A 32-year-old female with generalized anxiety and major depressive disorder presented to the emergency department after multiple witnessed seizure episodes. Upon arrival, she was hemodynamically stable and afebrile, with vital signs within normal limits. Initial laboratory tests were unremarkable. Physical examination revealed an unresponsive, well-nourished female with her eyes closed, jaw clenched, and arms and legs rigidly extended at 30 degrees to the horizontal. She received lorazepam, levetiracetam, and diphenhydramine which relaxed her jaw and extremities and ended the event. Twenty minutes later, she suddenly extended her arms and legs again, resembling a dystonic episode. This episode was terminated with the same medications. A computed tomography (CT) and magnetic resonance imaging (MRI) of the head were unremarkable. Electroencephalography (EEG) was negative for epileptiform discharges.
When able to speak, she denied a personal or family history of seizures, head trauma, or drug use. She denied a history of autoimmune, vascular, or neoplastic disease. She was on no home medications. She revealed that two days ago while at talk therapy, she disclosed an episode of prior sexual abuse, which was emotionally painful. In the ensuing hours, she experienced intermittent eyelid twitching followed by shaking of the lower extremities. Over the next day, the leg shaking increased in intensity and spread to the arms, prompting her to seek medical attention.
Over the course of her three-day hospitalization, she had multiple episodes, each one associated with a different rigid posture. These were captured on continuous video EEG and revealed no epileptiform discharges. Repeat laboratory testing was normal. She was diagnosed with PNES and was discharged home to be followed by psychiatry and neurology.
The aim of the present report is to highlight the difficulties in formulating a differential diagnosis for PNES and discuss the psychiatric and neurological aspects of its treatment. The exact number of people suffering with PNES is unknown due to the difficulty in establishing a diagnosis. The differential diagnosis is varied and includes neurophysiological disorders (e.g., epilepsy), movement disorders (e.g., acute dystonia and tic disorders), cardiovascular disorders (e.g., vasovagal syncope), and psychiatric disorders (e.g., PNES or schizophrenia). Affected patients are at an increased risk of iatrogenic harm (see below).
PNES are seizure-like events characterized by behaviors, movements, sensations, or states of awareness that lack an organic, neurobiological pathology. PNES are thought to be somatic manifestations of underlying psychological unrest,1 with most patients reporting a history of early psychological trauma, such as sexual abuse.2 The typical PNES semiology is characterized by transient signs of altered consciousness with shaking movements, resembling epileptic seizures. PNES attacks tend to be asymmetrical and asynchronous, have a longer duration, non-stereotyped movements, and may respond to bystander intervention. Pelvic thrusting and back arching have been observed frequently in PNES; however, it may be seen in epileptic seizures. Side-to-side head and body movements with eye and mouth closure are more likely observed with PNES. Epileptic seizures more commonly manifest lateral tongue biting and urinary incontinence. Preserved awareness during an ictus usually associated with loss of consciousness, such as bilateral extremity involvement, is concerning for PNES. Retained ability to visually track with their eyes, fend off or protest painful stimuli, or recall the event afterwards and lack of post-ictal confusion are factors in favor of PNES.3 The teddy bear sign, where an adult patient keeps a stuffed animal in the hospital bed, may also be seen in PNES.
PNES, in addition to resembling epileptic seizures, may mimic acute dystonia as in our case. These patients often suffer from psychiatric comorbidities and are exposed to dystonia causing anti-psychotic agents. Vasovagal syncope is considered when patients lose consciousness, but it is usually preceded by nausea, gradual constriction and loss of vision, and shorter ictal duration than PNES.3
Use of continuous video recording is helpful to analyze and capture the episodes reported by the patient and observers. Video EEG is used to support a PNES diagnosis if no epileptiform features are seen. When multiple seizure types are reported, each type should be captured on video EEG since PNES is comorbid in up to 30% of epileptic patients. When video EEG is not available, the presence of features noted in the table will help diagnose PNES. Surface recording may not always record deep sulcal epileptic foci, so the overall features of the events are important to support a diagnosis.
In our patient, acute dystonia was suspected while observing the posture of her limbs, trismus, and psychiatric comorbidity. Supporting this, her symptoms improved after administration of diphenhydramine. A recurrent spell that was dissimilar to the first spell (non-stereotypy) changed our diagnosis to PNES.
Patients with PNES are difficult to diagnose and manage. Their condition may be misdiagnosed or attributed to other etiologies. Multiple treating physicians may offer different diagnoses to the same patient.1 This increases iatrogenic harm from polypharmacy, emergency treatment leading to intubation, and hospital admissions.4 A benzodiazepine is frequently used to break PNES events. However, their overuse increases the risk of respiratory depression and withdrawal seizures upon discontinuation. Unlike patients with epileptic seizures, patients with PNES usually protect their airways, avoiding unnecessary intubation that increases risk of pulmonary infection and injury to the upper airway.
There are no established treatment guidelines for PNES. Treatment should focus on psychiatric comorbidities and minimize the use of anticonvulsants unless comorbid epilepsy is present. Once the diagnosis is made, it should be explained with great care to the patient. Avoid multiple anticonvulsants to reduce PNES events unless they are used for mood stabilization or other psychiatric reasons. Cognitive behavioral therapy is a first-line therapy, but evidence of its efficacy is lacking.2
PNES is a challenging diagnosis but should be considered in a patient with intractable seizures. It will guide future treatment options with the goal to decrease hospitalization and iatrogenic injury.