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Matt is a 46-year-old right-handed carpenter. While he was cutting wood, the saw jumped and lacerated his left hand resulting in multiple tendon lacerations but no fracture. He initially defined the pain as “tearing,” but after he underwent tendon repair and subsequent splinting for 3 weeks, he described it as, “Like my hand was in a pot of boiling water” and, “Like a thousand needles” and, “Like grabbing a wire brush.” His left hand took on a reddish-blue appearance and was swollen and very sensitive to light touch, which could precipitate a volley of “electrical shocks.” The pain spread up the forearm and also affected his shoulder but spared his elbow. He was unable to use it for anything and had to protect it with his right hand if he went out in a crowd. He wasn’t able to work and had to give up music and sports. Sleep became sporadic and non-restorative, as he’d awaken frequently with sudden pain in his left upper limb. He became quite depressed as a result of the unrelenting pain and the sudden deterioration of his circumstances.
I saw him 6 months after the injury and he already had a cold, pale, wasted left upper extremity. He had marked allodynia, which is pain elicited by light touch. There was a well-healed palmer surgical scar but the tendons distal to the scar were thickened and functionless. The fingers were fixed in a flexion contracture. There was robust hair growth of the forearm and dorsum of the hand. His nails were long and deformed, as he couldn’t tolerate attempts to trim them. However, he had a normal radial pulse and immediate capillary refill to his nail beds.
Matt was first treated with rofecoxib without improvement, which was stopped. He was given gabapentin, which helped only a little and this was switched to topiramate with improvement. He started morphine but as time went on it became less effective and he was switched to hydromorphone 2 mg tid and methadone for pain, 10 mg tid. For sleep he was given nabilone 1 mg hs and for his low mood duloxetine 60 mg qam. Three intravenous regional bretylium tosylate blocks were administered with improvement for only a few days at a time.
Matt’s diagnosis is complex regional pain syndrome type 1 (CRPS – 1) following soft tissue injury to his left hand.
Chronic, neuropathic type pain in an extremity was described as far back as 409 BC. Sophocles’ play Philoctetes describes a soldier with pain like, “the lightning bolts of Jove.” in his leg after a snake bite. The modern description of CRPS was by the physician, Silas Weir Mitchell. He described soldiers from the American Civil War who developed neuropathic pain in their wounded extremities and termed this agonizing pain “causalgia.” He noted it was caused by direct damage to a peripheral nerve that triggered autonomic and dystrophic changes in the extremity. Causalgia is now termed CRPS type 2.1 A similar neuropathic pain syndrome with autonomic and dystrophic signs, triggered by soft tissue injury or bone fracture without direct nerve injury, was described in 1947 and termed reflex sympathetic dystrophy (RSD). We now refer to RSD as CRPS type 1.1 Below I describe both type 1 and type 2 CRPS together as CRPS.
CRPS is a disabling chronic pain condition of unknown etiology. What distinguishes it from other chronic painful conditions of a limb is the hallmark autonomic instability and rapid onset of dystrophic changes. There’s usually a history of trauma that seems to precipitate the pain. The most common precipitating event is a limb fracture, usually the wrist, treated with a cast. However, many other injuries could trigger CRPS (Table 1).
The patient may complain of pain long after the healing of the injury. The character of the pain may gradually change from a post-fracture nociceptive type pain description of dull, pressure, throbbing and aching to a neuropathic type of pain, with terms such as burning, shooting, sharp, tingling, searing, cutting, tearing, lancinating, shocking, and so on. The pain may spread to involve the entire limb and even further to affect the trunk on the side of the original injury. The patient fears using the limb and often avoids even light touch to the skin, which may feel painful. The individual may observe that the affected limb feels hotter or colder than the unaffected limb and that the skin appears a different colour, either pale or alternatively dark red, purple or blue. There might be sweating and increased or decreased hair and nail growth of this limb. In time the tissues become dystrophic or wasted and this includes the muscles and subcutaneous tissue, and the bones become osteopenic. The skin becomes thin and in conjunction with dermal edema it takes on a stretched, shiny appearance. It may appear blue, cold and clammy, similar to the appearance of a limb in shock. The neuropathic pain sometimes manifests as pruritis and a neurodermatitis often results.
In advanced CRPS there may be a movement disorder of the affected limb with muscle weakness, paresis, dystonia, tremor or myoclonic jerks described in association with CRPS. The joints can undergo contracture and become fixed in partial flexion and the limb may become withered and useless. Other sequelae of CRPS might be visceral such as neurogenic bladder or gastroparesis.
