Cushing’s syndrome

Syndrome de Cushing

ACTH-independent hypercortisolism: Cushing’s disease; Ectopic ACTH, ectopic CRH secretion (especially bronchial carcinoma).

ACTH-dependent hypercortisolism: cortisolic adenoma; primary carcinoma; primitive hyperplasia and dysplasia.

A – SIGNS:

* Deformities: moderate weight gain that resists calorie restriction, facial-nerve block.

Muscular predominates at the belts and lap belt. The skin and subcutaneous atrophy is responsible for the slow healing.

Easy bruising.

Skin laid lines are characteristic (wide, purple).

The facial skin is érythrosique.

* Hyperandrogenism Symptoms usually limited to hirsutism, acne and seborrhea.

* Other symptoms: osteopenia and osteoporosis; gonadal disorders (spaniomenorrhea, helplessness …) HTA;psychiatric disorders (irritability, insomnia, depressive tendencies).

Cushing's syndrome
Cushing’s syndrome

B – NON-SPECIFIC BIOLOGICAL ANOMALIES:

– Intolerance to carbon hydrates and diabetes mellitus (secondary to insulin resistance)

– Moderate increase of triglycerides and cholesterol levels.

– Hyperleukocytosis PNN with relative lymphopenia (rarer).

– Hypokalemic alkalosis: at intense Cushing’s syndrome …

– Other: polycythemia moderate, moderate hypokalemia, hypercalciuria normocalcemic.

C – BIOLOGICAL DIAGNOSIS HYPERCORTICOLISM:

– The concentration of morning cortisol is very discriminating; it is necessary to dose the Vespers cortisol (salivary cortisol =).

– The measurement of urinary free cortisol (UFC) 24 hours is the examination of choice.

CLU> 4x normal => affirms the diagnosis. It starts with him
– Breaking the circadian rhythm of cortisol secretion.

– Physiological braking Loss by exogenous glucocorticoids (dexamethasone):

– A brake test “minute”: lack of freination still possible in situations of obesity, alcoholism and depression, and therefore can not confirm the diagnosis.

This is actually tested.

– A brake test “low” (or standard) allows the diagnosis of Cushing’s syndrome (confirmatory test).

It’s normal in-alcoho lic, obese and depressed (pseudo-hypercortisolism).

– Braking “strong”: full braking when dealing with Cushing’s disease; no braking in hypercorticism paraneoplastic.

Note: false positives may occur while taking enzyme inducers (rifampicin, phenobarbital, hydantoin …).

– Braking with Soludécadron: lack of even partial freination is in favor of a paraneoplastic origin.

D – DIFFERENTIAL DIAGNOSIS:

* Obesity: not generally leads to increased urinary free cortisol.

* Iatrogenic Cushing’s syndrome by taking (occult) corticosteroids: the adrenocorticotropic function is inhibited (plasma cortisol and

* Functional Hypercortisolismes: Severe depressions the HPA axis and causes a moderate rise in urinary free cortisol and / or a brake test “minute” negative. Ethyl subjects.

No catabolic signs.

The midnight plasma cortisol is normal (discriminant).

E – DIAGNOSTIC ETIOLOGICAL:

Differentiate Cushing’s disease from ectopic ACTH secretion:

– Clinical approach: Cushing’s disease preferentially affects young women and middle-aged; symptomatology is moderate and gradually evolves over many years. Conversely neuroendocrine tumors extra-pituitary lead more readily a more marked symptoms (signs catabolic) and rapidly progressive. Melanoderma is sometimes noted.

– Paraclinical approach: A frank decrease in cortisol levels during heavy braking test (dexamethasone) is in favor of the disease.

One approach mirroring the sensitivity of the tumor to corticosteroids is performed by the test metopirone (which inhibits 11? Hydroxylase) => explosive increase upstream steroids (17 urinary hydroxysteroids).

A frank elevated corticotropin after stimulation with CRH or lysine vasopressin or desmopressin, is in favor of Cushing’s disease.