Nerve pain
Complex Regional Pain Syndrome (CRPS / RSD)
CRPS (formerly RSD) is treatable and the first months matter most. Gulf Coast Pain & Spine in Houston: Budapest criteria, sympathetic blocks, DRG therapy.
Complex regional pain syndrome (CRPS), once called reflex sympathetic dystrophy (RSD), is severe, persistent pain in an arm or leg that is out of proportion to the injury that started it, with changes in skin color, temperature, swelling, sweating or movement. It most often follows a fracture, sprain or surgery. Outcomes are far better when treatment starts within the first months, so Gulf Coast Pain & Spine moves quickly: diagnosis by the Budapest criteria, sympathetic nerve blocks timed with physical therapy, and dorsal root ganglion stimulation for lower-limb CRPS that does not settle.
Key facts
| What it is | A pain condition of one limb (rarely more) with abnormal pain, skin, blood-flow and movement changes after an injury; the nervous system's response to the injury, not the injury itself, drives it |
|---|---|
| Most common causes | Wrist or ankle fracture (about 40 percent of cases), sprain, surgery, crush injury, prolonged immobilization in a cast; in roughly 1 in 10 no trigger is found |
| Typical course | Best chance of remission when treated in the first 3 to 6 months; many improve within a year; a minority develop long-term pain and stiffness |
| See a specialist when | Pain after an injury is far worse than expected, the limb changes color or temperature, swells, sweats, or you cannot bear to have it touched, especially beyond 4 to 6 weeks |
| Treatments we offer | Stellate ganglion block (arm) and lumbar sympathetic block (leg) coordinated with PT, medication management, dorsal root ganglion stimulation, spinal cord stimulation |
When to get emergency care
Seek same-day care (emergency room or urgent evaluation) if you have:
- A limb that is suddenly cold, pale or blue with no pulse you can feel, or new severe swelling of a calf or thigh (possible blood clot or blocked artery, not CRPS)
- Fever, spreading redness, or pus around a wound or surgical site
- Pain, tightness and numbness inside a cast or tight bandage that is getting worse (compartment syndrome needs immediate release)
- New weakness or numbness spreading up the limb over hours to days
- Thoughts of harming yourself. CRPS pain can be overwhelming; call or text 988 any time
The time-critical issue in CRPS is not an emergency but a deadline: every month without treatment lowers the chance of full recovery. Do not wait to see whether it passes.
What CRPS is, and why the name changed
CRPS is a disorder of the way the nervous system, blood vessels and immune system respond to an injury. After a fracture, sprain, surgery or sometimes a minor knock, the limb keeps behaving as if it is badly injured long after the tissue has healed: it hurts far more than it should, swells, changes color and temperature, sweats abnormally, and becomes stiff. The older name, reflex sympathetic dystrophy (RSD), assumed the sympathetic nervous system was the whole cause; we now know it is one part of a broader process that also involves inflammation, sensitized pain nerves, and changes in the brain's map of the limb. You will still see RSD on older records and support sites; it is the same condition.
CRPS is uncommon (roughly 5 to 26 new cases per 100,000 people per year), affects women three to four times more often than men, peaks around age 40 to 60, and most often involves the hand and wrist after a fracture. Gulf Coast Pain & Spine treats CRPS at its Houston, Webster and Pearland (opening November 2026) offices.
Type I and type II
- CRPS type I (the old RSD): no identifiable injury to a major nerve. About 90 percent of cases.
- CRPS type II (the old causalgia): the same picture, but following a documented injury to a named nerve, such as a laceration or a nerve stretched during surgery.
Treatment is largely the same for both; the distinction matters for prognosis and for whether a surgical nerve repair is part of the plan.
What triggers it
The most common triggers, in order, are fractures (especially distal radius or ankle fractures, particularly when the limb was casted tightly or immobilized for a long time), sprains and strains, surgery (carpal tunnel release, foot and ankle surgery, knee surgery), and crush injuries. A small number of cases follow a stroke, heart attack or minor injury, and in about 10 percent no trigger can be identified. The severity of the original injury does not predict CRPS; it can follow a trivial one.
