ICU Map
neurologic

Acute Altered Mental Status & ICU Delirium

Systematic neurologic evaluation: immediate metabolic/toxic screening (glucose, hypoxia, hypercapnia), nonconvulsive status epilepticus exclusion, structural CT triage, and CAM-ICU delirium management.

Acute altered mental status (AMS)—ranging from hyperactive delirium and acute agitation to hypoactive somnolence, stupor, and unresponsiveness—is one of the most common acute decompensations in the ICU. The bedside priority is a rapid, stepwise elimination of immediately fatal metabolic, hypoxic, toxic, and structural insults before attributing mental status changes to non-specific ICU delirium or sedation.

Caution

Dangerous Diagnosis Not to Miss: Acute Hypoglycemia (permanent brain injury in minutes), Acute Hypercapnic Coma (CO2 narcosis), Nonconvulsive Status Epilepticus (NCSE), Acute Intracranial Hemorrhage / Herniation, Basilar Artery Occlusion, and Bacterial Meningitis/Encephalitis.

1

IMMEDIATE BEDSCREEN (THE 60-SECOND CHECK)

  • Airway & Oxygenation: Verify patent airway, SpO2 ≥ 92%, and respiratory pattern.

  • Point-of-Care Blood Glucose: Mandatory immediate fingerstick; treat glucose < 70 mg/dL immediately with 1 ampule D50W (25 g dextrose).

  • Arterial Blood Gas: Check for severe hypercapnia (PaCO2 > 60–70 mmHg with acidemia) and severe metabolic acidosis.

  • Pupils & Brainstem Screen: Assess pupil size, symmetry, and reactivity (unilateral fixed dilated pupil = uncal herniation until proven otherwise).

2

DIFFERENTIAL BY MECHANISTIC DOMAIN

  • Metabolic & Endocrine: Hypoglycemia, severe hyponatremia (< 120) or hypernatremia (> 160), hepatic encephalopathy (hyperammonemia), uremic encephalopathy, myxedema coma, adrenal crisis.

  • Toxic & Pharmacologic: Opioid overdose (miosis, bradypnea; reverse with IV Naloxone 0.04–0.4 mg), benzodiazepine toxicity, anticholinergic toxidrome, alcohol/sedative withdrawal (delirium tremens), cefepime/fluoroquinolone neurotoxicity.

  • Structural Neurologic: Acute ischemic stroke (especially basilar artery thrombosis), intracranial hemorrhage (ICH/SAH), subdural hematoma, acute obstructive hydrocephalus, brain abscess.

  • Epileptic: Nonconvulsive Status Epilepticus (NCSE: subtle rhythmic twitching of eyes/fingers, gaze deviation, or pure unresponsiveness; confirmed on EEG).

  • Infectious: Sepsis-associated encephalopathy (SAE), bacterial meningitis, viral encephalitis, line sepsis.

3

TARGETED BEDSIDE INVESTIGATIONS

  • Urgent Non-Contrast Head CT: Indicated immediately for new focal neurologic deficits, pupillary asymmetry, post-trauma, anticoagulated patients, or unexplained persistent coma.

  • Continuous or Routine EEG: Mandatory for patients with unexplained fluctuating consciousness, post-cardiac arrest, or subtle motor twitches to rule out NCSE.

  • Lumbar Puncture: Indicated for fever + AMS with meningismus, or negative CT with suspected subarachnoid hemorrhage / encephalitis.

  • Delirium Screening: Perform CAM-ICU (Confusion Assessment Method for the ICU) or ICDSC to detect hypoactive delirium.

4

INITIAL MANAGEMENT & DELIRIUM BUNDLE

5

REASSESSMENT & ESCALATION

Caution

Common Diagnostic Trap: Dismissing hypoactive altered mental status as 'the patient is just quiet or tired'. Hypoactive delirium carries higher ICU mortality than hyperactive delirium and frequently conceals severe sepsis, hypercapnia, metabolic failure, or nonconvulsive seizures.

Destination Topics

  • Altered Consciousness: Glasgow Coma Scale, FOUR score, and coma localization pathways.

  • Status Epilepticus: Nonconvulsive status criteria, EEG monitoring, and anticonvulsant protocols.

