Underactive Adrenal or Hypocortisolism

What are the causes of Low cortisol hormone??

The disease of low cortisol production can arise either because of destruction of adrenal gland itself (Addison’s disease or primary hypocortisolism) or due to malfunction of pituitary or hypothalamus (secondary hypocortisolism). Common causes of secondary adrenal insufficiency are tumors of the pituitary, head injury, radiotherapy and long standing steroid medication suppressing the axis.

The primary adrenal deficiency, also called Addison’s disease, is the result of infective or inflammatory or infiltrative processes involving the adrenal glands. The most common is the autoimmune destruction of the glands. This is followed by less commoner conditions like metastasis, amyloidosis, tuberculosis, opportunistic infection in AIDS/HIV, infarction, haemorrhage, adrenomyeloneuropathy, congenital adrenal hyperplasia etc.

What are the clinical features of Addison’s disease?

Symptoms are non-specific. Common presentations are loss of weight, loss of appetite, tiredness, hyper-pigmentation of the skin, dizziness and low BP, nausea, vomiting, decreased axillary and pubic hair and reduced libido in women. It could be associated with vitiligo i.e. patchy whitening of the skin. Blood test may show low sodium, high potassium, elevated urea, low hemoglobin.

What other problems could be associated with this?

This disease could be a part a cluster of autoimmune diseases called autoimmune polyglandular syndrome where other than low cortisol there is low level of thyroid, parathyroid and sex hormones. Type 1 diabetes could also be a part of it.

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How do we confirm this?

There are several ways to confirm this problem. Low blood sodium, high blood potassium with elevated urea indirectly point to low cortisol. Finding low blood cortisol, which fails to increase after injection of synacthen is diagnostic of Addison’s disease. This test is called short synacthen test. Other tests that the doctor may want is adrenal CT scan

What is the treatment?

This problem of low cortisol is corrected by administration of the hormones in the tablet form. The most natural replacement is through tablet hydrocortisone, however prednisolone can be used for economic reason. The other hormone aldosterone is replaced by giving tablet fludrocortisone. The initiation of hydrocortisone requires monitoring. This monitoring can be done by observing for several parameters like weight, BP, blood sodium and potassium levels, blood cortisol levels in the form of cortisol day curve. One has to get admitted for a day for the last test. One more important thing to note is that this hydrocortisone tablet should be taken at particular time of the day i.e. on waking, at midday and at 5 pm. Compliance is very important here.

How to manage during an intercurrent illness?

The requirements of cortisol go up when a patient of cortisol deficiency undergoes a surgery or develops a severe illness like pneumonia. For moderate elective procedures or investigations e.g. Endoscopy or angiography, patients should receive a single dose of 100mg hydrocortisone before the procedure. For major surgery patient should take 20mg hydrocortisone orally or 100mg intrmuscular injection before surgery, and receive 100mg intrmuscular injection every sixth hourly for the first three days and then rapidly go back to pre surgery level. In case of pneumonia patients should receive 50-100mg intrmuscular injection every sixth hourly until completely cured.

Does management differ during pregnancy?

No. One can continue the same dose during the pregnancy. If the hyper emesis gravidarum i.e. the condition of excess vomiting in the first three months, ensues then intramuscular injection may be required. During labor 100mg of hydrocortisone is given by intramuscular injection every sixth hourly.

What are the implications of long-term steroid administration?

The steroid medications like prednisolone, betamethasone or dexamethasone are given for various medical conditions like asthma, rheumatoid arthritis and many connective tissue disorders like SLE for longer periods to achieve remission. If any of these are given for more than 3 weeks or if prednisolone or its equivalent is given at 40mg/day or more for less than 3 weeks or a short term therapy (< 3weeks) is given within one year of cessation of long term therapy (>3 weeks) or is given as a evening dose then the body fails produce its own cortisone when external therapy is withdrawn. Therefore in such situations the steroids should be withdrawn slowly. After the remission has been achieved these drugs are reduced to a dose of 7.5mg of prednisolone or equivalent per day and then further reduction is carried out more gradually over months. Ideal would be to start on hydrocortisone tablet and to do a test called short synacthen test to know whether the body has regained its capacity to produce cortisol on its own before finally stopping the drug.