Functional Neurologic Disorders

Patients with functional neurologic disorders (FND) commonly present to the emergency department, inpatient and consult services, and outpatient clinic. The concept behind this categorization is that a patient experiences physical symptoms that resemble a known neurologic disorder but does not actually have that disorder. Rather, abnormal neurologic signaling produces symptoms that mimic the disorder. These signals are believed, at least in many cases, to emerge when the brain “converts” overwhelming stress to physical symptoms. The degree to which the stress is overwhelming can emanate from either the severity of the stressor, the insufficiency of the patient’s coping response to stress, or both. Notably, in some patients, FND may coexist alongside the neurologic disorder that the FND is mimicking.

Examples of functional neurologic disorders include:

• dissociative events (pseudoseizures or psychogenic nonepileptic seizures [PNES])

• pain amplification

• functional gait disorder

• functional/psychogenic movement disorders (tremor, tics, dystonia)

• functional paralysis

• functional sensory loss (vision, tactile)

• functional neurologic disorder with mixed symptoms

Terminology

Historically, various terms and nosologies have been used to describe this presentation, including hysteria, abnormal illness behavior, conversion disorder, somatoform disorders, and somatic symptom and related disorders. The terminology a clinician uses for this diagnosis can influence acceptance of the diagnosis by the patient and family as well as the course of the disorder. If the clinician indicates that the symptoms are caused by stress or a psychiatric illness, caregivers of children with FNDs and affected adolescents may feel offended, dismissed, or stigmatized and find it difficult to accept the clinician’s judgment. Health care professionals and others may also be confused or have the misguided impression that the patient is malingering or purposely generating the symptoms to gain a reward (e.g., staying home or avoiding stress at school or at competitive extracurricular activities). Caregivers may be genuinely frightened by the child’s symptoms, even when it is obvious to a clinician that symptoms are psychogenic. It is important that clinicians not accuse the child of faking or malingering. Simultaneously, it is also important to guide caregivers so that their own responses to the child do not reinforce and perpetuate FND symptoms.

Classification

In the transition from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-4) to the DSM-5, the following two key changes influence the clinician’s approach to the patient:

• The role of conversion of an acute, traumatic stressor in FNDs has been reconceptualized and de-emphasized.

  • Previously, a critical component of the formulation of this diagnosis was the idea that an identifiable psychological stressor was overwhelming the patient and producing physical symptoms unconsciously (conversion disorder) or manipulatively (malingering). However, primary care clinicians, neurologists, psychologists, and psychiatrists often could not identify this stressor, leading to delays in diagnosis and provider frustration. It is now accepted that, at the time of clinical presentation, an acute stressor, a primary underlying psychiatric diagnosis, or both may not be identified.

• The diagnosis of conversion/functional disorders should not be considered one of exclusion.

  • Previously, the clinical approach was often to “rule out the organic disorder” first and then, when medical tests were negative, to inform the parent that their child’s condition was a mental or psychiatric disorder. This approach impeded acceptance of the diagnosis by parents and promoted “doctor shopping,” when families would travel to multiple institutions to find more-comprehensive testing to “rule in” an underlying medical diagnosis. It is now appreciated that neurologists can identify characteristic positive clinical findings that highly support a diagnosis of FND early in the course. So, while judicious medical testing may be indicated to rule out a limited number of medical causes, the presence of supportive findings in the history and examination at the time of presentation should prompt clinicians to not only suspect FND but also discuss that this diagnosis is under consideration in a nonjudgmental manner at the initial encounter.

Diagnosis

The diagnosis of FND is based on the following two factors:

• The history and physical examination have features that are more typical for FND than for the mimicked disorder.

• The history, physical examination, and if necessary, medical diagnostic testing, rule out or render improbable other possibilities in the differential diagnosis. Neurologic expertise to assess the patient is almost always needed to differentiate FND from a nonmimicked diagnosis.

A clinical diagnosis of FND requires humility and a high level of relevant medical knowledge. In some cases, the diagnosis can be made on clinical grounds without testing. This actuality poses a legitimate challenge, as presentations of even common neurologic conditions can vary greatly, and the underlying neuroanatomy and neurophysiology are complex. Specialists can be incorrect in making a diagnosis of FND.

Today, given the high likelihood that caregivers have already searched the internet for their child’s symptoms, it can be challenging for them to accept an FND diagnosis from a general or emergency physician rather than from a specialist. However, the primary care or emergency department physician still has an opportunity to play a vital positive role in introducing the possibility of the diagnosis.

Having conversations such as those described in the following examples prior to the specialist referral can reduce stress and improve chances for a more rapid resolution of symptoms.

