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Cushing Syndrome – A Complete Patient‑Friendly Guide

Overview

Cushing syndrome (also called hypercortisolism) is a hormonal disorder caused by prolonged exposure of the body’s tissues to high levels of the hormone cortisol. Cortisol, produced by the adrenal glands, helps regulate metabolism, blood pressure, immune response, and stress.

The condition can be exogenous (most often from taking glucocorticoid medications such as prednisone) or endogenous (the body makes too much cortisol on its own).

Who it affects: Adults are most commonly diagnosed, with a slight female predominance (≈ 3:1). Pediatric Cushing syndrome is rare (<1 per 1 000 000 children) but can occur, especially with tumors that secrete ACTH.

Prevalence: According to the CDC and NIH, the estimated incidence of endogenous Cushing syndrome is 10–15 cases per million people per year. The prevalence of exogenous Cushing syndrome mirrors the widespread use of corticosteroid drugs—up to 5% of patients on long‑term high‑dose steroids develop clinically significant hypercortisolism.

Symptoms

Signs develop gradually and may vary. Most patients have a combination of the following:

Physical changes

• Weight gain – especially around the trunk, face (“moon face”), and upper back (“buffalo hump”).
• Skin alterations – thin, fragile skin that bruises easily; purple stretch marks (striae) on the abdomen, thighs, breasts, or arms.
• Muscle weakness – proximal muscle wasting leads to difficulty climbing stairs or lifting objects.
• Facial changes – rounded “moon” face, facial redness (plethora).
• Excess hair growth (hirsutism) – more common in women; can affect the face, chest, or abdomen.
• Acne or oily skin.

Metabolic & systemic symptoms

• High blood pressure (hypertension).
• Elevated blood glucose – may lead to type 2 diabetes.
• Increased thirst and urination.
• Fatigue and generalized malaise.
• Osteoporosis or fractures due to bone loss.
• Psychiatric changes – mood swings, irritability, anxiety, depression, or cognitive difficulties (“brain fog”).
• Menstrual irregularities in women; decreased libido, erectile dysfunction, or infertility in men.

Rare/advanced signs

• Infections – cortisol suppresses the immune system.
• Gastro‑intestinal ulcer disease.
• Serious electrolyte disturbances (e.g., low potassium).

Causes and Risk Factors

Cushing syndrome can be divided into two broad categories.

Exogenous (Medication‑Induced)

• Long‑term oral or injected glucocorticoids (e.g., prednisone, methylprednisolone, dexamethasone) for conditions such as asthma, rheumatoid arthritis, lupus, or organ transplantation.
• Topical or inhaled steroids may contribute when used in high doses over many years, especially in children.

Endogenous

1. Adrenal adenoma or carcinoma – a tumor in the adrenal gland that secretes cortisol directly.
2. Pituitary adenoma (Cushing disease) – a benign tumor of the pituitary gland that releases excess ACTH, stimulating adrenal cortisol production. This accounts for ~70% of endogenous cases.
3. Ectopic ACTH secretion – non‑pituitary tumors (e.g., small‑cell lung cancer, bronchial carcinoids, pancreatic neuroendocrine tumors) produce ACTH.
4. Adrenal hyperplasia – diffuse overgrowth of adrenal tissue that secretes cortisol.

Risk Factors

• Prolonged use of high‑dose glucocorticoids (≥ 5 mg prednisone equivalent daily for > 3 months).
• Family history of pituitary or adrenal tumors.
• Certain genetic syndromes (e.g., Multiple Endocrine Neoplasia type 1, Carney complex).
• Smoking – increases risk of ectopic ACTH‑producing lung tumors.
• Older age – most endogenous cases are diagnosed between 30–50 years.

Diagnosis

Because many signs overlap with common conditions (obesity, hypertension, diabetes), a systematic approach is essential.

Step‑wise diagnostic algorithm

1. Confirm hypercortisolism using at least two of three screening tests:
• 24‑hour urinary free cortisol (UFC) – elevated in > 90% of cases.
• Late‑night salivary cortisol – cortisol should be low at midnight; high levels indicate loss of diurnal rhythm.
• Low‑dose dexamethasone suppression test (LDDST) – after 1 mg dexamethasone at night, cortisol > 1.8 µg/dL suggests Cushing syndrome.
2. Determine the source (exogenous vs. endogenous):
• Medication review – discontinue or taper steroids if possible.
• Measure plasma ACTH:
• Low ACTH → adrenal source.
• Normal/high ACTH → pituitary or ectopic source.
3. Localize the tumor when ACTH is elevated:
• High‑dose dexamethasone suppression test (HDDST) – suppression (> 50%) suggests pituitary adenoma; lack of suppression suggests ectopic ACTH.
• Magnetic resonance imaging (MRI) of the pituitary.
• If MRI is negative, perform Inferior petrosal sinus sampling (IPSS) – gold standard for distinguishing pituitary from ectopic ACTH.
4. Imaging for adrenal lesions if ACTH is low:
• CT or MRI of the adrenal glands to identify adenoma, carcinoma, or hyperplasia.

