Rosen & Barkin's 5-Minute Emergency Medicine Consult (166 page)

• Detect and treat reversible causes.
  
• Immediate exclusion of comalike states:
  
  • Noting resistance to passive opening of eyelids, fluttering of eyelids when stroked, abrupt eyelid closure, eye movements by saccadic jerks (rather than roving), or finding the eyes rolled back
    
  • Provocation of nystagmus with ice-water caloric testing
    
  • Before paralyzing a patient for intubation, an attempt should be made to detect a locked-in syndrome.
    
  • Demonstrating that the patient is able to blink on verbal command will establish this diagnosis.
    
  • Intubation is still indicated to prevent aspiration.
    

• Dextrostix
  
• CBC
  
• Electrolytes
  
• Blood and urine toxicologic screen
  

Head CT:

• Diagnosis of hemorrhage and midline shift
  
• CT angiography for suspected cerebrovascular accident
  

• Lumbar puncture:
  
  • All patients with coma of unknown etiology, particularly if fever is present
    
  • Antibiotics may be administered for as long as 48 hr before lumbar puncture.
    
  • CT should be performed before lumbar puncture if there is evidence of increased intracranial pressure, a mass lesion, pre-existing trauma, or focal findings.
    
• Risk of tonsillar herniation in patients with a mass lesion is very small.
  
• EEG:
  
  • Performed to rule out suspected seizure activities
    
  • Little use in the emergency evaluation
    
  • Unlike EEG studies performed in a lab, lighting will cause artifacts.
    

• Locked-in syndrome
  
• Psychogenic unresponsiveness
  
• Stupor
  
• Catatonia
  
• Akinetic mutism
  

TREATMENT

• Airway management if loss of airway patency
  
• Endotracheal intubation if no response to coma cocktail
  
• IV access
  
• Dextrose or Dextrostix
  
• Narcan
  
• Monitor
  
• Look for signs of an underlying cause:
  
  • Medical alert bracelets
    
  • GCS
    
  • Pupils
    
  • Extremity movements
    

• Airway management
  
• Empiric use of naloxone
  
• Empiric dextrose:
  
  • Administer if serum glucose cannot be measured at the bedside
    
  • Can safely be administered before thiamine
    
  • Does not worsen outcome in patients with stroke
    

• Specific therapy directed at underlying cause once identified
  
• Consider empiric use of antibiotics for coma of undetermined etiology:
  
  • Broad-spectrum with good cerebrospinal fluid penetration such as ceftriaxone
    
• Stop seizure activity with benzodiazepines, phenytoin, and phenobarbital.
  
• Empiric treatment for a toxic ingestion:
  
  • Activated charcoal
    
• Correct body temperature:
  
  • Aggressive rewarming for patients with core temperature between 32°C and 35°C and invasive rewarming for <32°C
    
  • Ice packs and forced air movement over exposed wetted skin if severe hyperthermia
    

• Ceftriaxone: 100 mg/kg IV
  
• Dextrose: 1–2 mL/kg of D
  ₅₀
  W IV; neonate 10 mL/kg D
  ₁₀
  W IV; peds 4 mL/kg D
  ₂₅
  W IV
  
• Diazepam: 0.1–0.3 mg/kg slow IV (max. 10 mg/dose) q10–15min × 3 doses
  
• Flumazenil: 0.20 mg IV qmin × 1–5 doses
  
• Fomepizole: 15 mg/kg IV
  
• Lorazepam: 0.05–0.1 mg/kg IV (max. 4 mg/dose q10–15min)
  
• Mannitol: 0.25–1 g/kg IV over 20 min
  
• Naloxone: 0.01 mg/kg to 0.01–0.1 mg/kg
  
• Phenobarbital: 10–20 mg/kg IV, monitor for respiratory depression
  
• Phenytoin: Infuse at <50 mg/min; 18–20 mg/kg IV/IO or fosphenytoin 15–20 mg/kg IV/IO
  
• Physostigmine: 0.5–2 mg IV
  
• Thiamine: 100 mg IM or 100 mg thiamine in 1,000 mL of IV fluid wide open
  
• Pyridoxine: 70 mg/kg IV (Max. 5 g on a 1:1 basis with INH overdose)
  

FOLLOW-UP

Patients who do not have a readily identifiable and completely reversible cause of coma should be admitted.

Comatose patients with correctable hypoglycemia and opiate toxicity who respond completely to aggressive ED treatment can be discharged.

Further delineation or prevention of possible adverse medication reaction

• If discharged, urgent PCP F/U is needed.
  
• Consideration of adverse medication reaction
  
• Supervision for 24 hr postdischarge
  

• Rapid medical stabilization
  
• Neuroimaging for structural lesions
  
• Metabolic and toxicologic assessment
  
• Identification of unusual causes of coma
  
• Dischargeable patients require period of ED observation.
  

• Glauser J. Coma: A systematic approach to patient evaluation and management 2008. Available at
  http://www.thefreelibrary.com/Coma+A+Systematic+Approach+to+Patient+Evaluation+and+Management.-a0206595218
  
• Plum F, Posner J.
  The Diagnosis of Stupor and Coma
  . 4th ed. Philadelphia, PA: FA Davis; 2007.
  
• The Martin A. Samuels neurology review for primary care physicians.
  Available at
  http//www.cmeinfo.com/store_temp/The_Martin_A._Samuels_Neurology_Review_for_Primary_Care_Physicians_305.asp
  
• Weiner W, Shulman L.
  Emergent and Urgent Neurology
  . 2nd ed. Philadelphia, PA: Lippincott, Williams & Williams; 1999.
  

CODES

780.01 Coma

BASICS

• Elevated tissue pressure in closed spaces that compromises blood flow through capillaries
  
• Normal tissue pressure is <10 mm Hg.
  
• Capillary blood flow in a compartment is compromised at pressures >20 mm Hg.
  
• Muscles and nerves can develop ischemic necrosis at pressures >30 mm Hg.
  
• When distal pulses are diminished on exam, muscle necrosis is probably present.
  
• The 4 compartments of the leg are most frequently involved, but compartment syndrome can occur in the arm, forearm, hand, foot, shoulder, buttocks, and thigh.
  

• Decreased compartment size: Circumferential cast, burn eschar, or military antishock trousers (MAST)
  
• Increased compartment contents: Compression of the compartment from edema or hematoma caused by direct trauma, fracture, overexertion of muscles, contrast extravasation, injection of recreational drugs, postischemic time, or limb compression during prolonged recumbency
  

DIAGNOSIS

• Severe, constant pain over the compartment that is disproportionate to extent of injury
  
• Pain increases with active contraction and passive stretching.
  
• Muscle weakness
  
• Hypesthesia
  
• 6
  P’
  s: Pain, pressure, paresis, paresthesia, and pulses present
  

• Elicit above symptoms in proper clinical setting.
  
• 6
  P
  ’s
  

• Tenderness of muscle compartment
  
• Assess motor and neurologic function.