Clinical Guides
Addison's Disease
A clinically focused guide to recognising and confirming primary adrenal insufficiency, providing physiological replacement, preventing adrenal crisis, and adapting long-term care to Indian practice.
MedNext Academy | 14 min read
Addison's Disease
A clinically focused guide to recognising and confirming primary adrenal insufficiency, providing physiological replacement, preventing adrenal crisis, and adapting long-term care to Indian practice.
Summary
Addison's disease is chronic primary adrenal insufficiency: the adrenal cortex cannot produce enough cortisol and, in many patients, aldosterone. The eponym should not be used for every low cortisol result. Secondary or tertiary adrenal insufficiency arises from impaired pituitary or hypothalamic drive or suppression by exogenous glucocorticoids; mineralocorticoid function is usually preserved in those central forms. This distinction determines investigation, replacement and education. Primary disease may develop gradually with fatigue, weight loss, nausea, postural symptoms, salt craving and hyperpigmentation, or first become evident as adrenal crisis.
Suspected crisis is treated before biochemical confirmation. Hypotension or shock, vomiting, abdominal pain, severe weakness, hyponatraemia, hyperkalaemia, hypoglycaemia or altered consciousness in an at-risk person should trigger immediate parenteral hydrocortisone, isotonic fluid resuscitation, glucose assessment and treatment of the precipitant. A diagnostic blood sample is useful only if it does not delay therapy.
Stable diagnosis combines an appropriately timed cortisol assessment with adrenocorticotropic hormone, then a validated corticotropin stimulation test when needed and clinically safe. Renin, aldosterone and electrolytes assess mineralocorticoid loss; subsequent tests seek the cause. Long-term care requires individualised glucocorticoid and, when indicated, fludrocortisone replacement, a written sick-day plan, injectable emergency steroid access, medical-alert identification and regular endocrine review. Pregnancy, childhood, surgery, fasting, gastrointestinal illness and limited medicine access require planned adaptations. This educational draft does not diagnose a patient or replace an emergency protocol.
How Common Is It?
Primary adrenal insufficiency is uncommon, and incidence depends on case definition, ancestry, autoimmune disease, infection, genetic disorders, cancer treatment and access to hormonal testing. Published European and North American estimates cannot be presented as a current India-wide rate. Specialist-centre series also over-represent complicated, referred and surviving cases. Addison's disease is nevertheless important because delay is common: early fatigue, appetite loss, dizziness, gastrointestinal symptoms and low mood are non-specific, while a crisis may resemble sepsis or an acute abdomen.
Autoimmune adrenalitis predominates in many high-income cohorts. In India, tuberculosis remains a relevant cause of bilateral adrenal destruction, but its current proportion varies by region and referral setting; it should be investigated from clinical, microbiological and imaging evidence rather than assumed from geography. Other causes include congenital adrenal hyperplasia, bilateral haemorrhage, metastases, infiltrative disease, infection in an immunocompromised person, adrenalectomy and selected medicines. Immune-checkpoint inhibitors have created an additional iatrogenic population, although they may produce primary or central failure.
Risk does not end after diagnosis. Gastroenteritis that prevents oral absorption, febrile infection, injury, surgery, labour, interrupted medicine supply and failure to increase glucocorticoid during physiological stress are recurring crisis pathways. A previous crisis increases concern but absence of one does not make a patient safe. Useful service measures include time to emergency hydrocortisone, continuity of hydrocortisone and fludrocortisone supply, provision and expiry of injection kits, documented education, and readmission after vomiting illness. These local measures are more actionable than importing a foreign prevalence figure.
Risk Factors
Risk factors should be divided into causes of primary adrenal destruction and circumstances that expose limited adrenal reserve. Autoimmune adrenalitis may occur alone or with autoimmune thyroid disease, type 1 diabetes, coeliac disease, premature ovarian insufficiency, vitiligo or pernicious anaemia. Family history and syndromic clustering can support autoimmune polyglandular disease, but screening should follow the person's manifestations and specialist plan. In boys and men, neurological change, behavioural decline or a family history compatible with X-linked adrenoleukodystrophy requires prompt specialist consideration.
