A patient with Cushingoid features presents with hemoptysis; he shows no response to dexamethasone suppression test; most likely diagnosis here is:
|C||Ca lung with ectopic ACTH production.|
Ca lung with ectopic ACTH production
The adrenal cortex produces steroids:
1). Glucocorticoids (eg cortisol)
1). This is chronic glucocorticoid excess.
2). The commonest cause is exogenous steroid treatment.
3). Endogenous causes are much rarer
4). 85% are due to ↑ACTH, of these a pituitary adenoma (Cushing's disease) is the commonest cause.
Causes of Cushing Syndrome
1). ACTH-dependent causes: (↑ ACTH)
a. Cushing's disease Bilateral adrenal hyperplasia due to an ACTH secreting pituitary adenoma
b. Ectopic ACTH production Especially small cell lung cancer and carcinoid tumours MCQ) , Pancrease Ca, bronchial adenoma.
2). ACTH-independent causes: (↓ACTH due to -ve feedback).
a. Iatrogenic Pharmacological doses of steroids (most common cause of Cushing).
b. Adrenal adenoma or carcinoma may be associated with abdominal pain and virilization in women
c. Adrenal nodular hyperplasia
Summary of Causes (Ref. Hari - 18th ed., Pg- 2945)
Cause S. ACTH Diagnosis Rx
Iatrogenic Reduce History Reduce dose
Pituitary adenoma Raise CT (Head) Surgery
Ectopic ACTH secreting tumorRaise CT (Chest) Surgery
Adrenal adenoma / Cancer Reduce CT abdomen Surgery
1). Adrenal adenoma has size less than 6cm and adrenal carcinoma has size more than 6 cm.
2). Loss of diurnal variation of steroid hormones in the body is the first feature of Cushing syndrome.