This presentation is a summary of several lectures given by the past president of the Reflex Sympathetic Dystrophy of America. The Power Point presents the appropriate way to diagnose CRPS (RSD), and has pictures of CRPS compared to nerve entrapment syndromes, mistakenly diagnosed as CRPS. A list of appropriate medical testing is included, as is an explanation of the pathophysiology. See www.DiagnoseMyPain.com to take a test to clarify the diagnosis.

1. Lecture 6
RECOGNIZING CRPS I
(RSD)
Nelson Hendler, MD, MS
Former Assistant Professor of Neurosurgery
Johns Hopkins University School of Medicine
Past president –American Academy of Pain Management
Past president- RSD Association of America
www.DiagnoseMyPain.com

2. Definitions
• Allodynia- a painful response to a normally
non-painful stimulus.
• CRPS I –complex regional pain syndrome
type I, which used to be called reflex
sympathetic dystrophy.
• CRPS II – complex regional pain syndrome
type II, which used to be called causalgia.

3. IASP Definition of CRPS I
(International Association for the Study of Pain)
• Pain in excess of what is expected. (This is a
very subjective definition, and not scientific)
• Swelling or edema
• Coldness or heat in limb
• Loss of hair
• Nail growth
• Can spread to other side

4. Diagnostic Criteria for CRPS I
The Sine Qua Non of Dx.
• Thermal allodynia (Raja, Campbell, Meyers-
American Pain Society abstract,’96)
• Circumferential pain (Raja and Hendler, Current
Practices in Anesthesiology, ‘90 )
• Not a cold limb –also found in radiculopathy, nerve
entrapment, CRPS II.
• Not mechanical allodynia – also seen in nerve
entrapment and radiculopathy as well.
• Not skin changes- also seen in CRPS II, N. entrap.
• Not edema – also seen in lymphatic damage,sprains

5. Flaws with Research Design
• Symptoms change over time, following three
stages (Schwartzman, and Payne)
• These stages are based on severity or clusters
of symptoms, not temporal staging.
• Many errors in literature, due to failure to
report the stage, or list the clinical diagnostic
criteria for the patient selection, resulting in
difficulty doing meta analysis research, with
highly variable outcome results, i.e. 12%-97%
success rate for sympathectomy (Payne).

6. Definitions
• Circumferential: a location which
described a circumference, i.e. all the way
around something, like a tree or a limb.
• Tinel: a response to a tap on a nerve that
sends a sensation in the anatomical
distribution of that nerve, like hitting your
“funny bone” (the ulnar nerve).

7. Anatomy of Spinal Cord
• Sympathetics
Sympathetic
Chain
Dorsal Horn
of Spinal
Cord
Wide Dynamic
Range Neurons

8. Concepts
• The sympathetic nerves have origin in the thoracic
spinal cord.
• They form ganglion outside the spinal cord.
• Their activity is controlled by the wide dynamic
range neurons of the posterior horn.
• Sympathetics control functions such as blood
vessel diameter, sweating, heart rate.
• The wide dynamic range neurons have neuronal
plasticity, i.e. they can change activity over time.

9. MEDICAL FACTS ABOUT CRPS I (RSD)
• In early stages, CRPS I (RSD) is a disorder of
sympathetic nerves.
• In later stages, CRPS I (RSD) is a disorder of the
spinal cord, of the wide dynamic range neurons, in
lamina II and V of the dorsal horn, and NMDA
• CRPS I (RSD) may spread to the countralateral
limb, or ipsilateral limb, due to neuronal plasticity
• 71% of patients diagnosed with CRPS I (RSD)
actually have just nerve entrapments, 27% have
both (Hendler, Pan Arab Journal of Neurosurgery,’02)
• 80% of patiet diagnosed with CRPS I have nerve
entrapments which respond to surgery (Dellon,et al,
J. Brachial Plex Peripher Nerve Inj, 2009)

10. Theories about the Etiology of
CRPS I
• Auto-immune - Knobler
• Central - angry back firing C fibers - Ochoa
• Wide Dynamic Range neurons - Roberts
• Neuronal plastisity- Dubner
• Hyperpathia- Bennett
• Ephaptic connections - Sweet
• In reality, no-one really knows the cause.