The patient may be observed constantly protecting the affected limb so that it’s not inadvertently touched by clothing, passersby or even subjected to wind, as all these stimuli result in severe pain. In advanced cases the individual may become reclusive and isolated because all movement and touch are painful and the fear of provoking pain is greater than the need to participate in social situations. It’s no wonder that they’re labelled with social phobia or other psychiatric diagnoses!
Fortunately, most patients have a milder form of the disease and don’t progress to this horrific outcome. We no longer believe that everyone afflicted progresses inexorably through various stages of CRPS but that each patient develops certain characteristics of the disease that’s unique to him or her. So some may have prominent sudomotor changes (sweating) and others no sweating but marked vasomotor changes, while still others may rapidly develop dystrophic changes.
Vasomotor phenomena may be transient and therefore patient reports of alterations of colour and temperature must be accepted, even if these changes aren’t present at the time of the clinical examination. The diagnostic criteria of the International Association for the Study of Pain (IASP) in 1994 for CRPS takes this variability into account (Table 2).
Diagnosis
There are no laboratory or imaging tests that will reliably rule in or out the diagnosis of CRPS. The commonly ordered 3-phase bone scan may show delayed uptake of the radioactive tracer in about 50% of cases and so this is a test with poor sensitivity. Therefore, the diagnosis remains clinical and is often not made on the first visit but only after careful follow-up.
Treatment
A good diet, exercise, physical and occupational therapy, and an overall healthier lifestyle all play a positive role in improving the patient’s health. Cessation of smoking may be particularly helpful.
Initial therapy is directed at enabling physical therapy and rehabilitation and pain control is essential for this. Pain control will allow the patient to sleep better and reduce fear and anxiety. The best way to achieve early and effective pain control is through pharmacotherapy.
Pharmacotherapy of CRPS should be considered according to the Canadian Guidelines for neuropathic pain (table 3).2
If the patient fails the medications in this algorithm he or she should probably be referred to a specialist who may consider using oral corticosteroids, bisphosphonates, photon therapy, dimethyl sulfoxide (DMSO) 50% cream and N-Acetylcysteine.3 Intravenous regional bretylium and ketanserin have been shown to improve pain control.3 Surgical sympathectomy and spinal cord stimulators are effective over the long term but are expensive therapies not readily accessible. Amputation is not recommended even though many patients may request it.
Once pain control is established, refer the patient as soon as possible for physiotherapy and occupational therapy, which are the mainstays of treatment. Physiotherapy, if instituted early enough, can reduce the pain and vasomotor symptoms and may prevent soft tissue and joint contractures.
The newest and most exciting therapy for refractory CRPS is the ketamine infusion. The usual protocol is a four-hour infusion of up to 250 mg on each day of a consecutive 10-day course. The results in one study4 were impressive with 7 of 12 patients experiencing complete pain relief for 1 year or more. Four patients remained pain free for > 3 years after their second infusion.
Psychological and family support for the individual is essential. Here in Ontario, I send all my CRPS patients to PARC5, a patient counselling, support and advocacy group based in St. Catherines. PARC holds meetings and sends out a newsletter with valuable information and provides a wallet card that explains the essentials of CRPS.
Recently studies have shown that it may be possible to prevent CRPS in the case of wrist fractures. It’s likely that oral administration of 500 mg of vitamin C per day for 50 days from the date of the injury reduces the incidence of CRPS-1 in patients with wrist fractures.3
Our case, Matt, has tried the medications in the neuropathic pain protocol and some advanced therapies as well. He’s in the process of referral for ketamine infusion.
References
1. Merskey H, Bogduk N. Classification of chronic pain: descriptions of chronic pain syndromes and definition of terms. 2nd edition Seattle: IASP Press, 1994 with modifications of the Budapest consensus group 2004.
2. Pharmacological management of chronic neuropathic pain — Consensus statement and guidelines from the Canadian Pain Society. Moulin DE, et al. Pain Res Manag 2007;12(1):13-21.
3. Evidence based guidelines for complex regional pain syndrome type 1. Perez RS, et al. BMC Neurology 2010;10:20, www.biomedcentral.com/1471-2377/10/20.
4. Subanesthetic ketamine infusion therapy: a retrospective analysis of a novel therapeutic approach to complex regional pain syndrome. Correll GE, et al. Pain Med 2004;5(3):263-75.
5. Promoting Awareness of RSD/CRPS (PARC). Contact rsdcanada.org.
