An older adult who is confused
New confusion in an older person is not 'just old age'. Delirium, a sudden and fluctuating confusion, is a sign of a physical illness and can be the only sign of a serious infection, low glucose or a medicine side effect. Dementia develops over months to years. Telling them apart starts with one question to the family: what was she like last week?
- Setting: Health centre in a small town with low malaria transmission, 1 hour by road from the district hospital
- For clinical officers, nurses and doctors at first-level facilities
- Reviewed October 2026
The presentation
Halima, 79, is brought by her daughter. For 2 days she has been confused: she does not recognise her grandchildren at times, sleeps in the day and is agitated and talking to herself at night. She has hardly eaten. She has high blood pressure and type 2 diabetes.
| Vital sign | Value |
|---|---|
| Temperature | 38.3 °C |
| Pulse | 106 per minute |
| Breathing rate | 24 per minute |
| Blood pressure | 106/62 mmHg (usually about 150/85) |
| SpO2 | 94% on air |
| Conscious level (AVPU) | V: drowsy, opens eyes to voice, muddled answers |
Tests at hand: Blood glucose (finger-prick) · Urine dipstick · Pulse oximetry (SpO2) · Haemoglobin (Hb) · Malaria rapid diagnostic test (RDT)
- Delirium from infection or sepsis Must not missStill possible
- Hypoglycaemia Must not missStill possible
- Stroke Must not missStill possible
- Head injury (bleeding around the brain) Must not missStill possible
- Medicine side effectStill possible
- DehydrationStill possible
- DementiaStill possible
- DepressionLess likely
Work through it
Read each question and decide your own answer first. Then open the model answer and see how the differential changes.
- Step 1 of 7 · Look
Halima responds only to voice. What do you do in the first minutes, and what is the first test?
Model answer
Altered mental status is a priority sign: she is seen now. Do the ABCDE, fixing problems as you find them.
- A: airway open; she is talking. If she becomes less responsive and there is no injury, put her in the recovery position.
- B: rate 24, SpO2 94%. No oxygen needed yet; give it if SpO2 falls below 92%.
- C: pulse 106, BP 106/62 (low for her), hands warm, capillary refill 2 seconds. Insert an IV cannula.
- D: AVPU 'V'. Check glucose now: hypoglycaemia is a rapidly reversible cause of confusion, especially in someone on diabetes medicines who has not been eating.
- E: temperature 38.3 °C; look for injuries, pressure sores and rashes.
Glucose: 5.8 mmol/L. Not low, but she takes a sulfonylurea and is not eating: it can fall. Recheck in a few hours.
Differential now- Delirium from infection or sepsis Must not missLeading (moved up)
- Stroke Must not missStill possible
- Head injury (bleeding around the brain) Must not missStill possible
- Medicine side effectStill possible
- DehydrationStill possible
- DementiaStill possible
- Hypoglycaemia Must not missLess likely (moved down)
- DepressionLess likely
- Step 2 of 7 · Ask
What do you ask the daughter? Which answers separate delirium from dementia?
Model answer
- What was she like before? Her usual memory, how she managed daily tasks, and when this change started.
- Onset and course: abrupt, over hours to days, and fluctuating through the day with disturbed nights (delirium); or slow, over at least 6 months (dementia).
- Falls or head injury, even minor ones.
- New weakness, speech difficulty or facial droop.
- Burning urine, passing little urine, cough, diarrhoea, pain anywhere.
- Every medicine, including from the pharmacy or market: sedatives, antihistamines and other medicines with anticholinergic effects; diabetes tablets.
- Alcohol, and how much she has been drinking and eating.
Before last week Halima cooked, went to the market and managed her money, although she has repeated herself more over the past year. This started suddenly 2 days ago; she is better in the mornings. Four days ago she complained of burning when passing urine. No falls seen. No weakness. Medicines: amlodipine and gliclazide; 3 days ago the pharmacy gave her chlorphenamine for an itch. No alcohol.
Differential now- Delirium from infection or sepsis Must not missLeading
- Medicine side effectStill possible
- DehydrationStill possible
- Hypoglycaemia Must not missLess likely
- Stroke Must not missLess likely (moved down)
- Head injury (bleeding around the brain) Must not missLess likely (moved down)
- DementiaLess likely (moved down)
- DepressionSet aside for now (moved down)
- Step 3 of 7 · Look
What do you look for on the secondary examination?
Model answer
- Neck stiffness and rash (meningitis).
