Cushing's Syndrome - Hypercortisolism - Diagnosis and Clinical Features
1) Skin
• Thin, easily bruisable skin with stretch marks (classically purple abdominal striae) and/or ecchymoses
• Delayed wound healing
• Flushing of the face
• Hirsutism
• Acne
• If secondary hypercortisolism: often hyperpigmentation (darkening of the skin due to an overproduction of melanin), especially in areas that are not normally exposed tothe sun (e.g., palm creases, oral cavity) Caused by excessive ACTH production because melanocyte stimulating hormone is cleaved from the same precursor as ACTH. Hyperpigmentation is not a feature of primary hypercortisolism.
2) Neuropsychological: lethargy, depression, sleep disturbance, psychosis
3) Musculoskeletal
• Osteopenia, osteoporosis, pathological fractures, avascular necrosis of the femoral head
• Muscle atrophy/weakness
4) Endocrine and metabolic
• Insulin resistance —+ hyperglycemia —+ mild polyuria in the case of severe hyperglycemia
• Dyslipidemia
• Weight gain characterized by central obesity, moon facies, and a buffalo hump
• Male: decreased libido
• Female: decreased libido, virilization, and/or irregular menstrual cycles
5) Secondary hypertension (90% of cases)
6) Increased susceptibility to infections
7) Peptic Ulcer disease
8) Cataracts
Labs:
Hypokalemia (rarely in Cushing's disease; ectopic ACTH production: 1. higher circulating cortisol 2. activity of 11ß-hydroxysteroid dehydrogenase type 2 (prevents mineralocorticoid activity of cortisol) is decreased), hypernatremia, metabolic alkalosis (Due to the mineralocorticoid effect Of cortisol), Hyperglycemia: due to stimulation of gluconeogenesis enzymes (e.g., glucose-6-phosphatase) and inhibition of glucose uptake in peripheral tissue, Hyperlipidemia (hypercholesterolemia and hypertriglyceridemia) and Leukocytosis (predominantly neutrophilic) → demargination of neutrophils from the endothelial lining of vessels, eosinopenia, thrombocytosis.
Screening:
↑ 24-hour urine cortisol
↑ early morning serum cortisol levels following a low-dose dexamethasone suppression test
↑ midnight salivary cortisol
↑ midnight serum cortisol
Imaging:
1) Primary hypercortisolism—+ CT and/or M RI of the abdomen for adrenal tumors
• The adrenal cortex contralateral to the tumor shows atrophy due to reduced ACTH stimulation
2) Cushing's disease —+ CT and/or MRI of the skull
• In Cushing's disease, CT and/or MRI of the abdomen shows bilateral hyperplasia of both the zona fasciculata and zona reticularis
• If no findings are present on neuroimaging, perform bilateral sampling of the inferior petrosal sinus in order to measure ACTH levels
3) Ectopic ACTH production is suspected: chest x-ray and/or CT, abdominal CT, pelvis CT
- Dr. Jorge Cortés @Jcortesizaguirr
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