Confusion (OSCE focused)

Candidate Instructions:You are the medical student on the acute medical take. A 79-year-old patient has been brought in by their carer with new-onset confusion for 1 day. Take a focused history from the carer, perform a rapid bedside assessment, and present your initial differential diagnosis and plan. You do not need to perform a full cognitive examination.

Key Areas to Cover ✅

• 🕒 Onset & course - acute (<48h → delirium) vs gradual (dementia).
• 📜 Baseline cognition - independence, memory, previous episodes.
• ⚡ Precipitants - infection, new drugs, pain, constipation, urinary retention, metabolic causes.
• 💊 Polypharmacy - sedatives, anticholinergics, opioids, benzodiazepines.
• 🏥 Red flags - head trauma, seizure, stroke, reduced GCS.

Focused History Questions 🗣️

• “When was the patient last seen well?”
• “Any recent fever, cough, urinary symptoms, constipation, or pain?”
• “Any new or changed medications?”
• “Past medical history - dementia, Parkinson’s, diabetes, renal/hepatic disease?”
• “Alcohol use? Any history of heavy drinking or recent abstinence?”
• “What’s their usual level of function - mobility, personal care, memory?”

Examination (Screening) 🔎

• 🧠 AVPU / GCS + bedside 4AT score (UK delirium screening tool).
• 📈 Vitals - fever, hypoxia, hypotension, tachycardia.
• 🩺 Chest, abdomen, neurological screen.
• 💧 Hydration status, urine retention, constipation.
• 👂 Ensure glasses/hearing aids in place.

Examiner Prompts 💬

• “What are your top 3 differentials for new confusion?”
• “What immediate investigations would you arrange?”
• “How would you manage this patient in the first hour?”

Differential Diagnoses 🧾

Immediate Investigations 🔬

• 🩸 Bloods: FBC, U&E, LFTs, CRP, glucose, calcium
• 💉 Blood cultures if febrile
• 🧪 Urine dip ± culture
• 🫁 CXR for infection
• 🧠 CT head if focal neurology, trauma, or reduced GCS
• 📊 ECG (AF, ischaemia, QT prolongation)

Initial Management 🩺

• 👩‍⚕️ ABCDE assessment, stabilise first
• 💧 Oxygen if hypoxic, IV fluids if dehydrated
• 🧪 Treat cause - e.g. IV antibiotics for sepsis, correct electrolytes, IV dextrose for hypoglycaemia
• 💊 Stop culprit medications (anticholinergics, sedatives, opioids)
• 🛏️ Supportive care - orientation, calm environment, avoid unnecessary catheters/restraints
• 🧠 Implement delirium prevention bundle (hydration, sleep hygiene, sensory aids)
• 👨‍👩‍👧 Involve family/carers for collateral history and reassurance

Mark Scheme (10 points) 📝

Teaching Commentary 📚

In OSCEs, new confusion = think delirium until proven otherwise 🔥. Always establish baseline cognition and ask about precipitants, especially infection and new medications. Examiners like when you mention: “First, I would perform an ABCDE assessment and use the 4AT screening tool to assess delirium risk, while checking for reversible causes such as infection, hypoglycaemia, and hypoxia.” Don’t forget to consider stroke, electrolyte/metabolic derangements, and polypharmacy. Ending with: “I would initiate delirium prevention measures, involve family for orientation, and escalate promptly to seniors” will score highly.

🧑‍⚕️ Case Examples - Confusion

• Case 1 (Delirium in Infection): 🦠 An 82-year-old woman in a care home becomes acutely confused, disoriented, and agitated. She has a fever and new urinary incontinence. Urinalysis shows nitrites and leukocytes. Diagnosis: Delirium due to urinary tract infection. Teaching point: Always think infection as a cause of acute confusion in the elderly; treat underlying cause and provide supportive care.
• Case 2 (Hypoglycaemia): 🍬 A 65-year-old man with type 2 diabetes on insulin is found confused and sweating. Capillary glucose = 2.4 mmol/L. He improves rapidly after IV dextrose. Diagnosis: Hypoglycaemia-induced confusion. Teaching point: Always check glucose in any confused patient - a rapid, reversible cause.
• Case 3 (Dementia with Superimposed Delirium): 🧠 A 78-year-old man with known Alzheimer’s disease becomes suddenly more disoriented and paranoid over 2 days. He is dehydrated with raised urea and creatinine. Diagnosis: Delirium on background of dementia due to dehydration/AKI. Teaching point: Delirium is acute and fluctuating, whereas dementia is chronic; both can coexist.
• Case 4 (Alcohol Withdrawal Delirium): 🍺 A 55-year-old man, admitted after a fall, becomes confused, tremulous, and hallucinating 48 hours after admission. History reveals heavy daily alcohol intake. Diagnosis: Delirium tremens. Teaching point: Confusion + hallucinations in withdrawal = medical emergency; manage with benzodiazepines and supportive care.
• Case 5 (Stroke): 🧾 A 70-year-old woman develops sudden confusion, slurred speech, and right arm weakness. CT head shows acute left MCA infarct. Diagnosis: Stroke presenting with confusion. Teaching point: Acute neurological deficits with confusion warrant urgent stroke assessment and reperfusion therapy if eligible.