Endocrine emergencies: an initial framework

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Endocrine emergencies often present through common final pathways: circulatory failure, altered mental state, arrhythmia, temperature disturbance, dehydration or electrolyte-mediated neuromuscular dysfunction. Initial care therefore starts with physiology, not a comprehensive hormone panel. Oxygen when indicated, vascular access, monitoring, bedside glucose and prompt laboratory assessment can reveal immediately treatable hypoglycaemia, acidosis or potassium disturbance. A focused history then seeks diabetes treatment and omission, steroid dependence, pituitary or adrenal disease, thyroid disease, pregnancy, recent surgery, infection, vomiting, fluid intake, psychotropic or diuretic medicines and recreational drugs. Obtain diagnostic samples early where practical, but never make cortisol, ketone or osmolality confirmation a reason to withhold lifesaving therapy.

The corrective trajectory differs by syndrome. In DKA, fixed-rate insulin, fluid, potassium management and ketone clearance are coordinated under the current JBDS and local pathway, with continuation or timely replacement of background basal insulin. In HHS, fluid often has the leading initial role and the fall in osmolality must be controlled; early insulin can accelerate dangerous shifts unless ketonaemia creates a mixed picture. Adrenal crisis requires immediate glucocorticoid and crystalloid, while severe symptomatic hyponatraemia uses closely monitored hypertonic saline boluses under specialist guidance, not unmeasured free correction. Pituitary apoplexy, thyroid crises and calcium emergencies need early specialist input and trigger treatment. The framework is deliberately not a substitute for current emergency algorithms, critical-care assessment or local medicine governance.

Key points

Bedside glucose is the fastest reversible endocrine assessment in any patient with altered behaviour, seizure, focal neurology or reduced consciousness.
DKA is defined by the combination of hyperglycaemia or known diabetes, ketonaemia and acidosis; glucose alone neither confirms nor grades it.
HHS produces profound hyperosmolality and dehydration with little significant ketonaemia, so fluid replacement and osmolality trajectory require particular care.
Suspected adrenal crisis is a clinical treatment decision: draw cortisol if this causes no delay, then give parenteral hydrocortisone and isotonic fluid promptly.
A sudden headache with visual or ocular-motor abnormality may be pituitary apoplexy; protect cortisol physiology and obtain urgent specialist imaging advice.
Severe symptomatic hyponatraemia, acute hypocalcaemia and marked hypercalcaemia each demand cause-aware protocols because overly rapid or inappropriate correction can injure.
Thyroid storm and myxoedema coma are multisystem syndromes rather than laboratory diagnoses; exclude infection, myocardial events, medicines and other precipitants concurrently.
Repeated observations and biochemical rate of change determine response; reaching a target too rapidly can be as hazardous as failing to improve.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Insulin-deficient emergencies

Omitted or inadequate insulin, infection and acute illness can precipitate ketoacidosis or hyperosmolar decompensation through hyperglycaemia, ketones and water loss.

Hormone failure

Acute cortisol deficiency or pituitary apoplexy can cause shock, hypoglycaemia, hyponatraemia and altered consciousness without a previously recognised endocrine diagnosis.

Hormone or electrolyte excess

Thyrotoxic decompensation and severe sodium, potassium or calcium disturbance can produce arrhythmia, neurological failure, dehydration or temperature instability.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Homeostatic reserve is overwhelmed
Abrupt hormone failure, hormone excess or electrolyte change disrupts vascular tone, membrane function, metabolism or water balance faster than compensation can respond.
2
Common physiological syndromes emerge
Different endocrine causes converge on shock, altered consciousness, arrhythmia, dehydration, temperature disturbance and neuromuscular dysfunction, so initial stabilisation must follow the physiological syndrome.
3
Correction can create secondary injury
Rapid changes in glucose, sodium or osmolality can move water across cell membranes, while treatment-related potassium shifts can destabilise cardiac conduction.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Diabetic ketoacidosis

Polyuria, vomiting, abdominal pain, dehydration, deep breathing and acetone odour with blood ketones and metabolic acidosis support DKA; SGLT2-associated episodes may have only modest glucose elevation.

Hyperosmolar state

Older or vulnerable adults may develop days of thirst, profound volume depletion, neurological change and very high effective osmolality without substantial acidosis; thrombosis and comorbidity are common concerns.

Adrenal crisis

Hypotension, collapse, vomiting, abdominal pain, fever, hyponatraemia, hyperkalaemia or hypoglycaemia in a steroid-dependent or at-risk patient should trigger immediate treatment, although electrolytes may be normal in central insufficiency.

Pituitary apoplexy

Abrupt severe headache, reduced acuity or visual field, diplopia, ophthalmoplegia, meningism or impaired consciousness with possible hypotension indicates sellar haemorrhage or infarction until assessed urgently.

