Complex Regional Pain

SyndromeAaron J. Mascarenhas

080201022

Background

•Recognized in during the civil war.

•The syndromes appearing under this include Sudeck’s atrophy, Sympathetic dystrophy, algodystophy, shoulder-hand syndrome, causalgia.

What do they have in common?

•Pain, OUT OF PROPORTION to the inciting cause.

•Vasomotor instability

•Trophic skin changes

•Regional osteoporosis

•Functional impairment

Consesus Expert panel recommended: CRPS

Definition?

“CRPS is a multi-symptom, multi-system, syndrome usually affecting one or more extremities, but may affect virtually any part of the body.”

-International Research Foundation For RSD/CRPS.

EtiologyA number of precipitating factors have been associated with RSD / CRPS including:

•Trauma (often minor)•Ischemic heart disease and myocardial infarction•Spinal cord disorders•Cerebral lesions•Infections•Surgery•However, in some patients a definite precipitating event can not be identified

Pathophysiology• Sympathetic pain results from tonic activity in myelinated

mechanoreceptor afferents. Input causes tonic firing in neurons that are part of a nociceptive pathway.

• Injury to central or peripheral neural tissue.

• Elevated levels of soluble tumor necrosis factor receptor 1 (sTNF-R1) and enhanced tumor necrosis factor-alpha activity in patients with polyneuropathy with allodynia

• Distal degeneration of small-diameter peripheral axons may be responsible for the pain, vasomotor instability, edema, osteopenia, and skin hypersensitivity of CRPS-1.

• Cortical changes, suggesting a possible role in pathophysiology

Clinical features1.PAIN

a.occurring in one or more extremities is described as severe, constant, burning and/or deep aching pain

b.All tactile stimulation of the skin (e.g. wearing clothing, a light breeze) may be perceived as painful (allodynia).

c.Paroxysmal dysaesthesias and lancinating pains

2.SKIN CHANGES

a.Skin may appear shiny (dystrophy-atrophy), dry or scaly

b.Hair may initially grow coarse and then thin. Nails in the affected extremity may be more brittle, grow faster and then slower.

c.Rashes, Ulcers and Pustules

d.Abnormal sympathetic (vasomotor changes) activity may be associated with skin that is either warm or cold to touch.

e.Increased sweating (sudomotor changes) or increased chilling of the skin with goose flesh (pilomotor changes)

3.SWELLING

a.Localised, initially pitting and later Brawny

b.Edema may be sharply demarcated along a line on the skin surface.*

4.MOVEMENT DISORDER

a.May develop dystonia

b.Tremors and involuntary jerking of extremities may be present.

c.Disuse atrophy sets in natural history.

1.SPREADING SYMPTOMS

a.A "continuity type" of spread where the symptoms spread upward from the initial site, e.g. from the hand to the shoulder.

b.A "mirror-image type" where the spread was to the opposite limb.

c.An "independent type" where symptoms spread to a separate, distant region of the body. This type of spread may be spontaneous or related to a second trauma.

d.*Total body RSD

When to make a diagnosis?

CRPS Type 1:1.Initiating noxious event or a cause of immobilization2.Continuing pain, allodynia, or hyperalgesia disproportionate to the inciting event3.Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the area of pain4.The diagnosis is excluded by the existence of any condition that would otherwise account for the degree of pain and dysfunction. CRPS Type 2:•Continuing pain, allodynia, or hyperalgesia after a nerve injury, not necessarily limited to the distribution of the injured nerve1.Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of pain2.The diagnosis is excluded by the existence of any condition that would otherwise account for the degree of pain and dysfunction.

Stage I1.Onset of severe, pain limited to the site of

injury2.Hyperesthesia3.Localized swelling4.Muscle cramps5.Stiffness and limited mobility6.At onset, skin is usually warm, red and dry and

then it may change to a blue (cyanotic) and become cold and sweaty.

7.Hyperhydrosis8.Lasts a few weeks, then subsides

spontaneously or responds rapidly to treatment.

Stage II1.Pain becomes even more severe and more diffuse

2.Swelling tends to spread and it may change from a soft to hard (brawny) type

3.Hair may become coarse then scant, nails may grow faster then grow slower and become brittle, cracked and heavily grooved

4.Spotty wasting of bone (osteoporosis) occurs early but may become severe and diffuse

5.Muscle wasting begins

Stage III1.Marked wasting of tissue (atrophic) eventually become irreversible.

2.For many patients the pain becomes intractable and may involve the entire limb.

3.A small percentage of patients have developed generalized RSD affecting the entire body.

Medical ManagementFor constant pain associated with inflammation

Nonsteroidal anti-inflammatory agents (e.g. aspirin, ibuprofen, naproxen, indomethacin, etc).

For constant pain not caused by inflammation:Agents acting on the central nervous system by an atypical mechanism (e.g. tramadol)

For constant pain or spontaneous (paroxysmal) jabs and sleep disturbances;

Anti-depressants (e.g. amitriptyline, doxepin, nortriptyline, trazodone, etc)Oral lidocaine (mexilitine - some what experimental)

For spontaneous (paroxysmal) jabsAnti-convulsants (e.g. carbamazepine, gabapentin may relieve constant pain as well)For widespread, severe RSD / CRPS pain, refractory to less aggressive therapies

Oral opiods tried.For the treatment of sympathetically maintained pain (SMP)

Clonidine Patch. For muscle cramps (spasms and dystonia)

Klonopin (clonazepam)Baclofen

Surgical

1.Sympathetic Blockade

2.Regional Block (Guanethidine)

3.Spinal cord stimulation

4.Morphine pump