Cushing's Syndrome

Cushing's syndrome results from prolonged exposure to excessive glucocorticoid. The commonest cause overall is corticosteroid medicine, although pituitary, adrenal and ectopic tumours can cause endogenous cortisol excess. Diagnosis requires careful biochemical confirmation, while treatment must control both the source and serious cardiovascular, infectious, thrombotic, skeletal and psychological complications.

What Cushing's syndrome is Cushing's syndrome is the collection of effects caused by prolonged exposure to more glucocorticoid than your body needs. The excess may come from corticosteroid medicine or from your body producing too much cortisol. Cortisol excess affects metabolism, circulation, skin, muscle, bone, immunity, mood and reproduction. Symptoms often develop gradually and overlap with obesity, diabetes, depression and other common conditions. A diagnosis therefore depends on the pattern, progression, medicine details and carefully selected hormone tests. Untreated endogenous Cushing's syndrome can cause serious cardiovascular, infectious, thrombotic and skeletal complications. Specialist assessment and cause specific treatment are important. Cushing's syndrome and Cushing's disease are not the same Cushing's syndrome is the broad term for chronic glucocorticoid excess from any cause. Cushing's disease is one specific cause. It results from an ACTH secreting pituitary adenoma that stimulates both adrenal glands to produce excessive cortisol. An adrenal tumour, ectopic ACTH producing tumour or prescribed corticosteroid can cause Cushing's syndrome without causing Cushing's disease. Using the terms accurately matters because the investigations, surgery and long term monitoring differ. What cortisol normally does Cortisol is a glucocorticoid hormone made by the adrenal cortex. It supports blood pressure, blood glucose availability and the response to illness, injury and surgery. It helps regulate immune and inflammatory activity. It also influences protein, fat and bone metabolism, mood, sleep and cognitive function. Normal cortisol follows a daily rhythm. Levels are usually highest around waking and lowest late at night. Cushing's syndrome disrupts the amount, timing or source of glucocorticoid exposure. Tissues remain exposed to cortisol like activity for too much of the day. The ACTH and cortisol feedback loop The hypothalamus signals the pituitary, and the pituitary releases adrenocorticotropic hormone, usually shortened to ACTH. ACTH stimulates the adrenal cortex to produce cortisol. Rising cortisol normally reduces further pituitary and hypothalamic stimulation through negative feedback. A pituitary ACTH adenoma or an ectopic ACTH producing tumour drives the adrenal glands despite this feedback. An adrenal cortisol producing tumour suppresses pituitary ACTH. External corticosteroids can suppress both ACTH and the body's own cortisol production. Exogenous corticosteroids are the commonest cause overall The commonest cause of Cushing's syndrome overall is exposure to corticosteroid medicine. Examples include prednisolone, dexamethasone, hydrocortisone and methylprednisolone. These medicines may be essential for asthma, inflammatory disease, cancer, transplantation and many other conditions. The risk depends on dose, duration, potency, route, timing, individual susceptibility and interactions with other medicines. A complete steroid history must be taken before testing for endogenous Cushing's syndrome. Overlooking prescribed or non prescribed corticosteroid exposure can lead to unnecessary tests and an incorrect diagnosis. Corticosteroid exposure is not limited to tablets Systemic effects are most obvious with long term oral or injected corticosteroids, but other routes can also contribute. High dose inhaled, topical, nasal, eye, rectal, intra articular and spinal corticosteroids can be absorbed into the bloodstream. Using several steroid products at the same time increases total exposure. A cream, inhaler and repeated joint injections may each appear local while adding to the overall glucocorticoid burden. Tell your clinician about every preparation, including private prescriptions, imported products, bodybuilding products and complementary remedies. Medicine interactions can increase steroid exposure Some medicines slow the breakdown of corticosteroids and greatly increase systemic exposure. Ritonavir and cobicistat, used to boost some antiviral treatments, can interact with inhaled, injected or topical corticosteroids such as fluticasone or triamcinolone. You may develop Cushingoid features while your own ACTH and cortisol production becomes suppressed. Clinicians should review interactions before changing treatment. Neither the steroid nor an essential antiviral medicine should be stopped without a coordinated plan. Why external steroids suppress the adrenal glands External glucocorticoid tells the hypothalamus and pituitary that enough