11. PATIENT HISTORY
• There is no way to predict who will get CRPS I
(RSD)
• Very often, a minor trauma will trigger CRPS I
(RSD)
• Post-operatively, if there is a painful limb, the
more likely diagnoses are nerve injury or
compression, due to surgery or to the use of a
tourniquet, infection, or an occult fracture
• Immediate post-op pain is not CRPS I (RSD)
• A tight cast may trigger CRPS I (RSD)

12. SYMPTOMS of CRPS I (RSD)
• Thermal allodynia is almost always present
• Pain is constant, but varies in intensity
• Pain is circumferential. The pain is not in a
peripheral nerve distribution
• Change of position of the limb does not
worsen the pain
• Other “classic” signs are highly variable

13. SIGNS of CRPS I (RSD)
• Pain is circumferential, around entire foot or arm.
• Pressure on the ulnar, radial, median, tibial, sural,
superficial and deep peroneal nerves will be no
more or less painful than pressure any where else
on the limb.
• “Classic” edema may or may not be present
• “Classic” mottled skin and shiny skin may or may
not be present.
• “Classic” hair/nail growth may or may not be
present.

14. “CLASSIC” DIFFUSE
SWELLING OF CRPS I (RSD)

15. “CLASSIC” PITTING EDEMA OF
CRPS I (RSD)
Pitting
Edema

16. “CLASSIC” MOTTLED SKIN OF
CRPS I (RSD)
Mottled skin

17. Not RSD- Residual After Twisted Ankle
Note: Stocking
distribution of swelling
and edema. No
mechanical nor thermal
allodynia. 3 + pitting
edema. Marked bruising
and discoloration.
Tender over 4th and 5th
metatarsal.

18. Not RSD (CRPS I)-
Pre-Op Skin Discoloration
Not RSD-Burning pain was in the top of
the foot, shin, and sole of foot after
severe auto accident, requiring L knee
replacement. Negative bone scan,
negative Indium scan, sed rate not
elevated, no thermal nor mechanical
allodynia, pain was not circumferential.
Pain was in distribution of tibial nerve,
and superficial peroneal nerve, and
100% relief with tibial nerve blocks, and
superficial peroneal nerve blocks.

19. Not RSD (CRPS I)- Post-Op
Not RSD-Burning pain
was in the top of the
foot, shin, and sole of
foot after severe auto
accident, requiring L
knee replacement. 100%
relief with left tibial,
common peroneal and
saphenous nerve
decompression, with
improved skin
coloration, bilaterally.
Tibial Decompression

20. THERMOGRAPHY OF CRPS I (RSD)
The left leg is so cold
it doesn’t show.

21. BONE SCAN OF CRPS I (RSD)
Localized
inflammation
of gout
Diffuse
hyperemia of
CRPS I

22. “CLASSIC” SHINY SKIN AND NAIL
GROWTH OF STAGE III CRPS I (RSD)

23. CRPS I (RSD) vs CRPS II (CAUSALGIA)
CRPS I (RSD)
• Circumferential in
distribution
• Good response to
sympathetic blocks
• No response to nerve
blocks
• Both thermal and
mechanical allodynia
CRPS II (CAUSALGIA)
• Follows discrete nerve
distribution
• Variable response to
sympathetic blocks
• Responds well to
nerve blocks
• Mechanical allodynia

24. CRPS I (RSD) vs Nerve Entrapment
CRPS I (RSD)
• Circumferential in
distribution
• Good response to
sympathetic blocks
• No response to
peripheral nerve
blocks
• Both thermal and
mechanical allodynia
Nerve Entrapment
• Follows discrete nerve
distribution
• Variable response to
sympathetic blocks
• Responds well to
peripheral nerve
blocks
• Mechanical allodynia

25. DIFFERENTIAL DIAGNOSIS OF CRPS
I (RSD) (Hendler, Pan Arab Journal of Neurosurgery, ’02)
• N = 38 patients referred to Mensana Clinic with the
diagnosis of CRPS I (RSD).
• 1/38 (3%) had pure CRPS I (RSD) without any other
illness.
• 10/38 (26%) had CRPS I (RSD) with nerve entrapment.
• 37/38 (97%) had nerve entrapment confirmed by
electrophysiological (CPT) testing, and nerve blocks but
missed by the referring doctor.
• 27/38 (71%) had no signs or symptoms compatible with
CRPS I (RSD). They had just nerve entrapment(s).
• Prior to admission, only 7/38 (21%) patients had bone
scans and only 22/38 (58%) had sympathetic blocks.

