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An Overview of CRPS
What is CRPS?
Complex regional pain syndrome (CRPS) is a broad term that covers long-lasting pain and inflammation that can happen after an injury or a medical event, such as surgery, trauma, stroke, heart attack, or sometimes it may not have definitive incident. Although complex regional pain syndrome (CRPS) can occur anywhere in the body, it usually affects a person’s arm, leg, hand, or foot. CRPS is usually triggered by trauma or injury to the affected limb or other body part.
It is classified as a rare disorder by the United States Food and Drug Administration. However, up to 200,000 individuals experience this condition in the United States, alone, in any given year.
CRPS is uncommon, and its cause isn't clearly understood. Treatment is most effective when started early. Yet, it can take some patients years to get a diagnosis.
CRPS occurs when the nervous system and the immune system malfunction as they respond to tissue damage from trauma. The nerves misfire, sending constant pain signals to the brain. The brain then interprets these signals, determining the intensity and location of the pain, and triggering responses, and responds. Essentially, think of it as the perfect storm in the brain.
The level of pain is measured as one of the most severe on the McGill University Pain Scale. Most patients describe it as a burning, stabbing, gnawing pain.
The symptoms of CRPS can greatly impact the function of your affected limb or area, sleep, daily activities and overall mental health.
The persistent pain and disability associated with CRPS require coordinated / patient-centered care to achieve pain reduction and better function.
While there is no cure at this time - it is possible to gain long-term remission.
CRPS Type 1 vs Type 2
There are two subtypes of CRPS.
CRPS-1 occurs after illness or injury but is not associated with any specific nerve damage. We've seen CRPS 1 occur after mosquito bites, bee stings and sprains.
CRPS-2 is associated with damage to a specific nerve.
The majority of cases of CRPS are CRPS-1.
It's not well understood why certain injuries in incidents can trigger CRPS. Not everyone who has such an injury/incident will go on to develop CRPS. It might be due to an interaction between your central and peripheral nervous systems that isn't typical and different inflammatory responses, or the perfect storm in the brain.
Some may talk of cold or hot CRPS, but the reality is every person's experience is different with CRPS. Our bodies are as unique as our fingerprint. Therefore, some may experience coldness, others hot, and some will fluctuate hot and cold.
How is CRPS Diagnosed?
Since CRPS is rare and healthcare providers don’t totally understand it, it’s often misdiagnosed.
There’s no specific test to diagnose CRPS. Healthcare providers mainly diagnose it through a careful medical history, physical examination and review of your symptoms. Your provider will ask you if you’ve had a recent injury or surgery.
Your provider may also order other tests to rule out other diagnoses/conditions that cause similar symptoms. For example, electromyography (EMG) may reveal other causes of neuropathy, which may result in some similar pain scenarios.
Once other possible diagnoses are ruled out, your provider will us the Budapest criteria to make the diagnosis.
Budapest criteria for CRPS
There are currently no medical tests for Complex Regional Pain Syndrome (CRPS). A clinical diagnosis is based entirely upon an accepted set of guidelines. At a medical conference in 2004, the International Association for the Study of Pain (IASP) adopted a new set of guidelines for diagnosing CRPS, superseding guidelines which had been in place for the previous decade. As the conference took place in Budapest, the new guidelines were named the Budapest Criteria.
Signs and Symptoms
The Budapest Criteria differentiates between ‘signs’, which are seen or felt by the person carrying out the examination and ‘symptoms’ which are reported by the patient.
Symptoms
Under the Budapest Criteria, for a diagnosis of CRPS, a patient must have at least one symptom in three of the following four categories:
Sensory: hyperaesthesia (an abnormal increase in sensitivity) and/or allodynia (pain caused by usually non-painful stimuli).
Vasomotor: skin color changes or temperature and/or skin color changes between the limbs.
Sudomotor/oedema: oedema (swelling) and/or sweating changes and/or sweating differences between the limbs.
Motor/trophic: decreased range of motion and/or motor dysfunction (weakness, tremor, muscular spasm (dystonia)) and/or trophic changes (changes to the hair and/or nail and/or skin on the limb).
Signs
At the time of clinical examination, at least one sign must be present in two or more of the following categories:
Sensory: hyperalgesia (to pinprick) and/or allodynia (to light touch and/or deep somatic (physical) pressure and/or joint movement).
Vasomotor: temperature differences between the limb and/or skin color changes and/or skin color changes between the limbs.
Sudomotor/oedema: oedema and/or sweating changes and/or sweating differences between the limbs.
Motor/trophic: decreased range of motion and/or motor dysfunction (i.e. weakness, tremor or muscle spasm) and/or trophic changes (hair and/or nail and/or skin changes).
Finally, it is important that no other diagnosis can explain the signs and symptoms.
While a diagnosis is fundamental if appropriate treatment is to be obtained, a common diagnostic problem is that not all symptoms and signs are always present at the same time.