cortisol like hormone is present. CRH and ACTH fall, and the adrenal cortex reduces its own cortisol production. Prolonged suppression can cause adrenal shrinkage and loss of stress responsiveness. This means that you can have features of glucocorticoid excess while also being at risk of adrenal insufficiency if the medicine is removed too quickly. The risk may continue after the Cushingoid appearance begins to improve because recovery of the hypothalamic pituitary adrenal axis takes time. Corticosteroids must not be stopped abruptly Long term or high dose corticosteroid treatment must not be stopped suddenly unless an emergency specialist plan specifically says otherwise. Abrupt withdrawal can cause severe adrenal insufficiency or adrenal crisis. It can also allow the original inflammatory or immune condition to flare dangerously. The prescriber gradually reduces the dose according to the underlying disease, duration of exposure and likelihood of adrenal suppression. During and after tapering, you may need sick day advice, a Steroid Emergency Card and testing of adrenal recovery. Cushing's disease from a pituitary adenoma Cushing's disease is caused by a usually benign pituitary corticotroph adenoma that secretes ACTH. The tumour is often very small and may be difficult to see on standard MRI. Its hormone effects can be severe despite its size. ACTH stimulates both adrenal glands, causing bilateral adrenal enlargement or hyperplasia and excessive cortisol production. Large pituitary tumours can also cause headache, visual field loss or deficiencies of other pituitary hormones, but most ACTH adenomas are microadenomas. Adrenal adenoma A cortisol producing adrenal adenoma is a usually benign tumour in one adrenal gland. It makes cortisol independently of pituitary control. The excess cortisol suppresses ACTH, so the other adrenal gland reduces its activity. After the affected gland is removed, the remaining gland may need months to recover. Temporary glucocorticoid replacement and adrenal crisis education are often required. An adrenal nodule is common on imaging and does not automatically produce cortisol. Biochemical confirmation is essential before linking a nodule to Cushing's syndrome. Adrenocortical carcinoma Adrenocortical carcinoma is a rare malignant tumour that can produce cortisol, androgens or several adrenal hormones. The presentation may progress rapidly. Features can include severe Cushing's syndrome, abdominal or flank pain, a large mass and rapid androgen effects such as hirsutism or virilisation. Imaging may show a large irregular adrenal lesion, but diagnosis and staging require specialist multidisciplinary assessment. Surgery aims for complete removal when possible. Mitotane, chemotherapy and other cancer treatments may be required. Ectopic ACTH secretion Ectopic ACTH syndrome occurs when a tumour outside the pituitary produces ACTH or a related hormone. Small cell lung cancer is an important cause. Bronchial, thymic, pancreatic and other neuroendocrine tumours can also produce ACTH. Some tumours grow slowly and produce a presentation similar to pituitary Cushing's disease. Aggressive tumours may cause rapid severe weakness, hypertension, diabetes, infection and hypokalaemia before a classic rounded appearance develops. Finding and treating the tumour is a central goal, but urgent cortisol control may be needed before localisation is complete. Rare CRH producing and adrenal causes A rare tumour can produce corticotropin releasing hormone, which stimulates pituitary ACTH and adrenal cortisol. Bilateral adrenal hyperplasia and primary pigmented nodular adrenal disease can also cause ACTH independent cortisol excess. Some of these conditions are associated with inherited syndromes such as Carney complex or genetic changes affecting adrenal signalling. Unusual age, health problems in the family, bilateral disease or other characteristic tumours may prompt genetic assessment. Cyclic Cushing's syndrome In cyclic Cushing's syndrome, cortisol excess appears and disappears over time. You may have periods of progressive symptoms followed by partial improvement. Tests can be normal during a low cortisol phase. Repeated late night salivary cortisol or urinary free cortisol testing may be more informative than a single dexamethasone test when cyclic disease is suspected. Normal tests do not justify endless investigation in everyone. Repeated testing is reserved for a strong evolving clinical pattern under endocrine supervision. Why symptoms vary The clinical picture depends on the amount and duration of cortisol exposure, age, sex, other illnesses and individual tissue sensitivity. A gradual pituitary disorder may produce classic physical changes over years. Ectopic ACTH from an aggressive tumour can cause severe biochemical illness with fewer visible changes. External corticosteroids can create a different pattern according to their anti inflammatory potency, mineralocorticoid