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Atypical presentation of illness in older adults
In an older adult, especially a frail one or one with dementia, acute illness often presents not with a symptom of the diseased organ but with a general "geriatric" symptom — confusion, a fall, functional decline, not eating or incontinence — so any sharp change in function is a sign of illness that must be looked for.
Why it matters in the exam
The exam presents a care-home resident who has stopped eating, become drowsy and fallen, with no fever and no cough, and asks for the next step: look for infection (pneumonia, urinary tract infection, abdomen), a silent infarction, dehydration, an electrolyte disturbance or a new drug. Candidates are also asked about the definition of fever in an institution: a single reading above 37.8°C, repeated readings above 37.2°C, or a rise of 1.1°C above the patient's baseline.
Examples that recur in the exam: myocardial infarction presenting with breathlessness, confusion or weakness without chest pain; an acute abdomen (perforation, appendicitis, ischaemia) with little tenderness and no fever; "apathetic" hyperthyroidism — weight loss, atrial fibrillation and depression, without tremor and a fast pulse; and depression presenting with physical complaints and functional decline rather than sadness.
The reasons are reduced reserve in many systems, a weaker immune response and fever, cognitive decline that makes reporting harder, and drugs that mask symptoms (beta-blockers, steroids, painkillers). So listen to caregivers and family — "he's not himself" is important clinical information.
Key points
- Acute illness in an older adult often presents as confusion, a fall or not eating.
- Fever in an institution: above 37.8°C once, above 37.2°C repeatedly, or a rise of 1.1°C.
- Silent infarction, a "quiet" abdomen, apathetic hyperthyroidism.
- Depression presents with physical complaints and functional decline.
- "He's not himself" — a reason for full work-up.
Summary table
| Disease | Typical presentation in a young person | Common presentation in an older adult |
|---|---|---|
| Infection (lungs, urine) | Fever, cough, burning | Confusion, a fall, not eating, no fever |
| Myocardial infarction | Chest pain | Breathlessness, confusion, weakness, syncope |
| Acute abdomen | Severe pain, tenderness, fever | Little pain, mild tenderness, confusion |
| Hyperthyroidism | Tremor, fast pulse, anxiety | Weight loss, atrial fibrillation, apathy |
| Depression | Sadness and guilt | Physical complaints, functional decline, memory complaints |
| Fever in an institution | 38°C or more | Above 37.8°C once, above 37.2°C repeatedly, or a rise of 1.1°C from baseline |
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Sources
- IDSA clinical practice guideline — Evaluation of fever and infection in older adult residents of long-term care facilities, 2008 — Definition of fever
- Hazzard's Geriatric Medicine and Gerontology, 8th edition (2022) — Atypical presentation of illness in older adults
- Geriatrics Review Syllabus (American Geriatrics Society), 11th edition (2022) — Infectious diseases and presentation of illness
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.