LOC

Altered Level of Consciousness

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Altered Level of Consciousness, Decreased Level of Consciousness, ALOC, Altered Mental Status, Altered Mental State, Altered State of Consciousness, Depressed Level of Consciousness, DONT Mnemonic

  • See also
  1. Altered Level of Consciousness in Children
  2. Altered Level of Consciousness Causes
  3. Altered Mental Status in Febrile Returning Traveler
  4. Mental Status Exam
  5. Level of Consciousness
  6. Coma
  7. Delirium
  8. Psychosis
  9. Dementia
  10. Coma Exam
  11. FOUR Score Coma Exam (Full Outline of Unresponsiveness)
  12. Glasgow Coma Scale (GCS)
  13. Unknown Ingestion
  • Epidemiology
  1. Altered Mental State accounts for 5% of emergency department visits (esp. elderly)
  • History
  1. See AMPLE History
  2. See Unknown Ingestion
  3. Recent Trauma or Head Injury
  4. Symptoms (e.g. fever, Headache) or exposure to infectious disease including recent travel
  5. New or changed medications (including over-the-counter, Herbals, supplements)
  6. History of Substance Abuse or mental illness
    1. Alcohol Abuse
    2. Recreational drug use
  7. Risk Factors
    1. See Delirium
  1. Vital Signs and general findings
    1. Obtain Blood Pressure, Heart Rate, Temperature, Respiratory Rate and Oxygen Saturation
    2. Obtain bedside Glucose and treat Hypoglycemia (see below)
    3. Initiate telemetry
    4. Initiate End-Tidal CO2 (if available)
    5. See Toxin Induced Vital Sign Changes
    6. See Toxin Induced Odors
    7. Blood Pressure is a sensitive indicator of Brain Lesions
      1. Systolic Blood Pressure <90: Brain Lesion unlikely
      2. Systolic Blood Pressure >170: Brain Lesion likely
      3. Ikeda (2002) BMJ 325:800-2 [PubMed]
  2. Level of Consciousness
    1. See Level of Consciousness
    2. AVPU Scale
    3. Glasgow Coma Scale (GCS)
    4. FOUR Score Coma Exam (Full Outline of Unresponsiveness)
  3. Trauma Exam allows for a complete survey (regardless of etiology)
    1. See Primary Survey (includes ABC Assessment)
    2. See Secondary Survey
    3. Evaluate for signs of Head Trauma
    4. Evaluate for loss of Gag Reflex, GCS 8 or less, and other indications for Endotracheal Intubation
    5. Fully expose the patient for an optimal exam
  4. Eye Exam
    1. See Eye Examination Signs of Chemical Dependency
    2. Pupil changes (Miosis, Mydriasis, and Pupil Reactivity)
    3. Pupil Constriction (Miosis) and a slowed Respiratory Rate (Bradypnea) suggests Opioid Overdose
      1. See Naloxone as below
    4. Examine for unilateral Pupil Dilation without pupil response (Blown Pupil) suggestive of Uncal Herniation
    5. Ophthalmoplegia (Extraocular Movement deficit)
      1. Cerebrovascular Accident
      2. Wernicke Encephalopathy
    6. Papilledema (Increased Intraocular Pressure)
  5. Complete Neurologic Exam
    1. See Emergency Neurologic Exam
    2. See Mental Status Exam
    3. See Confusion Assessment Method (CAM-S, bCAM)
    4. See Delirium
    5. See Toxin Induced Neurologic Changes
  6. Skin Exam
    1. See Rash in the Febrile Patient
    2. See Toxin Induced Skin Changes
    3. Jaundice
    4. Petechiae
    5. Skin Infection
  • Differential Diagnosis
  1. See Altered Level of Consciousness Causes
    1. Includes mnemonics "AEIOU TIPS" and "I WATCH DEATH"
    2. Includes pitfalls of critical diagnoses that are easily missed
  2. See Altered Mental Status in Febrile Returning Traveler