effect and dosing schedule. No single appearance proves Cushing's syndrome, and the absence of one classic sign does not exclude it. Central or truncal weight gain Cortisol excess changes fat distribution and often increases appetite. Fat tends to accumulate around the abdomen, chest and internal organs while the limbs may become relatively thin because of muscle loss. Total weight can increase, but some people with severe ectopic disease lose weight because of cancer or profound catabolism. Central weight gain is common in the general population. It becomes more concerning when it progresses alongside muscle weakness, easy bruising, purple striae or early osteoporosis. Rounded face The face can become rounder and fuller, sometimes called a moon face. Facial redness or plethora may become noticeable, particularly in endogenous disease. These changes develop gradually and can be emotionally difficult. Photographs taken over time may help demonstrate progression. A rounded face alone is not specific. Weight change, alcohol, medicines and other conditions can produce a similar appearance. Dorsocervical and supraclavicular fat Fat can accumulate over the upper back at the base of the neck. This is called a dorsocervical fat pad and is sometimes described informally as a buffalo hump. Fat may also collect above the collarbones, making the supraclavicular fossae appear full. These findings occur with obesity and some medicines as well as Cushing's syndrome. They support the diagnosis only when combined with a more specific and progressive feature pattern. Purple striae Cortisol weakens skin connective tissue while the body changes shape. Wide reddish purple stretch marks can develop across the abdomen, thighs, breasts, hips or upper arms. Striae wider than ordinary pale stretch marks are more suggestive of Cushing's syndrome, particularly when they appear without rapid pregnancy or growth related change. Colour may appear dark red, violaceous or different from your usual skin tone. Assessment should not rely on one colour description. Thin skin and easy bruising Cortisol excess reduces collagen formation and makes skin thinner and more fragile. You may bruise after minor contact or without remembering an injury. Small cuts can heal slowly. Blood vessels may become more visible, and adhesive dressings can damage delicate skin. Anticoagulants, platelet disorders, liver disease and physical injury can also cause bruising. Unexplained or severe bleeding requires a broader assessment. Acne, hair and androgen effects Acne can develop or worsen because cortisol and adrenal androgen patterns change. Women may develop increased coarse facial or body hair. Scalp hair can become thinner. Rapid virilisation, including deepening voice, clitoral enlargement or marked muscle pattern change, raises concern about an androgen producing adrenal tumour. Hair and skin changes are common in polycystic ovary syndrome and other endocrine conditions, so the complete pattern matters. Proximal muscle weakness Cortisol breaks down muscle protein and reduces muscle repair. Weakness is most noticeable in muscles close to the trunk. You may struggle to rise from a low chair, climb stairs, lift your arms or get out of a bath. This is different from feeling tired or having painful movement. Examination may show genuine loss of power and reduced muscle bulk. Severe weakness can impair mobility and increase falls, thrombosis and loss of independence. High blood pressure Cortisol increases vascular sensitivity and can activate mineralocorticoid pathways. Hypertension is common and may be difficult to control with ordinary treatment while cortisol remains excessive. Very high blood pressure can cause headache, chest pain, breathlessness or neurological symptoms. Blood pressure treatment begins promptly, but lasting improvement usually requires control of the cortisol source. High blood glucose and diabetes Cortisol raises blood glucose by increasing liver glucose production and reducing insulin sensitivity. Existing diabetes can worsen, or diabetes may appear for the first time. High glucose can increase thirst, urination, infection risk and impaired wound healing. Diabetes treatment may need rapid adjustment as cortisol rises or falls. After successful treatment, insulin or tablet requirements can fall quickly and hypoglycaemia becomes possible if doses are not reviewed. Bone loss and fractures Chronic cortisol excess reduces bone formation, increases bone breakdown and impairs calcium balance. Osteoporosis can develop at a younger age than expected. Vertebral, rib, wrist and hip fractures may occur after minor trauma. A vertebral fracture can present as sudden back pain, height loss or increasing spinal curvature. Bone density assessment, calcium and vitamin D adequacy, falls prevention and osteoporosis treatment may be required alongside control of hypercortisolism. Mood and cognitive changes Cushing's