Cushing's Syndrome

IWBCA
Feb 16
15 min read

Cushing syndrome, also called Cushing’s syndrome or hypercortisolism, is a rare endocrine disorder in which prolonged exposure to excess cortisol disrupts body fat distribution, weakens muscle and bone, alters skin, raises blood pressure and blood sugar, and increases cardiovascular and infection risk; it is most often caused by long-term glucocorticoid medication use or hormone-producing tumors in the pituitary, adrenal glands, or other organs, and treatment focuses on removing or controlling the source of excess cortisol and restoring hormone balance.

Overview

What is cushing syndrome?

Cushing syndrome is a hormonal condition that develops when cortisol levels remain too high for too long. Cortisol is a steroid hormone produced by the adrenal glands that helps regulate blood pressure, blood sugar, immune responses, and the body’s reaction to stress. In normal amounts, it is essential for health. When levels are chronically elevated, cortisol changes where and how the body stores fat, breaks down muscle and bone, thins the skin, and disrupts mood, sleep, and metabolism.

Cushing syndrome refers to the state of cortisol excess from any cause. When the excess cortisol is driven specifically by an adrenocorticotropic hormone (ACTH)–secreting pituitary tumor, the condition is called Cushing disease, which is one subtype of Cushing syndrome. The most common cause overall, however, is long-term treatment with glucocorticoid medicines such as prednisone, dexamethasone, or high-dose inhaled or injected steroids used for inflammatory and autoimmune conditions.

Endogenous Cushing syndrome, in which the body produces excessive cortisol, is rare, with only a few new cases per million people each year. It occurs more often in women and typically appears in mid-adulthood, although it can affect men and children as well. Because many features overlap with common problems such as weight gain, high blood pressure, and mood changes, diagnosis is often delayed. Treatment aims to identify the source of hormone excess, normalize cortisol levels through surgery, medication, or carefully guided changes in steroid therapy, and reduce the long-term complications associated with untreated hypercortisolism.

Symptoms

What are the most common symptoms of this condition?

Cushing syndrome affects multiple organ systems, and symptoms usually develop gradually over months to years. The specific pattern varies among individuals, but several features tend to co-occur and raise suspicion for cortisol excess.

Round, Full Face And Central Weight Gain: Many people notice progressive fullness of the face, often called “moon face,” along with weight gain focused on the trunk and upper body. The abdomen, chest, and upper back become more prominent, while the arms and legs may remain relatively slender. Fat pads can form at the back of the neck or between the shoulders, creating a “buffalo hump.”

Skin and Soft Tissue Changes: Cortisol weakens the skin and supporting tissues. This can cause thin, fragile skin that bruises easily after minor bumps or wounds, and that heals slowly. Wide purplish or reddish stretch marks (striae) often appear on the abdomen, breasts, hips, thighs, or upper arms. Acne, oiliness, and increased facial redness (facial plethora) are also common.
Bone and Muscle Effects: Excess cortisol breaks down protein in muscle and bone. Proximal muscle weakness, especially in the hips and shoulders, can make it difficult to climb stairs, rise from chairs, or lift objects overhead. Bone loss may lead to osteoporosis and fractures, including compression fractures of the spine, sometimes with back pain that has no obvious injury to explain it.
Cardiometabolic Changes: Cushing syndrome often leads to new-onset or worsening hypertension and hyperglycemia. Some people develop prediabetes or diabetes, and cholesterol and triglyceride levels may rise. These changes substantially increase the risk of heart attack, stroke, and blood clots if cortisol remains uncontrolled.
Neuropsychiatric Symptoms: Mood and cognitive changes are common. People may experience irritability, anxiety, low mood, emotional lability, difficulty concentrating, or problems with memory. Sleep can become fragmented, with insomnia or non-restorative sleep that aggravates fatigue and daytime dysfunction. In severe cases, more pronounced psychiatric symptoms can occur.
Reproductive and Endocrine Symptoms: In women, Cushing syndrome can cause menstrual irregularity or complete loss of periods, decreased fertility, and increased hair growth on the face, chest, or abdomen (hirsutism). In men, it may lead to reduced libido, erectile dysfunction, and decreased fertility. Both sexes can develop reduced muscle bulk and changes in body composition.
Infections and Wound Healing: Cortisol suppresses immune function. People with Cushing syndrome have an increased risk of skin infections, fungal infections, pneumonia, and other serious infections. Cuts and surgical wounds may heal more slowly, and infections may be more severe or recur more frequently than expected.
Children and Adolescents: In younger patients, Cushing syndrome often presents as weight gain with slowed or arrested linear growth. A child who becomes heavier but stops growing taller at the expected rate, especially with other typical features such as facial rounding or striae, should be evaluated for cortisol excess. Delayed or disrupted puberty can also occur.

