Cushings Syndrome

2017-07-25 Summary  By Debby

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say something about cortisol in healthy people

cortisol begins to rise between 3-4am and reach a peak between 7-9 am,then falls for the rest of the day to the lowest level at midnight.

furthermore ,cortisol can rise in response to stress:surgery,trauma, infection.

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the effecfs of cortisol:

1.helping maintain blood pressure and cardiovascular function;

2.reducing the immune systom's inflammation response;(infections)

3.balancing the effects of insulin;(glucose intoleration)

4.helping metabolism of proteins ,carbohydrates.and fats;(obesity)

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Defination:constellation of symptoms associated with cortisol excess.

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Causes:

Exogenous:caused by taking excessive amounts of medications:Dexamethasone,prednisone.

for examples：asthma;lupus; to suppress immune system after transplant to prevent rejection

Endogenous:

1.excessive cortisol produced by adrenal glands. it is rarer.

(more common in women than men;avarage age of onset is 40 years)

2.70% of chshing syndrome are caused by pituitary adenomas;

3.ACTH producing tumours:small cell lung cancer(13%），carcinoid tumours,medullary carcinomas of thyroid.

Distinguishs between adrenal glands and pituitary adenomas:

ACTH levels:

low:adrenal glands;

high:pituitary adenomas.

attention:

alcohol induced pseudo cushing's syndrome.

Patients with severe or rapid- onset cushing's syndrome often have ectopic ACTH secretion or cortisol-secreting adrenal tumours.

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Specific clinical manifestations:

1.spontaneous bruising

(common in thin skin,acne and skin infections,))

2.muscle and bone changes

(proximal myopathy,bone pain,thining of the bones ,which leads to rid and spine fractures)

3.abdominal striae

4.central obesity

5.buffalo hump

6.moon facies

(round, red , full faces)

Other clinical manifestations:

1.weight gain

2.glucose intolerance

3.hypokalemia

4.mental changes:depression,anxiety;

5,fatigue;

6.headache;

7.high blood pressure;

8.increased thirst and urination.

Men:

1.decreased fertility;

2.decreased or no desire for sex;

Women:

1.excess hairs grown on  the face,neck,chest,abdomen;

2.menstrual cycle becomes irregular or stops.

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First -line biochemical tests

1.urine free cortisol(UFC)

(levels higher than 50-100 micrograms a day for an adult suggests cushing's syndrome)

2.late night salivary cortisol

（cortisol production is normally suppressed in mod-night,but in cushing's syndrome,this suppression does not occur.）

3.1mg overnight Dexamethasone suppression test(DST)

4.longer low-dose Dexamethasone suppression test(LDDST)

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Complications:

1.diabetes;

2.kidney stones;

3.serious infections;

4.enlargement of any tumours;

5.fractures.