syndrome can cause depression, anxiety, irritability, emotional lability and difficulty concentrating. Some people develop severe insomnia, agitation, mania, paranoia or psychosis. Psychiatric symptoms are biological complications of cortisol excess and may also be intensified by the distress of physical illness. Suicidal thoughts, severe behavioural change or inability to remain safe requires urgent assessment. Endocrine treatment and mental health care may be needed together. Menstrual and fertility changes Periods may become irregular, lighter or stop because cortisol disrupts reproductive hormone signalling. Fertility can fall, although pregnancy can still occur. Men may develop reduced libido, erectile difficulty, low testosterone or reduced fertility. Symptoms can overlap with polycystic ovary syndrome, menopause, pituitary disease and chronic illness. Infection susceptibility Cortisol excess suppresses immune responses and can reduce the usual inflammatory signs of infection. Skin, urinary, respiratory, fungal and opportunistic infections can occur more often. A serious infection may cause less fever or redness than expected. Deterioration, confusion, breathlessness or low blood pressure should not be dismissed because temperature is normal. Infections are a major cause of illness and death in severe Cushing's syndrome and require prompt treatment. Poor wound healing Thin skin, impaired collagen production, high glucose and immune suppression delay wound healing. Cuts may reopen, surgical wounds may heal slowly and infection risk may rise. Pressure areas need protection when weakness and immobility are present. Planned surgery requires attention to glucose, nutrition, infection, thrombosis and cortisol control rather than treating the wound issue in isolation. Fluid retention and low potassium Cortisol can activate mineralocorticoid receptors when levels are very high. You may develop ankle swelling, hypertension and potassium loss. Severe hypokalaemia is particularly associated with aggressive ectopic ACTH syndrome. Low potassium can cause weakness, cramps, constipation and dangerous heart rhythms. Electrolytes require urgent correction while the cortisol source is treated. Children can stop growing In children, weight gain combined with slowing height growth is a particularly important clue. Ordinary weight gain often accompanies continued linear growth. Cortisol excess suppresses growth while increasing fat accumulation. Pubertal development can also be delayed. Paediatric Cushing's syndrome is rare and requires specialist endocrine assessment rather than broad screening of every child with obesity. Who should be tested Testing is appropriate when several progressive features suggest cortisol excess, particularly those unusual for age. Examples include early osteoporosis, unexplained proximal weakness, wide purple striae, easy bruising and difficult hypertension or diabetes. Children with increasing weight and decreasing height percentile and people with an adrenal incidentaloma showing suspicious features may also need assessment. Widespread testing of everyone with obesity, depression or diabetes produces many false positive results and is not recommended. First exclude exogenous glucocorticoid exposure A careful medicine details comes before biochemical screening. The clinician asks about tablets, inhalers, creams, nasal sprays, eye preparations, injections, implants and unregulated products. The exact drug, dose, frequency, duration and timing of recent injections matter. Interacting medicines are reviewed. If external glucocorticoid exposure explains the syndrome, tests designed to find endogenous overproduction may be misleading or unnecessary. Why random cortisol is not a screening test Cortisol changes throughout the day and rises with stress, pain and illness. A single random serum cortisol cannot reliably confirm or exclude Cushing's syndrome. Plasma ACTH is also not an initial screening test. It is used to locate the source only after endogenous hypercortisolism has been established. Imaging before biochemical confirmation risks finding incidental pituitary or adrenal abnormalities unrelated to the symptoms. The overnight dexamethasone suppression test Dexamethasone is a potent synthetic glucocorticoid. In a healthy feedback system, a small night time dose suppresses ACTH and lowers morning cortisol. In the usual one milligram overnight test, dexamethasone is taken late in the evening and serum cortisol is measured the next morning. Failure to suppress below the laboratory threshold suggests autonomous cortisol activity but does not confirm the diagnosis alone. The dose timing, absorption and interacting medicines must be reliable for the result to be interpretable. Factors that distort dexamethasone testing Enzyme inducing medicines can clear dexamethasone too quickly and create a false positive result. Some medicines slow its breakdown. Oral oestrogen