Cushing's Syndrome and Disease
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Introduction
Cushing's syndrome refers to any situation of excess cortisol. Cushing's disease refers specifically to a pituitary tumour secreting ACTH.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
ACTH independent causes include:
- exogenous glucocorticoids (the most common cause)
- adrenal neoplasm
- nodular adrenal hyperplasia
ACTH dependent causes include:
- pituitary adenoma (Cushing's disease, 2nd commonest)
- paraneoplastic ACTH production: (SCLC, carcinoids, pancreatic tumours, 3rd commonest)
Pathophysiology
Adrenal tumours can be treated with surgery.
Pituitary adenomas can be cured much of the time.
ectopic sources of ACTH can be surgically removed if possible.
Signs and Symptoms
Cushing's should be considered if people have:
appearance
- rounded face
- abnormal fat deposition in supraclavicular and doral fat pads (buffalo hump)
- weight gain
skin
- wide purple striae over 1 cm
- skin thinning
- easy bruising
- hirsuitism, acne
musculoskeletal
- proximal muscle weakness
- osteopenia or osteoporosis
- non-traumatic fractures in young people
cardiovascular
- hypertension in people under 40
- MI or stroke
metabolic
- glucose intolerance or diabetes
- hyperlipidemia
- kidney stones
gonadal dysfunction
- menstrual disorders
- impotence or decreased libido
other
- frequent infections and poor wound healing
mental health changes
- mood lability
- new onset of irritability, depression, or psychosis
- history
- physical exam
History
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Cortisol excess can be demonstrated by:
- 24 hour urine free cortisol (4x normal cortisol levels is diagnostic, though false +ves and -ves)
- low dose dex suppression test
- demonstrates resistance to suppression
- better sensitivity, but lower specificity
- diurnal cortisol rhythm
There are some things about false positive tests I don't know.
Diagnostic Imaging
Differential Diagnosis
pseudo-cushing's syndrome can result from mild physiologic hypercortisolism:
- stress
- acute or chronic illness
- high estrogen states
- uremia
- mental health disorders
- obesity
- alcoholism
Treatments
Consequences and Course
Resources and References
Topic Development
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