Endocrine #5 (Adrenal Disorders) Flashcards
In Addison’s Disease (Primary Chronic Adrenocortical Insufficiency), the adrenal gland is not making enough _______.
Causes of Addison’s Disease
Cortisol
Adrenal Gland Destruction (lack of cortisol AND aldosterone)
-Autoimmune (MC) in US
-Infection MC in developing countries
-Others: TB, Trauma, Ketoconazole, Rifampin, HIV
Symptoms of Addison’s Disease
-Symptoms due to lack of cortisol
–Sparse axillary and pubic hair
–Fatigue, weakening
–Hypotension (orthostatic)
–Hyperpigmentation (in waist line, fat creases, ORAL 1st)
–Salt craving
–Loss of libido, amenorrhea, n/v, weight loss
Explain the hypothalamus-pituitary-adrenal axis and how this affects cortisol
-Hypothalamus secretes CRH to stimulate pituitary gland to secrete ACTH to stimulate adrenals to secrete cortisol
Therefore, what do labs show in PRIMARY adrenocortical insufficiency?
-Elevated ACTH
–8AM ACTH, cortisol, and renin levels
–Increased renin levels in primary
However, in SECONDARY adrenocortical insufficiency, what labs are expected?
-Decreased ACTH
What other labs are obtained in primary (Addison’s) adrenocortical insufficiency?
-Hypoglycemia
-Hyperkalemia
-Hyponatremia
-Metabolic Acidosis
What is the effect of cortisol on blood sugar?
Cortisol raises blood sugar by releasing stored glucose.
Therefore, if cortisol is LOW, blood sugar will be low. Hypoglycemia is expected in Addison’s Disease.
What labs are diagnostic for chronic adrenocortical insufficiency?
Low plasma cortisol, elevated ACTH
What screening test can be done for primary adrenocortical insufficiency (Addison’s)?
High-dose ACTH Cosyntropin stimulation test
–Insufficiency (<18) or absent rise in serum cortisol after ACTH administration IV or IM
-Normal response is rise in serum cortisol
-Check after 60-90 minutes to determine if there is a rise or not
Treatment for Addison’s Disease (Primary Adrenocortical Insufficiency)
-Glucocorticoid Replacement: Oral hydrocortisone
-Mineralocorticoid Replacement as well: Fludricortisone if positive for Addison’s
Because cortisol is a stress hormone, people with chronic adrenal insufficiency must be treated with ______ and ________ before and after surgical procedures (mimicking the body’s natural response)
-IV Glucocorticoids and IV isotonic fluids
What is Adrenal (Addisonian) Crisis?
-Acute adrenocortical insufficiency: sudden worsening of symptoms precipitated by stressful event (illness, surgery, trauma, MI, fever) or abrupt withdrawal of glucocorticoids (MC)
Normal response to stress is a 3-fold increase in cortisol, but these patients cannot meet the demand.
Symptoms of Addisonian Crisis
-All the same symptoms of Addison’s Disease (salt craving, hyperpigmentation, muscle pain) + high fever, hypotension, hypovolemia (SHOCK)!!!!
Although the labs are the same as in Addison’s Disease, what are they?
-Hyponatremia, hyperkalemia, hypoglycemia
–Cortisol and aldosterone confirms diagnosis
Treatment for an Addisonian Crisis
-Isotonic fluids (normal saline or D5N5) + IV hydrocortisone or Dexamethasone
-Reversal of electrolyte disorders
-Fludricortisone
Back to chronic adrenocortical insufficiency, explain a secondary cause pathology and what is low in this condition?
Pituitary failure of ACTH secretion (lack of cortisol only). Aldosterone intact due to renin angiotensin aldosterone system (RAAS)
Primary Adrenocortical Insufficiency:
Secondary:
Lack of cortisol AND Aldosterone
Lack of cortisol only
What is Cushing’s Syndrome?
Syndrome: symptoms and signs related to cortisol excess.
There are exogenous causes of Cushing’s Syndrome and endogenous causes. Explain both.
Exogenous: long-term high dose glucocorticoid therapy
Endogenous:
-Cushing’s Disease (pituitary gland ACTH overproduction (pituitary adenoma) MCC)
-Ectopic ACTH-producing tumor (small cell lung cancer, etc.),
-Adrenal tumor (Adenoma) that secretes excess cortisol
Symptoms of Cushing’s Syndrome
-Proximal muscle weakness
-Weight gain
-Fat Redistribution: Central obesity, moon facies, Buffalo hump, supraclavicular fat pads, thin extremities
-Skin Changes: Striae, acanthosis nigricans, easy bruising, poor wound healing
-Androgen Excess: hirsutism, acne, oily skin
-Hypertension
What happens when the body recognizes there is low cortisol or experiencing stress?
