Paper II — Delirium and meningitis

How to differentiate the four delirium questions Question Pivot to use What NOT to spend words on Acute confusional state Terminology + causes + Detailed pathophysiology, prevention programmes

Numbers to memorise Item Value CAM sensitivity / specificity 94% / 89% 3D-CAM (with dementia / without) 96% & 86% / 93% & 96% Months of the year backwards (single item) Sens 83% / Spec 69% UB-2 two-item screen Sens 93% / Spec 64% DSD screens (1 / 2 / 3 items) — sensitivity 84% / 93% / 94% DSD screens — specificity 41% / 30% / 42% Delirium in ICU / medical wards / hospice / LTC 30–80% / 18–35% / 26–44% / 16% Pooled prevalence & incidence, hospitalised elderly (2025) 23.6% & 13.5% Still delirious at discharge / 1 / 3 / 6 months 45% / 33% / 26% / 21% Preventable proportion of delirium 30–40% Meningitis — headache / fever / stiff neck / GCS < 14 84% / 74% / 74% / 71% Meningitis — classic triad / at least 2 of 4 41–44% / 95% Meningitis — Kernig's / Brudzinski's / nuchal rigidity sensitivity 5% / 5% / 30% S. pneumoniae share of meningitis in adults ≥ 65 y ~70% Listeria meningitis case fatality (2023 cohort) 31%; unfavourable outcome 56% Dexamethasone regimen 0.15 mg/kg 6-hourly × 4 days

Named traps in this set Trap: writing that CAM diagnoses delirium. It screens; DSM-5/ICD-10 diagnose. Trap: writing the CAM algorithm as "any two features". It is (1 AND 2) + (3 OR 4), with features 1 and 2 mandatory. Trap: equating delirium with agitation. Hypoactive delirium is commonest. Trap: prescribing a benzodiazepine for restlessness — it causes and prolongs delirium. Trap: physical restraint as a safety measure — it is an independent risk factor. Trap: relying on Kernig's and Brudzinski's signs to exclude meningitis (5% sensitivity). Trap: omitting ampicillin from the empirical regimen in an older or diabetic patient — cephalosporins miss Listeria. Trap: continuing dexamethasone after Listeria is isolated — it increases mortality. Trap: delaying the first antibiotic dose for a CT scan or lumbar puncture. Trap: forgetting to check capillary glucose in a confused diabetic before doing anything else.

Indian context lines to add Under-recognition: Indian referral-based studies detect delirium in under 1% of inpatients, while CAM-ICU screening finds ~30% of elderly ICU patients delirious, ~45% of them hypoactive — the strongest argument for routine tool-based screening rather than waiting for a psychiatry referral. Tuberculous meningitis must appear in every Indian differential for fever with confusion and neck stiffness — send CSF CBNAAT and ADA alongside routine studies. Rifampicin caution: WHO 2025 permits rifampicin instead of vancomycin for resistant pneumococcus only in low tuberculosis-burden settings — in India, vancomycin is preferred. Alcohol withdrawal is a very common and under-declared cause of ward delirium in Indian men — always give parenteral thiamine before glucose. Family attendants at the bedside are the norm in Indian wards; formally enlisting them for orientation, hydration, feeding and mobilisation delivers an evidence-based delirium bundle at almost no cost. Vandana Card for those aged 70 and above; adult pneumococcal vaccination is not part of the Universal Immunization Programme and remains an out-of-pocket, opportunistic intervention — a legitimate policy-gap comment.

Fifteen-second answer skeletons Any delirium question: Define (acute, fluctuating, inattention, medical cause) → Subtypes → SIFH → Predisposing + Precipitating (DELIRIUM IS VERY PAINFUL) → Differentiate from dementia → Screen (CAM/4AT) then diagnose (DSM-5) → Targeted workup → Treat the cause → Non-pharmacologic bundle + T-A-DA → Drugs only for imminent harm → Prevent (HELP/mHELP/ABCDEF) → Prognosis and follow-up. Any acute meningitis question: Recognise (triad + meningism, but triad in <50%) → Resuscitate + glucose → Blood cultures → Decide on CT (only if GCS < 10, focal signs, papilloedema, seizure, immunocompromise) → Lumbar puncture → Dexamethasone + antibiotics within 1 hour (never delayed) → Empirical vancomycin + ampicillin + ceftriaxone over 50 years → De-escalate on culture; stop steroid if not pneumococcal → Supportive care, ICP, sodium, glycaemia, delirium bundle → Complications → Audiology and sequelae review before discharge → Vaccination and contact prophylaxis.