Adrenal Insufficiency

List the 3 main groups into which adrenal insufficiency can be classified

1) Primary

2) Secondary

3) Tertiary

In primary adrenal insufficiency, cortisol deficiency derives from a defect in which organ?

Adrenal glands

In secondary central adrenal insufficiency, cortisol deficiency derives from a defect in which organ?

Pituitary gland

In tertiary central adrenal insufficiency, cortisol deficiency derives from a defect in which organ?

Hypothalamus

How is serum ACTH (corticotropin) secretion affected by exogenous glucocorticoids?

Suppressed

What is the normal range of early morning (8am) serum ACTH?

2-14 pmol/L

(10-65 pg/ml)

How is serum ACTH affected in primary adrenal insufficiency?

Elevated

(Loss of cortisol-mediated negative feedback)

How is serum ACTH affected in central adrenal insufficiency?

Reduced, in the lower half of the normal range or lower

(Deficient pituitary ACTH secretion)

How is serum aldosterone often affected in primary adrenal insufficiency?

Reduced (mineralocorticoid deficiency)

How is serum renin often affected in primary adrenal insufficiency?

Elevated

How does mineralocorticoid activity affect serum renin?

Suppresses renin production

How is serum aldosterone often affected in central adrenal insufficiency?

Normal levels

How is serum renin often affected in central adrenal insufficiency?

Normal levels

Which test confirms autoimmune adrenal insufficiency?

Positive antibodies to 21-hydroxylase

List 2 infective causes of adrenal insufficiency

1) Tuberculosis

2) HIV

List 5 malignancies which may metastasize to the adrenal glands

1) Breast cancer

2) Lung cancer

3) Colon cancer

4) Melanoma

5) Lymphoma

List 3 infiltrative causes of adrenal insufficiency

1) Haemochromatosis

2) Sarcoidosis

3) Primary amyloidosis

Which test is used to assess for adrenoleukodystrophy?

Very long chain fatty acids (VLCFAs)

What is the mode of inheritance of adrenoleukodystrophy?

X-linked

What is the commonest cause of central adrenal insufficiency?

Prolonged exogenous glucocorticoids

How does exogenous glucocorticoid exposure affect ACTH secretion?

Suppresses secretion from pituitary gland (secondary adrenal insufficiency)

How does exogenous glucocorticoid exposure affect CRH (corticotropin-releasing hormone) secretion?

Suppresses secretion from hypothalamus

(tertiary adrenal insufficiency)