- Majority of the cases occur due to an autoimmune disease called Addison's disease or autoimmune adrenalitis.
- Congenital Adrenal Hyperplasia or an adenoma (tumor) of the adrenal gland is responsible for other cases.
- Secondary adrenal insufficiency: This is caused due to impairment of the hypothalamus or pituitary gland. Exogenous steroid use is the most common cause for this in USA. Other causes include pituitary adenoma/microadenoma, hypothalamic tumor (removing a pituitary tumor surgically may also suppress ACTH production and cause adrenal deficiency); impairment of the pituitary gland results in Sheehan's syndrome.
- Tertiary adrenal insufficiency: This occurs due to hypothalamic disease and decline in the corticotropin releasing factor (CRF).
Signs and Symptoms of Adrenal Insufficiency
- Weight loss
- Confusion or disorientation.
- Low blood pressure with orthostatic hypotension
- Cardiovascular collapse
- Muscle aches
- Skin tanning, which may be patchy or even throughout the body, is seen in skin creases and the inside of the cheek (buccal mucosa).
- Goitre and vitiligo may be present.
Causes and Risk Factors of Adrenal Insufficiency
Acute Adrenal Insufficiency: The primary cause for this is Waterhouse-Friderichsen syndrome along with abrupt withdrawal of long-term corticosteroid therapy. Stress in patients who have underlying chronic adrenal insufficiency (critical illness–related corticosteroid insufficiency) also causes acute adrenal insufficiency.
Chronic Adrenal Insufficiency: The primary contributors are tuberculosis, autoimmune adrenalitis, AIDS and metastatic disease. Other minor causes include: Systemic Amyloidosis, fungal infections, sarcoidosis and hemochromatosis.
Other causes of adrenal insufficiency include:Adrenoleukodystrophy and craniopharyngioma.
Tests to Diagnose Adrenal Insufficiency
- ACTH stimulation test
- Blood tests to check cortisol, ACTH, aldosterone, renin, potassium and sodium levels.
- X-rays of the adrenals
- CT of the adrenals
- Measurement of 21-hydroxylase autoantibodies
Treatment for Adrenal Insufficiency
- Rest is important.
- For adrenal crisis, the following is given: Intravenous fluids, intravenous steroid (Solu-Cortef injection) prednisone or methylprednisolone tablets..
- For primary and secondary cortisol deficiency: Hydrocortisone (Cortef), prednisone (Deltasone), prednisolone (Delta-Cortef), methylprednisolone (Medrol) and dexamethasone (Decadron) are given.
- For mineralocorticoid deficiency (low aldosterone), fludrocortisone acetate is given which helps in balancing sodium, potassium levels and increasing water retention.