Definition
Reflex sympathetic dystrophy,
a constellation of changes involving the sympathetic nervous system,
which has been known under many names (causalgia, Sudeck's
osteodystrophy, posttraumatic osteoporosis, algodystrophy, shoulder
hand syndrome). This syndrome can be precipitated by any neurally
related visceral, musculoskeletal, neurologic or vascular condition.
Frequently, however, a cause is not identifiable. Trauma,
cerebrovascular disorders, degenerative disease of the cervical
spine, discal herniation, postinfectious states, calcific tendinitis,
vasculitis and neoplasm have all been associated with reflex
sympathetic dystrophy.
Various theories have been advanced to explain the pathogenesis; the
most widely held explanation involves the existence of an "internuncial
pool." In this theory an injury or lesion is assumed to produce
painful impulses that travel via afferent pathways to the spinal
cord, where a series of reflexes are initiated that spread via the
interconnecting pool of neurons. The lateral and anterior tracts are
stimulated, which provokes efferent pathways to the peripheral
nerves, producing the local findings of reflex sympathetic
dystrophy.
Patients may exhibit variable symptoms and signs, often in the
shoulder and hand. Stiffness, pain, tenderness and weakness may be
associated with swelling, vasomotor changes, hyperaesthesia and
disability. Glenohumeral joint periarthritis may be accompanied by a
shoulder hand syndrome.
Radiographically, soft tissue swelling and regional osteoporosis are
the most important features (Fig.1). Metaphyseal bone resorption
leads to periarticular osteoporosis; subperiosteal bone resorption
resembles that seen in patients with hyperparathyroidism;
intracortical bone resorption produces excessive striation or
tunnelling in cortices; endosteal bone resorption causes initial
scalloping of the endosteal surface, with subsequent widening of the
medullary canal; and subchondral and juxta-articular erosion may
lead to small periarticular erosions. The extensive involvement and
the severity of the bone resorption may lead to the radiographic
appearance of rapid and severe osteopenia. However, the preservation
of the joint space in this syndrome cannot be overemphasized as a
characteristic feature of reflex sympathetic dystrophy
Scintigraphy of the bones and joints also shows increased
accumulation of radionuclide agents in joints and bones, which may
be related to an increased blood flow. Although the disease is
bilateral, the abnormalities are much more marked on one side than
on the other. Some patients reveal a segmental pattern affecting
only a portion of an extremity.
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Radiographic Appearance
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Useful Link
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