What causes CRPS after a cast or a fracture?

Complex regional pain syndrome (CRPS), the condition once called RSD, reflex sympathetic dystrophy, usually begins with an ordinary injury and an ordinary treatment. Terkelsen and colleagues put scaphoid casts on 30 healthy volunteers for four weeks. Then they measured what came off with the plaster. 27 of the 30 had pain on moving the joint. The group showed cold and mechanical hyperalgesia (extra pain from cold and pressure) and changed skin temperature. That limb had done nothing but sit still. Immobilization (holding the limb still) alone, in people with no fracture, produced the early signature of the disease. The cast did its job for the bone. It also quietly did something else to the nerves, the vessels and the map of the hand in the brain.

What happens in the body with CRPS?

The first driver is neurogenic inflammation. Sensory nerves in the injured limb release peptides. These open vessels, leak fluid and call in immune cells. That is why the hand is warm, swollen, red and shiny in the early months. The second is immune and central. Kohr and colleagues found autoantibodies against adrenergic and muscarinic receptors in CRPS patients. That is the nervous system attacking its own signals. At the same time, the part of the brain that maps the hand shrinks and blurs. Because of that, light touch is read as a threat. The limb feels foreign, too large or not yours. Moseley showed that retraining that map with graded motor imagery reduced pain and swelling in long-standing CRPS. The number needed to treat was about two, in a trial of 13 patients.

The third driver is behavior and process. This is where an Illinois work injury goes wrong. The hand hurts, so it is guarded. Guarding is more holding still, the very thing that started the loop. Meanwhile the cast comes off at a hand clinic. The adjuster asks why a healed fracture still hurts. The specialist referral waits on authorization. Each week of waiting deepens the remapping in the brain. A metabolic terrain makes all of it worse. Insulin resistance raises the inflammatory tone the limb is already drowning in. It stiffens the small vessels that a hand with unstable blood vessel control (vasomotor instability) depends on. And a short night of sleep lowers the point at which touch becomes pain.

How is CRPS diagnosed?

The Budapest criteria validated by Harden and colleagues are the standard. In plain language they ask four things. Is the pain ongoing and out of proportion to the injury? Does the patient report symptoms in at least three of four groups: sensory, color and temperature, sweating and swelling, and movement or skin and nail changes? Can the examiner find signs in at least two of those groups? And is there no other diagnosis that explains it better? A patient from O’Fallon or Alton who fits that picture gets the first open visit, because the outcomes in the first months are not the outcomes at year two.

How is CRPS treated, and in what order?

Movement first, because the loop runs on disuse. That means desensitization, mirror therapy and graded motor imagery to rebuild the brain’s map. Loading goes up on a schedule, not on how the hand feels that day. Sympathetic nerve blocks are used early: stellate ganglion for the arm and lumbar sympathetic for the leg. They test whether the sympathetic system is driving the pain. They also open a window in which the movement work can happen. Ketamine is the drug that reaches the central sensitization (a nervous system turned up too high). The usual routes here are sublingual and intranasal. A compounded topical cream of ketamine, lidocaine and an anti-inflammatory is used for skin-level allodynia (pain from light touch). Intravenous infusion is available but rarely chosen. Sigtermans and colleagues randomized 60 CRPS type 1 patients to a four-day low-dose intravenous infusion or placebo. Pain was significantly lower across the next twelve weeks, without a gain in function. That is exactly why ketamine is never given here without the movement program attached.

Some limbs have not turned around with all of that. For them, spinal cord stimulation or peripheral nerve stimulation is trialed before it is implanted. When the implant needs an operating room, it can be done at Anderson Hospital in Maryville under the privileges Dr. Gurpreet Singh Padda, MD, MBA, MHP, holds there. The needle-free 40 to 50 percent of the protocol runs the whole time. That means the movement schedule, sleep, insulin and weight for the reasons above. It also means the fear, which has its own treatment here. Acceptance and Commitment Therapy is done with a licensed behavioral clinician trained in pain, on staff and not a referral, because a hand you are afraid to use is a hand the brain keeps erasing.

Frequently asked questions

Do I need a referral for CRPS?

No. CRPS (RSD) visits are booked directly, and early is better. A few insurance plans want a referral from your primary doctor on file before they pay, so check yours. Sympathetic blocks are often the first test, and what a diagnostic block tells you explains how we read the response.

Is CRPS the same as RSD?

Reflex sympathetic dystrophy is the older name for what is now called CRPS type 1. The newer name dropped the idea that the sympathetic nervous system drives every case. Whether it drives yours is what a sympathetic nerve block is built to find out.

Can CRPS go away?

Early warm CRPS treated in the first months often resolves. The longer the limb has been guarded and unused, the more the brain’s map has to be rebuilt, and the slower that is. The movement side of that work is on sleep, movement and behavior.

Is ketamine for CRPS given through an IV?

The usual routes here are sublingual and intranasal, with a compounded topical cream for skin-level allodynia (pain from light touch). Intravenous infusion is available and rarely chosen. The ketamine for CRPS page explains what the infusion trials did and did not show.

Should I keep the hand still to protect it?

Stillness is what taught the nervous system to treat the hand as an injury. Healthy volunteers in a cast for four weeks developed the early signs with no fracture at all. Loading goes up on a schedule. What one block tells you about the pain before that starts is on what a diagnostic block tells you.

What if my CRPS started with an injury at work in Illinois?

Illinois generally lets an injured worker choose their own physician under the two-choice rule. The IWCC runs the claim. The delay between cast removal and specialist care is the thing that most needs shortening. Injured at work covers the process without giving legal advice.

What is the most effective treatment for CRPS?

No single shot or pill fixes CRPS. What works is a mix started early. Movement comes first, with desensitization, mirror therapy and graded motor imagery to rebuild the brain’s map of the limb. Sympathetic nerve blocks are used early to open a window for that work. Ketamine targets the oversensitive nervous system, but never without the movement program. If the limb still has not turned around, a stimulator is trialed before any implant.

What helps a CRPS flare-up?

The plan does not change with every bad day. Loading of the limb goes up on a schedule, not on how the hand feels that morning, because guarding it is what feeds the loop. Sleep counts, since a short night lowers the point at which touch becomes pain. A hot, swollen limb with fever, or a tense and painful calf or forearm, is not a flare; read when it is an emergency.

What are some tips for coping with CRPS?

Keep using the limb on the schedule you are given, even when you would rather protect it. Stillness is what taught the nervous system to treat it as an injury. Protect your sleep. Work on blood sugar and weight, which raise the inflammation the limb is already fighting. Fear gets its own treatment here: Acceptance and Commitment Therapy with a licensed, pain-trained behavioral clinician on staff, not a referral.

Related reading

• Ketamine for CRPS
• Sympathetic nerve blocks
• Spinal cord stimulation
• Peripheral nerve stimulation
• Injured at work
• Opioid stewardship