Synopsis
Recognise non-specific and muted presentations of serious illness, compare current function with a reliable baseline, avoid diagnostic overshadowing by age or frailty, and use disciplined broad-to-focused assessment without reflex overtesting.
- Atypical presentation means the initial symptom does not localise the cause: common signals are delirium, falls, immobility, incontinence, anorexia, fatigue and functional decline.
- First-line action is ABCDE, observations, capillary glucose, pain and full examination while collateral establishes exact onset and stable baseline.
- Serious infection can occur without fever or leukocytosis; use physiology, organ dysfunction, source assessment and trajectory rather than one absent classic sign.
- Delirium is acute brain failure and demands a cause search. Known dementia increases risk but never explains a sudden fluctuation by itself.
- Acute coronary syndrome may present with dyspnoea, weakness, nausea, syncope or delirium; obtain ECG and troponin when the context supports it.
- A fall is an event, not a diagnosis. Ask what happened before, during and after and examine for syncope, stroke, infection, medicine harm and injury.
- Reconcile recent prescriptions, missed doses and renal function early; a medicine that was previously tolerated can become toxic during dehydration or acute kidney injury.
- Do not diagnose urinary infection from bacteriuria or a positive dipstick alone in an older adult without compatible urinary or systemic evidence.
- Use targeted testing from competing high-consequence hypotheses and repeat examination; indiscriminate panels create incidental findings and treatment harm.
- Track function and cognition as vital outcomes. Failure to regain expected mobility or intake should reopen the diagnosis before discharge.
Key red flags
New delirium, drowsiness or agitation with physiological change requires urgent infection, hypoxia, metabolic, neurological, pain and medicine assessment.
Unexplained fall with syncope, chest discomfort equivalent, palpitations, focal neurology, head injury or inability to weight bear needs emergency evaluation.
New breathlessness, fatigue, nausea, diaphoresis or confusion may represent acute coronary syndrome without classic central chest pain.
Poor intake with hypotension, oliguria, hypoglycaemia, hyperglycaemia, electrolyte disturbance or acute kidney injury can deteriorate rapidly.
Abdominal distension, vomiting, altered bowel habit, guarding, retention or unexplained delirium may signal obstruction, perforation, ischaemia or urinary pathology despite modest pain.
A frailty or dementia diagnosis must not close the differential when change is acute, focal, progressive or inconsistent with baseline.
Acute inattention, fluctuation or altered arousal may be the only visible sign of systemic infection, hypoxia, pain or metabolic disease.
Dyspnoea, nausea, fatigue, collapse or confusion can replace chest pain in acute coronary, arrhythmic and thromboembolic disease.
Investigation priorities
Detect immediate physiological and metabolic threat.
Management branches
An older adult presents with a fall, confusion, weakness, poor intake or functional loss.
- Perform ABCDE, glucose, observations and immediate treatment while obtaining last-known-well and baseline collateral.
- Complete full examination and medicine reconciliation and investigate several plausible high-consequence causes in parallel.
- Repeat physiology, cognition and function and escalate when trajectory remains unexplained despite initially modest findings.