Adrenal glands Flashcards
What are the main functions of the adrenal glands?
The adrenal glands produce hormones that regulate various body functions. The adrenal cortex secretes:
Glucocorticoids (e.g., cortisol): Regulate metabolism and immune responses.
Mineralocorticoids (e.g., aldosterone): Regulate sodium and potassium levels, influencing blood pressure.
Adrenal androgens: Contribute to male sexual characteristics and pubic hair growth. The adrenal medulla produces epinephrine and norepinephrine, involved in the sympathetic nervous response.
How are cortisol levels regulated?
Cortisol is regulated by the HPA axis (hypothalamic-pituitary-adrenal axis). Corticotropin-releasing hormone (CRH) stimulates the release of ACTH from the pituitary, which in turn stimulates cortisol production in the adrenal glands. Negative feedback occurs when cortisol levels rise, inhibiting ACTH and CRH release.
What is Addison’s disease?
Addison’s disease, or primary adrenal insufficiency (Hypoproduction of adrenal hormones), is a condition in which the adrenal glands fail to produce sufficient amounts of cortisol, aldosterone, and adrenal androgens, often due to autoimmune destruction of the adrenal cortex. ACTH levels are elevated due to lack of feedback inhibition from cortisol.
What are the causes of Addison’s disease?
The most common cause is autoimmune destruction of the adrenal glands. Other causes include tuberculosis, metastatic carcinoma, fungal infections, and amyloidosis.
What are the clinical manifestations of Addison’s disease?
-Hyperpigmentation (due to elevated ACTH levels)
-Hypoglycemia (impaired stress response and glucose regulation)
-Hypotension (due to aldosterone deficiency)
-Weight loss and fatigue
-Muscle weakness
-Adrenal atrophy
-Urinary sodium loss
-Sparse axillary and pubic hair (due to -low adrenal androgens, especially in women)
What is the treatment for addisons disease?
It is a chronic metabolic disorder that requires lifetime hormone replacement therapy. The pharmacologic agent that is used should have both glucocorticoid and mineralocorticoid activities
What is Cushing’s syndrome?
Cushing’s syndrome refers to hypercortisolism, a condition in which excess cortisol is produced by the adrenal glands. (hyperproduction of adrenal hormones)
What causes Cushings syndrome
Pituitary adenoma (excessive ACTH production)
Adrenal tumors (benign or malignant)
Ectopic ACTH secretion (e.g., lung cancer)
Exogenous use of glucocorticoids
What are the clinical manifestations of Cushing’s syndrome?
-Weight gain, particularly central obesity and “moon facies”
-Emotional disturbance
-Hypertension
-Thin, wrinkled skin and poor wound healing
-Osteoporosis
-Abdominal striae
-Muscle weakness
What is congenital adrenal hyperplasia (CAH)?
CAH, also known as adrenogenital syndrome, is an autosomal recessive genetic disorder affecting the adrenal glands, particularly 21-hydroxylase deficiency. It leads to impaired cortisol and aldosterone production, resulting in elevated ACTH levels and excessive production of adrenal androgens.
What are the clinical manifestations of CAH?
In boys: Enlarged genitalia, salt loss, adrenal crisis.
In girls: Virilization, including enlarged clitoris, fused labia, and urogenital sinus (a common feature where the vagina and urethra share an opening).
What role do adrenal androgens play in the body?
Adrenal androgens, such as dehydroepiandrosterone (DHEA), are involved in the development of male secondary sexual characteristics and pubic hair growth during puberty. They are primarily synthesized in the zona reticularis and zona fasciculata of the adrenal cortex.
How is adrenal function tested?
- Blood tests to measure cortisol and ACTH levels, especially in the morning when cortisol is typically highest.
- 24-hour urine test to measure cortisol secretion.
- Salivary cortisol test as an alternative to blood tests.
- Dexamethasone suppression test to assess cortisol production.
- ACTH stimulation test to evaluate adrenal gland responsiveness.
- Adrenal imaging (CT/MRI) to detect tumors or glandular atrophy.
