Basics
Description
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.
Epidemiology
Incidence and Prevalence Estimates
- 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.
Etiology
- 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
Signs and Symptoms
History
- A patients 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:
- 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.
Physical Exam
- 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.
Diagnosis Tests & Interpretation
Perform any exam and lab or radiographic studies as indicated by the patients condition.
Essential Workup
- Obtain complete history of pain.
- When a person is nonverbal and cannot self-report pain, obtain history from caregivers/other relatives/friends/neighbors.
Diagnosis Tests & Interpretation
As appropriate for medical condition(s)
Imaging
As appropriate for medical condition(s)
Diagnostic Procedures/Surgery
As appropriate for medical condition(s)
Differential Diagnosis
- 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
Pre-Hospital
- 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.
Initial Stabilization/Therapy
- 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.
Ed Treatment/Procedures
- 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.
Medication
- 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
Disposition
Admission Criteria
Disposition determined by medical condition and persistence of pain.
- Medical condition requiring admission.
- Uncontrolled pain.
Discharge Criteria
- Medical condition(s) addressed
- Pain relief defined as a final evaluation of pain ≤3/10, or a decrease of pain ≥50% from the baseline, or if the acceptable level of pain is reached for an individual patient.
- Physicians may control pain well in the ED with IV titration, but risk poor pain control after discharge with oral opioids:
- Be aware of conversion rates between opioids.
- Be aware of conversion from IV to oral dosing.
- Opioids should be prescribed at fixed intervals to control pain, with additional as-needed doses as required.
Issues for Referral
Recurrence of pain despite adequate analgesic treatment or new unexpected pain requires a reassessment of the diagnosis and consideration of alternative causes for the pain.
Followup Recommendations
As appropriate for medical condition(s).
Pearls and Pitfalls
- In case of severe pain, initiate pain relief simultaneously with the primary assessment.
- Regular assessment of pain leads to improved pain management.
- Nonpharmacologic measures are effective in providing pain relief and should always be considered and used when possible.
- Titrating relatively high doses of opioid provides the best chance of delivering rapid and effective analgesia.
Additional Reading
- Albrecht E, Taffe P, Yersin B, et al. Undertreatment of acute pain (oligoanalgesia) and medical practice variation in prehospital analgesia of adult trauma patients: A 10 yr retrospective study. Br J Anaesth. 2013;110(1):96 " 106.
- Gueant S, Taleb A, Borel-K Όhner J, et al. Quality of pain management in the emergency department: Results of a multicentre prospective study. Eur J Anaesthesiol. 2011;28(2):97 " 105.
- Todd KH, Ducharme J, Choiniere M, et al. Pain in the emergency department: Results of the pain and emergency medicine initiative (PEMI) multicenter study. J Pain. 2007;8(6):460-466.
Codes
ICD9
- 338.19 Other acute pain
- 338.29 Other chronic pain
- 780.96 Generalized pain
- 729.2 Neuralgia, neuritis, and radiculitis, unspecified
- 307.80 Psychogenic pain, site unspecified
- 729.1 Myalgia and myositis, unspecified
ICD10
- G89.4 Chronic pain syndrome
- G89.29 Other chronic pain
- R52 Pain, unspecified
- M79.2 Neuralgia and neuritis, unspecified
- F45.41 Pain disorder exclusively related to psychological factors
- M79.1 Myalgia
SNOMED
- 22253000 Pain (finding)
- 274663001 Acute pain (finding)
- 82423001 Chronic pain (finding)
- 247398009 neuropathic pain (finding)
- 68962001 Muscle pain (finding)
- 8971008 Psychalgia (finding)