Infectious and structural risks include previous or active tuberculosis, disseminated fungal disease in an appropriate host, HIV-associated opportunistic infection, bilateral adrenal metastases, lymphoma, haemochromatosis, amyloidosis, adrenal haemorrhage, bilateral infarction and prior adrenal surgery. Anticoagulation, sepsis, major trauma, antiphospholipid disease and pregnancy-related catastrophe can increase haemorrhage or infarction risk. Some drugs accelerate cortisol metabolism or inhibit synthesis; checkpoint immunotherapy can injure adrenal or pituitary tissue. These exposures are clues, not proof, and stopping an essential drug without specialist discussion can cause harm.
Exogenous glucocorticoid exposure mainly creates secondary or tertiary insufficiency rather than Addison's disease. Risk can follow oral therapy and, at sufficient cumulative exposure, injections, potent topical products, inhaled treatment or interacting medicines. Abrupt withdrawal after hypothalamic-pituitary-adrenal suppression is dangerous. In established adrenal failure, vomiting, diarrhoea, fever, surgery, major dental procedures, fasting, strenuous endurance events, heat with salt loss and pregnancy-related hyperemesis can exceed ordinary replacement or prevent absorption. Financial barriers, travel, stock-outs, low health literacy and an emergency department unfamiliar with the diagnosis amplify physiological risk. Prevention must therefore address both disease and the care system.
Diagnosis
History
Ask about the tempo of fatigue, anorexia, unintentional weight loss, nausea, vomiting, abdominal discomfort, diarrhoea or constipation, salt craving, dizziness, syncope, muscle weakness and reduced function. Establish fever, infection, recent surgery, trauma, pregnancy, postpartum illness and inability to retain tablets. Review every glucocorticoid route, including injections, inhalers, skin preparations and unlabelled combination products, as well as antifungal, antiepileptic, tuberculosis and cancer therapies. Ask about autoimmune disease, tuberculosis exposure or treatment, malignancy, adrenal or pituitary surgery, postpartum haemorrhage and family history. Hyperpigmentation supports primary disease but its absence, especially in early disease or lighter change that is hard to recognise, does not exclude it.
Examination
Measure temperature, heart rate, supine and standing blood pressure when safe, hydration, weight and mental state. Look at palmar creases, scars, pressure points and oral mucosa for pigmentation, comparing with the patient's baseline rather than a colour chart. Assess vitiligo, thyroid signs and features of other autoimmune disease. In an acutely ill person, prioritise airway, breathing, circulation, capillary glucose, perfusion and urine output. Abdominal tenderness can occur in crisis, but guarding, bleeding, pregnancy complications or focal pathology still need independent evaluation.
Investigations
If crisis is possible, draw cortisol and ACTH together if immediately feasible, then treat without waiting. In a stable person aged at least one year, current guidelines uses an 8–9 am serum cortisol pathway with assay-aware thresholds and endocrine referral for indeterminate or low results. A standard corticotropin stimulation test confirms impaired reserve when circumstances allow. Interpret cortisol with timing, acute illness, albumin, pregnancy, oestrogen therapy, assay method and recent steroid exposure. Measure sodium, potassium, bicarbonate, glucose, renal function, ACTH, renin and aldosterone; primary failure typically has high ACTH and may have mineralocorticoid deficiency. After confirmation, determine cause using focused antibodies, imaging, infection testing or genetic/metabolic work-up rather than an indiscriminate panel.
