Pathophysiology · Endocrine and Metabolic Disorders
Adrenal Disorders and Stress Hormones
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In 30 seconds
The adrenal glands sit atop the kidneys and make two families of stress-related hormones. The outer cortex makes Cortisol Glucocorticoid that raises glucose, supports blood pressure, and suppresses inflammation Full entry → (a glucocorticoid that raises blood glucose, suppresses inflammation, and supports the stress response) and Aldosterone Mineralocorticoid that retains sodium/water and excretes potassium Full entry → (a mineralocorticoid that retains sodium and water and excretes potassium). The inner medulla makes the Catecholamines Epinephrine and norepinephrine epinephrine and norepinephrine, which drive the rapid fight-or-flight response. Too much cortisol (Cushing syndrome Chronic cortisol excess Full entry →), too little cortisol (Adrenal insufficiency Deficient cortisol (with or without aldosterone) Full entry →), excess aldosterone (Hyperaldosteronism Excess aldosterone Full entry →), or a catecholamine-secreting tumor (Pheochromocytoma Catecholamine-secreting tumor of the medulla Full entry →) each produces a distinct pattern of glucose, fluid, electrolyte, and blood-pressure changes.
Why this matters
Adrenal disorders can present subtly (fatigue, weight change, blood-pressure or glucose shifts) and can decompensate suddenly, as in adrenal crisis. Monitoring blood pressure, glucose, and potassium, recognizing skin changes or fat redistribution, and understanding that abrupt steroid withdrawal can precipitate adrenal insufficiency all support safe care and timely reporting. Patient education addresses medication adherence and the importance of not stopping steroid therapy abruptly. Lab ranges, diagnostic criteria, guidelines, and scope-of-practice vary by institution and jurisdiction and must be followed; pathophysiology supports assessment and reasoning but does not replace clinical training, supervision, or provider evaluation.
The college version
1. Normal function first
Each adrenal gland has two regions. The outer cortex makes steroid hormones: mineralocorticoids (mainly aldosterone), glucocorticoids (mainly cortisol), and small amounts of androgens. The inner medulla, a modified sympathetic ganglion, secretes the catecholamines epinephrine and norepinephrine directly into the blood.
Cortisol is regulated by the hypothalamic–pituitary–adrenal (HPA) axis: the hypothalamus releases corticotropin-releasing hormone (CRH), which prompts the pituitary to release adrenocorticotropic hormone (ACTH), which drives the cortex to secrete cortisol; cortisol then feeds back to suppress CRH and ACTH. Cortisol raises blood glucose, supports blood pressure, suppresses inflammation and immunity, and helps the body adapt to physical and emotional stress, following a daily rhythm that peaks in the early morning.
Aldosterone is controlled mainly by the renin–angiotensin–aldosterone system and by blood potassium, not by ACTH. It acts on the kidney to retain sodium and water and excrete potassium, maintaining blood volume and pressure. The catecholamines are released on sympathetic stimulation, raising heart rate and blood pressure, dilating airways, mobilizing glucose, and redirecting blood flow to muscles—the rapid fight-or-flight response.
2. What changes in disease
Cushing syndrome is chronic exposure to excess cortisol, most often from prolonged glucocorticoid medication, or from excess ACTH (a pituitary adenoma, called Cushing disease) or an adrenal tumor. Excess cortisol redistributes fat (moon face, truncal obesity, a fatty pad between the shoulders), thins skin, causes muscle weakness, raises blood glucose and pressure, and suppresses immunity.
Adrenal insufficiency is too little cortisol and, in primary forms, too little aldosterone. Primary adrenal insufficiency (Addison disease) is autoimmune or other destruction of the cortex, so both cortisol and aldosterone fall and ACTH rises. Secondary insufficiency results from inadequate ACTH (pituitary disease or abrupt withdrawal of long-term glucocorticoid therapy), so aldosterone, being ACTH-independent, is relatively preserved. Manifestations include fatigue, weight loss, low blood pressure, low blood glucose, and salt craving; primary disease adds skin darkening from excess ACTH and high potassium from aldosterone loss.
Hyperaldosteronism is excess aldosterone, most often from a benign adrenal adenoma, causing sodium and water retention with potassium loss—high blood pressure and low potassium. Pheochromocytoma is a rare catecholamine-secreting tumor of the medulla (or related tissue) that releases epinephrine and norepinephrine in bursts, causing episodic high blood pressure, pounding heartbeat, sweating, and headache.
