Cushing Syndrome

Anatomy of ADRENAL GLAND

-          Cortex

Hormone	Layers	Functions
Glucocorticoid  E.g. cortisol	zona glomerulosa	Affect carbohydrate, lipid and protein metabolism
Mineralocorticoid	zona fasciclata	Sodium & potassium balance
Androgen	Zona reticularis	Weak effect until peripheral conversion to testosterone & dihydrotestosterone

-          Medulla

o   Secretes adrenaline, noradrenaline, dopamine

o   Responds to symphatetisdc preganglionic neuron

CUSHING’SYNDROME

Def: glucocorticoid excess

Aetiology

      Exogenous (most common)

o   Steroid treatment

      Endogenous

o   ACTH dependant causes (↑ ACTH)

1.       Cushing’s disease          85%

Due to Pituitary microadenoma

à ↑ACTH à bilateral adrenal hyperplasia

·         F>M

·         30-50 yo

2.       Ectopic ACTH production

·         d/t        small cell lung ca

carcinoid syndrome

·         special features

                                                                                                               i.      weight loss

                                                                                                             ii.      pigmentation (d/t ↑ACTH)

                                                                                                            iii.      hyperglycaemia

                                                                                                           iv.      hypokalaemic metabolic alkalosis

(↑ cortisol à mineralocorticoid activity)

3.       Ectopic CRF production ( rare)

·         d/t        medullary thyroid ca

Prostate ca

4.       Iatrogenic : ACTH administration

o   ACTH independant causes (↓ ACTH d/t –ve FB)

1.       Iatrogenic

·         Steroid (common)

2.       Adrenal adenoma / carcinoma

·         a/w abdominal pain, virilisation

3.       Adrenal nodular hyperplasia

4.       Rare      Carney complex

Mc Cune Albright syndrome

Clinical features

C             central obesity, + proximal weakness

U            unusual bruising

S             striae

H             hypertension, hyperglycaemia, buffalo hump

I              impotence (M), irregular menses (F), infection

N

G            growth retardation

+            

2M         moon face

                Mood changes

                             i.      Depression

                           ii.      Lethargy

                          iii.      Irratibility

Investigations

Treatments

Depends on cause

1.       Iatrogenic

§  Stop medication

2.       Cushing’s disease

§  Selective removal of pituitary adenoma via transphenoidal approach

§  Bilateral adrenalectomy if

                                                               i.      Source cant be located

                                                             ii.      Recurrent

§  Radiotherapy of pituitary

3.       Adrenal adenoma/carcinoma

§  Adrenalectomy

§  If cancer             -radiotherapy

-adrenolytic drug e.g. mitotane

4.       Ectopic ACTH

§  Tumor resection

Prognosis

1.       Treated

§  Good prognosis

§  Resolution of physical and psychological feature

2.       Untreated

§  ↑ mortality rate

d/t cardiovascular complication