raises cortisol binding globulin and can make total serum cortisol appear higher. Poor adherence, vomiting, altered sleep schedules and laboratory variation can also affect the test. Unexpected results should be reviewed with the complete medicine and reproductive history rather than repeated mechanically. Twenty four hour urinary free cortisol Urinary free cortisol estimates the unbound cortisol filtered into urine over a complete day. At least two correctly collected 24 hour samples are commonly required because cortisol production varies. Incomplete collection, excessive fluid intake and kidney impairment can make the result unreliable. A normal result can occur during a low phase of cyclic disease, while severe stress can raise cortisol without a tumour. Late night salivary cortisol Healthy cortisol reaches a low point around late evening or midnight. A saliva sample collected at home can show whether this normal night time fall has been lost. Two measurements are commonly obtained because biological variation is expected. Shift work, irregular sleep, smoking near collection, oral bleeding and contamination with steroid cream can distort the result. Why confirmation usually needs two concordant tests One abnormal screening result may reflect stress, medicine interference, collection error or non neoplastic hypercortisolism. Endocrine assessment usually repeats the same test or performs a different recommended test. Concordantly abnormal results from two appropriate tests support endogenous Cushing's syndrome when exogenous exposure and pseudo Cushing states have been considered. Discordant or repeatedly normal results require interpretation according to clinical probability and possible cyclic disease. They do not justify jumping directly to tumour surgery. Pseudo Cushing states Some conditions activate the hypothalamic pituitary adrenal axis without an autonomous cortisol producing tumour. Alcohol dependence, major depression, severe obesity and poorly controlled diabetes can produce clinical and biochemical overlap. Severe stress, eating disorders and obstructive sleep apnoea can also contribute. The term pseudo Cushing can sound dismissive. Non neoplastic hypercortisolism is a more accurate description because the physiological cortisol disturbance is real. Treating the underlying condition and repeating carefully chosen tests may clarify whether autonomous Cushing's syndrome remains present. Alcohol related hypercortisolism Sustained heavy alcohol use can cause central weight change, facial redness, hypertension, muscle weakness and abnormal cortisol tests. Liver disease can further alter cortisol metabolism and binding proteins. Alcohol dependence must be managed safely because abrupt withdrawal can cause seizures and delirium. Improvement after supported abstinence can help distinguish alcohol related activation from autonomous Cushing's syndrome. Depression and severe stress Major depression can disturb sleep and the daily cortisol rhythm. Weight change, hypertension, diabetes and cognitive symptoms can overlap with Cushing's syndrome. Severe endogenous Cushing's syndrome can itself cause depression or psychosis, so a mental health diagnosis does not exclude an endocrine disorder. Clinicians look for progressive discriminatory physical features and use repeated specialist testing when the distinction remains uncertain. Obesity and poorly controlled diabetes Obesity and diabetes are common, while endogenous Cushing's syndrome is rare. Both can raise cortisol responses and produce central weight gain, hypertension, infection and menstrual change. Wide purple striae, spontaneous bruising, proximal muscle weakness and unexpectedly early fractures increase the probability of Cushing's syndrome. Testing should be targeted to the complete pattern rather than triggered by body size alone. Confirm the syndrome before locating the tumour Cause finding tests are only interpreted reliably after endogenous cortisol excess has been confirmed. A pituitary microadenoma or adrenal nodule may occur incidentally in someone without Cushing's syndrome. Starting with imaging can anchor the diagnosis to an unrelated lesion and expose you to unnecessary surgery. The safe sequence is to establish hypercortisolism, determine ACTH dependence and then use targeted imaging or venous sampling. Plasma ACTH after confirmation Plasma ACTH divides endogenous Cushing's syndrome into ACTH dependent and ACTH independent groups. A suppressed ACTH suggests that an adrenal source is producing cortisol independently. A measurable or raised ACTH suggests a pituitary or ectopic source. Intermediate results can occur and require repeat measurement, correct sample handling and specialist dynamic testing. Investigating ACTH independent disease When ACTH is suppressed, adrenal imaging is used to identify a cortisol producing lesion. CT or MRI assesses size, density, shape, invasion and whether one or both