Rosen & Barkin's 5-Minute Emergency Medicine Consult (504 page)

BASICS

Unpleasant sensory and emotional experience that may be secondary to actual or perceived damage to tissue, the somatosensory system, or a psychogenic dysfunction.

• It is an individual, subjective, multifactorial experience influenced by culture, medical history, beliefs, mood and ability to cope.
  

• Most common reason for seeking health care
  
• Up to 78% of visits to the emergency department.
  
• Pain is severe for 2/3rds of patients presenting with pain.
  
• Chronic pain is present in up to 35% of the population.
  
• Prevalence of neuropathic pain is 21.4% in emergency departments.
  

• Different components of pain can be combined in a same patient.
  
• Nociceptive pain:
  
  • Stimulation of peripheral nerve fibers (nociceptors) that arises from actual or threatened damage to non-neural tissue.
    
  • Visceral pain:
    
    • Stimulation of visceral nociceptors
      
    • Diffuse, difficult to locate, and often referred to a distant, usually superficial, structure.
      
    • Sickening, deep, squeezing, dull.
      
  • Deep somatic pain:
    
    • Stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae, and muscles
      
    • Dull, aching, poorly localized pain.
      
  • Superficial pain:
    
    • Stimulation of nociceptors in the skin or other superficial tissue.
      
    • Sharp, well defined, and clearly located.
      
• Neuropathic pain:
  
  • Exacerbation of normally nonpainful stimuli (allodynia).
    
  • Paroxysmal episodes likened to electric shocks.
    
  • Continuous sensations include burning or coldness, “pins and needles” sensations, numbness and itching.
    
• Psychogenic pain:
  
  • Pain caused, increased or prolonged by mental, emotional, or behavioral factors.
    

DIAGNOSIS

• A patient’s self-report is the most reliable measure of pain.
  
• Obtain a detailed description of pain:
  
  • Onset
    
  • If caused by an injury, determine the mechanism of injury
    
  • Localization of pain
    
  • Severity of pain:
    
    • Mild pain from >0 to ≤3/10
      
    • Moderate pain from >3 to <6/10
      
    • Severe pain ≥6/10.
      
  • Type of pain
    
  • Duration of pain
    
  • Variations of pain:
    
    • Daily/weekly/monthly variations
      
    • Variations caused by physical activities
      
  • Effect of previous analgesic drugs taken before the consult.
    
• Acute vs. chronic pain:
  
  • Acute pain:
    
    • Transitory, usually <30 days
      
    • Lasting only until the noxious stimulus is removed or the underlying damage has healed
      
    • Resolves quickly
      
  • Subacute pain:
    
    • Lasting 1–6 mo
      
  • Chronic pain:
    
    • Lasts more than 3–6 mo
      
    • Pain that extends beyond the expected period of healing
      
• Numerical Rating Scale (NRS):
  
  • Patients estimate their pain intensity on a scale from 0 to 10
    
• Visual Analog Scale (VAS):
  
  • Patients indicate their pain by a position along a 10 cm continuous line between 2 end points, the left one representing no pain and the right one the worst pain they can imagine.
    
• Clinically relevant change varies from 13 to 19 mm on a VAS or 1.3–1.9/10 on an NRS.
  
• Faces Pain Scale:
  
  • Self-report measure of pain intensity developed for children (4–10 yr old).
    
• DN4 test:
  
  • Screening tool for neuropathic pain
    
  • The score ranges from 0 to 10
    
  • A score of 4 or more classifies the pain as neuropathic rather than nociceptive.
    
  • Pain characteristics:
    
    • Burning? (Yes = 1)
      
    • Painful cold (Yes = 1)
      
    • Electric shocks (Yes = 1)
      
  • Symptoms associated with the pain in the same area:
    
    • Tingling (Yes = 1)
      
    • Pins and needles (Yes = 1)
      
    • Numbness (Yes = 1)
      
    • Itching (Yes = 1)
      
    • Decrease in touch sensation (Yes = 1)
      
    • Decrease in prick sensation (Yes = 1)
      
    • Can the pain be caused or increased by brushing (Yes = 1)
      
• Remember to always use the same assessment tool for an individual patient.
  