(H-P-A axis)
Hypothalamus releases CRH that stimulates the pituitary to release ACTH to stimulate adrenal gland to secrete cortisol
What vision changes are expected with Cushing’s Syndrome?
Bitemporal vision changes
What are three screening tests for Cushing’s Syndrome?
-24 hour urinary free cortisol (most specific)
-Nighttime salivary cortisol
-Low dose (1mg) overnight Dexamethasone suppression test
What is expected on the Dexamethasone suppression test if the patient has Cushing’s?
-Elevated cortisol or no suppression with low dose Dexamethasone
How do you differentiate Cushing’s Disease from other causes of Cushing’s Syndrome?
Baseline ACTH + High Dose Dexamethasone suppression test
–Increased ACTH + suppression of cortisol on high dose.
What is expected on high dose dexamethasone suppression test if the Cushing’s Syndrome is due to ectopic ACTH producing tumor or adrenal tumor or steroid use?
Ectopic ACTH tumor: increased ACTH + no suppression
Adrenal tumor and steroids: decreased ACTH + no suppression
What other labs are expected in Cushing’s?
-Hyperglycemia (high cortisol –> pulls glucose out)
-Leukocytosis
-Hypokalemia
-Metabolic alkalosis
Treatment for Cushing’s Syndrome
-If due to corticosteroid steroid: gradual taper to prevent Addisonian crisis
-if Cushing Disease: Transsphenoidal resection
-Adrenal Tumor: tumor excision
-Ectopic tumor: resection
What is a pheochromocytoma?
What is it associated with?
Catecholamine secreting adrenal tumor (chromaffin cells)
MEN Syndrome II
A pheochromocytoma secretes _____, _______, and _______ autonomously and intermittently from triggers including surgery, exercise, pregnancy, meds (TCA, opiates, histamine, glucagon)
Serotonin
Norepi
Epi
Symptoms of a pheochromocytoma (PHE)
-HYPERTENSION**
-Palpitations
-Headache
-Excessive Sweating
What diagnostic can be done to diagnose a pheochromocytoma?
-Plasma fractionated metanephrines confirmed by 24 hour urinary fractionated catecholamines including metabolites (increased metanephrines and vanillylmandelic acid)
Treatment for a pheochromocytoma
-Nonselective alpha blockade: Phenoxybenzamine or Phentolamine for 1-2 weeks, then Beta Blockers or CCB to control BP prior to surgery
-Complete adrenalectomy after 1-2 weeks of medical therapy
Primary hyperaldosteronism occurs renin-independently. What are some causes of this?
-Idiopathic or bilateral adrenal hyperplasia (MC)
-Conn Syndrome: adrenal aldosteronoma
On the other hand, what is secondary hyperaldosteronism?
-Due to increased renin (from the kidneys), via the RAAS.
–Renal artery stenosis MCC of secondary
Symptoms of hyperaldosteronism
-Usually asymptomatic
-Triad of hypertension + hypokalemia + metabolic alkalosis
–Hypokalemia: proximal muscle weakness, polyuria, decreased DTR’s
–Hypertension: headache, flushing
True or False: Primary hyperaldosteronism is a cause of secondary hypertension?
True!
Suspect in patients who develop hypertension at extremes of age (<30 or >60), not controlled on 3 blood pressure medications, or with classic triad
What is a screening test that can be done for hyperaldosteronism?
-Plasma renin and aldosterone levels: aldosterone to renin ratio: ARR > 20:1.
–High aldosterone and low renin levels = primary
–High plasma renin levels = secondary
Confirmatory tests for hyperaldosteronism include…
Oral sodium loading test: high urine aldosterone = primary
Saline infusion test: no suppression of aldosterone levels = primary
CT or MRI to look for adrenal mass or extra-adrenal mass
Treatment for bilateral hyperplasia of adrenals (primary cause)
-Spironolactone or Eplerenone (they block aldosterone), ACE inhibitors, CCB
Treatment for Conn Syndrome
-Surgical Excision + Spironolactone (blocks aldosterone)
