Section 4: Adrenal Disorders Flashcards
(21 cards)
Clinical presentation of Cushing syndrome
- Fat redistribution: Truncal obesity, “moon face,” buffalo hump, thin arms and legs
- Easy bruising and striae: Loss of collagen from the cortisol thins the skin
- Hypertension: From fluid and sodium retention (look for hypokalemia in hyperaldosteronism)
- Muscle wasting
- Hirsutism: From increased adrenal androgen levels
Anosmia with hypogonadism (low GnRH, FSH, and LH)
Kallman’s syndrome
Clinical features of Klinefelter’s syndrome
- Insensitivity of the FSH and LH receptors on their testicles XXY on karyotype
- The FSH and LH levels are very high, but no testosterone is produced from the testicles.
Features common to all forms of congenital adrenal hyperplasia (CAH)
- Elevated ACTH
- Low aldosterone and cortisol levels
- Treatable with prednisone, which inhibits the pituitary.
What forms of CAH has HTN
11 and 17 hydroxylase deficiencies
Virilization is seen in which of the CAH
21 and 11 hydroxylase deficiencies
Diagnosis: CAH with increased 17 hydroxyprogesterone level
21 hydroxylase deficiency
Cause of Hirsutism in 21 and 11 hydroxylase deficiencies
Increased andrenal androgens
List the steps in the diagnosis of hypercortisolism (Cushing syndrome)
- Establish the presence of hypercotisolism
- Establish the cause of hypercotisolism
Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 119). Kaplan Medical Test Prep. Kindle Edition.
What is the best initial test(s) to establish the presence of hypercortisolism?
- 24-hour urine cortisol
- 1 mg overnight dexamethasone suppression test
Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 119). Kaplan Medical Test Prep. Kindle Edition.
The 1 mg overnight dexamethasone suppression test should normally suppress the morning cortisol level. If this suppression occurs, what does this imply?
Hypercortisolism is excluded
Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 119). Kaplan Medical Test Prep. Kindle Edition.
List the causes of false positive 1 mg overnight suppression testing
- Depression
- Alcoholism
- Obesity
Hypercotisolism + Decreased ACTH level
What is the source of the hypercotisolism?
Adrenal source
- List the best initial test to determine the cause (source) or location of hypercotisolism
- What is the interpretation of the possible results of (1)?
- Adrenocorticorticotropic hormone (ACTH) testing
- Low ACTH means an adrenal source while a high ACTH means either a pituitary source or an ectopic source (e.g. lung cancer, carcinoid)
Hypercortisolism is established and there is elevated ACTH level, what is the next best test to do? Interpret the results of the test
The next best test to do is the dexamethasone suppression test
If the dexamethasone suppression test suppresses ACTH then the source is the pituitary
If the dexamethasone suppression test does not suppresses ACTH then the source is an ectopic one such as lung cancer or carcinoid
- Hypercortisolism is established and there is elevated ACTH level and dexamethasone suppression test suppresses ACTH, what is the next best test to do?
- What will be the next line of action based on the result of (1)?
- MRI of the brain
- If the MRI shows a pituitary lesion then treat. If the MRI does not show a clear
pituitary lesion, sample the inferior petrosal sinus for ACTH, possibly afterstimulating the patient with corticotrophin releasing hormone (CRH). An elevated ACTH from the venous drainage of the pituitary confirms the pituitary as the source. The petrosal venous sinus must be sampled because somepituitary lesions are too small to be detected on MRI.
- Hypercortisolism is established and there is elevated ACTH level, and dexamethasone suppression test does not suppress ACTH, what is the next best test to do?
Scan the chest for lung cancer or carcinoid
Cortisol is a stress hormone that is an antiinsulin. In addition, there is some aldosteronelike effect of cortisol that has an effect on the kidney’s distal tubule of excreting potassium and hydrogen ions.
List the metabolic effects of hypercortisolism
- Hyperglycemia
- Hyperlipidemia
- Hypokalemia
- Metabolic alkalosis
What is the effect of hypercortisolism on leukocytes?
Leukocytosis from demargination of white blood cells. At least half of
white cells in the blood are on the vessel wall waiting for an acute stress to
come into circulation. They are like parked police cars waiting to be called
Fischer, Conrad (2012-11-01). Master the Boards USMLE Step 2 CK (Page 120). Kaplan Medical Test Prep. Kindle Edition.
Step to take in the evaluation of adrenal “Incidentaloma” (an unexpected, asymptomatic adrenal lesion found on CT)?
- Metanephrines of blood or urine to exclude pheochromocytoma
- Renin and aldosterone levels to exclude hyperaldosteronism
- 1 mg overnight dexamethasone suppression test to exclude hypercortisolism
Fill in the blanks for the tests to be done for hypercorticolism
Results are shown below
