Day # 120: Functional Neurologic Disorder (Conversion Disorder)
Today we will continue our current theme of psychosomatic disorders as we discuss functional neurologic disorder.
Today's Content Level: Beginner, Intermediate
Patients with functional neurologic disorder (FND) have at least one real (not feigned) neurological symptom (sensory or motor) that cannot be fully explained by a neurological condition.
FND is also known as "conversion disorder". This is based on the psychoanalytic hypothesis that unconscious psychological distress or conflict is "converted" into neurologic symptoms.
The term "functional" implies that symptoms arise from abnormal functioning of the nervous system rather than structural pathology.
Some examples of neurological symptoms include weakness, paralysis, abnormal movements, blindness, paresthesias, and more.
Diagnostic Criteria 2
One or more symptoms of altered voluntary motor or sensory function.
Clinical evidence of incompatibility between the symptom and recognized neurological or medical conditions.
Not better explained by another medical or mental disorder.
Causes significant distress or impairment in social or occupational functioning or warrants medical evaluation.
Specifiers / Common Symptoms and Deficits 2
Weakness or paralysis
Abnormal movements -> gait disorder, tremor, dystonia, myoclonus, etc.
Swallowing symptoms -> difficulty swallowing, globes sensation (sensation of lump in throat), etc.
Speech symptoms -> slurred speech, dysphonia, etc.
Attacks or seizures -> also known as psychogenic non epileptic seizures (PNES) which we will cover on day # 122.
Sensory loss or anesthesia.
Special sensory symptoms -> visual, auditory, smell, or tase disturbances.
Mixed symptoms -> ≥ 2 other symptoms.
Specify if acute (symptoms < 6 months) or chronic (≥ 6 months).
Specify with a specific psychological stressor or without psychological stressor.
The exact incidence/prevalence is unknown and difficult to study.
Studies estimate that functional neurologic symptoms are the 2nd most common complaint to neurology clinics after headaches and diagnosed in 16% of neurology outpatients. More tightly defined FND still accounts for at least 5%–10% of new neurological consultations.
The incidence of individual persistent conversion symptoms is estimated to be 2-5/100,000 per year in the general population.
Higher female representation (female-to-male ratio about 3:1).
Can occur at any age, but more often in adolescence or early adulthood.
Risk factors include history of trauma, childhood neglect, insecure attachment style, current psychosocial stressors, recent physical injury or head trauma, female sex, preexisting psychiatric disorder, comorbid medically unexplained symptoms, or other neurologic disease. Perpetuating factors include reconditioning, illness beliefs, disability, and social benefits of being ill.
Patients often spontaneously recover, however, the prognosis is poor, as symptoms may persist, recur, or worsen in ~40-70% of patients.
Obtain a thorough history, a full review of systems, and a comprehensive physical/neurologic exam.
Important elements to consider when gathering the history-> determine patients beliefs about cause of symptoms; associated thoughts, behaviors, emotions, and impact on function; duration of symptoms; mitigating and exacerbating factors; prior pattern of similar presentations; prior and concurrent workups; relationships with previous providers; and insight regarding symptoms and behaviors.
Performing a neurological exam can help to validate the patients concerns and reveal undiagnosed medical/neurologic problems.
There are specific physical exam techniques that can be used to differentiate "functional symptoms" from recognized neurological conditions. Examples include: Hoover's sign; give-way weakness; bizarre gaits (walking on a tightrope, histrionic lurching without losing balance, dragging monoplegic gait); distraction; entrainment; non-anatomical deficits; splitting of vibration sense; and more.
Limited laboratory testing is recommended as it is common for patients with FND to have had a thorough prior workup, excessive testing introduces the risk of false-positive results, and may enforce over-utilization of medical resources. Collaborate with other treating providers, obtain prior diagnosis and treatment records, and collect indicated laboratory and radiologic tests.
A full psychiatric evaluation should also be performed given the high frequency of comorbid psychiatric disease. Rule out anxiety, mood, substance use, personality, trauma, and other somatic disorders.
Patients with FND may be surprisingly calm and unconcerned (la belle indifférence) when describing their symptoms. This has been classically associated with FND, however it has been shown that there it has no validity in discriminating conversion disorder from neurologic disorders.
Differential diagnosis: consider neurologic disorders depending on the specific symptoms such as movement disorders, Parkinson's disease, multiple sclerosis, myasthenia graves, stroke, seizures [particularly frontal lobe seizures], spinal cord disease, autoimmune encephalitis, laryngeal dystonia, and more. Also consider somatic symptom disorder, delusional disorder, dissociative disorders, factitious disorder, or malingering.
Keep in mind that symptoms may or may not be associated with another medical condition. The diagnoses of FND and a concurrent medical/neurologic illness are not mutually exclusive, and these frequently occur together. For example patients experiencing psychogenic non-epileptic seizures (PNES) can also have a comorbid seizure disorder with actual epileptic events.
Also keep in mind that conversion-like presentations in elderly patients have a higher likelihood of representing an underlying neurological deficit.
Treatment of FNDs is a process that starts with explaining the diagnosis in a way that helps the patient understand and gain confidence in it. This in turn enhances the odds of adherence to and success from therapeutic strategies.
Education: The primary treatment is education about the illness. It should be emphasized that the patients symptoms are real while emphasizing which medical and neurologic conditions have been considered and rule out. The diagnosis of "functional neurologic disorder" should be clearly shared. Explain how the diagnosis was made by demonstrating relevant clinical findings. Consider providing written materials explaining the diagnosis or referring the patient to neurosymptoms.org.
General approach: Team-based approach with primary care, neurology, behavioral health, and physical therapy. There should be regularly scheduled visits to one primary care physician with a focus on reassurance, acknowledging health fears, education about coping, and limiting unnecessary tests/referrals. Educate and empathically acknowledge that real symptoms can be present even in the absence of other disease. It is often best to address psychological issues slowly, and patients may initially resist referral to a mental health professional. The main goal of treatment is to improve patients functional status and coping rather than elimination of symptoms.
Although randomized clinical trial evidence is limited, promising data are emerging from cohort and pilot randomized studies to support specific treatments.
Psychotherapy: Cognitive behavioral therapy (CBT) is first-line psychological treatment. CBT and other psychotherapies designed for FNDs include components such as education, skills in gaining control of symptoms, recognizing triggers, cognitive restructuring of dysfunctional beliefs, modification of maladaptive behaviors associated with symptoms, and widening therapy to other aspects of interpersonal functioning. Other psychological treatments with emerging evidence includes hypnotherapy, relaxation techniques, psychodynamic psychotherapy, family therapy, and group therapy.
Physical therapy: Recently, a greater role for physical therapy has been recognized when motor symptoms predominate. Motor rehabilitation strategies aim to help the patient to establish normal control of movement through physical therapy, occupational therapy or speech therapy, informed by an understanding of FNDs.
Pharmacotherapy: Comorbid anxiety and depressive disorders should be treated with selective serotonin reuptake inhibitors (SSRIs) or other appropriate psychotropic medications (see treatment of depression; treatment of anxiety). Improvement of FNDs to any pharmacological treatment can occur because of positive effects on mood, coexisting disease, or placebo response. Medications directed at FND symptoms (eg, antitremor medications) are not appropriate.
Next lesson we will have a review quiz and after that we will cover psychogenic non epileptic seizures (PNES). If you want more learning resources then check out our recommended resources page.
Resources for today's post include: Pocket Psychiatry, DSMV-5, and First Aid for the Psychiatry Clerkship.