3. Why the changes matter
These disorders converge on the same vital variables—blood glucose, blood pressure, fluid volume, and electrolytes—yet in opposite directions depending on the hormone. Cortisol excess raises glucose and pressure and suppresses immunity; cortisol deficiency drops glucose and pressure and impairs the stress response. Aldosterone excess retains sodium and water while wasting potassium; aldosterone deficiency does the reverse. Catecholamine excess produces dangerous blood-pressure spikes. Recognizing these patterns (high glucose with high pressure in Cushing syndrome versus low glucose with low pressure in adrenal insufficiency) supports assessment, monitoring, and early escalation.
How it works
- A stressor activates the hypothalamus, which releases CRH.
- The pituitary releases ACTH, which stimulates the Adrenal cortex Outer region making steroid hormones (cortisol, aldosterone) Full entry → to release cortisol.
- Cortisol raises blood glucose, supports blood pressure, and dampens inflammation to meet the demand.
- Rising cortisol feeds back to suppress CRH and ACTH, returning the HPA axis Hypothalamus–pituitary–adrenal control loop for cortisol Full entry → to baseline when the stress resolves.
Common confusions
| Do not confuse | With | Difference |
|---|---|---|
| Cushing syndrome | Cushing disease | Cushing syndrome is any cortisol excess; Cushing disease is specifically a pituitary ACTH-secreting adenoma |
| Primary adrenal insufficiency | Secondary adrenal insufficiency | Primary involves the adrenal gland itself (low cortisol and aldosterone, high ACTH); secondary involves low ACTH with relatively preserved aldosterone |
| Cortisol | Aldosterone | Cortisol mainly affects glucose, stress, and inflammation; aldosterone mainly affects sodium, water, and potassium |
| Adrenal cortex | Adrenal medulla | Cortex makes steroid hormones; medulla makes catecholamines |
Memory aids
Remember the three adrenal cortical layers as "Salt, Sugar, Sex—the deeper you go, the sweeter it gets": the outer zone makes aldosterone (salt), the middle makes cortisol (sugar), and the inner makes androgens (sex hormones). For the medulla, think "medulla = machine-gun catecholamines—fast and short."
Quick review
Topic Recap
- The adrenal cortex makes steroid hormones (cortisol, aldosterone); the medulla makes catecholamines.
- The HPA axis regulates cortisol, which raises glucose, supports blood pressure, and suppresses inflammation.
- Aldosterone governs sodium, water, and potassium and is controlled mainly by renin–angiotensin and potassium.
- Cushing syndrome (cortisol excess) and adrenal insufficiency (cortisol deficiency) produce opposite glucose, pressure, and electrolyte patterns.
- Hyperaldosteronism causes hypertension with hypokalemia; pheochromocytoma causes episodic catecholamine symptoms.
Knowledge Check
- Which adrenal region makes aldosterone and cortisol, and which makes the catecholamines?
- What are the main metabolic and cardiovascular effects of cortisol?
- Why does primary adrenal insufficiency differ from secondary adrenal insufficiency in aldosterone and ACTH levels?
- What is the classic presentation of hyperaldosteronism?
- Why does pheochromocytoma cause episodic, rather than constant, symptoms?
Answers and Rationales
- Answer: The adrenal cortex makes aldosterone and cortisol (steroids); the Adrenal medulla Inner region making catecholamines Full entry → makes epinephrine and norepinephrine. Why: The two regions have different embryonic origins and products.
- Answer: Cortisol raises blood glucose, supports blood pressure, suppresses inflammation and immunity, and aids the stress response. Why: These actions prepare the body for prolonged stress and are what excess or deficiency disrupts.
- Answer: Primary insufficiency destroys the cortex, so both cortisol and aldosterone fall and ACTH rises; secondary insufficiency is from low ACTH, so aldosterone (ACTH-independent) is relatively preserved. Why: Aldosterone regulation is mainly renin/potassium-driven, not ACTH-driven.
- Answer: Hypertension with low potassium, from sodium/water retention and potassium excretion. Why: Excess aldosterone retains sodium and water while wasting potassium.