Additional tests

• Bone density scan (DEXA) – assesses osteoporosis.
• Blood glucose, HbA1c, lipid panel – evaluate metabolic impact.
• Electrolytes (potassium, sodium) – cortisol excess can cause hypokalemia.

Treatment Options

Therapy is individualized based on cause, severity, patient age, and comorbidities.

1. Surgical Management

• Pituitary adenoma – Transsphenoidal surgery is first‑line; cure rates 70–90% for microadenomas.
• Adrenal tumor – Laparoscopic adrenalectomy (unilateral) for adenoma or carcinoma; for carcinoma, open surgery plus possible lymph node dissection.
• Ectopic ACTH tumor – Resection of the primary tumor (e.g., lung resection) when feasible.

2. Radiation Therapy

Used when surgery is incomplete or not possible, especially for pituitary adenomas. Fractionated stereotactic radiotherapy or radiosurgery (Gamma Knife) can achieve remission in 30–50% over several years.

3. Medical Therapy

Medications control cortisol when surgery is delayed, contraindicated, or after postoperative recurrence.

• Adrenostatic agents – Ketoconazole, metyrapone, or osilodrostat inhibit cortisol synthesis.
• Pituitary-directed drugs – Pasireotide (somatostatin analog) reduces ACTH secretion; cabergoline (dopamine agonist) may help in mild cases.
• Glucocorticoid receptor antagonists – Mifepristone improves hyperglycemia and blood pressure but does not lower cortisol levels.
• All medications require close monitoring for liver toxicity, adrenal insufficiency, and electrolyte disturbances.

4. Lifestyle & Supportive Measures

• Gradual tapering of exogenous steroids under physician supervision.
• Management of hypertension (ACE inhibitors, ARBs), diabetes (metformin, insulin), and dyslipidemia.
• Calcium + vitamin D supplementation and weight‑bearing exercise to protect bone health.
• Psychological counseling or support groups to address mood changes and body‑image concerns.

Living with Cushing Syndrome

Even after successful treatment, many patients need ongoing care.

Daily Management Tips

• Medication adherence – take prescribed drugs exactly as scheduled; never stop abruptly.
• Blood pressure & glucose monitoring – home devices help track control; report spikes to your provider.
• Bone health – aim for 1,200 mg calcium and 800–1,000 IU vitamin D daily; consider bisphosphonates if bone density is low.
• Weight management – balanced diet rich in fruits, vegetables, lean protein, and whole grains; limit sodium to <2,300 mg/day.
• Physical activity – at least 150 min moderate aerobic activity per week plus strength training twice weekly (adjust to tolerance).
• Stress reduction – techniques such as mindfulness, yoga, or gentle walking help mitigate cortisol‑related mood swings.
• Regular follow‑up – endocrinology visits every 3–6 months initially, then annually, with repeat hormone testing and imaging as advised.

Emotional & Social Support

Feelings of embarrassment about weight gain or facial changes are common. Connect with patient advocacy groups (e.g., The Cushing’s Support Group) and seek psychotherapy if anxiety or depression interferes with daily life.

Prevention

While endogenous Cushing syndrome cannot be prevented, exogenous forms are largely avoidable.

• Prudent steroid prescribing – Use the lowest effective dose for the shortest duration; discuss alternative therapies when possible.
• Periodic review – Patients on chronic steroids should have routine endocrine evaluation (e.g., annual cortisol testing) to catch early hypercortisolism.
• Smoking cessation – Reduces risk of lung tumors that can cause ectopic ACTH production.
• Healthy lifestyle – Maintaining a normal BMI and regular exercise lowers the chance of developing adrenal adenomas, which are more common in obese individuals.

Complications

If left untreated, excess cortisol damages many organ systems.

• Cardiovascular disease – hypertension, atherosclerosis, increased risk of myocardial infarction and stroke.
• Metabolic syndrome – persistent diabetes, dyslipidemia, and central obesity.
• Osteoporosis and fractures – especially vertebral compression fractures.
• Infections – impaired immune response leads to frequent or severe bacterial, viral, or fungal infections.
• Psychiatric disorders – major depression, anxiety, and, rarely, psychosis.
• Pregnancy complications – gestational diabetes, hypertension, preterm birth.
• Mortality – studies in the NIH show a 2‑3‑fold increase in 5‑year mortality if cortisol excess is not corrected.

When to Seek Emergency Care

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Information in this guide is based on current clinical evidence from reputable sources including the Mayo Clinic, CDC, NIH, WHO, and peer‑reviewed endocrinology literature. It is intended for educational purposes and does not replace personalized medical advice. Always consult a qualified health professional for diagnosis and treatment decisions.

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