Why some people develop CRPS and most do not is not fully understood. Prolonged immobilization, high early pain, and possibly genetic factors raise the risk. It is not caused by anxiety or personality, although living with it is stressful and anxiety about moving the limb can worsen stiffness.
Symptoms, and the Budapest criteria
CRPS is diagnosed clinically. The internationally accepted standard is the Budapest criteria. All four parts must be met:
- 1. Continuing pain that is out of proportion to the original injury.
- 2. You report at least one symptom in three of the four categories below.
- 3. The examiner finds at least one sign in two or more categories at the time of the visit.
- 4. No other diagnosis explains it better (infection, blood clot, fracture non-union, nerve entrapment, arthritis flare).
The four categories:
- Sensory: pain from light touch, clothing or a breeze (allodynia); exaggerated pain from a pinprick (hyperalgesia)
- Vasomotor: the limb is warmer or cooler than the other side, or its color is mottled, red, purple or pale, or shifts
- Sudomotor / edema: swelling, or sweating that is more or less than the other side
- Motor / trophic: reduced range of motion, weakness, tremor or dystonia (abnormal posturing); changes in hair, nail or skin growth (thin shiny skin, brittle nails, altered hair)
Bring a list of what you have noticed at home, including things that come and go; color and temperature changes often are not present during a short exam. Photographs of the limb on bad days are genuinely useful.
How CRPS differs from look-alikes
Nerve entrapment (carpal tunnel, tarsal tunnel) follows one nerve's territory and rarely changes skin color. A deep vein thrombosis causes swelling and warmth but not allodynia or trophic change and needs an ultrasound. Infection brings fever and redness centered on a wound. Ordinary post-fracture stiffness improves steadily week over week; CRPS does not.
How we diagnose it
The diagnosis rests on history and examination against the Budapest criteria; no test confirms CRPS. We measure and record skin temperature on both sides, range of motion, sensory testing with light touch and pinprick, swelling, and skin, hair and nail changes, so that progress can be tracked. Tests are used to rule out other causes and to grade severity:
- X-rays of both limbs can show patchy bone loss (osteopenia) after several weeks, and rule out non-union or hardware problems.
- Three-phase bone scan can support the diagnosis in the first 6 to 12 months but is often normal later; a negative scan does not exclude CRPS.
- Nerve conduction studies / EMG if a nerve injury (type II) or entrapment is suspected.
- Ultrasound or blood tests if a clot, infection or inflammatory arthritis is possible.
A sympathetic block serves as both a test and a treatment. If pain drops and the limb warms after a stellate ganglion or lumbar sympathetic block, the pain is "sympathetically maintained," and repeated blocks paired with therapy are likely to help. If the block does nothing, that is also useful: the plan shifts toward medications and neuromodulation rather than more blocks.
Treatment options, in order
Months matter. Studies of CRPS after fracture show most recovery happens in the first year and that patients treated within the first 3 to 6 months do best. The goal of every step below is the same: reduce pain enough that you can move the limb, because movement is what restores it. We do not wait for one step to fail before adding the next; blocks, medication and therapy usually run together.
- Physical and occupational therapy from day one
Desensitization (touching the skin with progressively rougher textures), gentle active range of motion, weight-bearing as tolerated, and graded motor imagery or mirror therapy. Casting, splinting or resting the limb makes CRPS worse. Learn more →
- Medication
Started early: a short course of oral corticosteroids in the first weeks has the best evidence for early CRPS; gabapentin or pregabalin for burning pain; duloxetine or a low-dose tricyclic for pain and sleep; bisphosphonates in early cases with bone-scan changes; topical lidocaine. Opioids are not effective for CRPS and are not the plan. Learn more →
- Sympathetic nerve blocks, timed with therapy
A stellate ganglion block for the arm or hand, or a lumbar sympathetic block for the leg or foot, done under X-ray or ultrasound guidance. A rise in limb temperature of 1 to 3 degrees Celsius confirms the block worked. Relief typically lasts days to weeks; the point is to schedule therapy inside that window. A series of 3 to 6 blocks over several weeks is common. This is both a test and a treatment. Learn more →
- Pain psychology
Fear of moving the limb is a major driver of stiffness. Cognitive behavioral therapy and relaxation training are standard parts of CRPS care, not an afterthought.