No single symptom establishes the diagnosis of Cushing syndrome, but the combination of central obesity, thin skin with easy bruising, wide purple striae, muscle weakness, and metabolic changes is particularly suggestive and should prompt targeted evaluation.

Causes

What are the most common causes of this condition?

Cushing syndrome occurs when cortisol levels remain inappropriately high over time. Causes are grouped into exogenous sources, related to medications, and endogenous sources, in which the body’s own hormone system produces the excess.

Glucocorticoid Medications: The most common cause of Cushing syndrome overall is prolonged exposure to glucocorticoid drugs. These include oral, intravenous, high-dose inhaled, and potent topical steroids, such as prednisone, prednisolone, dexamethasone, methylprednisolone, and hydrocortisone, used to treat conditions such as asthma, rheumatoid arthritis, inflammatory bowel disease, organ transplantation, and certain cancers. When administered at moderate to high doses for extended periods, these medicines can reproduce the effects of endogenous cortisol excess. Reduction or tapering of them must be performed gradually and under medical supervision to avoid adrenal insufficiency.

Pituitary Tumors (Cushing Disease): In ACTH-dependent Cushing syndrome, pituitary adenomas (usually benign tumors) secrete excess ACTH, the hormone that stimulates the adrenal glands. This excess ACTH drives the adrenals to overproduce cortisol. Pituitary tumors are the most common cause of endogenous Cushing syndrome. This pattern is termed Cushing's disease and typically produces a relatively gradual onset of symptoms.

Adrenal Cortical Tumors: In ACTH-independent Cushing syndrome, one or both adrenal glands produce too much cortisol directly, without needing extra ACTH. This often occurs due to an adrenal cortical adenoma, a benign tumor that autonomously secretes cortisol. Less commonly, an adrenocortical carcinoma, a malignant tumor, is responsible. In some people, both adrenal glands are enlarged or nodular (forms of bilateral adrenal hyperplasia) and collectively overproduce cortisol.

Ectopic ACTH-Producing Tumors: Some tumors outside the pituitary produce ACTH, which then stimulates the adrenal glands in the same way as a pituitary tumor. This is called ectopic ACTH syndrome. Common sources include certain lung cancers (such as small cell carcinoma), bronchial or thymic neuroendocrine tumors, and some pancreatic or other neuroendocrine tumors. Ectopic ACTH production can lead to particularly severe and rapidly progressive Cushing syndrome, often with marked muscle wasting, profound weakness, and significantly low potassium levels.

Other Endogenous Causes: Rarer causes of endogenous Cushing syndrome include ectopic production of corticotropin-releasing hormone (CRH) by non-pituitary tumors, primary bilateral macronodular adrenal hyperplasia, and primary pigmented nodular adrenal disease, which may be associated with genetic syndromes such as Carney complex. These conditions are uncommon but important to recognize in specialized endocrine evaluation.

In every case, accurate diagnosis requires confirming cortisol excess, determining whether it is ACTH-dependent or ACTH-independent, and then localizing the source. That information guides decisions about surgery, medical therapy, radiation therapy, or changes in glucocorticoid medication, so that cortisol can be returned to a healthy range and the complications of chronic hypercortisolism can be reduced.

