When you evaluate patients whose seizures could be epileptic or psychogenic, the evidence points to three useful diagnostic steps:
- Step 1: Characterize the seizure by its triggers and presentation.
- Step 2: Identify psychiatric comorbidity that might be precipitating psychogenic nonepileptic seizures (PNES).1
- Step 3: Obtain video EEG and blood tests for physiologic confirmation of epilepsy.
Using a case illustration, this article describes how to accomplish these steps by seeking clues in the patient’s seizure and psychiatric histories and choosing high-yield laboratory tests. When a PNES diagnosis becomes clear, we suggest an empathic approach that can help patients develop healthier responses to stress.
Psychiatric profile of patients with psychogenic seizures
Patients with psychogenic nonepileptic seizure (PNES)have high rates of repressed anger and life stressors. Psychodynamic interpretations postulate PNES as an unconscious conversion of emotional distress into physical symptoms, unlike factitious disorder’s intentionality. Repressed traumatic childhood sexual experience may be significant.2
Family dynamics. PNES may be a maladaptive communication method by which an individual uses behavior to manipulate the environment to meet emotional needs or to compensate for an environment intolerant of direct verbal expression.3
Characteristics. PNES patients are a heterogeneous group. They average a full-scale IQ of 92 in the lower quartile of intellectual capacity and neuropsychological functioning. PNES usually presents in the 20s but may occur at any age. PNES is more common in women than men (ratio 4:1).4,5
Comorbidities. Up to 40% of patients treated at epilepsy centers are reported to have both epilepsy and PNES.4,5 In a 1-year study at an EEG-video monitoring unit, however, only 9.4% of PNES patients had interictal epileptiform discharges to support a coexisting diagnosis of epilepsy.4
PNES may be highly associated with somatoform disorder, mood disorder, anxiety disorder, brief reactive psychosis, or schizophreniform disorder.6
CASE: A DIFFERENT KIND OF SEIZURE
Ms. X’s husband brought her to the emergency room after her third tonic-clonic convulsion within 1 week. He reported that her eyes suddenly rolled up and she became limp and fell down after they argued about money. She suffered a minor temple laceration, but this seizure—unlike past episodes—was not associated with mouth foaming or fecal or urinary incontinence.
Ms. X, age 35, has a history of seizure disorder and 5 years of unemployment when seizures were uncontrolled. Her seizures have been stabilized for 18 months with phenytoin, 300 mg bid. She has been hospitalized twice for major depressive disorder, most recently 2 years ago. Since then, her depression has been in remission with paroxetine, 20 mg once daily. She does not abuse drugs or alcohol. She has been married 8 years, has no children, and receives disability income.
Ms. X was stabilized and admitted for neurologic evaluation. CT and MRI were normal, EEG recordings were unremarkable, and blood workup revealed slightly elevated creatine kinase but normal prolactin. Her phenytoin serum level was 12 mcg/mL (therapeutic range, 5 to 20 mcg/mL). When video-EEG recording during one seizure revealed no abnormality, the neurologist requested psychiatric consultation.
PNES: NOT A ‘PSEUDO’ SEIZURE
Patients with PNES are a heterogeneous population (Box)2-6 that appears repeatedly at emergency rooms, resulting in multiple investigations and treatment with antiepileptic medications. Those with both PNES and epileptic seizure disorders, such as Ms. X, present a particularly difficult clinical dilemma as:
- discontinuing anticonvulsants may exacerbate epileptic seizures
- increasing the medication in the mistaken belief that a seizure breakthrough has occurred could result in toxic serum levels.
Psychological stressors may precipitate PNES in a person who has never had a seizure or in someone with co-existing epilepsy. Patients with PNES frequently deny a correlation between emotional stress and their seizures, whereas the opposite usually holds for patients who have experienced an epileptic seizure.7,8
PNES has been called “pseudoseizure” a term we believe is unfair to patients because the etiologic determinants are mostly subconscious.9 Although one author has defended the term,10 we agree with others that “pseudoseizure” can give a misleading impression that patients feign their symptoms.9
Psychiatric comorbidity. When PNES is suspected, a careful history is essential to identify precipitating psychiatric comorbidity, such as somatoform, somatization, conversion, or dissociative disorder. PNES may also be precipitated by or coexist with mood and anxiety disorders, schizophrenia, malingering and factitious disorders, diffuse organic brain disease, and developmental disorders (Table 1).11,12
CASE CONTINUED: AN IMPORTANT CLUE
Ms. X was admitted to the psychiatric unit. Her psychiatric history showed recurrent depressive disorder and excluded head injury. She was mildly depressed but expressed minimal cognitive and biological depressive symptoms in the mental status examination. She denied suicidal or homicidal thoughts. Perception, thought process, and cognition were normal.