Definitions

microadenoma

Adrenal insufficiency

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 mineralcorticoid) 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 is the worst degree of adrenal insufficiency, which if not treated, severe abdominal pains, diarrhea, vomiting, profound muscle weakness and fatigue, extremely low blood pressure, weight loss, kidney failure, changes in mood and personality and shock may occur (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, doesn't 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.

Types

There are two major types of adrenal insufficiency. Primary adrenal insufficiency is due to impairment of the adrenal glands. The most common subtype is called idiopathic or unknown cause of adrenal insufficiency. Some 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. These can be due to a form of cancer: a pituitary microadenoma, a pituitary macroadenoma, or a hypothalamic tumor; Sheehan's syndrome, which is associated with impairment of only the pituitary gland; or a past head injury.

Causes

* Autoimmune (may be part of a polyglandular autoimmune disorder which can include type I Diabetes Mellitus, autoimmune thyroid disease (also known as autoimmune thyroiditis, Hashimoto's thyroiditis and Hashimoto's disease)
* Adrenoleukodystrophy
* Discontinuing corticosteroid therapy without tapering the dosage (severe adrenal suppression with ACTH suppression)
* Illness or any other forms of stress (this is termed critical illness–related corticosteroid insufficiency)
* kidney injury
* environmental
* genetics
* Head injury
* Radiation
* Surgery
* infections (eg, meningitis)
* congenital hypopituitarism
* congential hypoadrenalism

Symptoms

The person may show symptoms of hypoglycemia, dehydration, weight loss and disorientation. They may experience weakness, tiredness, dizziness, low blood pressure that falls further when standing (orthostatic hypotension), muscle aches, nausea, vomiting, and diarrhea. These problems may develop gradually and insidiously. Addison's can present with tanning of the skin which may be patchy or even all over the body and in some cases a person with light skin can look so dark people mistake them for being from another country. 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.

Diagnosis

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.

Treatment

*;Adrenal crisis
*Intravenous fluids
*Intravenous steroid (Solu-Cortef or Solumedrol), later hydrocortisone, prednisone or methylpredisolone tablets
*Rest

*;Cortisol deficiency (primary and secondary)
*Adrenal cortical extract (usually in the form of a supplement, non prescription in the United States)
*Hydrocortisone (Cortef) (between 20 and 35 mg)
*Prednisone (Deltasone) (7 1/2 mg)
*Prednisolone (Delta-Cortef) (7 1/2 mg)
*Methylprednisolone (Medrol) (6 mg)
*Dexamethasone (Decadron) (1/4 mg, some doctors prescribe 1/2 to 1 mg, but those doses tend to cause side effects resembling Cushing's disease)

*;Mineralcorticoid deficiency (low aldosterone)
*Fludrocortisone (Florinef) (To balance sodium, potassium and increase water retention)

Simple diagnostic chart

Source of pathology CRH ACTHDHEADHEA-Scortisol aldosteronerenin NaKCauses5
hypothalamus
(tertiary)1
low low lowlow low3 lowlow lowlowtumor of the hypothalamus (adenoma), antibodies, environment, head injury
pituitary
(secondary)
high2 low lowlow low3 low lowlowlowtumor of the pituitary (adenoma), antibodies, environment, head injury,
surgical removal6, Sheehan's syndrome
adrenal glands
(primary)7
high high high highlow4low highlowhightumor of the adrenal (adenoma), stress, antibodies, environment, Addison's, injury, surgical removal

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, doesn't include all possible causes
6 Usually because of very large tumor (macroadenoma)
7 Includes Addison's disease

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