Risk Factors

What are the most common risk factors associated with this condition?

Cushing syndrome can occur in anyone, including children, but it appears more often in specific groups and settings. Endogenous forms are rare and most often diagnosed in adults, while medication-induced hypercortisolism is far more common and reflects how widely glucocorticoids are used in clinical practice.

Sex and Age: Cushing syndrome is diagnosed more frequently in women than in men, particularly for pituitary and adrenal causes, and is most common between about 25 and 50 years of age. This pattern is especially clear in Cushing disease, where small ACTH-secreting pituitary tumors often present in women in midlife with slowly evolving changes in weight, blood pressure, mood, and menstrual cycles.
Long-Term Glucocorticoid Therapy: People who take systemic glucocorticoid medications at moderate or high doses for months or years have the highest overall risk of developing Cushing syndrome. This includes oral and intravenous steroids, as well as potent inhaled, injected, or topical formulations when used extensively. Conditions such as severe asthma, rheumatoid arthritis, inflammatory bowel disease, vasculitis, and organ transplantation often require these medicines, and cumulative dose and duration strongly influence risk.
Pituitary or Adrenal Tumors: Individuals with pituitary adenomas or adrenal cortical tumors that alter hormone production are at increased risk of endogenous hypercortisolism. Most of these tumors are benign, but they can secrete ACTH or cortisol autonomously, driving cortisol levels above the normal range. A history of pituitary disease, adrenal incidentaloma, or other endocrine abnormalities should prompt closer attention to subtle features of Cushing syndrome.
Ectopic ACTH-Producing Tumors: People with certain neuroendocrine tumors, particularly in the lungs, thymus, or pancreas, can develop ectopic ACTH production that raises cortisol dramatically. This form of Cushing syndrome tends to progress quickly, and the risk concentrates in those with known or suspected malignancy. Rapid onset of severe muscle weakness, profound hypokalemia, and difficult-to-control diabetes or hypertension in the setting of cancer should raise concern for ectopic ACTH secretion.
Genetic and Familial Syndromes: Rare hereditary conditions such as multiple endocrine neoplasia, Carney complex, or familial pituitary or adrenal tumor syndromes increase the likelihood of hormone-producing tumors, including those that cause Cushing syndrome. In these families, new changes in appearance, blood pressure, or glucose tolerance should trigger a low threshold for endocrine evaluation.

Complications

What are the most important complications associated with Cushing syndrome?

Without effective treatment, chronic cortisol excess damages multiple organs and shortens life expectancy. Complications reflect the combined effects of hypertension, diabetes, abnormal lipids, bone loss, immune suppression, and clotting abnormalities that accompany hypercortisolism.

Cardiovascular Disease and Blood Clots: Cushing syndrome significantly increases the risk of heart attack, stroke, and venous thromboembolism. Elevated cortisol raises blood pressure, worsens cholesterol and triglycerides, promotes central obesity, and makes blood more prone to clotting. Deep vein thrombosis, pulmonary embolism, and arterial events occur more often in people with untreated Cushing syndrome, and these events are a major cause of serious illness and death.
Metabolic Complications: Many people with Cushing syndrome develop prediabetes or Type 2 diabetes because cortisol opposes insulin and increases glucose production by the liver. These metabolic changes often co-occur with elevated cholesterol and triglycerides. Together, they accelerate atherosclerosis and compound cardiovascular risk even after cortisol levels are eventually controlled.
Bone Loss and Fractures: Excess cortisol accelerates bone breakdown and impairs bone formation, leading to osteopenia and osteoporosis. Vertebral compression fractures and rib fractures can occur with minimal trauma and may present as persistent back pain or height loss. Bone fragility can persist even after cortisol levels normalize, underscoring the importance of early diagnosis and fracture prevention.