• Observation needed to determine pain scale in nonverbal patients:
  
  • Vocalization, e.g., whimpering, groaning, crying, or moaning
    
  • Facial expression, e.g., looking tense, frowning, grimacing, looking frightened
    
  • Analgesic attitudes aimed to protect a body zone in rest position (seated or lengthened)
    
  • Careful movements, spontaneously or when asked.
    
• All aspects of the physical exam should be gently done.
  
• Posture, point tenderness, percussion tenderness, passive and active range of motion as well as active resistance.
  
• It is recommended to move smoothly between the different components of the exam while warning the patient about each phase.
  
• Always examine uninjured tissues first and avoid sudden movement.
  
• Repeat physical exam after pain relief.
  

Perform any exam and lab or radiographic studies as indicated by the patient’s condition.

• Obtain complete history of pain.
  
• When a person is nonverbal and cannot self-report pain, obtain history from caregivers/other relatives/friends/neighbors.
  

As appropriate for medical condition(s)

As appropriate for medical condition(s)

As appropriate for medical condition(s)

• Drug-seeking behavior in opioid dependent patients:
  
  • Frequent use of emergency facilities, moving from 1 provider to another without coordinated care.
    
  • Unclear history of illness, only subjective complaints (difficult to objectively verify).
    
  • Patients tend to be obsessive and impatient, and request repeatedly analgesic medications.
    
  • Some aspects of the physical exam should be inconsistent.
    
  • Lab and radiologic studies may remain normal.
    

TREATMENT

• Nonpharmacologic measures are effective in providing pain relief in a pre-hospital setting.
  
• Nitrous oxide is an effective analgesic agent in pre-hospital situations.
  
• Morphine, fentanyl, and tramadol can be used in a pre-hospital setting.
  

• ABCs
  
• Treat life-threatening medical/traumatic conditions as appropriate.
  
• Patients with severe pain should be triaged as a priority and dispatched in a rapid care sector, ensuring rapid pain control.
  

• Nonpharmacologic measures are effective in providing pain relief and should be systematic:
  
  • Immobilization of injured extremities.
    
  • Elevation of injured extremities.
    
  • Ice.
    
• Opioids for severe pain:
  
  • Preferably IV or intraosseous if IV not possible
    
  • Wide interindividual variability in dose response and the delayed absorption with IM or SC routes
    
  • Oral opioids associated with acetaminophen represent reasonable alternatives for less severe pain:
    
    • Oxycodone 5–10 mg
      
    • Hydrocodone 5–10 mg
      
    • Codeine 30–60 mg
      
    • Tramadol 50–100 mg
      
• Nonsteroidal anti-inflammatory drugs:
  
  • Mild to moderate trauma pain
    
  • Musculoskeletal pain
    
  • Renal and biliary colic
    
  • Relatively high rate of serious adverse effects including GI bleeding and nephropathy.
    
• Acetaminophen provides safe and effective analgesia for mild to moderate pain with minimal adverse effects.
  
• Treat associated anxiety or emotion.
  
• Regional anesthesia should be considered for acute well-localized problems such as toothache, fractures, hand and foot injuries.
  

• Acetaminophen: 500 mg (peds: 10–15 mg/kg, do not exceed 5 doses/24h) PO q4–6h, do not exceed 4 g/24h
  
• Codeine: 30–60 mg PO q4–6h prn
  
• Morphine:
  
  • Initial bolus of 0.05–0.1 mg/kg IV
    
  • 15–30 mg PO q4–6h
    
• Hydromorphone:
  
  • Initial bolus 1 mg IV
    
  • 2–4 mg PO q4–6h
    
• Oxycodone: 5–10 mg PO
  
• Hydrocodone: 5–10 mg PO
  
• Tramadol: 50–100 mg PO
  
• Hydrocodone/acetaminophen: 5/500 mg PO q4–6h
  
• Ibuprofen: 600–800 mg PO q6–8h (peds: 10 mg/kg q6h)
  
• Naproxen: 250–500 mg PO q12h
  

FOLLOW-UP