Rosen & Barkin's 5-Minute Emergency Medicine Consult (422 page)

• Dependent upon clinical scenario
  
• Cell count differential with absolute cell counts may be helpful if the etiology is not apparent based on history and physical exam alone, or if hematologic malignancy is considered
  
• If hematologic malignancy is suspected patients will require peripheral blood smear and bone marrow biopsy following admission
  

See etiology. Narrow diagnosis based on corresponding clinical presentation.

TREATMENT

• Based on underlying disease process.
  
• Leukostasis secondary to the extremely high WBC counts of malignancy may require acute management with:
  
  • IV hydration
    
  • Transfusion
    
  • Allopurinol
    
  • Hydroxyurea
    
  • Hematology consult for leukapheresis
    

FOLLOW-UP

Dependent upon clinical scenario. Avoid making disposition decisions based solely on the WBC count.

• Be aware that the decision making of health care providers is significantly influenced by the presence of a leukocytosis
  
• Increased admission rate
  
• Increased number of tests and cost
  
• Wide variety of conditions can cause a leukocytosis, including normal variants
  
• Poor sensitivity and specificity for predicting severity of illness
  
• Extremely high WBC counts typically in the setting of hematologic malignancy can be associated with leukostasis which can be life threatening and require emergent therapy
  

• Callaham M. Inaccuracy and expense of the leukocyte count in making urgent clinical decisions.
  Ann Emerg Med.
  1986;15(7):774–781.
  
• Cerny J, Rosmarin AG. Why does my patient have leukocytosis?
  Hematol Oncol Clin North Am.
  2012;26:303–319.
  
• Janz TG, Hamilton GC. Anemia, polycythemia, and white blood cells disorders. In: Marx JA, Hockberger RS, Walls RM, et al., eds.
  Rosen’s Emergency Medicine: Concepts and Clinical Practice
  . 7th ed. Philadelphia, PA: Mosby Elsevier; 2009.
  
• Shah SS. Clinical significance of extreme leukocytosis in the emergency department evaluation of young febrile children.
  Acad Emerg Med.
  2003;10(5):443–444.
  

CODES

• 288.8 Other specified disease of white blood cells
  
• 288.60 Leukocytosis, unspecified
  
• 288.61 Lymphocytosis (symptomatic)
  

BASICS

• Lightning is a discharge of energy that occurs cloud to cloud (90%) or cloud to ground (10%).
  
• Exposure to lightning:
  
  • Brief duration (1–100 msec)
    
  • Typically occurs during outdoor activity
    
  • Highest incidence in summer months, between 3 and 6
    pm
    
  • Fatality rate of 8–10%
    

• Mechanism of injury—electrical:
  
  • Direct strike (5%)
    
  • Contact potential (15–25%):
    
    • Current passes through an object the victim is touching.
      
  • Side splash (20–30%):
    
    • Current jumps from nearby object to the victim.
      
  • Earth potential rise/ground current (40–50%):
    
    • Current moves through the ground surface and may injure multiple victims.
      
    • Current moves through hard-wired telephone lines, metallic pipes, or a structure’s electrical equipment, causing lightning injury to victims indoors.
      
  • Upward streamer (10–15%):
    
    • Negatively charged lightning strikes from a cloud and induces positive current from the ground to rise and meet it to complete the lightning channel.
      
• Mechanism of injury—trauma:
  
  • Barotraumas
    
  • Blunt trauma:
    
    • Muscle contractions can throw the victim and/or cause a fall.
      
  • Thermal burn
    

DIAGNOSIS

• Consider lightning strike in unwitnessed falls, cardiac arrests, or unexplained coma in an outdoor setting.
  
• Conscious patients may report:
  
  • Muscle aches and pains
    
  • Chest pain
    
  • Shortness of breath
    
  • Extremity pain or discoloration
    
  • Burns
    
  • Neurologic deficits including:
    
    • Paresthesia
      
    • Dysesthesias
      
    • Weakness or paralysis
      
    • Visual disturbance or blindness
      
    • Headache
      
    • Confusion or amnesia
      
    • Hearing loss or deafness
      
    • Dizziness
      

• HEENT:
  
  • Blunt head trauma
    
  • Ruptured tympanic membrane with ossicular disruption (up to 50%)
    
  • Ophthalmic injuries:
    
    • Cataracts
      
    • Corneal lesions
      
    • Intraocular hemorrhages
      
    • Retinal detachment
      
• Neck:
  
  • Cervical spine injury
    
• Cardiopulmonary injuries:
  
  • Primary cardiac arrest:
    
    • Cardiac asystole:
      
    • Due to direct current injury
      
    • May resolve spontaneously as the heart’s intrinsic automaticity resumes.
      
  • Hypertension: Transient
    
  • Pulmonary contusion or hemorrhage
    
  • Respiratory arrest:
    
    • Caused by paralysis of medullary respiratory center
      
    • May persist longer than primary cardiac arrest and lead to hypoxia-induced secondary cardiac arrest and/or brain injury
      
• Extremities:
  
  • Fractures/dislocations
    
  • Muscle tears, contusions
    
  • Compartment syndromes
    
  • Mottled or cold:
    
    • Caused by autonomic vasomotor instability
      
    • Usually resolves spontaneously in a few hours
      
• Skin:
  
  • Burns:
    
    • May evolve over several hours after injury
      
    • Discrete entrance and exit wounds are uncommon.
      
    • Superficial in nature; deep burns uncommon
      
    • Direct thermal injury is uncommon due to the brevity of electrical currents.
      
    • Thermal burns can arise from evaporation of water on skin, ignited clothing, and heated metal objects (buckles, jewelry).
      
    • Feathering pattern of fernlike “burns” are pathognomonic of lightning injuries and resolve within 24 hr.
      
• Neurologic injuries:
  
  • Confusion, cognitive or memory defects
    
  • Altered level of consciousness (>70% of cases)
    
  • Flaccid motor paralysis
    
  • Seizures
    
  • Cerebrovascular accident
    
  • Fixed dilated pupils due to either serious head injury or autonomic dysfunction
    
• Shock:
  
  • Neurogenic (spinal injury)
    
  • Hypovolemic (trauma)
    

Confirmatory history from bystanders or rescuers of the circumstances of the injury

• CBC
  
• Urinalysis for myoglobin (rare)
  
• Electrolytes for acidosis
  
• BUN, creatinine for renal function
  
• Troponin, creatine kinase, and cardiac enzymes for muscle/cardiac damage
  

• CXR:
  
  • Pulmonary edema
    
  • Pulmonary contusion/hemorrhage
    
  • Rib fractures
    
• Cervical spine radiograph
  
• Head CT for altered mental status or significant head trauma
  
• Relevant imaging for specific injuries