Complex Regional Pain Syndrome

Complex Regional Pain Syndrome

By Julie Hastings MD

Complex regional pain syndrome (CRPS) is a painful and sometimes disabling condition that usually affects the limbs, most often after a trauma, nerve injury or surgery. The degree of pain is greater and longer lasting that the initial event would typically cause. When a patient is experiencing this type of pain, he or she may be referred to a physiatrist to evaluate for CRPS. Symptoms of CRPS include severe pain, skin sensitivity, temperature changes, skin color changes, swelling, increased sweating, stiffness, weakness, and/or hair and nail changes. There are 2 types of CRPS – type I and type II CRPS. Type I CRPS (previously referred to as “reflex sympathetic dystrophy”) comprises 90% of all cases of CRPS and includes cases where there are no identified nerve injuries. Type II CRPS (“causalgia”) is diagnosed when there is evidence of nerve damage. An accurate diagnosis and individualized treatment plan are instrumental in relieving the pain and suffering caused by CRPS.

How does CRPS occur? CRPS arises from many different factors including inflammatory changes, nervous system sensitization, and autonomic dysfunction. After trauma, some inflammation is physiological, meaning normal, useful feedback from the body’s pain receptors.  In CRPS this inflammation persists for months, beyond the time that damage is present. This pro-inflammatory network increases sensitivity of the peripheral and spinal nociceptive (pain sensing) systems as well as facilitates the release of chemical signalers called neuropeptides which then cause visible signs of inflammation. Chemical signalers also stimulate fibroblast (cells that make collagen) proliferation and vascular changes. Due to neuronal plasticity, or nervous system “learning”, sensory-motor integration may become disturbed leading to motor dysfunction. Despite ongoing research, however, there continues to be much that is unknown about CRPS including the role of the sympathetic nervous system, genetic factors, and psychological factors.

CRPS typically follows three stages of development, although it is important to note that every CRPS patient is different in terms of their symptoms and response to treatment. Early diagnosis and treatment may help prevent CRPS from progressing to the next stage. Stage I is the Dysfunction Stage and usually lasts 1-3 months. Stage I typically includes severe pain and hypersensitivity, fluctuations in skin temperature between hot and cold, irregular growth of hair and nails, increased sweating, and changes in the skin’s appearance, including color and texture. Stage 2 is the Dystrophy Stage and typically lasts between 3-6 months. Stage 2 is defined by worsening of pain and sensitivity as well as muscle weakness and joint stiffening and continued abnormality of the skin, hair, and nails of the affected limb. Stage 3 is known as the Atrophic Stage and includes decreases in bone mass of the affected limb, coolness of the limb, and increased limb weakness and stiffening.

Diagnosis of CRPS is made clinically, often by a physiatrist, based on diagnostic criteria called the “Budapest criteria”. The Budapest criteria has 4 components. First, the patient has continuing pain that is disproportionally painful to the event that provoked it. Second, the patient must report symptoms in at least 3 of the 4 following categories: sensory (increased skin sensitivity), vasomotor (temperature and/or skin color changes), sudomotor/edema (swelling and/or sweating changes), and motor/trophic (decreased ROM and/or motor impairment (weakness, tremor, involuntary contraction) and/or changes in the hair/nails/skin). Third, the patient must also exhibit signs, which are observable by the health care provider, in at least 2 of the 4 categories above (sensory, vasomotor, sudomotor/edema, motor/trophic). The last component of the Budapest criteria is that no other diagnosis can better explain the signs and symptoms.

In addition to the physical exam, there are no specific laboratory tests or images used to diagnose CRPS, however there are several tests and procedures that may be helpful in establishing or clarifying the diagnosis. These include bone scans (bone scintigraphy) which help identify changes in bone density and blood flow to the bone-related tissues.  X-Rays and MRIs may be helpful in identifying changes due to CRPS and ruling out other potential causes of pain. In addition, electrodiagnostic studies (EMG/NCS) also help evaluate for other diagnoses such as radiculopathy, plexopathy and peripheral nerve entrapment. Finally, sympathetic blocks, described in further detail below, may also help both in diagnosing and treating CRPS.

The multi-disciplinary treatment of CRPS aims to manage pain and increase mobility and function of the affected limb. A physiatrist may recommend specialized physical or occupational therapy including desensitization, strength and flexibility training, postural control, gait retraining, activities of daily living and/or vocational support, coping skills training, relaxation techniques, graded motor imagery, and mirror therapy. Medications may be utilized as well to decrease pain and increase tolerance to therapy. In the early stages of CRPS, glucocorticoids (steroid medications) may be used to help decrease inflammation. Neuropathic pain medications such as Neurontin (gabapentin) and Lyrica (pregabalin) are often used to treat pain that is thought to be caused by nerve damage or aberrant nerve firing.  Another commonly used class of medication are antidepressants, specifically tricyclic antidepressants (TCAs), which may be helpful even in patients who are not depressed by affecting chemical changes in the brain that help reduce pain and improve sleep which is a common problem among CRPS patients. Less frequently used medications include bisphosphonates, NSAIDS, muscle relaxers, and opioids. Finally, pain management psychology is an integral component of multi-disciplinary pain management.

Interventional procedures may also be helpful for patients who do not experience adequate relief with more conservative options. For example, sympathetic nerve blocks, performed by a physiatrist under fluoroscopic (X-Ray) guidance are commonly used to help decreased symptoms of CRPS. In patients with CRPS affecting the arm, a stellate block is performed to target the sympathetic nerves in the upper spine, while in those with CRPS affecting the leg, a lumbar sympathetic block targets the sympathetic nerves in the lower spine. In many cases, sympathetic blocks are performed several times or in a series to maximize pain relief and functional improvement. The number of sympathetic blocks required varies between patients and will be determined by the patient and the physiatrist.  Spinal cord stimulation (SCS) may be beneficial for patients who have not adequately responded to the interventions above. SCS is an implanted device which uses an electric pulse stimulation to control the transmission of pain signals in the spinal cord.

At Desert Spine and Sports Physicians, we offer the complete array of conservative care for CRPS and other spine, sports and musculoskeletal pain and injury. If you are a doctor and have a patient who has symptoms of CRPS or if you are a patient and have these symptoms yourself, please contact us at DSSP. As always, we are here for you and are passionate about helping people decrease pain and improve their function and quality of life.

 

References:

Birklein F, Dimova V. Complex regional pain syndrome-up-to-date. Pain Rep. 2017;2(6):e624. Published 2017 Oct 5. doi:10.1097/PR9.0000000000000624

Shim H, Rose J, Halle S, Shekane P. Complex regional pain syndrome: a narrative review for the practising clinician. Br J Anaesth. 2019;123(2):e424-e433. doi:10.1016/j.bja.2019.03.030



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