Chronic pain is defined as a painful condition that lasts longer than 3 months. It also can be defined as pain that persists beyond the reasonable time for an injury to heal or a month beyond the usual course of an acute disease. Complete eradication of pain is not a reasonable endpoint in most cases. Rather, the goal of therapy is pain reduction and a return to functional status.
Signs and symptoms of chronic pain syndromes are summarized in Table 8-1. Most of these syndromes will be familiar to emergency physicians.
Table 8-1 Signs and Symptoms of Selected Chronic Pain Syndromes ||Download (.pdf)
Table 8-1 Signs and Symptoms of Selected Chronic Pain Syndromes
|Myofascial headache||Constant dull pain, occasionally shooting pain||Trigger points on scalp, muscle tenderness, and tension|
|Transformed migraine||Initially migraine-like, becomes constant, dull, nausea, vomiting||Muscle tenderness and tension, normal neurologic examination|
|Fibromyalgia||Diffuse muscular pain, stiffness, fatigue, sleep disturbance||Diffuse muscle tenderness, > 11 trigger points|
|Myofascial back pain syndrome||Constant dull pain, occasionally shooting pain, pain does not follow nerve distribution||Trigger points in area of pain, usually no muscle atrophy, poor ROM in involved muscle|
|Chronic back pain||Constant dull pain, occasionally shooting pain, pain does not follow nerve distribution||No trigger points, poor ROM in involved muscle|
|Sciatica (Neurogenic back pain)||Constant or intermittent, burning or aching, shooting or electric shock-like, may follow dermatome; leg pain > back pain||Possible muscle atrophy in area of pain, possible reflex changes|
|Complex regional pain types I and II||Burning persistent pain, allodynia, associated with immobilization/ disuse (type I) or peripheral nerve injury (type II)||Early: edema, warmth, local sweating; Late: the early signs alternate with cold, pale, cyanosis, eventually atrophic changes|
|Postherpetic neuralgia||Allodynia, shooting, lancinating pain||Sensory changes in the involved dermatome|
|Painful diabetic neuropathy||Symmetric numbness and burning or stabbing pain in lower extremities; allodynia may occur||Sensory loss in lower extremities|
|Phantom limb pain||Variable: aching, cramping, burning, squeezing or tearing sensation||May have peri-incisional sensory loss|
Complex regional pain type I, also known as reflex sympathetic dystrophy, and complex regional pain type II, also known as causalgia, may be seen in the emergency department (ED) 2 weeks or more after an acute injury. These disorders should be suspected when a patient presents with classic symptoms: allodynia (pain provoked with gentle touch of the skin) and a persistent burning or shooting pain. Associated signs early in the course of the disease include edema, warmth, and localized sweating.
The most important task of the emergency physician is to distinguish chronic pain from acute pain that heralds a life- or limb-threatening condition. A complete history and physical examination should confirm the chronic condition or point to the need for further evaluation when unexpected signs or symptoms are ...