Thyroid decompensation

Hyperthermia, agitation, tachyarrhythmia, heart failure and gastrointestinal disturbance suggest thyroid storm; hypothermia, bradycardia, hypoventilation, hyponatraemia and obtundation suggest myxoedema coma.

Calcium or sodium neurotoxicity

Tetany, laryngospasm, prolonged QT or seizure suggests acute hypocalcaemia, whereas dehydration, shortened QT and confusion can accompany severe hypercalcaemia; acute sodium shifts commonly cause headache, seizure or coma.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Capillary glucose and blood ketonesFirst step
Why
Identify hypoglycaemia immediately and establish whether ketonaemia is driving an acute diabetic presentation.
Interpretation and limitations
Treat low glucose at once. Significant ketonaemia requires acid-base assessment and a DKA or mixed pathway even when glucose is not strikingly high.
02
Venous blood gas
Why
Measure pH and bicarbonate rapidly while providing lactate and other point-of-care information.
Interpretation and limitations
Metabolic acidosis with ketonaemia supports DKA; lactate, renal failure, toxins and sepsis remain alternative or additional causes and influence resuscitation.
03
Electrolytes, renal function and osmolality
Why
Quantify dehydration, sodium disturbance, potassium risk and hyperosmolar physiology and create a baseline for correction rate.
Interpretation and limitations
Use serial trends and the syndrome-specific calculation accepted by the local pathway. Potassium can fall rapidly during DKA treatment despite an initially normal or high value.
04
ECG and continuous rhythm monitoring
Why
Detect potassium, calcium, temperature and ischaemia-related electrical instability during presentation and correction.
Interpretation and limitations
Rhythm or interval abnormalities increase urgency and can guide monitored replacement, but a normal tracing does not exclude a serious biochemical disturbance.
05
Cortisol and paired ACTH before steroids when feasible
Why
Preserve diagnostic information in possible adrenal crisis without postponing glucocorticoid administration.
Interpretation and limitations
A pre-treatment sample can support later confirmation; emergency management remains clinical and an indeterminate result after exogenous steroid needs endocrine interpretation.
06
Precipitant screen
Why
Find infection, infarction, medicine interruption, pregnancy, trauma or other trigger that will perpetuate the emergency.
Interpretation and limitations
Tailor cultures, imaging, troponin, lipase and other tests to the presentation. Treating the metabolic syndrome without its precipitant invites relapse or failure to improve.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Sepsis

Fever, shock, confusion and lactate elevation overlap strongly; infection can also precipitate endocrine collapse, so both pathways may require simultaneous action.

Cardiovascular catastrophe

Acute coronary syndrome, pulmonary embolism, haemorrhage or arrhythmia can explain circulatory collapse and should be assessed alongside endocrine triggers.

Toxicological emergency

Overdose, withdrawal or recreational drugs can produce temperature, rhythm, acid-base and mental-state changes that mimic endocrine disease.

Primary neurological disease

Stroke, seizure, meningitis or intracranial haemorrhage can cause altered consciousness and endocrine-like biochemical changes, requiring parallel neurological assessment.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01First ten minutesStabilise and identify reversible physiologyFirst stepAn acutely unwell patient may have endocrine or metabolic decompensation.

1Run ABCDE with monitors and intravenous access, check bedside glucose and ketones, and treat hypoglycaemia immediately while confirming response.
2Send blood gas, electrolytes, renal function, calcium and syndrome-specific samples, recording all treatment given before sampling.
3Call senior acute support and activate the current local emergency protocol as soon as DKA, HHS, adrenal crisis, severe electrolyte disturbance or apoplexy is suspected.

02Controlled correctionTreat the syndrome and follow its trajectoryInitial results support a specific endocrine emergency and resuscitation is underway.

1Use protocolised fluid, insulin, glucocorticoid, electrolyte or hypertonic therapy appropriate to the syndrome, with critical-care input when severity or comorbidity warrants.
2Measure the variable that reflects resolution: ketone clearance and bicarbonate in DKA, osmolality in HHS, haemodynamics in adrenal crisis, or symptoms and sodium after hypertonic saline.
3Adjust treatment when the rate is unsafe, potassium changes, fluid overload appears or neurological state worsens; do not chase glucose or sodium as an isolated target.

03Prevent recurrenceFind the cause and plan transitionDefinitiveThe immediate physiological threat is resolving but definitive diagnosis and discharge safety remain incomplete.

