Adrenal Disorders Flashcards
Adrenal insufficiency, of which there are two forms:
○ Primary adrenal insufficiency (Addison’s disease): Results from destruction or dysfunction of the adrenal cortex
○ Secondary adrenal insufficiency: Results from inadequate stimulation of adrenal cortex by ACTH
Glucocorticoid
General classification of adrenal cortical steroid hormones that are primarily active in protecting against stress & in affecting protein & carbohydrate metabolism
Mineralocorticoid
Steroid hormone regulating the retention & excretion of fluids & electrolytes
(especially Na & K) by the kidneys
Adrenal Medulla releases
Catecholamines
○ Epinephrine
○ Norepinephrine
BP =
CO x TPR
What is cardiac output (CO) determined by?
Stroke volume & heart rate
Epinephrine & Norepinephrine CV actions
● Strengthens heart contractility
○ β1 action (inotropic, increases muscle contraction)
● Increases heart rate of contraction
○ β1 action (chronotropic, affects the rhythm/rate)
● Constricts arterioles in the skin ( 𝛂 1 action)
● Dilates blood vessels to liver & skeletal muscle ( β2 action)
Epinephrine & Norepinephrine respiratory actions
Powerful bronchodilation by acting directly on bronchial smooth muscle (β2 action)
Epinephrine & Norepinephrine other actions
● Raises blood sugar
○ Increases release of glucagon
○ Increases glycogenolysis
○ Increases lipolysis
Secretion of aldosterone is mainly dictated by changes in _____
blood pressure
What lab results and symptoms would you see with a small tumor of the zona glomerulosa cells
● Primary aldosteronism = sodium conservation and potassium excretion
○ Hypernatremia ➔ increased volume ➔ Hypertension
○ Hypokalemia ➔ if severe enough can cause muscle paralysis
Cascade for the release of cortisol initiated at the hypothalamus in response to _____
infection, pain, hypoglycemia, trauma, hemorrhage, sleep
*all associated with stress except for sleep
Cortisol
● Stimulates glucose production by the liver (gluconeogenesis increases blood sugar)
(Anabolism)
● Promotes protein breakdown (Catabolism)
● Mobilization of fatty acids
● Immunologic & anti-inflammatory effects
Some MAJOR adverse effects of excess glucocorticoid (cortisol)
○ Elevated glucose levels (hyperglycemia)
○ Suppression of the immune system
○ Decreased bone density
○ Central nervous system & mental status effects (anxiety/depression, seizures…)
○ Elevation of blood pressure
○ Stimulates gastric acid & pepsin production
Androgens
● Zona Reticularis
● Dehydroepiandrosterone (DHEA),
Androstenedione
Results from destruction or dysfunction of the adrenal cortex
Primary adrenal insufficiency (Addison’s disease)
Results from inadequate stimulation of adrenal cortex by adrenocorticotropin hormone (ACTH)
Secondary adrenal insufficiency
Primary adrenal insufficiency (Addison’s disease) pathophysiology
○ Usually results from autoimmune destruction of the adrenal glands
○ BOTH glucocorticoid AND mineralocorticoid secretion diminished in this condition
○ If untreated may be fatal
○ Adrenal medulla function usually spared
Secondary adrenal insufficiency (uncommon) pathophysiology
○ Usually occurs after discontinuation of exogenous steroids after prolonged use
and prolonged suppression of the HPA (Hypothalamic-pituitary-adrenal) axis
○ Endogenous steroids (ie, tumor)
○ Hypothalamic-pituitary disease
Adrenal Insufficiency clinical presentation
● Hypotension
● Weight loss
● Increasing fatigue
● Vomiting
● Diarrhea
● Anorexia
● Muscle & joint pain
● Abdominal pain
● Postural dizziness
_____ are only seen with primary adrenal insufficiency (Addison’s Disease)
Hyperpigmentation & salt craving
Hyperpigmentation pathophysiology in Adrenal insufficiency
○ ↓ levels of cortisol means less inhibition of HPA axis
○ ↑ proopiomelanocortin (POMC) synthesis, a precursor for ACTH.
■ POMC molecule contains melanocyte-stimulating hormone (MSH) fragments
■ When POMC levels ↑, so are levels of MSH, → ↑ pigmentation of the skin
Salt craving pathophysiology in Adrenal insufficiency
○ Primary adrenal insufficiency (Addison’s disease) is a disease of the adrenal gland itself
○ Low secretion of aldosterone → hyponatremia & salt craving
Lab Considerations in Adrenal Insufficiency
● AM plasma cortisol level
○ Low plasma cortisol (<3-5 ug/dL) → strong evidence for diagnosis of adrenal
insufficiency
○ Higher levels of plasma cortisol (>20ug/dL) → strong evidence against diagnosis
of adrenal insufficiency