26. Missed Diagnoses-CRPS I
(Hendler, N, Differential Diagnosis of CRPS I, Pan Arab Journal of
Neurosurgery, ’02)
• Of the 38 patients referred to Mensana Clinic with
the diagnose of RSD (CRPS I):
• 42 % never had a sympathetic block.
• 79 % never had a bone scan.
• 100% never have a peripheral nerve block.
• 71% had pain in a peripheral nerve distribution,
not circumferentially.
• The word “allodynia” was not found in 100% of
the charts.

27. Discharge Diagnosis in Patients From
Mensana Clinic, referred with only CRPS I
(Hendler, N, Differential Diagnosis of CRPS I, Pan Arab Journal of
Neurosurgery, ’02)
• Discharge Diagnosis
• N =10 - CRPS I
• N = 2 - CRPS II
• N = 9 - Disrupted Disc
• N = 37 - Nerve entrapments
• N = 9 - Radiculopathy
• N = 16 - Thoracic Outlet

28. Testing Done in Patients (number done) From
Mensana Clinic, referred with only CRPS I
(Hendler, N, Differential Diagnosis of CRPS I, Pan Arab Journal of
Neurosurgery, ’02)
• Test # of pts # of tests/pt + tests
finding*
• Sympathetic blocks 11 pts (1-5) 10/11
• Bone Scans 38 pts (1-1) 11/38
• Phentolamine I.V. 7 pts (1-3) 4/7
• EMG/NCV 38 pts (1-2) 37/38
• Peripheral N. block 35 pts (1-6) 35/35
• Root blocks 10 pts (3-10) 9/10
• Provocative discog. 10 pts (1-3) 9/10
• Dopplers of arms 17 pts (1-2) 16/17
* not published

29. CRPS I (RSD) PRESENTS WITH A COLD LIMB, BUT NERVE
INJURIES MAY ALSO BE COLD
(Uematsu, Hendler,Hungerford, Long and Ono, Electromyogr. Clin. Neurophysiol.
#21, pp165-182, 1981) N = 803 cases

30. Thermography and Electromyography in the
Differential Diagnosis of Chronic Pain Syndromes
and Reflex Sympathetic Dystrophy
• Uematsu, Hendler, Hungerford, Long and Ono,
Electromyogr Clin. Neurophysiology, ’81
• Review of 803 patients with chronic limb and axial pain.
• 431 had abnormal skin (>1 C) temperature in the affected
limb.
• 140 had increase temperature: 291 had lower temperature.
• In 73 cases of patients with abnormal neurological
examination, 89% of patients had thermography
abnormalities > 1 C.
• In 56 cases with abnormal EMG/NCV, 89% also had
thermography abnormalities > 1 C, 42 % > 2 C.
• In 42 patients with RSD, 92 % had thermography
abnormalities >1 C, 67% > 2 C.

31. Degree of Coldness in Limb with
CRPS I Measured by Thermography
1-1.9 C
2-2.9 C
> 3 C

32. Degree of coldness, measured by
thermography, in a limb with nerve
injury, confirmed by EMG/NCV
1-1.9 C
2-2.9 C
> 3 C

33. Hendler Alcohol Drop and Swipe Test
(Hendler, Complex Regional Pain Syndrome I and II, Chapter 20, in Pain
Management, Edited by Richard Weiner, Ph.D, CRC Press, 2002)
• Squeeze an alcohol swab, and let a drop fall on
the affected area.
• If the patient immediately responds with severe
pain, this is thermal allodynia.
• Let the alcohol remain on the foot for 2 minutes. If
there is pain, this is chemical allodynia.
• Use the swab and gently swipe the affected area.
• Immediate pain is mechanical allodynia.

34. TESTS YOU CAN DO IN YOUR OFFICE
(Hendler, Complex Regional Pain Syndrome I and II, Chapter 20, in Pain
Management, Edited by Richard Weiner, Ph.D, CRC Press, 2002)
• Interpretation of the Hendler Alcohol Drop and Swipe
Test: A patient should have both thermal and
mechanical allodynia to have CRPS I (RSD).
• Just mechanical allodynia suggests nerve entrapment or
causalgia or radiculopathy.
• Just thermal or chemical allodynia suggests CRPS I
(RSD).
• If Tinel is + in sural, tibial, superficial, deep peroneal
ulnar, or radial nerve reproduces pain, block this nerve.
• If a nerve block gives total relief, then the diagnosis is
nerve entrapment not CRPS I (RSD).

