Cushing's Syndrome

Question 1

Define Cushing’s syndrome

Answer 1

It is the result of chronic exposure to excess glucocorticoids (eg Cortisol), which is commonly iatrogenic

it is a problem of the adrenal cortex in a way

Question 2

Cushing’s syndrome vs disease

Answer 2

Cushing’s disease is when there is hypersecretion of ACTH by the pituitary (pituitary adenoma secreting)

Question 3

Causes of cushing’s syndrome

Answer 3

Exogenous - iatrogenic glucocorticoids (cortisol)

Endogenous - rare
ACTH dependent (increased ACTH)
80% - Cushing’s disease
Ectopic ACTH production - small cell lung cancer

20% non-ACTH: (reduced ACTH)
Cancer - adrenal adenoma
Adrenal nodular hyperplasia
Rare causes
Steroid use

Question 4

When is cortisol secretion highest

Answer 4

On waking

Question 5

Symptoms of Cushing’s syndrome

Answer 5

increased weight

Mood change - lethargy, depression, irritabilty, phsycho

proximal weakness

Gonadal dysfunction - irregular period (amenorrhoea), hirsutism

Acne

Recurrent Achilles tendon rupture

Occasionaly virilization female

Question 6

What is virilization

Answer 6

the development of male physical characteristics (such as muscle bulk, body hair, and deep voice) in a female or precociously in a boy, typically as a result of excess androgen (testosterone) production.

Question 7

What is hirsutism

Answer 7

Growth of excess hair, especially in F

Question 8

Investigations for Cushing’s syndrome

Answer 8

Does the patient have cushing’s syndrome?

increased 24-hr urinary cortisol and serum cortisol that fails to suppress with low-does and high dose dexamethasone test

Loss of diurnal variation with elevated night salivary or serum cortisol is also Cushing’s syndrome

What is the cause of the Cushing’s syndrome?

Plasma ACTH is one point one in 2 occasions –> adrenal tumor

Plasma ACTH > 3.3 pmol/L –> pituitary or ectopic source

Bloods

CXR - lung cancer

DEXA bone

Question 9

What should you do in a history of suspected Cushing’s syndrome

Answer 9

A careful drug history is vital to exclude iatrogenic causes; even inhaled or topical glucocorticoids can induce Cushing’s syndrome

Question 10

Management of Cushing’s syndrome

Answer 10

Treat cause

Iatrogenic - stop medication if possible

Cushing’s disease:

selective removal of pituitary adenoma

Bilateral adrenalectomy

Adrenal adenoma or carcinoma;

adrenalectomy “cures adenoma” but not cancer

Ectopic ACTH - surgery if tumor located and not metastasized

Question 11

Prognosis of Cushing’s syndrome

Answer 11

if treated it is relatively good, but some symptoms may still persisit

if not treated causes high vascular mortality

Question 12

Where is adrenaline (epinephrine) secreted from

Answer 12

adrenal medulla

and secretes catecholamines

Question 13

What does the adrenal cortex secrete

Answer 13

glucocorticoids (Cortisol) - affects carb, lipid, and protein metabolism

Mineralcorticoids (aldosterone) - control Na and K balance

Adrenal androgens - sex hormones

Question 14

The hypothalmic-pituatiry-adrenal axis (simplified)

Answer 14

Corticotropin-releasing factor (CRF) from hypothalamus stimulates pituitary to release ACTH then ACTH stimulated adrenals to release there stuff. Cortisol gives negative feedback to pituitary to control secretion

Question 15

Signs of Cushing’s syndrome

Answer 15

Central obesity

Moon face

Hirsuitism in F

Bruises

Purple abdominal striae

Osteoporosis

HTN

increased glucose

poor healing

prone to infections

Question 16

What would U&E show in patient with Cushing’s syndrome

Answer 16

Hypokalaemia

Hypernatraemia