Infections and Impaired Wound Healing: Cortisol suppresses immune function and blunts inflammation, so people with Cushing syndrome are more susceptible to bacterial, viral, and fungal infections. Skin and soft tissue infections, pneumonia, urinary tract infections, and opportunistic infections occur more frequently, and minor wounds often heal slowly. Surgical incisions may dehisce or become infected, increasing postoperative risk.
Neuropsychiatric and Quality of Life Effects: Mood swings, depression, anxiety, irritability, and cognitive difficulties are common and can be profoundly disabling. Sleep disturbance, fatigue, and loss of physical strength further impair quality of life, relationships, and work performance. These neuropsychiatric complications often improve when cortisol is controlled, but can leave lingering effects, especially if they were present for a long time before diagnosis.
Abnormal Weight Gain and Body Composition Changes: Progressive central weight gain, fat accumulation in the face and upper back, and thinning of the limbs alter body shape in ways that are both medically significant and emotionally distressing. These changes are not simply cosmetic; they signal underlying metabolic stress and are closely tied to hypertension, diabetes, and sleep apnea. Even after successful treatment, weight and body composition may not fully revert to baseline.
Mortality Risk: If left untreated, Cushing syndrome carries a significantly increased risk of premature death, mainly from cardiovascular disease, infections, and thromboembolic events. Timely diagnosis and effective reduction of cortisol levels can substantially lower this risk, but residual cardiovascular and metabolic vulnerability may persist, underscoring the need for long-term follow-up and risk factor management.

Diagnosis and Testing

How is Cushing syndrome diagnosed?

Cushing syndrome is diagnosed by combining a careful clinical assessment with biochemical tests that document cortisol excess and then identify its source. Because many features, such as weight gain, fatigue, and mood changes, are common in other conditions, clinicians look for specific patterns of signs and use validated hormone assays to confirm or exclude hypercortisolism before proceeding to detailed imaging.

Initial Clinical Assessment: Diagnosis begins with a detailed history of symptom onset and progression, medication use, including all forms of glucocorticoids, and past or current cancers or endocrine disorders. A focused physical examination looks for classic findings such as central obesity, moon facies, buffalo hump, wide purple striae, easy bruising, proximal muscle weakness, and hypertension. This assessment helps determine whether laboratory screening for Cushing syndrome is warranted.
Twenty-Four-Hour Urinary Free Cortisol: A twenty-four-hour urinary free cortisol test measures the amount of cortisol excreted in the urine over a full day. Participants collect all urine produced over a defined twenty-four-hour period, and the laboratory quantifies cortisol in the pooled sample. Values above the normal range on at least two separate collections support the diagnosis of Cushing syndrome, while normal results make clinically significant hypercortisolism less likely.
Late Night Salivary Cortisol: A late-night salivary cortisol test evaluates cortisol at a time when levels should be very low. Saliva is collected at home between about 11 p.m. and midnight using a special container. In healthy individuals, cortisol falls to near baseline by that time. Persistently elevated late-night salivary cortisol on more than one occasion is a sensitive indicator of Cushing syndrome because loss of the normal day-night rhythm is an early hallmark of hypercortisolism.
Dexamethasone Suppression Testing: Dexamethasone suppression testing examines how the body’s cortisol production responds to a small dose of a synthetic glucocorticoid. In the overnight version, a person takes dexamethasone at night and has blood drawn for cortisol the next morning. In healthy physiology, dexamethasone suppresses ACTH secretion and reduces cortisol levels. In Cushing syndrome, this suppression is blunted or absent, and morning cortisol remains inappropriately high, suggesting autonomous cortisol production.
ACTH Blood Testing: An ACTH blood test helps distinguish ACTH-dependent from ACTH-independent causes once hypercortisolism is confirmed. Low ACTH levels suggest that the adrenal glands are producing cortisol on their own, often due to an adrenal tumor or hyperplasia. Normal or high ACTH levels point to a pituitary source, such as Cushing's disease, or to ectopic ACTH secretion from a non-pituitary tumor. This distinction guides the next steps in imaging and treatment planning.
Imaging to Localize The Source: After biochemical testing indicates Cushing syndrome and suggests whether it is ACTH dependent or independent, imaging is used to look for the source. Adrenal CT or MRI scans evaluate the adrenal glands for adenomas, carcinomas, or hyperplasia. Pituitary MRI looks for small adenomas that may be producing ACTH. When ectopic ACTH production is suspected, chest CT and sometimes abdominal imaging are performed to search for lung or other neuroendocrine tumors.
Inferior Petrosal Sinus Sampling: Bilateral inferior petrosal sinus sampling is a specialized procedure used when ACTH-dependent Cushing syndrome is confirmed, but pituitary imaging is normal or ambiguous. A specialist threads catheters into the veins draining the pituitary gland and measures ACTH levels in both the venous drainage and a peripheral vein, often before and after stimulation. Higher ACTH levels in the petrosal sinuses compared to the periphery indicate a pituitary source, while similar levels point toward ectopic ACTH production. This information is critical for deciding whether pituitary surgery is likely to be effective.