  3. See Unknown Ingestion
  4. See Coma
  5. See Delirium
  6. See Dementia
  7. See Psychosis
  8. See Agitated Delirium
  9. Toxic or metabolic condition?
  10. Structural CNS disease?
  11. Encephalitis or Meningitis?
  • Labs
  1. Immediate
    1. Bedside Glucose (Dextrostick or Glucometer)
  2. First-line
    1. Complete Blood Count (CBC)
    2. Comprehensive Metabolic Panel (Electrolytes, Renal Function tests, Liver Function Tests)
    3. Serum Osmolality (if available)
    4. Serum Calcium
    5. Serum Magnesium
    6. Urinalysis
    7. Urine Pregnancy Test (all women of child bearing age)
    8. Thyroid Stimulating Hormone (TSH)
  3. Toxicology Screening (most cases)
    1. Urine Tox Screen
    2. Venous Blood Gas
      1. Consider Arterial Blood Gas instead if concerned for hypercarbia
    3. Blood Alcohol Level
    4. Acetaminophen level
    5. Salicylate level
    6. Other drug levels (as indicated)
  4. Infection screening (fever, infection suspected or unknown cause)
    1. Blood Culture
    2. Urine Culture
    3. Lumbar Puncture
    4. Serum Lactic Acid
    5. Procalcitonin level
  5. Other Diagnostic studies to consider
    1. Blood Ammonia
    2. Carboxyhemoglobin level
    3. HIV Test
      1. If unable to obtain, consider a surrogate: Absolute Lymphocyte Count Estimation of CD4 Count
    4. Rapid Plasma Reagin (RPR)
    5. Heavy Metal screen
    6. Vitamin B12 Level
    7. Serum Cortisol
    8. Electroencephalogram (EEG)
      1. Consider nonconvulsive Seizure
  1. Findings suggestive serious cardiotoxicity (and risk of Ventricular Tachycardia or Torsades)
    1. Prolonged QT interval
    2. Wide QRS
    3. Tall R Wave (or Terminal R Wave) in AVR
  2. Interventions to consider for EKG changes
    1. Sodium Bicarbonate for wide QRS Complex
      1. Especially consider if Terminal R Wave in aVR, Anticholinergic findings, suspected Overdose
    2. Magnesium for QT Prolongation (especially if QTc > 600 msec)
  1. Indications
    1. Altered Level of Consciousness without obvious non-infectious cause identified in first hour
    2. Fever or other signs of infection without an identified source and Altered Level of Consciousness
  2. Precautions
    1. Do not delay Antibiotics (e.g. Ceftriaxone 2 g) for the Lumbar Puncture if Meningitis or Encephalitis suspected
    2. Lumbar Puncture may be safely performed in the ALOC patient (after CT Head negative)
      1. Perform in left lateral decubitus position
    3. Perform an opening pressure in addition to standard CSF Exam
      1. Observe for markedly increased CSF Opening Pressure or cloudy CSF Color
      2. Early findings at the time of Lumbar Puncture may prompt reflexive start of Antibiotics prior to lab results
  • Imaging
  1. Head CT
    1. Obtain in most patients with Altered Level of Consciousness
    2. Evaluate for Intracranial Hemorrhage (esp. Trauma, anticoagulated state)
    3. Evaluate for Ischemic CVA
  2. MRI Brain
    1. Consider in non-diagnostic CT Head
  3. Cervical Spine CT
    1. Strongly consider at the time of Head CT if any risk of Trauma
    2. Examples: Found down or fall from height or even from standing height in the elderly
  4. Chest XRay
  • Management
  • Initial
  1. ABC Management
  2. Assess Level of Consciousness
    1. Endotracheal Intubation for GCS 8 or less (or other Advanced Airway Indications)
  3. Trauma-related management for Closed Head Injury