- Dorsal root ganglion (DRG) stimulation
For CRPS of the leg or foot that has not responded within a few months, DRG stimulation has the strongest evidence of any device. In the ACCURATE randomized trial, 81 percent of patients with lower-limb CRPS or causalgia had at least 50 percent pain relief at 3 months with DRG stimulation versus 56 percent with conventional spinal cord stimulation. It is FDA-approved for this indication and covered by most insurers after a successful trial. A temporary trial of about 3 to 7 days comes first. Learn more →
- Spinal cord stimulation
The alternative for arm CRPS, where DRG leads are harder to place, and for patients who are not DRG candidates. Also trial-first. Learn more →
What you can do now
- Use the limb. Not to the point of a flare, but daily, with small increases. Protecting it in a sling or keeping it still is the single most harmful thing you can do.
- Desensitize. Several times a day, rub the painful skin with soft cloth, then towel, then rougher textures for a few minutes each. It feels wrong and it works.
- Contrast baths (warm, then cool water, 3 minutes each, repeated) can reduce swelling and help retrain temperature control.
- Elevate a swollen hand or foot when resting.
- Ask your surgeon or PCP for a referral now rather than at the next routine follow-up if the symptoms above fit. Our referral page explains what to send; new patients can start at new patient information.
Frequently asked questions
Is RSD the same as CRPS?
Yes. Reflex sympathetic dystrophy is the older name for what is now called CRPS type I. Causalgia is the older name for CRPS type II, where a specific nerve was injured. The treatment approach is the same.
Can CRPS go away?
Yes, particularly when it is recognized and treated in the first months. Population studies show many patients improve substantially within a year. A minority, more often those diagnosed late or with cold, dystonic limbs, develop long-term symptoms, which is why we treat it as urgent.
Does a stellate ganglion block hurt, and what are the side effects?
It is done with local anesthetic and often light sedation and takes about 10 to 15 minutes. A droopy eyelid, small pupil and red eye on that side (Horner's syndrome) are expected and mean the block reached the right place; they wear off in a few hours. Hoarseness and a feeling of a lump in the throat are common and temporary. Serious complications are rare with image guidance. Details are on the stellate ganglion block page.
Why DRG stimulation instead of regular spinal cord stimulation?
The dorsal root ganglion is the cluster of nerve cell bodies that serves one specific area, such as the foot. Placing a lead there lets the stimulation cover the exact painful region without spreading to the whole leg, and the ACCURATE trial showed better results than conventional SCS for lower-limb CRPS. For the arm, conventional SCS is often the more practical choice.
Will insurance cover DRG stimulation?
Most commercial plans and Medicare cover DRG stimulation for CRPS I or II of the lower limb after conservative treatment has failed and a trial has shown at least 50 percent relief. Prior authorization is required and we handle it.
Can CRPS spread to other limbs?
It can, in a minority of patients, most often to the opposite limb or the limb on the same side. Early treatment and keeping all limbs active reduce the chance. New symptoms in another limb should be reported promptly.
Should I take vitamin C after a wrist fracture to prevent CRPS?
Some studies found that 500 mg of vitamin C daily for 50 days after a wrist fracture lowered the rate of CRPS, and it is low-risk, so many orthopedic surgeons recommend it. The evidence is mixed, and it does not treat CRPS once it has started.
Sources
- Complex Regional Pain Syndrome (opens in new tab) — National Institute of Neurological Disorders and Stroke
- Validation of proposed diagnostic criteria (the Budapest Criteria) for CRPS (opens in new tab) — Harden RN et al., Pain 2010 (PubMed)
- Dorsal root ganglion stimulation yielded higher treatment success rate for CRPS and causalgia at 3 and 12 months (ACCURATE trial) (opens in new tab) — Deer TR et al., Pain 2017 (PubMed)
- Complex Regional Pain Syndrome: Practical Diagnostic and Treatment Guidelines, 4th edition (opens in new tab) — Harden RN et al., Pain Medicine 2013 (PubMed)
Request an appointment
Call (832) 916-2075 or request an appointment online. New patients are welcome; the team confirms insurance and referral requirements before scheduling.