Differential Diagnosis
Central adrenal insufficiency is the most important endocrine distinction. It may follow pituitary tumour or treatment, traumatic brain injury, postpartum pituitary necrosis, infiltrative disease or suppression after glucocorticoid therapy. ACTH is low or inappropriately normal, hyperpigmentation and hyperkalaemia are usually absent, and other pituitary hormone deficits may coexist. Recent glucocorticoid administration can both suppress cortisol and interfere with some assays. A random cortisol drawn at an unhelpful time, especially during changing illness, cannot by itself label either primary or central disease.
Common mimics include anaemia, hypothyroidism, chronic infection, malnutrition, malignancy, heart failure, chronic kidney or liver disease, coeliac disease, depression and medicine adverse effects. Postural dizziness may reflect dehydration, autonomic dysfunction or antihypertensive therapy. Hyponatraemia has many causes, including diuretics, gastrointestinal loss, heart or liver failure and inappropriate antidiuresis. Hyperkalaemia may arise from renal failure, laboratory haemolysis, potassium-sparing medicines or renin-angiotensin blockade. Weight loss and pigmentation can suggest malignancy, haemochromatosis or constitutional skin variation. Each feature changes probability; none is a solitary diagnostic stamp.
Acute crisis overlaps with septic, hypovolaemic, cardiogenic and obstructive shock; diabetic ketoacidosis; severe hypoglycaemia; acute abdomen; gastroenteritis; poisoning and pregnancy emergencies. These conditions can coexist with adrenal failure. Treating suspected cortisol deficiency must accompany, not replace, cultures, antimicrobials, bleeding control, imaging or obstetric care when indicated. Bilateral adrenal enlargement can represent tuberculosis, fungal infection, haemorrhage, metastasis, lymphoma or other infiltration, and imaging appearance rarely proves the cause. Autoimmune primary disease may have normal or atrophic glands. A coherent diagnosis therefore links physiology, hormone pattern and cause instead of relying on one symptom or scan.
Management
For stable confirmed primary adrenal insufficiency, the core plan is physiological glucocorticoid replacement, mineralocorticoid replacement when aldosterone is deficient, education and surveillance. Dose timing should approximate the normal circadian pattern while fitting work, school, fasting and sleep. Review wellbeing, postural symptoms, weight, blood pressure, electrolytes, salt craving, oedema and clinical evidence of glucocorticoid excess. Persistent fatigue is not an automatic reason to escalate steroid; first revisit adherence, timing, anaemia, thyroid disease, sleep, mood and other comorbidity.
Prevention of crisis is a treatment, not an optional leaflet. Give a written, rehearsed sick-day plan stating how the person's oral glucocorticoid changes during fever or significant illness, when to use the emergency intramuscular injection, and where to seek urgent care. The patient and at least one willing relative or carer should practise with the actual device if possible. Vomiting shortly after a dose, repeated vomiting, severe diarrhoea, collapse or clinical deterioration makes oral absorption unreliable and requires injection plus urgent assessment. Ensure spare tablets, an in-date kit, medical-alert information and a travel supply; record what is actually available locally.
Operations, invasive procedures, prolonged fasting, labour and severe illness need advance stress-cover instructions agreed with anaesthesia, endocrine and procedural teams. Treat the precipitant as well as cortisol deficiency. Pregnancy should be co-managed by endocrinology and obstetrics: clinical review is required through gestation, replacement may need adjustment, mineralocorticoid assessment is complicated by normal pregnancy physiology, and parenteral stress cover is required for labour according to the obstetric plan. Hyperemesis is particularly hazardous. No web guide can safely supply a universal pregnancy or perioperative regimen for every patient.
Prescribing Information
Hydrocortisone is commonly preferred for adult physiological replacement because its shorter action permits divided dosing. The Endocrine Society guideline describes a usual total adult range of 15–25 mg daily in two or three doses, with the largest dose on waking; this is an educational range, not an instruction to start or alter treatment without the prescriber. Prednisolone may be selected in some circumstances, while dexamethasone is generally difficult to titrate for routine primary disease. Children require body-size and growth-aware specialist dosing. Undertreatment risks fatigue, weight loss and crisis; chronic overreplacement risks weight gain, hypertension, diabetes, infection, osteoporosis, skin change and sleep or mood disturbance. Hormone levels are not used alone to chase a replacement dose.