- Face, arm and leg strength, speech, pupils (stroke, bleeding).
- Scalp and face for bruising or wounds (head injury).
- Chest: crackles in one area (pneumonia).
- Abdomen and loins: tenderness; a full bladder (urinary retention, which anticholinergic medicines can cause).
- Mouth, skin turgor and urine colour (dehydration).
- Skin: pressure areas, cellulitis, foot ulcers (she has diabetes).
No neck stiffness, no rash. She moves all four limbs equally, face symmetrical, pupils equal. No head injury. Chest clear. Tender right loin; bladder not palpable. Dry mouth. Feet and skin intact.
Differential now- Delirium from infection or sepsis Must not missLeading
- Medicine side effectStill possible
- DehydrationStill possible
- Hypoglycaemia Must not missLess likely
- DementiaLess likely
- Stroke Must not missSet aside for now (moved down)
- Head injury (bleeding around the brain) Must not missSet aside for now (moved down)
- DepressionSet aside for now
- Step 4 of 7 · Test
Which other tests help, and what do the results mean?
Model answer
- Urine dipstick: mhGAP advises a urine test to look for infection in suspected delirium.
- Pulse oximetry: low SpO2 can cause confusion and points to pneumonia or heart failure.
- Haemoglobin: severe anaemia can cause confusion and changes how you give fluids.
- A malaria RDT is not needed here: low transmission and no travel. In a malaria area, test everyone with fever and confusion.
Results: urine leucocytes 3+, nitrite positive, blood 1+, glucose 1+. SpO2 94%. Hb 11.6 g/dL.
Differential now- Delirium from infection or sepsis Must not missLeading
- Medicine side effectStill possible
- DehydrationStill possible
- Hypoglycaemia Must not missLess likely
- DementiaLess likely
- Stroke Must not missSet aside for now
- Head injury (bleeding around the brain) Must not missSet aside for now
- DepressionSet aside for now
- Step 5 of 7 · Do
Put it together. Is this delirium or dementia, and why does that matter today?
Model answer
This is delirium: an abrupt, fluctuating disturbance of attention over 2 days, worse at night, with reduced consciousness. The cause is a probable kidney infection with sepsis (fever, fast pulse, fast breathing, BP well below her usual, loin tenderness, positive dipstick), made worse by chlorphenamine and by not eating or drinking.
Dementia cannot be diagnosed during delirium. Her mild forgetfulness over the past year deserves a proper memory assessment once she has recovered.
Take it seriouslyDelirium in an older person with fever and a fast pulse is a sign of serious illness. Very ill people may not mount a fever, so a normal temperature never rules out infection.Differential now- Delirium from infection or sepsis Must not missLeading
- Medicine side effectStill possible
- DehydrationStill possible
- DementiaLess likely
- Hypoglycaemia Must not missSet aside for now (moved down)
- Stroke Must not missSet aside for now
- Head injury (bleeding around the brain) Must not missSet aside for now
- DepressionSet aside for now
- Step 6 of 7 · Do
What do you do before and during transfer?
Model answer
- Give the first dose of a parenteral antibiotic as soon as possible, per your national protocol for sepsis or kidney infection.
- IV fluids for poor perfusion, given in small amounts with frequent checks of the lungs for crackles: older people tip into fluid overload easily.
- Stop the chlorphenamine. Hold the gliclazide while she is not eating; recheck glucose before transfer and treat if low.
- Paracetamol for fever, per national formulary.
- Keep her safe and calm: a family member stays with her, a light on at night, simple reassurance. Avoid sedatives where possible: they can deepen the confusion.
- Refer now, accompanied, with a note: baseline function, onset, vital signs, glucose results, dipstick, medicines and what was given with times.
This is an immediate referral: suspected sepsis with delirium and falling BP needs hospital care.
- Step 7 of 7 · Ask
What do you tell the daughter, and what happens after Halima recovers?
Model answer
- Explain delirium: a sudden confusion caused by the infection and the medicine, which usually improves as the cause is treated, sometimes slowly.
- Familiar faces, glasses and hearing aids, a clock and daylight help her orientation.
- After recovery: a memory and daily-functioning assessment (mhGAP dementia module); review all her medicines; avoid antihistamines like chlorphenamine; review the diabetes treatment for an older person living alone at times.
- Support for the daughter as carer.
Your mother's confusion is caused by an infection in her kidneys and by the itch tablets. She needs treatment in hospital today. Stay with her and talk to her calmly. When she is better, we will check her memory properly.
