Chapter 8. Management of Patients with Chronic Pain

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.

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 elicited.

Rarely is a provisional diagnosis of a chronic pain condition made for the first time in the ED. The exception is a form of post nerve injury pain, complex regional pain. The sharp pain from acute injuries, including fractures, rarely continues beyond 2 weeks' duration. Pain in an injured body part beyond this period should alert the clinician to the possibility of nerve injury.

Definitive diagnostic testing of chronic pain conditions is difficult, requires expert opinion, and, often, expensive procedures such as magnetic resonance imaging, computed tomography, or thermography. Therefore, referral to the primary source of care and eventual specialist referral are warranted to confirm the diagnosis.

1. There are two essential points that affect the use of opioids in the ED: (a) opioids should be used only in chronic pain if they enhance function at home and at work, and (b) a single practitioner should be the sole prescriber of opioids or be aware of their administration by others. A previous narcotic addiction is a relative contraindication to the use of opioids in chronic pain.

2. The evidence based management of chronic pain conditions is listed in Table 8-2. The need for longstanding treatment of chronic pain conditions limits the safety of the nonsteroidal anti-inflammatory drugs. Doses of drugs are as follows. Nortriptyline, starting at 25 milligrams/day PO, or amitriptyline, starting at 25 milligrams/day PO. Gabapentin is started with an initial dose of 300 milligrams daily and is increased up to a maximum of 1200 milligrams 3 times daily according to response. Pregabalin, start 50 milligrams three times daily. Cyclobenzaprine, begin with 10 milligrams up to 3 times daily. Tramadol, start 50 to 100 milligrams every 4 to 6 hours as needed. Duloxetine, start 30 milligrams PO daily.

3. Referral to the appropriate specialist is one of the most productive means to aid in the care of chronic pain patients who present to the ED. Possible outcomes of referral to pain specialists include optimization of medical therapy, trigger point injections, dedicated exercise programs, physical therapy, epidural steroid injections, or nerve blocks as indicated.

The spectrum of drug-seeking patients includes those who have chronic pain and have been advised to avoid taking narcotics, drug addicts who are trying to supplement their habit, and “hustlers” who are obtaining prescription drugs to sell on the street.

Because of the spectrum of drug-seeking patients, the history given may be factual or fraudulent. Drug seekers may be demanding, intimidating, or flattering. In one ED study, the most common complaints of patients seeking drugs were (in decreasing order) back pain, headache, extremity pain, and dental pain. Many fraudulent techniques are used, including “lost” prescriptions, carrying abnormal x-rays or doctor's note explaining need for opioids, “impending” surgery, fictitious hematuria with a complaint of kidney stones, self-mutilation, and fictitious injury.

The diagnosis of drug-seeking behavior may not be possible in the ED. The medical record can provide a wealth of information regarding the patient, including documentation proving that the patient is supplying false information. Most states now have controlled drug databases that can be queried. Behaviors predictive of drug seeking are listed in Table 8-3. The predictive behaviors are illegal in many states and form a solid basis to refuse narcotics to the patient.

The treatment of drug-seeking behavior is to refuse the controlled substance, consider the need for alternative medication or treatment, and consider referral for drug counseling.