Adrenal Failure
Adrenal failure Called Addison's disease - is rare in childhood. It results from a deficiency in the function of the cells from the outer layers of the adrenal gland. This may be because of autoimmune attack, as a result of congenital adrenal hyperplasia (described below) or a consequence of long-term therapy with steroids used in the treatment of diseases such as asthma. In the infant it can cause circulatory collapse because the lack of aldosterone means that there is not sufficient salt to support the blood pressure. In the older child, besides low blood pressure resulting from lack of aldosterone, low levels of cortisol, responsible for the function of many cells, results in weakness, tiredness and low blood sugar levels. The symptoms may develop insidiously and, because they are none specific, may be difficult to diagnose. The function of the adrenal gland can be tested by stimulating it using an injection of adreno-cortico trophic hormone (ACTH) and then measuring the amount of cortisol produced: if it's lower than it should be then the hormones can be replaced with synthetic ones taken by mouth. It's important to remember that the normal adrenal produces more cortisol in times when the body is stressed, such as when we have a viral infection, so under these circumstances the amount of synthetic cortisol - hydrocortisone - taken should be increased.
Acute adrenal failureCalled Addisonian crisis, can occur in patients on long-term steroid therapy who stop their treatment abruptly, perhaps because they have forgotten to take their tablets. One effect of long-term steroid therapy is to turn off the production of ACTH by the pituitary; a consequence of this is that the adrenal gland shrinks, and when the supply of steroids stops it is unable to respond and produce enough cortisol to support body functions. The patient may collapse with low blood pressure, nausea and vomiting and very low blood sugar. This, as the name suggests, needs urgent medical attention. Is also the reason why patients who have been taking steroids for more than a week are often tailed off them slowly in order to give the adrenal gland time to recover.
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