  • Ischemic Stroke: Large vessel occlusion screening and neurovascular rescue.

  • Intracranial Hemorrhage: Hematoma expansion, blood pressure targets, and reversal.

  • Severe Sodium Disorders: Osmotic shifts, cerebral edema, and ODS prevention.

  • Sepsis: Sepsis-associated encephalopathy and systemic inflammation.

Evidence status

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Actionable Clinical Workflows (17)

Step-by-step ICU Processes
Neuromuscular Respiratory Failure

Bedside trajectory assessment, respiratory mechanics, bulbar function, airway timing, and disease-specific immunotherapy in acute neuromuscular crisis.

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Initial Hemodynamic Resuscitation & Shock Bundling

From recognizing hypoperfusion and initial crystalloid bolus to dynamic fluid responsiveness assessment and vasopressor targets.

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Shock

Initial resuscitation and classification once shock is established.

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Renal Replacement Therapy & CRRT Initiation

From urgent 'AEIOU' indication screening and modality selection to vascular access, dosing, and anticoagulation.

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Deep-Dive Topic Destinations (13)

Reference Knowledge
Altered Consciousness, Coma, & Delirium in the ICUneurology

ARAS neuroanatomy, structural vs toxic-metabolic coma, the comprehensive Coma Exam (pupils, cold calorics, posturing), FOUR score, and CAM-ICU delirium.

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ICU Sedation, Analgesia, Delirium & Liberationneurology

Analgesia-first sedation, light sedation targets, ABCDEF bundle, spontaneous breathing trials, and non-pharmacologic delirium mitigation.

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Acute Liver Failure (ALF)gi-hepatic

Hyperammonemia, cytotoxic cerebral edema, balanced coagulopathy, N-acetylcysteine, 3% saline neuroprotection, CRRT ammonia clearance, and King's College transplant criteria.

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Endocrine Emergencies in Critical Careendocrine-metabolic

Bedside recognition and organ-support priorities for thyroid storm, myxedema coma, adrenal crisis, pheochromocytoma crisis, and severe hypercalcemia.

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Toxicologic Emergencies in Critical Caretoxicology

Resuscitate first, identify toxidromes and ECG/acid-base threats, use toxin-specific antidotes, and escalate early to poison-center, extracorporeal, or ECLS support when physiology demands it.

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Diabetic Ketoacidosis (DKA)endocrine-metabolic

Pathophysiology, SGLT2i euglycemic DKA, balanced fluid resuscitation, potassium-before-insulin safety rules, dextrose addition kinetics, and subcutaneous transition.

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Acute Meningitis & Encephalitisneurology

CT-before-LP criteria, CSF interpretation matrix, de Gans Dexamethasone timing, empiric age/host antimicrobial coverage + Ampicillin + Acyclovir, and neurocritical ICP management.

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Status Epilepticusneurology

Recognition and time-sensitive escalation of care for prolonged or repeated seizures.

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Acute Ischemic Strokeneurology

Core vs penumbra dynamics, ASPECTS & CT perfusion, Tenecteplase/Alteplase thrombolysis, DAWN/DEFUSE 3 extended thrombectomy, BP targets, and malignant MCA hemicraniectomy.

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Intracranial Hemorrhage: ICH & SAHneurology

Spontaneous ICH vs Aneurysmal SAH, INTERACT-2/ATACH-2 blood pressure targets, emergency anticoagulant reversal, ENRICH minimally invasive evacuation, ISAT coiling, and Nimodipine for delayed cerebral ischemia.

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Intracranial Hypertension & Cerebral Edemaneurology

Monro-Kellie doctrine, ICP waveforms (P2>P1, Lundberg A-waves), CPP targets (60–70 mmHg), herniation syndromes, and the 4-tier BTF management protocol.

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Severe Sodium Disorders: Hyponatremia & Hypernatremiarenal

Tonicity assessment, etiologic classification, 3% hypertonic saline bolus protocols, individualized ODS-safe correction limits, DDAVP relowering, DI diagnostics, and evidence-aware hypernatremia correction.

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Sepsisinfectious-disease

Life-threatening organ dysfunction caused by a dysregulated host response to infection — recognized by an acute rise in SOFA score, not by infection plus fever alone.

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