How do you Diagnose Complex Regional PainSyndrome?
The diagnosis is mainly clinical and can be challenging and missed, especially inthe early stages of the syndrome. To make a clinical diagnosis all the following criteria have to be present
- Pain which is disproportionate to the initial triggering event
- Presence of at least one of the following symptoms
- Increased sensitivity to painful stimuli and experiencing pain even with non-pain causing stimuli such as light touch
- Skin pigmentation and marked temperature differences (> 1oC) between the two limbs
- Skin swelling and increased sweating on the affected limb
- Loss of mobility or reduced mobility and weakness of affected limb associated with hair and nail changes
- Inability to attribute patient’s symptoms to any other cause
This above criteria mean that diagnosisof CRPS can only be made if there are recognizable signs in the limb when thepatient is seen. However, many patients can experience a delay in diagnosis andsome changes (eg, swelling and sweating) may reduce or resolve over time. Thus,in those patients who still report pain and who have had the above criteria inthe past, a diagnosis of CRPS-NOS (nototherwise specified) can be made.
Roleof Investigations in CRPS – Minimally useful
- No blood tests are available to confirm or rule out diagnosis of CRPS
- Investigations such as x-rays, electromyography (EMG), nerve conduction studies, CT scans and MRI studies may be normal and do not add value to diagnosis
- Definitive tests of nerve damage, such as electromyogram (EMG), that may help differentiate between CRPS I and CRPS II, are deemed painful to patients and unnecessary
- Thermography can confirm presence of body temperature changes that are commonly seen in CRPS.