Must-not-miss conditions
| Condition | Clues | What to do at first-level care |
|---|---|---|
| Hypoglycaemia | Confusion, sweating, fits or drowsiness; on insulin or a sulfonylurea, not eating; glucose below 3.5 mmol/L (treat at 3.9 or less in people on diabetes medicines). | Glucose by mouth if able to swallow; if not, IV dextrose (25 to 50 mL of 50%, or 125 to 250 mL of 10%); recheck; find the cause. |
| Sepsis | Fever or low temperature, fast pulse and breathing, low BP for the person, confusion; a urinary, chest, skin or abdominal source. | ABCDE; first antibiotic dose early; careful IV fluids; refer now. |
| Stroke or bleeding in the brain | Sudden weakness on one side, speech difficulty, facial droop, unequal pupils; a fall or head injury, especially on blood thinners. | ABCDE, check glucose, nothing by mouth, refer now. |
| Meningitis or cerebral malaria | Fever with neck stiffness, rash or light sensitivity; positive malaria test in a malaria area. | First antibiotic dose (and pre-referral artesunate in a malaria area); refer now. |
| Medicine toxicity or withdrawal | New sedatives, antihistamines, antidepressants or other anticholinergic medicines; alcohol withdrawal. | Stop or review the medicine; manage withdrawal per protocol; refer if severe. |
Decision at first-level care
Halima has delirium caused by probable pyelonephritis with sepsis (fever 38.3 °C, pulse 106, breathing 24, BP 106/62 against a usual 150/85, loin tenderness, positive dipstick), worsened by chlorphenamine and poor intake. Glucose is normal but at risk on gliclazide. She is given a first antibiotic dose and careful fluids, the chlorphenamine is stopped, and she is referred now. A memory assessment follows recovery.
Source: WHO and ICRC Basic emergency care (2018); WHO mhGAP Intervention Guide 2.0 (2016).
- Hypoglycaemia that corrects fully with glucose, cause clear and treatable, back to normal and able to eat, with someone to stay with her: treat, adjust medicines, review the next day.
- Mild confusion from a single new medicine, vital signs normal, improving after stopping it: review within 24 hours.
- Gradual memory loss over at least 6 months with normal vital signs and no acute change: mhGAP dementia assessment at a planned visit, not an emergency.
- Mild fluctuating confusion with a clear minor cause, normal vital signs and reliable carers: review within 24 hours.
- Delirium with fever, fast breathing, low BP or SpO2 below 92%: now.
- New focal weakness, head injury or reduced consciousness: now.
- Hypoglycaemia on a long-acting sulfonylurea or insulin that recurs, or does not correct: now.
- Delirium with no cause found at first-level care: the same day.
Key learning points
- Check glucose in every confused person, early.
- Delirium: abrupt onset, days to weeks, fluctuating, worse at night, with impaired attention or consciousness. Dementia: slow, over at least 6 months.
- Always ask a family member what the person was like before.
- Look for infection, medicines (especially anticholinergic ones), dehydration, pain and urinary retention.
- Do not diagnose dementia during delirium; reassess memory after recovery.
Sources
- World Health Organization and International Committee of the Red Cross. Basic emergency care: approach to the acutely ill and injured. Participant workbook. 2018 (ISBN 9789241513081). Module 5, altered mental status: delirium always requires full assessment; ask about baseline; rapidly reversible causes (hypoglycaemia below 3.5 mmol/L, dehydration, hypoxia); infection; recovery position; glucose (dextrose) doses for adults; antibiotics as soon as possible.
- World Health Organization. mhGAP Intervention Guide for mental, neurological and substance use disorders in non-specialized health settings, version 2.0. 2016. DEM module: delirium (abrupt onset, short duration, night-time disturbance, impaired consciousness, disorientation) versus dementia (slowly progressive for at least 6 months); evaluate for medical causes with urinalysis; review anticholinergic medicines; evaluate pain and nutrition; key informant interview.
- World Health Organization. Diagnosis and management of type 2 diabetes (HEARTS-D). 2020. Hypoglycaemia at 3.9 mmol/L or less in people on diabetes medicines; gliclazide as the preferred sulfonylurea; caution in older people (as summarised in the type 2 diabetes protocol).
- World Health Organization, International Committee of the Red Cross and Médecins Sans Frontières. Interagency Integrated Triage Tool (age 12 and over). 2023. Altered mental status and SpO2 below 92% as triage criteria.