glands are involved. A small benign appearing adenoma produces a different management pathway from a large irregular lesion suspicious for carcinoma. Hormone testing can assess additional adrenal products when carcinoma or another functioning tumour is possible. Investigating ACTH dependent disease When ACTH is not suppressed, the main distinction is pituitary Cushing's disease versus ectopic ACTH secretion. Pituitary MRI is the preferred first imaging test for an ACTH secreting adenoma. Chest and abdominal imaging may be required to look for a neuroendocrine tumour when ectopic secretion is possible. Small incidental pituitary lesions are common, so MRI findings must match the biochemical evidence. High dose dexamethasone testing A high dose dexamethasone suppression test may be used as one part of distinguishing pituitary from ectopic ACTH secretion. Some pituitary corticotroph tumours retain partial glucocorticoid feedback and suppress cortisol at a high dose. Ectopic tumours often do not. The separation is imperfect. Some pituitary tumours fail to suppress and some ectopic tumours show suppression. Modern specialist practice interprets this test alongside MRI, ACTH, other dynamic tests and, when necessary, inferior petrosal sinus sampling. Inferior petrosal sinus sampling Inferior petrosal sinus sampling is a specialised procedure used when ACTH dependent Cushing's syndrome is confirmed but the pituitary source remains uncertain. Catheters are passed through veins to sample blood draining both sides of the pituitary and compare ACTH with peripheral blood. A central to peripheral ACTH gradient supports Cushing's disease. Lack of a gradient supports an ectopic source when the procedure is technically successful. The test should be performed in an experienced centre. It is not a screening test and does not diagnose cortisol excess by itself. Pituitary MRI limitations Many ACTH producing pituitary adenomas are only a few millimetres across. Standard MRI may not show them, while a small incidental lesion may be seen in someone with ectopic ACTH. Higher resolution imaging and expert neuroradiology review can improve detection but cannot replace biochemical localisation. A negative MRI does not exclude Cushing's disease when the ACTH dependent evidence is strong. Treat the cause and the complications The central treatment goal is to remove or control the source of excess glucocorticoid. At the same time, clinicians treat hypertension, diabetes, hypokalaemia, infection, osteoporosis, psychiatric illness and thrombosis risk. Severe hypercortisolism may need urgent medical control before definitive tumour surgery. Care usually involves endocrinology, endocrine surgery or neurosurgery, anaesthesia and other specialties according to the cause. Managing exogenous Cushing's syndrome The first step is to confirm every glucocorticoid source and why each product is needed. The prescriber reduces exposure to the lowest effective dose, considers steroid sparing treatment and removes unnecessary duplication. Tapering is individual because the underlying disease and the suppressed adrenal axis both need protection. Physical changes can improve gradually, while diabetes, blood pressure, bone and infection risks require active management during recovery. Glucocorticoid tapering and adrenal safety Higher supraphysiological doses can often be reduced more quickly than doses near the body's normal cortisol requirement. The taper usually slows near the physiological range because the adrenal axis may need time to recover. Symptoms during withdrawal can reflect recurrent inflammatory disease, adrenal insufficiency or glucocorticoid withdrawal syndrome. These require different responses. NICE guidance provides structured withdrawal approaches, but the prescribing team adapts them to the medicine, duration and clinical condition. Transsphenoidal pituitary surgery First line treatment for Cushing's disease is usually selective removal of the pituitary adenoma by an experienced pituitary surgeon. A transsphenoidal approach reaches the pituitary through the nose and sphenoid sinus rather than through the skull from above. Successful surgery lowers ACTH and cortisol and can lead to remission. Risks include bleeding, infection, cerebrospinal fluid leak, diabetes insipidus and deficiency of other pituitary hormones. Persistent or recurrent Cushing's disease Pituitary surgery does not cure every case, and disease can recur years after apparent remission. Options include repeat surgery, pituitary radiotherapy, pituitary directed medicine, adrenal steroidogenesis inhibitors or bilateral adrenalectomy. The choice depends on tumour visibility, cortisol severity, previous treatment, fertility plans and other pituitary function. Lifelong biochemical follow up is required even after successful pituitary surgery. Adrenal surgery A benign unilateral cortisol producing adrenal adenoma is usually treated by removing the