Fludrocortisone replaces aldosterone in confirmed mineralocorticoid deficiency. Monitor postural symptoms, salt craving, blood pressure, oedema, sodium, potassium and, when used by the specialist, renin. Heat, heavy sweating and gastrointestinal fluid loss can change needs, but patients should not self-adjust repeatedly without a documented plan. Fludrocortisone is usually unnecessary in central adrenal insufficiency and does not replace glucocorticoid.
For suspected adult adrenal crisis, authoritative protocols use immediate hydrocortisone 100 mg intravenously or intramuscularly followed by ongoing stress-dose hydrocortisone and rapid isotonic saline, with glucose treatment when needed. Do not delay for a cortisol result or fear of a single emergency dose. Paediatric dosing is age- or body-surface-area specific and must follow a current paediatric emergency protocol. Sick-day oral doses, injection products, strengths and availability vary; instructions must match the patient's prescribed formulation. Check interactions, especially medicines that alter steroid metabolism. Pregnancy, breastfeeding, renal or cardiac fluid risk and transition from infusion require specialist decisions.
When to Refer
Refer promptly to endocrinology when a properly timed morning cortisol is low or indeterminate in the local assay pathway, ACTH is abnormal, a stimulation test is needed, primary disease is suspected, or symptoms persist despite an apparently reassuring but contextually unreliable result. Same-day specialist or emergency assessment is warranted for acute illness, symptomatic hypotension, vomiting that prevents replacement, significant electrolyte or glucose disturbance, or rapidly progressive symptoms. A patient already treated for crisis still needs etiological and long-term endocrine follow-up after stabilisation.
Additional referral follows cause and complication. Suspected pituitary disease needs pituitary hormone assessment and imaging under endocrine direction. Bilateral adrenal lesions, suspected tuberculosis or opportunistic infection, metastatic disease, haemorrhage or infiltrative disease require coordinated radiology, infectious-disease, oncology, haematology or surgical input. Children, adolescents and possible congenital or inherited disease need paediatric endocrinology and genetic counselling where appropriate. Associated autoimmune thyroid, coeliac, gonadal or diabetic disease should be investigated proportionately; starting thyroid hormone in unrecognised severe cortisol deficiency can precipitate deterioration.
Pregnancy merits preconception counselling when possible and coordinated endocrine-obstetric care throughout gestation, delivery and postpartum. Recurrent crises, repeated emergency injections, inability to recognise sick-day triggers, cognitive or language barriers, medicine stock-outs and financial access problems require more than another dose adjustment. Involve a pharmacist, primary-care team, educator, social worker or local emergency service as available, with consent. Referral does not transfer all responsibility: the referring clinician should provide interim safety instructions, reconcile medicines, document allergies and steroid dependence, and tell the receiving service if the patient is unstable.
Red Flags
Treat possible adrenal crisis as a time-critical emergency. Red flags include collapse, shock or persistent hypotension; marked weakness; repeated vomiting or diarrhoea; severe abdominal, back or leg pain; fever or hypothermia; confusion, unusual drowsiness, seizure or coma; hypoglycaemia; and major hyponatraemia or hyperkalaemia in a compatible setting. Risk is higher with known adrenal insufficiency, recent glucocorticoid withdrawal, pituitary or bilateral adrenal disease, checkpoint immunotherapy, major infection, trauma, surgery or labour. Normal pigmentation, a normal potassium or lack of a prior diagnosis does not rule crisis out.
