Cushing syndrome and adrenal insufficiency: the signs !

Syndrome

Too much cortisol (Cushing) or too little adrenal hormone (Addison): two opposite pictures you can recognize on examination.

Updated 2026-11-01

See it in 3D: Left adrenal gland · Right adrenal gland · Pituitary gland · Hypothalamus · Adrenal arteries · Skin

What it is

Cushing syndrome is the set of signs produced by prolonged glucocorticoid excess, and adrenal insufficiency is a lack of cortisol, sometimes with a lack of aldosterone. Their signs are nearly opposite: central weight gain, hypertension and fragile skin in one; weight loss, hypotension and hyperpigmentation in the other. Adrenal crisis is an emergency that can mimic an acute abdomen or sepsis.

Key findings

Cushing: moon face, buffalo hump, supraclavicular fullness, wide violet striae, ecchymoses, acne and hirsutism, edema and poor wound healing.
Cushing in children: weight gain with slowed growth.
Blood pressure: high in Cushing, low with an orthostatic drop in adrenal insufficiency.
Addison: hyperpigmentation of palmar creases, oral mucosa, recent scars and knuckles.
Addison: weight loss, nausea, abdominal pain and dehydration.
Proximal strength: ask the patient to rise from a chair without using the arms.

Pathophysiology

The hypothalamus releases CRH, the pituitary ACTH and the adrenal cortex cortisol, which suppresses both.
Excess cortisol breaks down protein (muscle and collagen): proximal weakness, thin skin, striae and bruising; it shifts fat to the trunk, face and nape; it raises glucose and blood pressure and suppresses immunity.
In primary insufficiency the cortex is destroyed: cortisol and aldosterone are lacking and the pituitary releases a lot of ACTH.
ACTH shares a precursor with melanocyte-stimulating hormone, so ACTH excess darkens the skin.
Lack of aldosterone causes renal sodium loss and potassium retention: hypotension, hyponatremia, hyperkalemia and salt craving.

Common causes

Exogenous Cushing: oral, inhaled, topical or injected glucocorticoids used for a long time.
Endogenous Cushing: ACTH-secreting pituitary adenoma, ectopic ACTH production (for example, small cell lung carcinoma) and adrenal tumors.
Primary insufficiency: autoimmune (the commonest in high-income countries), tuberculosis, HIV-related infections, metastases and adrenal hemorrhage in meningococcemia.
Secondary insufficiency: abrupt withdrawal of long-term glucocorticoids and pituitary disease.
Newborns: congenital adrenal hyperplasia can cause a salt-wasting crisis.

Tests that confirm it

Cushing: 24-hour urinary free cortisol, late-night salivary cortisol or a dexamethasone suppression test; then ACTH to locate the source.
Adrenal insufficiency: morning cortisol, ACTH and an ACTH stimulation test; sodium and potassium.
Pituitary or adrenal imaging only after the hormonal disorder is confirmed.

Test yourself

Think of the answer, then tap the question to see it.

Why does primary adrenal insufficiency darken the skin while secondary does not?

In primary disease cortisol is lacking and the pituitary releases a lot of ACTH, which shares a precursor with melanocyte-stimulating hormone; in secondary disease ACTH is low.

Which signs best separate Cushing syndrome from ordinary obesity?

Wide violet striae, easy bruising, facial plethora and proximal muscle weakness.

What is the commonest cause of Cushing syndrome?

Long-term glucocorticoid use (exogenous Cushing); among endogenous causes, an ACTH-secreting pituitary adenoma.

Why does primary adrenal insufficiency cause hyperkalemia?

Destruction of the cortex also removes aldosterone, which normally makes the kidney retain sodium and excrete potassium.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

← All of the clinical exam

Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: Cushing Syndrome | Hypercortisolism | MedlinePlus (MedlinePlus, U.S. National Library of Medicine, 2026); Addison Disease | Adrenal Insufficiency | MedlinePlus (MedlinePlus, U.S. National Library of Medicine, 2026); 17.6 The Adrenal Glands - Anatomy and Physiology 2e | OpenStax (OpenStax, Rice University, 2022).

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Representative model, for educational purposes only.