Fact-sheet: Transient regional osteoporosis
Updated on 06/25/2020 at 9:37 AM
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Definition
The term "complex regional pain syndrome" (CRPS) refers to a painful clinical presentation whose main characteristics are:
- regional, continuous pain, spontaneous or evoked, which appears disproportionate in intensity or duration relative to the expected course of the triggering event
- this regional pain does not correspond to a peripheral nerve territory (truncal or radicular)
- this pain may be associated with motor, sensory, sudomotor, vasomotor, and trophic clinical signs, which may be inconsistent and variable over time.
- Can occur at any age in adults (possible in children and adolescents but remains exceptional)
- Female predominance (three women to one man)
- Low annual incidence, estimated between 5 and 25 per 100,000
Etiologies: multiple, with anxio-depressive psychological risk factors
- Trauma: accounts for more than half of CRPS cases. There is no relationship between the onset of CRPS and the severity of the trauma. The interval between trauma and CRPS 1 is variable (a few days to a few weeks). Surgery, particularly orthopedic surgery, is a frequently identified precipitating factor. Similarly, overly intensive and painful rehabilitation may aggravate or trigger CRPS, as may, conversely, prolonged inappropriate immobilization.
- Neurologic: stroke, multiple sclerosis
- Oncologic: locoregional neoplastic invasion, underlying thoracic tumor (for upper limb CRPS), rare paraneoplastic forms
- Vascular: deep vein thrombosis
- Infectious: shingles, felon
- Endocrine: diabetes, thyroid dysfunction
- Drug-induced: barbiturates
- Obstetric: (hip, during pregnancy)
Clinical features
See introduction
Laboratory findings
No biological abnormality
Radiography
Clinical-radiological delay of a few weeks to a month.
Value of comparative views
- Demineralization, initially mild with thinning of the subchondral plates, then heterogeneous and mottled, sometimes with near-complete disappearance of the trabecular pattern and cortices.
This demineralization is regional, usually involving both sides of a joint.
- Joint space always preserved throughout the course of the disease
CT
See radiographic features
MRI
It is now the reference examination.
A normal MRI does not, however, rule out the diagnosis of CRPS, as it may be normal in forms that are cold from the outset.
Regional bone marrow edema, involving several bones, associated with soft tissue edema
- Hypointense on T1-weighted sequences, corrected by gadolinium injection
- Hyperintense on T2-weighted and STIR sequences
Nuclear medicine
Bone scintigraphy: locoregional hyperfixation is the characteristic finding but is not specific.
It precedes radiographic signs, with an "extension" to neighboring joints, and is present on all three phases:
- early phase (vascular)
- intermediate phase (soft tissue)
- delayed phase (bone)
Hyperfixation may be absent in some cases, sometimes replaced by hypofixation, which is more common in children and adolescents (cold form from onset).
Management
The course is spontaneously favorable in 90% of cases but may be prolonged (12 to 24 months).
More rarely (5 to 10% of cases), the course is slower, with pain persisting for several years, associated with trophic disorders and aponeurotic retractions.
Treatment includes:
- Rest
- Rehabilitation and physical therapy
- Analgesic treatment
Differential diagnosis
Occult fracture