Spells: An adolescent may present with episodes that the parents and patient are convinced are seizures. The emergency department physician may suspect that these episodes are paroxysmal nonepileptic events (pseudoseizures). If the family seems fairly fixated on the idea that the adolescent is having epileptic seizures, the primary physician may inadvertently antagonize the caregivers by listing “pseudoseizures” as the top diagnosis. However, the clinician may help the family by providing a list of other possible diagnoses that present with similar symptoms, using statements such as the following:

• “In otherwise healthy teens, a number of medical conditions can present with similar symptoms. The two most common are epilepsy and dissociative spells that resemble epileptic seizures. Both of these neurologic conditions can be serious in that they keep your child from participating in normal life activities. Both are treatable, but the treatments are different. Because it is critical to make an accurate diagnosis, I am going to refer your child urgently to a pediatric neurologist who may order additional tests. In the meantime, your son is not allowed to drive and should not spend any time unsupervised in a swimming pool, bathtub, or in any water where he could drown if he has an episode. He should attend school full-time, as it is important for his general well-being. Please restrict activities such as playing video games and watching videos on social media until the diagnosis is clarified, as these might trigger an episode. If these are nonseizure dissociative events, they tend to improve faster in children who do not get into a pattern of missing school.”

Abnormal movements: A child may present with movements that the patient and parents are convinced are involuntary. The pediatrician may suspect that the patient has FND manifesting with abnormal movements. Particularly when the primary physician has a long-term relationship with the family, suggesting that stress is involved may be perceived as less threatening. If the family seems accepting of the idea that the movements are related to concurrent stressors, the physician may help the family by providing a list of possible diagnoses, using statements such as the following:

• “In otherwise healthy children, we commonly see emotional stressors cause physical symptoms, and some of these symptoms can be similar to your child’s movements. Sometimes, however, the possibility of a neurologic condition needs to be evaluated by a specialist. I am going to place two referrals today. The first is to a psychologist to help your child work on the stresses we have been discussing. Even if stress did not cause this movement, it is stressful to have this symptom, and a psychologist can help. The second referral is to a pediatric neurologist who may confirm the diagnosis or order additional tests. In the meantime, your child should attend school full-time and participate as much as possible in all other usual activities. She should also avoid playing video games and watching videos on social media, as these might trigger these unusual movements. I think it makes sense to take a two-pronged approach, with both neurology and psychology, to get your daughter the help she needs.”

Management

Education, reassurance, and psychological or psychiatric treatment: The primary intervention for FND is education, reassurance, and psychological or psychiatric treatment. Sometimes both the patient and the parents require mental health treatment. However, at the time of presentation, families may not be ready for the psychological component of this treatment plan. Some experts recommend triaging patients and families initially into one of two groups:

• patient/family is open to psychological diagnoses and interventions

• patient/family is resistant to psychological diagnoses and interventions

It may be counterproductive to immediately recommend psychological or psychiatric treatment to the second group for identification of stressors, training in coping skills, or for making a DMS-5 psychiatric diagnosis (e.g., general anxiety disorder).

Behavioral health services: Utilization of behavioral health services is vital. Sometimes additional diagnoses (e.g., depression) can be identified at the time of presentation with FND or the diagnosis is apparent over time, although some children may never meet criteria for an additional DSM-5 diagnosis. Therapeutically, behavioral specialists can teach healthy coping mechanisms for the child and family regardless of another diagnosis.

Other therapies: Besides behavioral health, other referrals may be appropriate, either initially or as part of a multidisciplinary treatment plan (e.g., speech therapy for functional speech problems or physical therapy for functional gait problems or weakness).

Formulate a plan for resuming normal activity: Once a diagnosis of FND is made, resumption of normal activities should be encouraged, and a specific plan should be formulated. This tends to work best as a collaborative process with the clinician, caregivers, and school staff. When the duration of illness is short, returning to school full-time may be feasible. When the duration has been longer-term, the disorder has modified the entire structure of the family’s life, or both, a more gradual return to school may be necessary. Direct communication between the medical team and school personnel can enhance the likelihood of successful return to school.

Follow-up: In general, regular follow-up with the medical or neurologic team is vital for success.

• Neurology “signing off” on consultations for patients with an FND diagnosis should be discouraged. Follow-up with thorough serial neurologic examinations can provide reassurance that the correct diagnosis has been made, the child’s problems are “real,” and that all clinicians involved are taking everyone’s concerns seriously.

• In contrast, when a neurologist or other medical physician discharges the child on the basis of a psychological origin for FND, a number of negative outcomes may ensue:

  • Families who feel dismissed may seek other medical opinions, traveling to multiple academic medical centers to obtain a diagnosis that fits with their belief that the diagnosis is mischaracterized as psychological.

  • Families may migrate from science-based medical practices to medical charlatanism that can cause harm to both the child and family.

  • The initial diagnosis can be incorrect or the functional symptoms are correctly diagnosed but are superimposed on an underlying neurologic diagnosis. Ongoing medical or neurologic follow-up can ensure that a co-occurring neurologic diagnosis is not missed.

Finally, it is not uncommon for patients to manifest additional functional symptoms over time. If these new symptoms seem reasonably different from the presenting symptoms, an urgent in-person physical and neurologic examination may be warranted before incorporating this into a diagnosis of FND with mixed symptoms. The ongoing involvement of a medical team helps ensure that such patients’ disorders are promptly and appropriately diagnosed and addressed.