1Identify and treat the precipitant, complete endocrine confirmation once emergency medicines permit interpretation, and reconcile all diabetes or steroid prescriptions.
2Transition infusions only when pathway resolution criteria are met and overlap subcutaneous insulin safely where required, with specialist agreement for complex cases.
3Before discharge, provide condition-specific sick-day rules, emergency supplies or identification, follow-up ownership and a written explanation of when to seek urgent help.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Rapidly replaces deficient glucocorticoid and supports vascular responsiveness during adrenal crisis or acute pituitary ACTH failure.

Hydrocortisone

For suspected adrenal crisis, give 100 mg intravenously or intramuscularly immediately, followed by the current Society for Endocrinology or local emergency replacement regimen with specialist review.

Treatment should not await cortisol results. Monitor glucose, potassium, sodium and fluid status, and plan step-down and mineralocorticoid management with endocrinology once stable.

Suppresses ketogenesis and clears ketoacidosis; glucose reduction is not its sole therapeutic purpose.

Intravenous insulin for DKA

Use the current JBDS-aligned fixed-rate intravenous insulin infusion based on measured body weight, with fluids, potassium and background basal-insulin decisions specified by the local pathway.

Check potassium before and during therapy, add glucose-containing fluid when required to permit ongoing ketone clearance, and never stop solely because capillary glucose normalises.

Restores circulating glucose rapidly when oral treatment is unsafe or ineffective.

Intravenous glucose for severe hypoglycaemia

Give a locally approved intravenous glucose preparation and amount when access is available, then recheck promptly and provide longer-acting carbohydrate or infusion according to recurrence risk.

Protect the cannula because hypertonic preparations can extravasate. Persistent or sulfonylurea-related hypoglycaemia needs prolonged observation and cause-specific management.

Produces a small controlled sodium rise to reduce acute cerebral oedema and stop severe neurological symptoms.

Hypertonic sodium chloride

For severe symptomatic hyponatraemia, administer protocol-defined boluses in a monitored setting with senior or specialist oversight and very frequent sodium reassessment.

Overcorrection risks osmotic demyelination. Account for chronicity, spontaneous water diuresis and potassium replacement, and follow explicit limits and rescue steps in current guidance.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Multiorgan failure

Persistent shock, severe metabolic disturbance or delayed diagnosis can impair kidney, cardiac, respiratory and neurological function simultaneously.

Arrhythmia and cardiac arrest

Potassium, calcium, temperature and catecholamine abnormalities alter myocardial conduction and contractility, sometimes without a reliable stepwise warning pattern.

Iatrogenic neurological injury

Over-rapid correction of sodium or osmolality can cause osmotic brain injury, making repeated measurements and controlled trajectories central to safe care.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Chart consciousness, respiratory pattern, blood pressure, pulse, temperature, oxygenation and urine output at a frequency matched to instability.
Trend glucose, ketones, pH or bicarbonate, potassium and fluid balance through DKA rather than treating the capillary glucose value alone.
Calculate and plot osmolality during HHS so fluid and insulin changes respond to the direction and rate of physiological correction.
During sodium emergencies, document the cumulative rise over relevant time windows and have an escalation plan if correction exceeds the local limit.
Repeat ECG and calcium or potassium testing after replacement, watching for arrhythmia, extravasation and renal impairment.
Use a structured handover listing the syndrome, precipitant, trajectory, outstanding results, medicine transition and specialist decisions.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Normal glucose can conceal DKA

SGLT2 inhibitors, pregnancy or reduced intake may produce clinically important ketoacidosis without marked hyperglycaemia. Ketones and acid-base status answer the question.

Potassium is a moving target

Insulin deficiency and acidosis shift potassium extracellularly despite whole-body loss. Insulin and improving acidosis can then reveal dangerous hypokalaemia quickly.

HHS is not simply severe DKA

The dominant problems are extreme water deficit and hyperosmolality. Applying an aggressive insulin-first approach can make osmotic change too rapid.

Steroid treatment preserves life

A pre-treatment cortisol is helpful, but hydrocortisone should precede diagnostic certainty in an unstable patient. The diagnosis can be refined after survival is secured.

Trigger treatment is definitive care

Infection, myocardial infarction, missed insulin or interrupted glucocorticoids may be the ongoing driver. Metabolic numbers will not remain corrected if the precipitant persists.

11Common pitfallsFrequent interpretation and management errors.

01
Excluding DKA because glucose is below the level expected in a classic presentation.
02
Stopping intravenous insulin when glucose improves while ketonaemia and acidosis remain unresolved.
03
Starting insulin early in pure HHS without first considering fluid-led osmolality correction and potassium.
04
Waiting for a cortisol result before giving hydrocortisone to a shocked steroid-dependent patient.
05
Correcting chronic hyponatraemia without plotting cumulative sodium change and anticipating water diuresis.
06
Discharging after biochemical recovery without sick-day education, emergency supplies and treatment of the trigger.