Epilepsy-Misdiagnosis is Common
Nonepileptic Seizures are Easily Confused With Epileptic Disorders
Apr 8, 2009
The mistaken diagnosis can lead to loss of driving privileges, job discrimination, and inappropriate medication. In some cases this could be life threatening. While under a diagnosis of epilepsy, the actual cause of seizures may be going undiagnosed and untreated. Many people may be taking anticonvulsants and suffering their side effects when it isn't necessary.
Epilepsy is Many Disorders Under One Name
Epilepy is not a single disorder, but many, better described as the "epilepsies." In Preventing the Misdiagnosis of Epilepsy, pediatric neurologist CD Ferrie writes, "It is often stated that epilepsy is the commonest "serious" neurological condition. This is an illusion, sometimes convenient when arguing for funds. The term refers to a large and diverse group of disorders (probably hundreds) which share the tendency to have recurrent epileptic seizures."
Poor History Taking Linked to Misdiagnosis
Writing in 'Epilepsy and Intellectual Disabilities,' SM Zuberi states, "Unfortunately, the principal reason why many individuals are wrongly diagnosed is a lack of time and effort spent on the difficult art of history-taking."
When epilepsy is suspected, a full history may indicate other possible causes for seizures which can be evaluated before making a definite diagnosis.
Causes of Nonepileptic Seizures
The list of conditions causing seizures that are not epilepsy is very long. More Common Causes of Seizures include the following disorders:
- Migraines: These painful episodes are due to diminished blood flow in some area of the brain. They may have auras like those observed in epilepsy.
- TIAs: Transient Ischemia Attacks are caused by a sudden diminished blood flow in some areas of the brain that may be stroke related. Seizure-like symptoms may include changes in consciousness, speech or vision problems.
- Cardiac Disorders: Syncope is the disorder most often misdiagnosed as epilepsy. Bradycardia, Vasovagal syncope, Long QT Syndrome, are just a few cardiac disorders which are easily confused with epilepsy.
- Sleep Disorders: According to the Cleveland Clinic, about 75% of the adult population in the United States suffers from some type of sleep disorder.These include:
- Sleep Apnea
- Insomnia
- Restless legs Syndrome
- Circadian Rhythm Sleep Disorders
- Narcolepsy
- Parasomnias: these are behavioral changes which occur during sleep that include sleepwalking, and talking in one's sleep, sleep paralysis, and night terrors,
- Benign nocturnal myoclonic seizures-mild and chronic muscle spasms that occur during sleep.
Failed Drug Therapy may Indicate Misdiagnosis.
One reason drug therapy fails is that cause of the seizures is not epilepsy. The frequency of misdiagnosis became well known when studies of people with drug resistant seizures in the UK found a high percentage of epilepsy patients actually had cardiovascular disorders.
SUDEP and Cardiac Disorders
ECGs alone may not clearly distinguish epilepsy from cardiac disorders. Numerous studies point to a connection between SUDEP, Unexplained Death in Epilepsy, and cardiac problems. More extensive evaluation by a cardiologist can help identify cardiac disorders which may be an underlying cause of an individual's seizures.
EEGs
EEGs alone are not sufficient to make a definite diagnosis of epilepsy. It is not a sensitive enough to distinguish many disorders causing seizures from epilepsy. When anticonvulsants don't control seizures or there is a question about the diagnosis of epilepsy, the neurologist, patient, or care giver can seek further evaluation to find the underlying cause of seizures.
Sources:
Ferrie CD; Preventing the Misdiagnosis of Epilepsy; (Arch Dis Child. 2006 March; 91 (3): 206-209
Fisher RS; Imitators of Epilepsy, 2nd edition;
Stephenson, JBP, MA, BM, DM, FRCP, HonFRCPCH and Zuberi S, MB, ChB, MRCPCH, FRCP;
Nonepileptic Seizures and Similar Phenomena in Children and Adolescents, in: Imitators of Epilepsy, Kaplan PW, MB, FRCP and Fisher, MD, PhD (eds);Demos Medical Publishing, 2005
Zuberi SM; The Differential Diagnosis of Epilepsy, in Epilepsy and Intellectual Disabilities; VP Prasher, MP Kerr(eds); Springer (pub), 2008
Resources:
Sleep Centers.org (American Academy of Sleep Medicine)
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