- Answer: The tumor releases catecholamines in surges, so symptoms (hypertension, palpitations, sweating, headache) come and go rather than staying constant. Why: Intermittent secretion produces a paroxysmal, episodic pattern.
Eli explains
The same idea, in plain words
Explain it like I’m 10
Think of the adrenal glands as the body's emergency management office. Cortisol is the long-term crisis coordinator—it raises blood sugar, keeps inflammation in check, and prepares the body for ongoing stress. Aldosterone is the plumbing manager—it tells the kidneys how much salt and water to keep and how much potassium to release, which sets blood pressure. The catecholamines are the fire alarm and sprinklers—instant, short-lived bursts that speed the heart and raise blood sugar the moment danger appears. The comparison stops being exact because these "managers" operate continuously at low levels, not only during crises, and they interact with many other hormones. Still, the picture holds: when any one manager over- or under-works, predictable problems follow.
Simple Example
A morning cortisol rise helps mobilize energy, like a coach arriving early to open the gym and get the team ready, while aldosterone keeps the water fountains (blood pressure) working all day.
Worked example
- Predisposing factors or causes: Prolonged glucocorticoid medication, pituitary or adrenal tumors, autoimmune destruction, infection, or sudden steroid withdrawal can alter adrenal hormone output.
- Initial physiologic change: Cortisol, aldosterone, or catecholamines rise above or fall below the body's needs.
- Compensation or adaptation: Feedback loops respond—ACTH rises in primary adrenal insufficiency or falls in cortisol excess of adrenal origin—but compensation is limited when the defect lies in the axis itself.
- Progression or decompensation: Prolonged imbalance produces target-organ effects such as hypertension, glucose intolerance, immune suppression, muscle and skin changes, or fluid and electrolyte derangements.
- Broad manifestations and possible complications: Weight and fat redistribution, blood-pressure changes, glucose and potassium shifts, and, in severe deficiency, an adrenal crisis with low blood pressure that requires urgent evaluation.
Key takeaways
- High yield: Cortisol excess (Cushing syndrome) raises glucose and blood pressure and suppresses immunity; cortisol deficiency (adrenal insufficiency) lowers glucose and blood pressure and impairs the stress response.
- The cortex makes steroids (cortisol, aldosterone); the medulla makes catecholamines (epinephrine, norepinephrine).
- Aldosterone retains sodium and water and excretes potassium; it is regulated mainly by renin–angiotensin and potassium, not ACTH.
- Primary adrenal insufficiency (Addison) involves low cortisol and aldosterone with high ACTH; secondary insufficiency involves low ACTH with relatively preserved aldosterone.
- Hyperaldosteronism classically presents as hypertension with hypokalemia.
- Pheochromocytoma causes episodic hypertension, palpitations, sweating, and headache from catecholamine surges.
- Cushing syndrome is most often caused by prolonged glucocorticoid medication; Cushing disease refers specifically to a pituitary ACTH-secreting adenoma.
Study tools & related lessonsYou’ll learn to · Key vocabulary · Related
You’ll learn to
- Distinguish the adrenal cortex from the adrenal medulla and the hormones each produces.
- Describe the hypothalamic–pituitary–adrenal (HPA) axis and the roles of cortisol, aldosterone, and the catecholamines.
- Explain the effects of cortisol and aldosterone on glucose, fluid, electrolytes, and the stress response.
- Contrast Cushing syndrome with adrenal insufficiency (primary versus secondary).
- Describe the concepts of hyperaldosteronism and pheochromocytoma and their characteristic effects.
Key vocabulary
- Adrenal cortex
- Outer region making steroid hormones (cortisol, aldosterone)
- Adrenal medulla
- Inner region making catecholamines
- Cortisol
- Glucocorticoid that raises glucose, supports blood pressure, and suppresses inflammation
- Aldosterone
- Mineralocorticoid that retains sodium/water and excretes potassium
- Catecholamines
- Epinephrine and norepinephrine
- HPA axis
- Hypothalamus–pituitary–adrenal control loop for cortisol
- Cushing syndrome
- Chronic cortisol excess
- Adrenal insufficiency
- Deficient cortisol (with or without aldosterone)
- Hyperaldosteronism
- Excess aldosterone
- Pheochromocytoma
- Catecholamine-secreting tumor of the medulla
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