Give emergency hydrocortisone and resuscitation when clinically suspected, drawing cortisol and ACTH only if this causes no delay. Check glucose and electrolytes, obtain vascular access, give isotonic crystalloid with reassessment, and treat sepsis, bleeding, cardiac disease or another precipitant concurrently. Fluid amount and speed must be individualised in children, pregnancy, older people and cardiac or renal impairment. Transfer to monitored care and contact endocrine expertise. A transient blood-pressure response does not prove the diagnosis and does not end evaluation.
Patients and families should regard inability to keep replacement tablets down, use of the emergency injection, worsening illness despite sick-day dosing, syncope or altered mental state as reasons for urgent medical care. Do not advise a person in shock to drive. A missing injection kit should never delay ambulance activation or emergency-department treatment. During handover, state the underlying diagnosis or risk, usual steroid, last dose, emergency dose and time, fluid given, precipitating symptoms, pregnancy status and relevant comorbidity. The safe principle is treat first, confirm when stable.
Indian Clinical Context
Indian practice spans endocrine centres with modern assays and districts where a morning cortisol, ACTH result, corticotropin ampoule or emergency hydrocortisone may not be immediately available. The response should be explicit uncertainty and a safe referral pathway, not a confident diagnosis from sodium or pigmentation. Laboratories use different cortisol methods and reference intervals; quote the assay, timing and recent steroid exposure. Corticotropin availability and storage can affect testing, while hydrocortisone and fludrocortisone brands, strengths and stock vary. The written plan should name the products the patient can actually obtain and an alternative facility, without improvising therapeutic substitutions.
Tuberculosis is an important aetiological consideration, particularly with constitutional symptoms, prior disease, immunosuppression or bilateral adrenal abnormalities. Investigate active and previous infection using current national tuberculosis pathways and site-appropriate microbiology; adrenal imaging alone neither confirms infection nor justifies empirical therapy in every patient. Autoimmune adrenalitis, cancer, haemorrhage, HIV-related infection and central or glucocorticoid-induced insufficiency remain competing explanations. Coordinate tuberculosis medicines with endocrine care because enzyme induction can alter glucocorticoid exposure.
Medical-alert cards modelled on overseas systems are useful, but an Indian patient also needs plain-language instructions, local-language translation where helpful, emergency contacts and a plan that works during travel, fasting, festivals, examinations and hot weather. Discuss affordability, refrigeration or storage instructions for the actual injection, expiry checks and who can administer it. Never promise uninterrupted national availability. Government and private services should document steroid dependence prominently and avoid abrupt discontinuation during admission. The MedNext guide adapts international endocrine evidence; it does not claim a single Indian dosing policy or replace institutional emergency, paediatric, obstetric or perioperative protocols.
NMC Competency Mapping
Addison's disease integrates physiology of the hypothalamic-pituitary-adrenal axis, adrenal cortex and renin-angiotensin-aldosterone system with biochemistry, pharmacology, pathology, medicine, emergency care and communication. Using the NMC Competency Based Medical Education Curriculum 2024 as the framework, an undergraduate should explain cortisol and aldosterone actions, feedback regulation, stress response and the biochemical consequences of primary versus central failure. The learner should connect autoimmune destruction, infection, haemorrhage, infiltration and treatment-related suppression to the observed hormone pattern.
Clinical competence means eliciting weight change, gastrointestinal symptoms, postural features, salt craving, infection, steroid exposure and autoimmune history; measuring haemodynamic and hydration status; recognising pigmentation without treating it as mandatory; and interpreting timed cortisol, ACTH, electrolytes and stimulation testing in context. The student should distinguish diagnostic sampling from emergency action and state that suspected crisis is treated before confirmation. They should also understand why renin and aldosterone matter in primary disease and why fludrocortisone is not routinely required in central disease.
A skills assessment can ask the learner to identify crisis, call for help, check glucose, establish monitoring, explain immediate hydrocortisone and fluids, and give a structured handover. Long-term communication includes teach-back of sick-day rules, vomiting actions, medical alerts, injection technique and medicine continuity. These are supervised competencies. Curriculum mapping does not authorise a student to prescribe replacement, conduct an unsupervised stimulation test, certify fitness, design pregnancy or surgical cover, or manage shock alone. Ethical practice includes acknowledging assay and access limitations and avoiding a tuberculosis label without evidence.