    1. See Management of Severe Head Injury
    2. See Status Epilepticus
    3. C-Spine Immobilization
  4. Protect patient and staff from injury
    1. See Agitated Delirium
    2. See Delirium
    3. See Violent Behavior
    4. See Agitation in Dementia
    5. Consider Physical Restraints or Chemical Restraints
  5. IV-O2-Monitor
    1. Intravenous Access (or IO Access if delays and patient unstable)
    2. Oxygen Delivery
    3. Cardiac Monitor
  6. Empiric reversal agents
    1. See agent protocols below
    2. Consider DONT Mnemonic empiric management (Dextrose, Oxygen, Naloxone, Thiamine)
    3. Correct Electrolyte abnormalities (e.g. Hyponatremia)
  7. Empiric infection management
    1. Consider for fever, signs infection or if no obvious non-infectious ALOC cause identified in first hour
    2. See Sepsis for Antibiotic selection
    3. If no obvious source, cover for Meningitis and Encephalitis
      1. See Bacterial Meningitis Management
      2. Includes Vancomycin, Ceftriaxone, Acyclovir (and in some cases Ampicillin)
      3. Consider Dexamethasone prior to Antibiotics if Bacterial Meningitis is strongly suspected
  • Management
  • Empiric reversal agents
  1. Dextrose
    1. Indicated for Hypoglycemia on bedside Glucometer
    2. May be given empirically
      1. Do not give empirically to a brain injured patient (check Glucometer first)
      2. Give Thiamine 100 mg before Dextrose in suspected Wernicke's Encephalopathy
    3. Dosing
      1. Adult or child >25 kg: 50 ml of D50 IV
      2. Child 5 to 25 kg: 2-4 ml/kg (0.5-1.0 g/kg) D25 IV
      3. Neonate: 5 ml/kg D10 (0.5 g/kg) IV
  2. Naloxone (Narcan)
    1. Indicated for signs of Opioid Overdose such as Pupil Constriction and respiratory depression (but may be given empirically)
    2. Precaution: Naloxone can act as Sympathomimetic and my theoretically exacerbate myocardial irritability
    3. Child: 0.01 mg/kg IV
      1. May repeat with 0.1 mg/kg IV (up to 2 mg) if inadequate response to the first dose
    4. Adult
      1. Respiratory depression: 0.4 mg IV (up to 1-2 mg IV every 2-3 minutes)
      2. Cardiac Arrest: 2 mg IV (if possible Overdose induced Cardiac Arrest)
      3. Concern for Opioid Withdrawal (slow titration method)
        1. Draw up Naloxone 1 ml (0.4 mg/ml) and 9 ml Normal Saline
        2. Inject at 1-2 ml/dose (0.04 mg/ml) titrating and observe for increased responsiveness
  3. Thiamine
    1. Dosing
      1. Adult: 100 mg IV
      2. Child: 10-25 mg IV
    2. Indications
      1. See Thiamine deficiency
      2. Suspected Wernicke's Encephalopathy (oculomotor dysfunction, Ataxia)
      3. Alcoholism
      4. Gastric Bypass Surgery
      5. Malnutrition
  • Management
  • Other empiric reversal agents less commonly indicated
  1. Flumazenil (rarely used in acute Altered Mental Status)
    1. Indications
      1. Not typically used due to the risk of withdrawal Seizures in chronic Benzodiazepine use
      2. Consider if Altered Level of Consciousness follows a single dose of Benzodiazepine
    2. Dosing
      1. Flumazenil 0.2 - 1.0 mg IV
    3. Precautions
      1. Tricyclic Antidepressant Overdose
      2. Benzodiazepine Abuse
  • References
  1. Orman and Chang in Herbert (2017) EM:Rap 17(4): 8-9
  2. (2016) CALS, 14th ed, 1:52-3
  3. Herbert et al. in Herbert (2014) EM:Rap 14(10): 11-2
  4. Herbert et al. in Herbert (2014) EM:Rap 14(11): 10-12
  5. Veauthier (2021) Am Fam Physician 104(5): 461-70 [PubMed]