Cushing's syndrome

Question 1

Pathomechanism of Cushing’s syndrome

Answer 1

■ Iatrogenic: from steroid use. Most common
■ Ectopic: cancers produce ACTH (e.g. small cell lung cancer)
■ Secondary: ACTH-secreting pituitary tumor, aka Cushing’s disease
■ Primary: Adrenal cortex adenoma making glucocorticoids

Question 2

Symptoms of Cushing’s syndrome

Answer 2

Hypertension, weight gain, moon facies, abdominal striae, truncal
obesity, buffalo hump, skin changes (thinning, striae), hirsutism, osteoporosis,
hyperglycemia, amenorrhea, immunosuppression, emotional disturbances

Question 3

Diagnosis of Cushing’s syndrome

Answer 3

■ First measure ACTH and see if it’s elevated. If ACTH is low, consider
exogenous glucocorticoids or adrenal tumor.
■ Small dose dexamethasone test: suppresses ACTH/cortisol if patient is just
overweight. Cushing’s will not be suppressed.
■ High dose dexamethasone test: Cushing’s disease will be suppressed,
ectopic production will not be.
■ CRH stimulation test: sample from inferior petrosal sinus.
■ MRI, CT

Question 4

Treatment of Cushing’s syndrome

Answer 4

Surgery: If Cushing’s syndrome is caused by a tumor, such as an adrenal tumor or a pituitary adenoma (Cushing’s disease), surgical removal of the tumor is often the preferred treatment. The goal is to remove the source of excess cortisol production.

Medications: In cases where surgery is not an option or as a temporary measure until surgery can be performed, medication may be used to manage Cushing’s syndrome. The most commonly used medications include:

Adrenal steroidogenesis inhibitors: These medications, such as ketoconazole or metyrapone, work by inhibiting cortisol production in the adrenal glands.
Pituitary-directed medications: In the case of Cushing’s disease caused by a pituitary adenoma, medications like cabergoline or pasireotide may be used to reduce cortisol production.

Radiation therapy: If surgery is not fully successful or if a tumor cannot be surgically removed, radiation therapy may be used to target and shrink the tumor, particularly in cases of Cushing’s disease.

Bilateral adrenalectomy: In rare cases where all other treatment options have failed or are not feasible, surgical removal of both adrenal glands may be considered. This procedure eliminates the source of excess cortisol production but necessitates lifelong hormone replacement therapy to compensate for the loss of adrenal function.

Management of underlying conditions: Sometimes, Cushing’s syndrome may be caused by other underlying conditions, such as ectopic ACTH-secreting tumors or certain forms of adrenal hyperplasia. Treating these conditions is crucial to resolve the excess cortisol production.

Question 5

What is the difference between Cushing’s syndrome and Cushing’s Disease?

Answer 5

Cushing’s syndrome and Cushing’s disease are related conditions, but they differ in their underlying causes :
Cushing’s syndrome is a broader term that encompasses all causes of excessive cortisol production, including adrenal tumors, ectopic ACTH production, and pituitary adenomas.
Cushing’s disease, on the other hand, is a specific form of Cushing’s syndrome caused by a pituitary adenoma.