The Cost of Waiting: What Happens When CRPS Is Left Untreated

Left untreated, CRPS does not stay still. Lasting pain signals drive central sensitization — the nervous system turns the volume up. And the longer it runs, the less it responds to any treatment. Joseph, a 55-year-old roofer with three decades on ladders, learned that after one fall and one injury that was not correctly identified.

What followed was complex regional pain syndrome. What made it catastrophic was not the diagnosis. It was the eighteen months of nothing that came after it.

What is CRPS, and what happens if it is left untreated?

Complex regional pain syndrome is a disorder where the nervous system’s response to an injury fails to switch off after the tissue has healed. Pain grows out of proportion to the first injury. Then it becomes constant. Then it brings changes in temperature, color, sweating and movement in the affected limb.

We have written elsewhere about how CRPS is actually diagnosed using the Budapest criteria and about whether it can be cured. This article is about a different and harder question. What happens in the months when nothing is done?

The answer is that CRPS does not wait politely. Lasting pain signals change the brain and spinal cord. This is usually called central sensitization. The spinal cord and brain turn up incoming signals instead of turning them down. The longer that runs, the more it sets in, and the less the condition responds to any treatment.

Early intervention is not a preference in CRPS. It is the treatment variable with the most leverage.

What Joseph was offered

Anti-inflammatories. A referral to physical therapy. And a flat refusal to consider anything stronger, because of addiction risk.

Each of those makes some sense on its own. Together, as the whole plan, they added up to a decision not to treat.

• NSAIDs reduce inflammation at the injury site. But CRPS pain is mostly nerve pain kept going by the brain and spinal cord, and NSAIDs do not reach it. They also carry heart, kidney and stomach risks with long-term use.
• Physical therapy truly helps in CRPS — early, and built up with care. But apply it to a limb that is already badly sensitized, without pain control first, and movement hurts. The patient pulls back, the limb weakens, and the pain deepens. The therapy was not wrong. The order was.
• Doing nothing else was treated as the safe option. It was not.

Does untreated CRPS pain affect the brain?

The most underappreciated consequence of untreated chronic pain is cognitive.

Constant pain signals switch on microglia, the immune cells that live in the brain and spinal cord. They keep releasing inflammation signals. Lasting pain also keeps the stress system switched on, with cortisol that stays high. Both are bad for the hippocampus and prefrontal cortex. Those are the brain areas that handle memory and planning.

Studies that observe people have again and again found links between chronic pain and later decline in thinking. The size of the effect varies by study and by how pain was defined. These are links, not proven causes, and they should be read that way. But the direction is consistent. And it changes the question. Leaving pain untreated is itself an exposure with a cost. It is not a neutral holding position.

We covered the mechanism in more depth in what untreated chronic pain does to the brain.

How is CRPS treated early?

This is where the conversation usually goes wrong, so it is worth being unambiguous.

Treating CRPS early does not mean reaching for opioids. This practice’s work mostly goes the other way. We spend most of our clinical effort cutting opioid doses in patients who arrive on high doses. We have written about why those doses stop working in opioid bankruptcy and why tapering is a bridge, not a destination.

What early treatment means in CRPS is:

• Sympathetic blocks — targeted shots that interrupt the sympathetic nerves’ part in the pain. They are used both to test and to treat, and they help most early.
• Ketamine, when the case calls for it, to block the NMDA receptor that drives central sensitization. How it is given matters a lot. We lay out the evidence by route in ketamine for a limb that burns after the injury healed.
• Graded motor imagery and desensitization, done after pain is controlled enough for movement to be bearable.
• Neuromodulation for long-standing cases that have not responded to less invasive options.
• Addressing the metabolic terrain, because inflammation is not only neurological. See hyperinsulinemia and chronic pain.

Does a short, tightly limited course of pain medicine have a place while those treatments take effect? That is a judgment made one patient at a time, and it is truly debated in the field. It is not a policy that can be set in advance by either eagerness or fear.

What does delaying CRPS treatment cost?

Joseph lost the ability to climb, then the job, then the income. Medical bills piled up against no earnings. The marriage did not survive it. He drank because when the medical system refuses to treat pain, people find their own means. The ones they find are worse.

None of that appears in a chart as a complication of CRPS. All of it followed from the decision not to treat.

By the time he reached us, the question was no longer how to prevent central sensitization. It was how much function could be won back from a long-standing case. That is a much harder problem, with a worse expected outcome, in a patient who had lost the means to pursue it.

Individual results vary, and Joseph’s course is one patient’s, not a prediction. What applies to everyone is the pattern. Pain that is brushed off early becomes pain that is costly to treat late.

Frequently asked questions

How quickly does CRPS need to be treated?

Sooner is much better. The window when the condition responds well is measured in months, not years. That is because central sensitization sets in more the longer the pain signal runs. If a limb hurts out of proportion after an injury has healed, that is the time to get evaluated — see how CRPS is diagnosed.

Are anti-inflammatories useless for CRPS?

Not useless, but not enough. CRPS pain is mostly nerve pain kept going by the brain and spinal cord. NSAIDs act mainly on inflammation at the injury site. They carry real heart, kidney and stomach risks with long-term use. Do not start, stop, or change any medication without consulting your physician.

Is physical therapy harmful in CRPS?

No — but order matters. Early and built up slowly, it is valuable. Forced on a badly sensitized limb without pain control first, it often backfires. The therapy should follow enough pain control to make movement bearable.

Does treating pain require opioids?

No. Most of what we do for CRPS is procedures and metabolic care. Much of our practice is spent cutting opioid doses, not adding to them. See why opioids stop working.

Where can I be evaluated?

Padda Institute, 4477 Woodson Rd, Suite 100, St. Louis, MO 63134, serving the St. Louis region across Missouri and Illinois. Call (314) 481-5000 or text (314) 886-5902.

What is the most common cause of CRPS?

CRPS starts with an injury. Then the nervous system’s response to that injury fails to switch off after the tissue has healed. The pain grows out of proportion to the first injury, then becomes constant. It is joined by changes in temperature, color, sweating and movement in the affected limb. For Joseph it followed one fall and an injury that was not correctly identified.

What happens if CRPS is left untreated?

It does not stay still. Lasting pain signals drive central sensitization. The spinal cord and brain turn up incoming signals instead of turning them down. The longer that runs, the more it sets in and the less it responds to any treatment. Movement hurts, the limb weakens, and the pain deepens. Lasting pain also keeps the stress system switched on, which works against memory and planning.

Key takeaways

• CRPS treated early responds better. Delay lets central sensitization set in.
• NSAIDs and physical therapy done in the wrong order are not a treatment plan for CRPS.
• Untreated pain is an exposure in its own right. It is linked to later decline in thinking.
• Early treatment here means sympathetic blocks, ketamine when needed, graded rehab and metabolic work — not opioids.
• The costs that end a career and a marriage are not recorded as complications. But they follow from the same delay.

This article is educational and is not a substitute for evaluation, diagnosis, or treatment by a physician. Individual results vary. Do not start, stop, or change any medication without consulting your physician.

Medically reviewed by Gurpreet Singh Padda, MD, MBA, MHP — Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed August 2026.

Dr. Gurpreet Singh Padda, MD, MBA, MHP