affected adrenal gland. An adrenal carcinoma requires cancer specialist surgery aimed at complete removal, sometimes with additional mitotane or systemic treatment. Bilateral adrenalectomy rapidly removes cortisol production but creates permanent primary adrenal insufficiency. Anyone losing both adrenal glands needs lifelong glucocorticoid, mineralocorticoid, sick day and emergency injection management. Treating an ectopic ACTH tumour When possible, the ACTH producing tumour is localised and surgically removed with appropriate lymph node assessment. Small neuroendocrine tumours can be difficult to find. Repeated specialist imaging may be required. Metastatic or unresectable disease may need tumour directed oncology treatment and cortisol lowering medicine. In uncontrolled life threatening disease, bilateral adrenalectomy can provide rapid cortisol control even when the ACTH source remains. Metyrapone Metyrapone blocks an adrenal enzyme needed to make cortisol. It can lower cortisol relatively quickly and is used before surgery, when surgery is delayed, or for persistent or recurrent disease. Treatment can increase androgen and mineralocorticoid precursors, causing acne, increased hair growth, hypertension, swelling or low potassium. Excessive dosing can cause adrenal insufficiency. Specialist biochemical monitoring and sick day education are essential. Ketoconazole Ketoconazole can inhibit several adrenal steroid producing enzymes. It may be used to control cortisol when surgery is not possible, has not cured the disease or while definitive treatment is arranged. It has major medicine interactions and can cause serious liver injury. Liver testing and specialist prescribing are required. Ketoconazole used for Cushing's syndrome is not ordinary self treatment with an antifungal medicine. Other cortisol lowering medicines Osilodrostat is another adrenal steroidogenesis inhibitor available through selected specialist pathways. Mitotane damages adrenal tissue and is used particularly for adrenocortical carcinoma, although its effects develop slowly and monitoring is complex. Etomidate can lower cortisol intravenously in critically ill people who cannot take oral medicine. These treatments can produce adrenal insufficiency, electrolyte change and interactions and require specialist supervision. Pituitary directed medicines Pasireotide and cabergoline can reduce ACTH secretion from some pituitary corticotroph tumours. They do not treat an adrenal cortisol producing tumour and are not reliable treatments for every ectopic source. Pasireotide can worsen hyperglycaemia. Cabergoline requires monitoring for effectiveness and adverse effects. They are generally used when pituitary surgery is unsuitable, incomplete or followed by recurrence. Glucocorticoid receptor blockade A glucocorticoid receptor antagonist can block cortisol action without reducing the measured cortisol concentration. Mifepristone is used in selected settings, particularly when hyperglycaemia is prominent, but access and licensing vary. Because cortisol remains high, ordinary cortisol measurements cannot guide the response safely. Low potassium, blood pressure, endometrial effects and clinical signs of excessive blockade require expert monitoring. Radiotherapy Pituitary radiotherapy can control residual or recurrent ACTH secreting tumour tissue. Its effect develops slowly over months or years, so medical cortisol control may be needed meanwhile. Radiotherapy can damage normal pituitary cells and cause delayed deficiencies of thyroid, gonadal, growth or ACTH hormones. Long term pituitary hormone testing and imaging are required. Cardiovascular disease Cortisol excess promotes hypertension, insulin resistance, dyslipidaemia, visceral fat and vascular injury. The risk of heart attack, stroke, heart failure and arrhythmia is increased. Cardiovascular risk does not disappear immediately after cortisol normalises. Blood pressure, diabetes, lipids, smoking and physical activity still need long term management. Chest pain, acute breathlessness or stroke symptoms require emergency action regardless of the endocrine diagnosis. Venous thromboembolism Cushing's syndrome creates a hypercoagulable state and increases the risk of deep vein thrombosis and pulmonary embolism. Risk is particularly important around surgery and can remain raised after biochemical cure. Clinicians assess personal bleeding and clotting risks and may prescribe perioperative or extended thromboprophylaxis. A swollen painful leg, sudden unexplained breathlessness, coughing blood, chest pain or collapse requires urgent assessment. Osteoporosis and fracture care Bone loss can be substantial even when you are relatively young. Assessment may include DXA scanning, vertebral imaging, calcium and vitamin D review and treatment with an osteoporosis medicine. Muscle rehabilitation and falls prevention are important because weakness adds to fracture risk. Bone density