Together, clinical findings, hormone tests, and targeted imaging enable clinicians to confirm Cushing syndrome, distinguish medication-induced from endogenous causes, and localize the source of excess cortisol, thereby informing appropriate surgical or medical treatment planning.

Management and Treatment

How is Cushing syndrome treated?

Treatment for Cushing syndrome focuses on lowering cortisol to a safe range and correcting the underlying driver of hormone excess. The exact approach depends on whether cortisol comes from long-term glucocorticoid medication, a pituitary tumor, an adrenal lesion, or an ectopic ACTH-producing tumor in another organ. In almost all cases, the goal is to normalize cortisol gradually, avoid sudden adrenal insufficiency, and then manage the cardiovascular, metabolic, bone, and mental health consequences that accumulated during the period of hypercortisolism.

Adjustment of Glucocorticoid Medications: When Cushing syndrome is caused by prescribed glucocorticoids, the first step is to lower the steroid burden as safely as possible. Your healthcare team may reduce the dose, change how often you take it, switch to a less potent steroid, or move to nonsteroid alternatives when those are available for your underlying condition. Tapering must be gradual because the adrenal glands often shrink and stop producing cortisol during long-term therapy and need time to recover, and stopping suddenly can cause adrenal crisis with low blood pressure, severe fatigue, and electrolyte problems.

Surgery for Pituitary Tumors: In Cushing disease, where an ACTH-secreting pituitary adenoma drives cortisol excess, transsphenoidal pituitary surgery is usually the preferred first-line treatment. An experienced neurosurgeon accesses the pituitary gland through the nose and removes the tumor while preserving as much normal pituitary tissue as possible. Successful surgery can normalize ACTH and cortisol, although short-term adrenal insufficiency is common afterward and requires temporary steroid replacement until the normal axis recovers. Close follow-up is needed because some tumors recur and may require additional surgery or other treatments.

Surgery for Adrenal and Ectopic Tumors: When an adrenal adenoma or carcinoma produces cortisol directly, removal of the affected adrenal gland is often recommended, usually with a minimally invasive laparoscopic approach if the tumor is benign and confined. In ectopic ACTH syndrome, surgical removal of the ACTH-producing tumor, such as a lung or thymic neuroendocrine tumor, is pursued whenever technically and oncologically feasible. In both scenarios, cortisol levels can decline rapidly after surgery; therefore, patients are monitored closely and typically receive temporary glucocorticoid replacement until the remaining adrenal tissue can meet the body’s needs.

Radiation Therapy: If pituitary surgery does not fully control Cushing disease or the tumor is not operable, focused radiation may be used to target residual pituitary tissue. Conventional fractionated radiation or stereotactic radiosurgery can gradually reduce ACTH secretion, although the effect often unfolds over months to years. During this interval, medical therapies that block cortisol production are often used as a bridge, and long-term monitoring is required because pituitary hormone deficiencies may develop as a delayed consequence of radiation.