35. OUTSIDE LABORATORY STUDIES YOU CAN
ORDER WHILE WAITING FOR THE
CONSULTANT TO SEE PATIENT
• A bone scan can be a helpful diagnostic test, but
varies over the stages of the disease.
• An effective sympathetic block should warm the
limb. When the limb is warm, a patient with CRPS I
(RSD) will have 100% relief, for 2-6 hours.
• EMG/NCV measures only A beta sensory fibers and
motor fibers, but not C & A delta fibers.
• Current perception threshold measures A beta, A
delta and C sensory nerve fibers.

36. WHERE TO REFER THE PATIENT
AND WHAT YOU SHOULD EXPECT
• Refer the patient to a multi-disciplinary pain diagnostic
and treatment center, not a monomodal center (just
blocks, just medicine, etc).
• The center should do a bone scan and CPT (next page)
• No more than 6 sympathetic blocks should be done.
The limb must become warm in response to the block.
During the time the limb is warm, the patient should
experience 100% relief of all pain. Blocks last 2-6 Hrs.
• Nerve blocks should be done if the sympathetic block
does not produce 100% relief when the limb is warm.
• The treating doctor has an obligation to monitor the
progress of the patient.

37. Painless Electrodiagnostic Current Perception Threshold and
Pain Tolerance Threshold in CRPS Subjects and Healthy
Controls: A Multicenter Study- Texas Tech, Stanford, Mensana Clinic,
Mayo Clinic, Cleveland Clinic, Johns Hopkins, Vanderbilt, UC-SD, Uni. of
Texas, (P. Raj, H. Chado, R. Dotson, N. Hendler, et al, Pain Practice, 2001)
• CPT/PTT uses A.C. sinusoid waveforms at 5 Hz, 250 Hz, and
2,000 Hz (2 kHz), for C, A delta, A beta sensory fiber testing
respectively.
• Current Perception Threshold (CPT) is the threshold of feeling
electrical current. Early nerve entrapments have low CPT
(hyperalgesia), later, high CPT (hypoalgesia)
• Pain Tolerance Threshold (PTT) is the maximum amount of pain
from the current tolerated by the patient.
• In normal patients, non-nerve PPT is higher than CPT
• In CRPS I (RSD) patients, PPT is close to CPT, which gives
objective confirmation of clinical mechanical allodynia.

38. EXPECTED TREATMENT PROTOCOLS
• High dose steroid and exercise for 2-4 weeks.
• Ca++ blocking agents and phenoxybenzamine
• Use Anti-convulsants such as Neurontin 300mg
qid up to 900 mg qid. Add Topamax if needed.
• Use narcotics if needed, and titrate according to
response (5th vital sign -JCAHO).
• Use tricyclic antidepressants, not SSRIs.
• If the first sympathetic block worked, get a
series of 5 more sympathetic blocks.
• If sympathetic blocks provided 100% relief, but
did not last, do a surgical sympathectomy.

39. CONCLUSIONS
• There is no way to predict who will develop
CRPS I (RSD). Get early confirmation.
• The clinical presentation of CRPS I (RSD) is
variable.
• The clinical stages are not temporal but
symptom related.
• Early, accurate diagnosis is essential for
successful treatment, before it progresses to the
spinal cord level.

40. CONCLUSIONS (continued)
• CRPS I (RSD) is misdiagnosed 71% of the
time. You should refer the patient only to an
expert experienced with CRPS I (RSD).
• Early diagnosis of CRPS I (RSD) improves
the treatment outcome.
• Essential features of CRPS I (RSD) are a
positive bone scan, thermal and mechanical
allodynia, circumferential pain, and total
relief from effective sympathetic blocks
• For comprehensive information and a test to
provide a proper diagnosis, see
www.DiagnoseMyPain.com

41. The 6 blind wise men examining an elephant, in order to
describe it to their king. The king can visualize an elephant,
only by integrating all the descriptions.