Five words that are guaranteed to annoy your patient with a diagnosis of psychogenic movement disorder (PMD) are "It's all in your head."
"It's the worst thing you can say," said Katie Kompoliti, MD, associate professor of neurological sciences at Rush University Medical Center in Chicago. Patients who hear this are likely to reject the diagnosis and seek further opinions; some will visit half a dozen specialists or more. They can run up thousands of dollars in health care costs and be subjected to unnecessary drug regimens and risky procedures.
"Patients can end up worse than they were at the onset of the disorder," said Joseph Jankovic, MD, professor of neurology and director of the Movement Disorders Clinic at Baylor College of Medicine in Houston. Finally, their chances of recovery appear to decrease the longer their condition goes untreated. This is why it is essential to make an accurate diagnosis in a reasonable amount of time and to deliver the news with sensitivity. The good news? Patients who accept their diagnosis and follow through with treatment have a good chance of recovery.
"It's a very difficult diagnosis," said Vanessa K. Hinson, MD, director of the Movement Disorders Program at the Medical University of South Carolina in Charleston. "But it's so important to make it, because if you do, these patients can get better."
DEFINING THE DISORDER
A patient with a PMD may exhibit any of the movements seen in organic movement disorders, including tremor, dystonia, chorea, bradykinesia, myoclonus, tics, athetosis, ballism, and lack of coordination. The person may also have disrupted speech and gait.1
The most common cause of PMD is a conversion disorder, in which psychological stressors cause the person to experience physical symptoms. The second most common cause is somatization disorder, in which the person seeks medical attention for recurrent and changing somatic complaints. Neurologists need to remember that the symptoms of conversion and somatization disorders are not under the person's conscious control.2
A less common cause is factitious disorder, in which the person achieves a psychological gain from his or her disease. As with conversion disorder and somatization disorder, persons with factitious disorder generally do not produce their symptoms intentionally, although some patients are malingerers, meaning that they produce their symptoms intentionally to achieve financial or other gain. Malingering is the least common cause of the disorder.1
Patients with PMD account for an estimated 2% to 3% of those in movement disorder clinics,3 and some centers report even higher rates. For example, about 15% of patients evaluated in the Baylor College of Medicine Movement Disorders Clinic have a psychogenic cause for their symptoms.4
"I think the reason [for the high rates at our center] is that community neurologists recognize the common movement disorders and refer the atypical ones to movement disorder centers," said Jankovic. "Many, if not most, of these cases turn out to be psychogenic."
The average age at onset ranges from 37 to 50 years, and women account for more than half of cases—estimates range from 61% to 87%.3,5,6 Although they usually occur alone, 10% to 15% are associated with organic neurological disorders.7 Many patients have a coexisting axis I diagnosis, such as major depression or an anxiety disorder, or an axis II diagnosis, such as personality disorder.
Known risk factors for PMD include a history of sexual abuse or rape, surgery or other physical trauma, and highly emotionally stressful life events.5,8,9
NOT A Dx OF EXCLUSION
Jankovic said that he is seeing more cases of PMD than ever before, probably because the disease is being recognized more frequently. "In the past, cases would often be misdiagnosed," he said.
Neurologists have plenty of ways to make the diagnosis, however. Hinson emphasized that there are specific clinical characteristics that the neurologist should be looking for and that the diagnosis should not be viewed as a diagnosis of exclusion.
For example, PMDs tend to come on abruptly. "It will often be very specific; the patient will tell me, 'I was sitting in the fourth row of church, it was 10:30 in the morning, I felt a cold sweat on my face, my arm started shaking,'" said Kompoliti. The symptoms will also progress quickly, which is unusual in an organic movement disorder.