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November 17, 2022/Neurosciences

Case Study: The Overlap of Complex Regional Pain Syndrome and Functional Neurologic Disorder in Pediatrics

Two complex conditions with clinical and diagnostic similarities

A 13-year-old female presented to the Pediatric Pain Rehabilitation Program at Cleveland Clinic Children’s Hospital for Rehabilitation (CCCHR) with a diagnosis of complex regional pain syndrome (CRPS) of her left leg. Along with her leg greatly inhibiting her normal daily functioning, she had a history of depression, conversion disorder (known today as functional neurologic disorder), panic attacks and generalized anxiety disorder, as well as peroneal tendonitis and frequent sprains due to dance.


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The patient participated in the intensive interdisciplinary pain rehabilitation program for four weeks with day hospital and inpatient elements. She received daily physical and occupational therapy, individual and group psychotherapy, recreation therapy, educational services, and medical services.

Untangling symptoms

As the patient’s CRPS treatment in the program progressed and assistive devices were weaned, “her presentation was much more functional in the way that her symptoms were limiting her,” says Heidi Kempert, physical therapy assistant at CCCHR and author of a case study published in the Journal of Pediatric Rehabilitation Medicine. With CRPS, the typical symptoms that hinder progress are pain, swelling, decreased range of motion, allodynia and weakness. Instead, the patient’s balance, mobility and tremors worsened.

The interdisciplinary team began searching for answers. “We were all seeing that it was looking like functional neurological disorder (FND), but we were also very cautious about giving her that diagnosis because once you have it, unfortunately, many providers assume that all future medical issues you have could be related to FND,” Ms. Kempert says.

Once the patient was treated according to her FND diagnosis, her participation and response to treatment increased. On discharge, she showed improvement in her functional strength and mobility. She was sent home with a 10-week exercise program and went back to school and dance classes with fully resolved mobility.

Commonalities of CRPS and FND

“CRPS and FND are both caused by an abnormal, malfunctioning nervous system that creates symptoms related to sensory changes, movement disorders (e.g., tremors, dystonia) and weakness through the involved extremity,” says Ms. Kempert. Both diagnoses have also been linked to stressful life events, along with anxiety and depression. Additionally, the patient’s function needs to improve before all symptoms typically resolve, Ms. Kempert says.


Treatment differences

Both diagnoses significantly benefit from multidisciplinary intervention but differentiating between the two conditions is critical. “We have to determine which diagnosis is interfering with function more because we need to address that one before we can address the other,” Ms. Kempert says.

Research shows with CRPS, medication or medical intervention can sometimes be used to improve mood and tolerance to activity. “There may be other helpful treatments aside from what we provide,” says Ms. Kempert.

With FND, all the viable tests have been done and there is no further medical treatment that can benefit the patient. Instead, she notes that the focus should be on self-management, education and movement retraining. “The research shows that when FND patients shift the focus from external to internal and start acknowledging that they need to play a role, they get better, faster,” she says.

Though the treatment interventions may look similar for both diagnoses, the education, patient interaction, expectations and skill progression are different, according to Ms. Kempert. With CRPS, providers stress ensuring that the activities they engage their patients in are throughout their treatment.

Patients with FND typically feel that all activities are too difficult, and they may be unaware of where their body is in relation to space, explains Ms. Kempert. This lack of spatial awareness can increase stress when it comes to accomplishing a task, which in turn may increase symptoms, making the patient unable to participate.


To overcome this, providers focus less on the actual task and use distraction techniques to accomplish it. For example, instead of having the patient walk on the treadmill for five minutes, they walk with the therapist to get something from another room for five minutes.

Treating complex cases

Another benefit of a multidisciplinary approach is family education. This is vital—especially with an FND diagnosis—because the family plays a large role in supporting ongoing function at home. “We need the family to understand why the diagnosis is happening, how it can change and what and what not to do,” says Ms. Kempert. They also need to be prepared for relapses.

Education with various interdisciplinary team members greatly benefited the family in the study when the patient sustained two acute injuries after discharge before her 10-week follow up. Her parents were able to help her maintain function and strength to continue with her progress. At her last appointment, she was functioning well and participating in high-level dance classes and competitions.

“Our rehabilitation program is designed to treat chronic pain as a primary condition. It’s time limited and focused and it has shown good benefits for individuals with chronic pain for the last 15 years,” says Ethan Benore, PhD, Director of Outpatient Services for the Cleveland Clinic Center for Pediatric Chronic Pain. “Some kids, such as the one in this case study, do quite well in our program because we’ve been able to address some of the functional neurologic symptoms that co-occur with pain.”

However, Dr. Benore cautions that the program wasn’t designed for treating FND as a primary condition, and it may not be beneficial for kids whose FND symptoms eclipse their chronic pain. “They really need a more individualized program that may not be time limited, that may be symptom specific or focused on reduction of their acute symptoms,” he explains.


To determine this, the center screens and evaluates potential patients. “We have a pain assessment clinic that clarifies the diagnosis we will treat for rehabilitation, any comorbidities that we could address or that might be a barrier to treatment for chronic pain and the patient’s readiness for the program,” says Dr. Benore.

A rise in FND

“CRPS and FND as comorbid diagnoses is becoming much more common,” Ms. Kempert says. The case study patient was seen about four years ago, but in the past six months, she says their program has seen five or six kids with similar presentations and both diagnoses.

Despite its increase, Ms. Kempert says FND may not be familiar to all healthcare providers, and many aren’t comfortable with it. Called “conversion disorder” in the past, there’s still a stigma that FND is all in the patient’s mind, which led to patients not getting the treatment they needed.

“If you see an FND diagnosis, do your research and reach out to providers that have experience with it,” Ms. Kempert advises. “We’ve been seeing a lot more of it, even in social media, and I think it’s going to become more and more common. As clinicians, we need to be prepared for how we treat it.”


Popkirov S, Hoeritzauer I, Colvin L, Carson AJ, Stone J. Complex regional pain syndrome and functional neurological disorders – time for reconciliation. J Neurol Neurosurg Psychiatry. 2019 May;90(5):608-614. doi: 10.1136/jnnp-2018-318298. Epub 2018 Oct 24. PMID: 30355604.

Kempert H. Clinical overlap of functional neurologic symptom disorder and complex regional pain syndrome in pediatrics: A case report. J Pediatr Rehabil Med. 2021;14(1):113-120. doi: 10.3233/PRM-200700. PMID: 33720859.


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