Key Exam Pearls for NEET PG
Primary adrenal insufficiency produces deficient cortisol with high ACTH and may reduce aldosterone, causing salt wasting, volume depletion, hyponatraemia, hyperkalaemia and raised renin. Hyperpigmentation reflects increased proopiomelanocortin-derived peptides and supports primary rather than central failure, but it is not universal. Secondary or tertiary insufficiency usually preserves aldosterone because the renin-angiotensin system remains intact; potassium may therefore be normal. Hyponatraemia can occur in both forms. Exogenous glucocorticoid withdrawal classically suppresses the axis and should not be mislabeled autoimmune Addison's disease.
In stable evaluation, a correctly timed morning cortisol is a screening step whose thresholds depend on assay and context. The standard corticotropin stimulation test assesses adrenal reserve; ACTH separates primary from central physiology, and renin with aldosterone assesses mineralocorticoid deficiency. Acute severe illness changes the sequence: obtain paired samples if immediately possible, but do not postpone parenteral hydrocortisone and resuscitation. Imaging is an aetiological investigation after hormonal reasoning, not the first diagnostic test for every tired patient.
Chronic primary disease needs glucocorticoid replacement and, when aldosterone is deficient, fludrocortisone. The largest hydrocortisone dose is generally given in the morning to approximate circadian physiology. Overreplacement has Cushingoid and metabolic consequences; persistent symptoms do not justify automatic escalation. Illness and surgery require stress dosing, while vomiting makes oral dosing unreliable. Pregnancy needs specialist monitoring and stress cover for labour. The classic emergency answer is immediate hydrocortisone plus isotonic saline and glucose correction when indicated, while searching for infection or another trigger. A single emergency dose is safer than delaying treatment for laboratory certainty.
Frequently Asked Questions
Is every low morning cortisol result the same as Addison's disease?
No. Timing, assay, acute illness, cortisol-binding proteins, pregnancy, oestrogen and recent glucocorticoids affect interpretation. Addison's disease specifically means primary adrenal failure, usually with high ACTH and sometimes mineralocorticoid loss. Central or steroid-induced failure has different physiology. A low or indeterminate result needs an assay-aware endocrine pathway and often stimulation testing; suspected crisis is treated immediately rather than waiting.
What should a patient do if vomiting prevents steroid tablets from staying down?
Follow the individual's written emergency plan. Repeated vomiting makes oral absorption unreliable: use the prescribed emergency intramuscular hydrocortisone if trained and able, call for urgent medical help, and take the injection kit and medicine list to hospital. Collapse, confusion, severe weakness or worsening illness requires emergency transport. An injection does not remove the need for fluids, glucose assessment, monitoring and treatment of the cause.
Does a person with Addison's disease need both hydrocortisone and fludrocortisone?
Glucocorticoid replacement is required in confirmed primary disease. Fludrocortisone is used when aldosterone deficiency is present and is adjusted using symptoms, postural blood pressure, electrolytes and specialist assessment. It is usually unnecessary in central adrenal insufficiency. Patients should not add, stop or repeatedly alter either medicine from a webpage, because underreplacement can cause crisis and overreplacement causes harm.
Can pregnancy proceed safely in someone with primary adrenal insufficiency?
Many people can have a successful pregnancy with planned endocrine and obstetric care. Replacement is reviewed clinically during gestation, hyperemesis is treated as an absorption and crisis risk, and a written parenteral stress-cover plan is required for labour and delivery. Normal pregnancy changes complicate renin and cortisol interpretation. Doses should not be copied from a generic guide; urgent assessment is needed for persistent vomiting, collapse or reduced wellbeing.
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