can improve after cure, but previous fractures and residual osteoporosis still require follow up. Infection prevention and treatment Cortisol control improves immune function, but recovery is not immediate. Vaccination, dental care, skin care and prompt investigation of infection may be recommended according to individual risk. Opportunistic infection prophylaxis can be needed in severe hypercortisolism. Fever may be absent or muted, so clinical deterioration matters more than one temperature reading. Psychological support Mood, cognition and identity can remain affected after cortisol normalises. Rapid physical and hormonal change after surgery can temporarily worsen fatigue, depression or anxiety. Psychological therapy, psychiatric treatment, occupational support and rehabilitation can be part of endocrine care. Symptoms should not be dismissed as a failure to appreciate being cured. Adrenal insufficiency after successful treatment When a cortisol producing source is removed, the normal hypothalamic pituitary adrenal axis may remain suppressed. After pituitary surgery or unilateral adrenalectomy, you may need hydrocortisone replacement until ACTH and the remaining adrenal tissue recover. Recovery can take months or longer. Morning cortisol or ACTH stimulation testing guides when replacement can stop. Until recovery is confirmed, sick day rules, emergency steroid access and a Steroid Emergency Card may be required. Glucocorticoid withdrawal syndrome After successful cure, you may feel worse before you feel better. Fatigue, nausea, reduced appetite, muscle and joint aches, low mood and flu like symptoms can occur as tissues adapt to normal cortisol exposure. These symptoms can occur despite adequate replacement and can overlap with adrenal insufficiency or recurrence. Frequent endocrine review is needed. Increasing steroid indefinitely can recreate Cushing's syndrome, while reducing too quickly can be dangerous. Adrenal crisis after withdrawal or surgery Adrenal crisis can occur if suppressed cortisol production is not replaced during illness, vomiting, trauma or surgery. Warning features include severe weakness, repeated vomiting, abdominal pain, low blood pressure, collapse, confusion and reduced consciousness. Emergency treatment is immediate intramuscular or intravenous hydrocortisone and intravenous fluids. This safety issue directly links treatment of cortisol excess with the adrenal insufficiency principles used in Addison's disease care. Pregnancy Endogenous Cushing's syndrome during pregnancy is rare and difficult to diagnose because pregnancy changes cortisol binding proteins and cortisol production. Uncontrolled disease increases risks including hypertension, diabetes, pre eclampsia, infection, preterm birth and poor fetal growth. Testing and treatment require a specialist endocrine and maternal fetal medicine team. If you take long term corticosteroids, you should not stop them because of pregnancy. Both the underlying illness and adrenal suppression require planned care. Long term monitoring Follow up assesses cortisol control, recurrence and treatment related adrenal insufficiency. Blood pressure, glucose, lipids, weight, electrolytes, bone health, infections, mental health and reproductive function require review. Pituitary disease needs long term MRI and pituitary hormone surveillance. Adrenal carcinoma and ectopic tumours require cancer specific follow up. A new progressive Cushingoid pattern years after treatment should prompt reassessment rather than being attributed automatically to old damage. Recovery takes time Bruising and glucose control may improve relatively quickly after cortisol falls. Muscle strength, skin integrity, bone health, mood and body composition often recover over months or years. Some complications, including fractures, cardiovascular disease or persistent pain, may not reverse completely. Realistic rehabilitation focuses on rebuilding function while continuing surveillance for recurrence and adrenal insufficiency. The main diagnostic and safety lessons The commonest cause overall is corticosteroid treatment, so every route and interaction must be identified first. Endogenous Cushing's syndrome should be confirmed with appropriate concordant biochemical testing before imaging is used to find a tumour. Treatment removes or controls the cortisol source and actively manages infection, thrombosis, cardiovascular, bone and psychiatric complications. Steroids must never be withdrawn abruptly, and successful tumour treatment can create temporary or permanent adrenal insufficiency requiring emergency preparation.

Always identify prescribed or hidden corticosteroid exposure before investigating endogenous Cushing's syndrome. External steroids require safe supervised reduction, while confirmed endogenous disease is localised and treated without forgetting the major risk of adrenal insufficiency during withdrawal or after successful surgery.