Secondary adrenal insufficiency

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Adrenal insufficiency
Adrenal gland
ICD-10	E27.1-E27.4
ICD-9	255.4
MeSH	D000309

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: hypocortisolism; adrenal fatigue; hypoadrenia

Overview

Adrenal insufficiency (or "hypocortisolism") is the inability of the adrenal gland to produce adequate amounts of cortisol in response to stress. See also: Adrenal Fatigue or Hypoadrenia.

Adrenal insufficiency is a condition in which the adrenal glands, located above the kidneys, do not produce adequate amounts of steroid hormones (chemicals produced by the body that regulate organ function), primarily cortisol, but may also include impaired aldosterone production (a mineralocorticoid) which regulates sodium, potassium and water retention. Craving for salt or salty foods due to the urinary losses of sodium is common.

Addison's disease and congenital adrenal hyperplasia can manifest as adrenal insufficiency. If not treated, adrenal insufficiency may result in severe abdominal pains, diarrhea, vomiting, profound muscle weakness and fatigue, depression, extremely low blood pressure (hypotension), weight loss, kidney failure, changes in mood and personality, and shock (adrenal crisis). An adrenal crisis often occurs if the body is subjected to stress, such as an accident, injury, surgery, or severe infection; death may quickly follow.

Adrenal insufficiency can also occur when the hypothalamus or the pituitary gland, both located at the base of the skull, does not make adequate amounts of the hormones that assist in regulating adrenal function. This is called secondary adrenal insufficiency and is caused by lack of production of ACTH in the pituitary or lack of CRH in the hypothalamus.

Classification

There are three major types of adrenal insufficiency.

• Primary adrenal insufficiency is due to impairment of the adrenal glands.
  • One subtype is called idiopathic or unknown cause of adrenal insufficiency.
  • 80% are due to an autoimmune disease called Addison's disease or autoimmune adrenalitis.
  • Other cases are due to congenital adrenal hyperplasia or an adenoma (tumor) of the adrenal gland.
• Secondary adrenal insufficiency is caused by impairment of the pituitary gland or hypothalamus. The most common cause in the United States is exogenous steroid use. Other causes are a pituitary adenoma or microadenoma, hypothalamic tumor (surgical removal of a pituitary tumor can also suppress production of ACTH and lead to adrenal deficiency); Sheehan's syndrome, which is associated with impairment of only the pituitary gland.
• Tertiary adrenal insufficiency is due to hypothalamic disease and decrease in corticotropin releasing factor (CRF).

Causes

Causes of acute adrenal insufficiency are mainly Waterhouse-Friderichsen syndrome, sudden withdrawal of long-term corticosteroid therapy and stress in patients with underlying chronic adrenal insufficiency. The latter is termed critical illness–related corticosteroid insufficiency.

For chronic adrenal insufficiency, the major contributors are autoimmune adrenalitis, tuberculosis, AIDS and metastatic disease. Minor causes of chronic adrenal insufficiency are systemic amyloidosis, fungal infections, hemochromatosis and sarcoidosis.

Autoimmune adrenalitis may be part of Type 2 autoimmune polyglandular syndrome, which can include type 1 diabetes, hyperthyroidism, autoimmune thyroid disease (also known as autoimmune thyroiditis, Hashimoto's thyroiditis and Hashimoto's disease). Hypogonadism and pernicious anemia may also present with this syndrome.

Adrenoleukodystrophy can also cause adrenal insufficiency.

Adrenal Insufficiency can also be caused when a patient has a Craniopharyngioma which is a benign tumor that can damage the Pituitary gland causing the Adrenal Glands not to function. This would be an example of Secondary Adrenal Insufficiency Syndrome.

Causes

• Acute adrenal insufficiency
  • Addison's disease (autoimmune adrenalitis)
  • Septic shock
  • Waterhouse-Friderichsen syndrome
  • Addisonian crisis in case of:
    • Discontinuing corticosteroid therapy without tapering the dosage
    • Surgery, illness or any other form of stress in patients with long-term corticosteroid therapy
• Chronic adrenal insufficiency
  • Addison's disease
  • Congenital Adrenal Hyperplasia
  • Antiphospholipid syndrome
  • Haemochromatosis

Diagnosis

Symptoms

• Hypoglycemia
• Dehydration
• Weight loss
• Disorientation
• Weakness
• Tiredness
• Dizziness

Physical Examination

Vital Signs

low blood pressure that falls further when standing (orthostatic hypotension), cardiovascular collapse, muscle aches, nausea, vomiting, and diarrhea. These problems may develop gradually and insidiously. Addison's can present with tanning of the skin that may be patchy or even all over the body. Characteristic sites of tanning are skin creases (e.g. of the hands) and the inside of the cheek (buccal mucosa). Goitre and vitiligo may also be present.

Laboratory Findings

ACTH Stimulation Test

If the person is in adrenal crisis, the ACTH stimulation test may be given. If not in crisis, cortisol, ACTH, aldosterone, renin, potassium and sodium are tested from a blood sample before the decision is made if the ACTH stimulation test needs to be performed. X-rays or CT of the adrenals may also be done. The best test for adrenal insufficiency of autoimmune origin, representing more than ninety percent of all cases in a Western population, is measurement of 21-hydroxylase autoantibodies.

Source of pathology	CRH	ACTH	DHEA	DHEA-S	cortisol	aldosterone	renin	Na	K	Causes5
hypothalamus (tertiary)1	low	low	low	low	low3	low	low	low	low	tumor of the hypothalamus (adenoma), antibodies, environment (i.e. toxins), head injury
pituitary (secondary)	high2	low	low	low	low3	low	low	low	low	tumor of the pituitary (adenoma), antibodies, environment, head injury, surgical removal6, Sheehan's syndrome
adrenal glands (primary)7	high	high	high	high	low4	low	high	low	high	tumor of the adrenal (adenoma), stress, antibodies, environment, Addison's Disease, trauma, surgical removal (resection), miliary tuberculosis of the adrenal

1	Automatically includes diagnosis of secondary (hypopituitarism)
2	Only if CRH production in the hypothalamus is intact
3	Value doubles or more in stimulation
4	Value less than doubles in stimulation
5	Most common, does not include all possible causes
6	Usually because of very large tumor (macroadenoma)
7	Includes Addison's disease

Treatment

• Adrenal crisis

  • Intravenous fluids
  • Intravenous steroid (Solu-Cortef/injectable hydrocortisone) later hydrocortisone, prednisone or methylpredisolone tablets
  • Rest

• Cortisol deficiency (primary and secondary)

  • Hydrocortisone (Cortef)
  • Prednisone (Deltasone)
  • Prednisolone (Delta-Cortef)
  • Methylprednisolone (Medrol)
  • Dexamethasone (Decadron)

• Mineralocorticoid deficiency (low aldosterone)

  • Fludrocortisone Acetate

(To balance sodium, potassium and increase water retention)

See also

• Addison disease, primary adrenocortical insufficiency
• ACTH stimulation test
• Cushing's syndrome, overproduction of cortisol
• Insulin tolerance test, another test used to identify sub-types of adrenal insufficiency
• Adrenal fatigue (hypoadrenia), a term used in alternative medicine to describe a believed exhaustion of the adrenal glands

References

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