Complex Regional Pain Syndrome (CRPS) or Reflex Sympathetic Dystrophy (RSD) (Part 1)

As I mentioned in a previous post, pain management doctors typically do not treat a disease, but rather treat the symptom of pain. However, there is one "disease" specifically treated by pain management doctors, and that is complex regional pain syndrome (CRPS). Previously known as Reflex Sympathetic Dystrophy (RSD), CRPS is a chronic pain condition that usually affects the limbs and typically develops after an injury or trauma.

CRPS is characterized by severe, prolonged pain that is disproportionate to the original injury or trauma, and classically described as burning, stabbing, throbbing, or tingling. In order to technically meet the diagnostic criteria for CRPS, the pain has to be accompanied by a few autonomic symptoms (the autonomic nervous system is the part of the nervous system that we do not consciously control). These symptoms can include swelling, changes in skin temperature or color, sweating changes, or abnormal hair or nail growth. The Budapest Criteria are a specific set of signs and symptoms that one must report and be evident on exam in order to technically be given the diagnosis.

Speaking from experience, CRPS is poorly understood. In 2018, I was reaching for something on a top shelf in my kitchen, felt a pop, and my life has never been the same. I quickly developed burning, searing pain in the outside of my ankle. The doctors with whom I was working understandably thought that I had somehow torn a tendon. After a couple of months, a "normal" MRI of my ankle (it wasn't normal, more on that in a different post), and continued pain out of proportion to the initial injury, I vividly remember the first time I felt the cold, clammy skin of my right calf. My heart sank. I knew I had CRPS.

CRPS usually develops after an injury or trauma, such as a fracture, sprain, surgery, but can certainly occur after a minor injury like a sprained ankle. The exact cause of CRPS remains unclear, and it is likely that multiple factors contribute to its development. Some theories suggest that it may result from a malfunction of the peripheral and central nervous systems, immune system, and/or abnormalities in blood flow regulation. Emotional stress or psychological factors can also play a role in triggering or exacerbating CRPS symptoms.

Diagnosing CRPS can be challenging due to the absence of specific diagnostic tests. For the most part, it is a clinical diagnosis based on the history and the physical exam. The Budapest criteria, established in 2003, are widely used as diagnostic guidelines and emphasize the presence of continuous, disproportionate pain, and related symptoms. CRPS is further classified into two types:

1. CRPS Type 1 (formerly RSD): This occurs without any confirmed nerve injury.

2. CRPS Type 2 (formerly causalgia): This occurs after a specific nerve injury.

I often have people referred to me for evaluation of CRPS who have severe pain out of proportion to the inciting event, but who lack the autonomic nervous system changes. The lack of such changes by no means discounts that individual's experience. He or she still has neuropathic pain, just does not technically meet the diagnostic criteria for CRPS.

I have seen it cited many times that there is no cure for CRPS. I actually take issue with this claim, as I have seen it resolve entirely in a number of cases. That being said, the vast majority of the time, it ends up being a lifelong disease.

I want to end this post by talking about how horrible the pain from CRPS truly is. One patient of mine described the pain as "pure evil." I can honestly say it is something one will never understand unless they experience it. Numerous female patients of mine have said that the pain is worse than childbirth. The first few times I heard that, I responded by asking if my patient really meant it. Then men with CRPS could make the say that they knew pain that was worse than childbirth. I expected my female patients to walk back the claim, not wanting men to have the ability to report having a worse experience. However, 100% of patients have maintained that it is worse than childbirth. Imagine that misery, constantly, without relief.