# Postoperative Confusion and Delirium

> Postoperative delirium for NEET-PG Surgery: risk factors, CAM diagnosis, hypoactive subtype, reversible causes, haloperidol use and withdrawal.

- Canonical URL: https://prepelephant.com/topics/neet-pg/surgery/postoperative-confusion-delirium
- Exam / course: NEET-PG · Subject: Surgery
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Postoperative Confusion and Delirium", PrepElephant, https://prepelephant.com/topics/neet-pg/surgery/postoperative-confusion-delirium

## Direct answer

The elderly man who pulls out his catheter at 3 a.m. is not being difficult; he is delirious. Postoperative delirium is an acute, fluctuating disorder of attention and cognition, peaking on days 1-3, affecting a third of older surgical patients (over half after hip fracture), in agitated hyperactive or quiet hypoactive forms — the latter commoner, easier to miss, worse. Diagnosis uses the Confusion Assessment Method: acute onset with fluctuation plus inattention, plus either disorganised thinking or altered consciousness. Delirium is a sign, not a disease; behind it stands a searchable cause: infection, hypoxia, urinary retention, electrolytes, drugs (anticholinergics, benzodiazepines, opioids), pain or constipation. Fix the cause and the confusion clears; restrain or sedate the patient without fixing the cause and it deepens.

## What you must remember

- **CAM diagnostic rule:** (1) acute onset and fluctuating course, (2) inattention, and (3) disorganised thinking or (4) altered level of consciousness — features 1 and 2 plus either 3 or 4 make the diagnosis.
- **Subtypes:** hyperactive (agitated, hallucinating — recognised early) and hypoactive (quiet, withdrawn, "pleasantly confused" — missed and associated with worse outcomes and higher mortality); mixed forms alternate.
- **Risk factors:** age over 65-70, pre-existing cognitive impairment (strongest), missing glasses and hearing aids, infection, dehydration, hyponatraemia and hypercalcaemia, hypoxia, urinary retention, opioids, benzodiazepines and anticholinergics, pain and sleep deprivation.
- **The search mnemonic:** Pain, INfection, Constipation, deHydration, Medication, Environment/Electrolytes — run it every time before reaching for a prescription pad.
- **Management hierarchy:** treat the cause; then non-pharmacological measures — reorientation with clock and daylight, glasses and hearing aids restored, family presence, early mobilisation, sleep protection, catheter and drains removed; physical restraints worsen delirium and are last resorts.
- **Drugs only for safety-threatening agitation:** low-dose haloperidol (watch QTc; avoid in Parkinsonism — quetiapine preferred) or olanzapine; benzodiazepines are deliriogenic and reserved for one situation — alcohol withdrawal, where symptom-triggered chlordiazepoxide with thiamine given before glucose is the regimen.
- **Distinguish delirium from dementia** (acute, fluctuating, inattention prominent, often reversible, against a background that may be intact) and from postoperative cognitive dysfunction — subtler deficits lasting weeks to months, detected on neuropsychometric testing, not bedside drama.
- **Prevention works:** geriatric co-management models (orthogeriatrics), delirium watch programmes and avoiding deliriogenic drugs reduce incidence — asked as the "can delirium be prevented" answer.

## Walking the ward at night

The 78-year-old, day 2 after hemiarthroplasty, is found trying to climb over the rails. Before any syringe: oxygen saturation 90% on room air (hypoxia), bladder scan 500 mL (retention), sodium 128 (hyponatraemia on postoperative fluids and poor intake). The sequence writes itself — oxygen, catheterisation with a volume chart to prompt removal, slow sodium correction, glasses from the locker, his daughter summoned, lights dimmed with a night light on. By morning he is orientated; the catheter comes out next day. Contrast the quiet failure in the next bed — "no trouble at all", not eating, answering "hmm" — hypoactive delirium, unrecognised, tomorrow labelled "poor participation in physiotherapy" while pneumonia consolidates. The exam wants: the noisy patient gets diagnosed, the quiet one neglected, and both share a treatable differential.

## Perspective: exam framing and Indian wards

Theory stems test recognition: day 2 after prostatectomy, an 80-year-old becomes agitated at night and is lucid by morning — answer delirium, and the next question asks the strongest risk factor (pre-existing cognitive impairment) or the diagnostic method (CAM). The viva trap is management: reaching for haloperidol as first-line fails; the sequence cause-search, environment, family, then drugs only for safety is the passing answer. Two Indian-context points earn marks: alcohol withdrawal masquerading as postoperative delirium is common in Indian male surgical populations, making drinking history a preventive step — chlordiazepoxide and thiamine for that patient, not haloperidol; and in crowded wards, the family is the most available prevention resource — structured into a care plan, not treated as an obstruction.

## Frequently asked questions

### How is postoperative delirium diagnosed at the bedside?

By the Confusion Assessment Method: acute onset with fluctuation plus inattention, with either disorganised thinking or altered consciousness — no investigation substitutes for this.

### What is the difference between hyperactive and hypoactive delirium?

Hyperactive delirium produces agitation and hallucinations and is recognised early; hypoactive delirium presents as quiet withdrawal, is frequently missed and carries a worse prognosis.

### Which reversible causes must be excluded in any postoperative confused patient?

Infection, hypoxia, urinary retention, constipation, dehydration, electrolyte derangement (hyponatraemia, hypercalcaemia), pain, and deliriogenic drugs — anticholinergics, benzodiazepines and opioids head the list.

### When is haloperidol appropriate in delirium?

Only for agitation threatening safety, in low doses with QTc monitoring, after addressing causes; it is not a first-line treatment and is avoided in Parkinsonism, where quetiapine is preferred.

### How does alcohol withdrawal differ in management?

Withdrawal is the one delirium where benzodiazepines are the treatment — symptom-triggered chlordiazepoxide with thiamine supplementation given before any glucose-containing fluid.