Epilepsy (Seizure disorders)
The word epilepsy is derived from Greek word meaning "to seize upon" or a "taking hold of". Our predecessors referred to it as the "falling sickness" or the "falling evil." Approximately 1.77 million individuals in the United States were subject to epilepsy and that about 44 new cases per 100,000 population occur each year. It has also been estimated that approximately 1 percent of the persons in the United States will have epilepsy by the age of 20 years.
What is epilepsy?
Seizure is due to an abnormal paroxysmal electrical activity in the cerebral neurons present in the outer core of the brain (called cerebral cortex), which results in alteration of sensation, motor function, behavior or consciousness. Epilepsy is a disorder, not a single disease. It is characterized by recurrent (2 or more), unprovoked seizures. Status epilepticus is a condition where there is more than 30 minutes of continuous seizure activity or multiple seizures without full recovery of consciousness between seizures.
What are the different types of epilepsy?
Epilepsy has been classified in several ways. The International Classification of Epileptic Seizures is as follows.
Generalized seizures: The seizures begin bilaterally symmetrical and synchronous involving both cerebral hemispheres at the onset, no local onset and consciousness in lost from the start. This type of seizures represents 40% of all the seizures.
Partial or focal seizures:
- Tonic, clonic or tonic-clonic (grand mal)
- Absences (petit mal)
- Lennox-Gastaut syndrome
- Juvenile myoclonic epilepsy
- Infantile spasms (West syndrome)
- Atonic seizures
The seizures beginning locally and one cerebral hemisphere is involved at the onset. It constitutes about 57% of all the seizures.
Special epileptic syndromes:
- Simple partial seizures-Motor, Somatosensory, Autonomic, Pure psychic
- Complex partial seizures
- Partial seizures with secondary generalization.
What are the factors that provoke epilepsy in a patient?
- Myoclonus and myoclonic seizures
- Reflex epilepsy
- Acquired aphasia with convulsive disorder
- Febrile seizures
- Hysterical seizures
What are the causes for epilepsy?
- Sleep deprivation (inadequate sleep)
- Photic stimulation (flashes of light)
- Metabolic disturbances-electrolyte imbalance
- Head trauma-Closed head injury, penetrating trauma
- Cerebral ischemia- Cerebro vascular accident.
What are the investigations to be done if a patient presents with epilepsy?
- Cerebrovascular accident-4.2% of the patients with stroke had seizures
- Head trauma
- CNS infection like meningitis, cerebral abscess, subdural empyema
- Febrile seizures
- Birth asphyxia
- Congenital CNS abnormalities
- Brain tumour
- Arterio venous malformations of the brain (congenital abnormality of the blood vessels)
- Electrolyte disturbances- Uremia, hyponatremia, hypoglycemia
- Cocaine toxicity
- Phenothiazine antiemetics
- Eclampsia (seizures that occur during pregnancy associated with hypertension)
- Idiopathic (cause not known)
When an adult patient presents with a seizures for the first time, underlying medical disorder if any, should be ruled out. Idiopathic seizures are more common in adolescence. CT scan or MRI with and without contrast enhancement should be performed. A systemic workout should be done to rule out medical disease or any electrolyte abnormalities. If all are negative, repeat CT scan or MRI should be done in 6 months and 1 and 2 years to rule out a tumour which is not evident in the initial study. Electroencephalogram (EEG) is done to record the electrical activity of the brain. It is helpful in diagnosing the seizure type, where specific pattern of waves are seen.
In children with the first-time seizures, laboratory and radiological evaluations were often costly and not helpful A detailed history and physical examination are more helpful.
What are the conditions that may look like seizures?
What are the treatments available for epilepsy?
- Psychological disorders
- Somatoform disorder especially conversion disorder
- Anxiety disorder
- Dissociative disorders
- Impulse control disorders
- Attention deficit disorder
- Cardiovascular disorders
- Cardiac arrhythmias
- Transient ischemic attacks
- Breath holding spells
- Migraine syndrome
- Complicated migraine
- Basilar migraine
- Movement disorders
- Tics, spasms
- Parosomnias and sleep related disorders
- Night terrors, night mares
- Narcolepsy, cataplexy
- Nocturnal paroxysmal dystonia
- Gastrointestinal disorders
- Episodic nausea
- Cyclic vomiting syndrome
- Medication effects
Both medical and surgical treatments are available for epilepsy. Initially antiepileptic drugs are given to control epilepsy. The goal of the drug treatment is to make the epileptic person to lead a normal lifestyle without epilepsy related restrictions. About 75% of the persons respond to drug therapy.
The various drugs available for treating epilepsy are Valproic acid, phenytoin sodium, carbamazepine clonazepam, lamotrigine, topiramate, gabapentin, vigabatrin,tiagabine etc.,
20% of the patients continue to have seizures even with antiepileptic drugs. Many of these patients may be benefited by surgical procedures like corpus callosotomy, anterior temporal lobectomy with amygdalohippocampectomy, vagal nerve stimulation etc.