Cushing's Syndrome Flashcards
What is Cushing’s syndrome.
The clinical state produced by chronic glucocorticoid excess and loss of the normal feedback mechanisms of the hypothalamo-pituitary-adrenal axis.
There is also loss of circadina rhythm of cortisol secretion.
What are the causes of Cushing’s syndrome. (3)
Exogenous cortisol.
ACTH dependent.
ACTH independent.
What are the exogenous causes of Cushing’s syndrome. (5)
Iatrogenic. Steroids. Pseudo Cushing's. Excess alcohol. Depression.
What are the ACTH dependent causes of Cushing’s syndrome. (5)
Pituitary overproduction of ACTH stimulating adrenal gland to produce cortisol. Cushing's disease. Ectopic ACTH secretion. Small-cell lung cancer. Carcinoid.
What are the ACTH independent causes of Cushing’s syndrome. (2)
Autonomous cortisol secretion.
Adrenal adenoma/carcinoma/hyperplasia.
What are the symptoms of Cushing’s syndrome. (11)
Increased weight gain. Poor wound healing. Recurrent infections. Mood changes (depression, irritability, psychosis, lethargy). Gonadal dysfunction (irregular menses, erectile dysfunction). Proximal weakness. Acne. Recurrent Achilles tendon rupture. Low libido. Hirsutism. Headache.
What are the physical signs of Cushing’s syndrome. (17)
Plethoric moon face. Proximal myopathy. Hirsutism. Thin skin. Easy bruising. Hypertension. Central obesity. Buffalo neck hump. Supraclavicular fat distribution.. Skin and muscle atrophy. Purple abdominal striae. Osteoporosis. Raised BP. Raised glucose. Infection prone. Poor healing. Signs of the cause (eg abdominal mass).
What tests can be done to confirm Cushing’s syndrome. (4)
24hour urine collection for free cortisol.
Random blood cortisol (loss of circadian rhythm).
Low dose dexamethasone suppression test to see if ACTH can indeed be suppressed.
High dose dexamethasone suppression test to differentiate between pituitary and ectopic ACTH secretion.
What are the treatment options for Cushing’s syndrome. (2)
Medical.
Surgery.
What are the medical treatment options for Cushing’s syndrome. (2)
Metyrapone.
Ketoconazole.
What is the treatment for Cushing’s disease.
Trans-sphenoidal surgery.
What is the surgical treatment for Cushing’s syndrome.
Adrenalectomy.
What are the complications post adrenalectomy. (2)
Nelson’s syndrome.
Adrenal insufficiency.
What is the prognosis for patients with Cushing’s syndrome.
Very poor if left untreated.
What are the complications post-transphenoidal surgery.
Hypopituitarism.
What is the most common cause of Cushing’s syndrome.
Oral steroids.
What percentage of Cushing’s cases are due to endogenous causes of cortisol secretion.
80%.
When is cortisol normally highest.
In the morning.
What is the commonest cause of endogenous cortisol secretion.
Pituitary adenoma (Cushing’s disease).
What are the ACTH dependent (raised ACTH) causes of Cushing’s. (3)
Cushing’s disease.
Ectopic ACTH production.
Rarely, ectopic CRF production.
What are the ACTH independent (low ACTH due to loss of negative feedback(causes of Cushing’s. (4)
Adrenal adenoma/cancer.
Adrenal nodular hyperplasia.
Iatrogenic.
Rarely, Carney complex, McCune Albright syndrome.
What is Cushing’s disease.
Bilateral adrenal hyperplasia from an ACTH secreting pituitary adenoma.
What sort of adenoma is usually the cuse of Cushing’s disease.
Microadenoma in the pituitary.
What is the male:female ratio for Cushing’s disease.
1:1.
What is the peak age for Cushing’s disease.
30-50.
What happens in a low dose dexamethasone test in a patient with Cushing’s disease.
No change in plasma cortisol.
What is the ‘normal’ response to a low dose dexamethasone test.
Plasma cortisol should go down.
What is the usual cause of ectopic ACTH production. (2)
Small cell lung tumours.
Carcinoid tumours.
What are some specific features of ectopic secretion of ACTH. (5)
Pigmentation. Hypokalaemic metabolic alkalosis. Weight loss. Hyperglycaemia. Classical features of Cushing's are often absent.
What occurs in a low dose dexamethasone suppression tests in a patient with an ectopic secretion of ACTH.
No change in plasma cortisol.
What are some cause of ectopic CRF production. (2)
Some thyroid (medullary) cancers. Prostate cancer.
What is the most common iatrogenic cause of cushing’s.
Pharmacological dose of steroids.
What occurs in a dexamethasone suppression test in a patient with adrenal adenoma.
No change in cortisol levels.
What occurs in a dexamethasone suppression test in a patient with adrenal nodular hyperplasia.
No change in cortisol levels.
