Cushing syndrome

Def-symptoms n sign associated wth corticosteroid excess,of long duration.

CAUSES-
1>ACTH dependent-cushing disease,ectopic ACTH syndrome,iatrogenic,ectopic corticotropin releasing hormone,macronodular hyperplasia.
2>ACTH Independent-iatragenic,adrenal adenoma,adrenal carcinoma,micronodular hyperplasia,macronodular hyperplasia.         Cushing syndrome of pituitary origin common in females.Ectopic ACTH syndrome common in males.
C/F
A>symptoms
1>wt gain-accumulation of fat n fluid retension 2>hirsutism-incresed adrenal androgen secretion 3>back pain-osteoporosis n vertebral compression fratures 4>muscle weaknes-proximal myopathy n hypokalemia 5>oligomenorrhoea,amenorrhoea,impotence-gonadal dysfunction 6>depression.B>

SIGN
1>central obsity-centripetal distribution of fat 2>buffalo hump-fat accumulation at the lower part of neck 3>plethoric appearance-thinning of skin 4>moon face -rounded plethoric appearance 5>brusing-thinning of bld vessles from collagen breakdown 6>purplish striae over abdo,buttocks n thigh-thinning of skin from collagen breakdown 7>HTN-increase in plasma volume n Na retention 8>proximal myopathy-loss of protein in muscle

INVESTIGATION-
A>test establishing presence of cushing syndrome-1>plasma cortisol level-Normal at 8am n lower at 12 midnight.In cushing this rhythm is lost n cortisol level same throughout day 2>overnight dexamethasone suppresion test-normal <1.8 ug/dl.In cushing cortisol r not suppresed 3>24-hr urinary cortisol excretion is raised hn cushing syndrome. 4>low dose dexamethasone suppresion test 5>late night salivary cortisol-recent introdused test 4 screening of cushing syndrome.B>test establishing cause of cushing syndrome- 1>plasma ACTH level at 8 am-a>very high level suggdst ectopic ACTH syndrome b>normal level suggest pituitary source.C>Intermediate value suggest either pituitary dependent disease or ectopic ACTH syndrome. D>low ACTH suggest adrenal tumour,macronodular adrenal hyperplasia or exogenous steroid administration. 2>high dose dexamethasone suppression test-2 mg dexamethasone administered 6 hrly for 2 day.24 hr urine is collected from 2nd day n plasma is collected for cortisol on 3rd day. If urinary free cortisol below 10 ug/day or plasma cortisol is below 1.8 ug/dl it indicate suppresion of axis n is positive.Test positive in pituitary dependent disease.Negative in ectopic acth syndrome.3>metyrapone test-a>markedly incresed - pituitary dependent disease.b>incresed-ectopic acth syndrome c>normal in adrenal tumours.4>plasma K level-a>normal in pituitary dependent disease adrenal.B>low in ectopic acth syndrome.Other invertigation-x ray skull,CT head,chest x ray
,MRI abdo n head.Mangement-1>adrenal tumour -a>metyrapone reduce cortisol overprodution b>adrenal adenoma removed surgically.Replacement therapy wth prednisolone postopratively. C>adrenal carcinma removed surgically. 2>cushing disease-a>metyrapone or ketoconazole given during preperation for surgery b>transphenoidal surgical removal of adenoma c>if tumour found,radical hypophysectomy. 3>ectopic acth syndrome-a>benign tumour removed. B>malignant tumour treated wth radiotherapy n chemotherapy. C>recurrence treated wth metyrapone.