Medications That Lower Cortisol: Several medications can lower cortisol when surgery is not possible, the disease has not been cured, or surgery is planned. Steroidogenesis inhibitors, such as ketoconazole, metyrapone, or newer agents, reduce cortisol synthesis within the adrenal glands. In some cases, drugs that block the action of cortisol at its receptors or agents that suppress ACTH secretion are used instead. These medicines require careful dose titration and regular blood tests to monitor liver function, electrolytes, and cortisol levels, and they are often combined with other treatments in a long-term plan.

Bilateral Adrenalectomy In Refractory Cases: In rare, severe cases where cortisol excess cannot be controlled by pituitary or tumor-directed treatments and medications, removal of both adrenal glands may be considered to eliminate the source of cortisol production. This approach effectively cures the hypercortisolism but creates permanent adrenal insufficiency, which means lifelong glucocorticoid and mineralocorticoid replacement and education about stress dosing and adrenal crisis. Patients who undergo this procedure require close endocrine follow-up and clear emergency plans.

Long-term Follow-up and Risk Reduction: Regardless of the initial treatment, long-term management is essential because cardiovascular disease, diabetes, bone loss, and mood disorders may persist or emerge even after cortisol normalizes. Follow-up care typically includes monitoring blood pressure, glucose, and lipids; screening for osteoporosis and fractures; adjusting hormone replacement therapy as needed; and addressing sleep, mood, and quality of life. Regular visits also help detect tumor recurrence or new hormone abnormalities early so that additional interventions can be planned promptly.

Outlook and Prognosis

What can I expect if I have Cushing syndrome?

With appropriate treatment, many people experience substantial improvement in the features of Cushing syndrome and a meaningful reduction in long-term health risk. Some changes, such as blood pressure, blood sugar, and sleep, may improve within weeks to months as cortisol levels fall, while others, such as body shape, skin thickness, and bone strength, recover more slowly and sometimes only partially. Prognosis depends on the duration of cortisol elevation before diagnosis, the rate at which the underlying cause can be controlled, and the degree to which cardiovascular and metabolic risk factors are managed thereafter.

Recovery of Physical Changes: Weight distribution, facial rounding, skin fragility, and muscle weakness often begin to shift in the first year after successful treatment, although they rarely return to a pre-illness state overnight. Many people lose central fat, regain muscle strength, and notice fewer bruises and improved wound healing over time. Children treated for Cushing syndrome may resume more normal growth and pubertal development once cortisol levels are controlled, although catch-up growth is influenced by age at diagnosis and disease duration.
Cardiometabolic Risk Over Time: Treating Cushing syndrome lowers but does not completely erase the elevated risk for hypertension, diabetes, dyslipidemia, and cardiovascular events, especially when the diagnosis was delayed. Blood pressure and blood sugar may improve sufficiently to reduce or discontinue some medications, but some individuals remain on treatment for these conditions long-term. Ongoing attention to weight, physical activity, diet, smoking status, and sleep apnea is important because these factors strongly influence long-term outcomes even after cortisol is normalized.
Mental Health and Support: The emotional and cognitive effects of Cushing syndrome can be as disruptive as the physical changes. Anxiety, depression, irritability, body image distress, and problems with concentration may persist for some time after biochemical cure. Working with a mental health professional, joining a support group of others living with or recovering from Cushing syndrome, and involving family in education about the condition can help people process what they have experienced and rebuild confidence and daily routines. Recognizing that recovery is a process rather than an instant event can make this transition easier to navigate.
Life Expectancy With Cushing Syndrome: Untreated Cushing syndrome carries a significantly higher risk of premature death, largely because of cardiovascular disease, infections, and thromboembolic events driven by chronic cortisol excess. With timely diagnosis and effective treatment that normalizes cortisol and addresses blood pressure, glucose, lipids, bone health, and mental health, survival approaches that of people without Cushing syndrome, although careful follow-up remains important. The earlier hypercortisolism is identified and corrected, the greater the likelihood of avoiding irreversible complications and maintaining near-normal life expectancy.

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