Seizure and Epilepsy Dr. Navin Adhikari IM Resident
Definition A seizure is a transient occurrence of motor, sensory or autonomic signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Epilepsy - Epilepsy is a state of an enduring predisposition to recurrent seizures.
Acute symptomatic seizure – An acute symptomatic seizure (also referred to as a provoked seizure or reactive seizure) is a seizure that occurs in close temporal association with an acute systemic illness or brain insult. within one week of stroke, traumatic brain injury, anoxic encephalopathy, or intracranial surgery. at first identification of subdural hematoma . during the active phase of a central nervous system infection; within 24 hours of a severe metabolic derangement) Examples include hyponatremia , hypocalcemia , high fever, toxic exposure . Acute symptomatic seizures are not classified as epilepsy unless they become a recurrent process beyond the acute illness .
Unprovoked seizure – An unprovoked seizure is a seizure that occurs in the absence of a potentially responsible clinical condition or occurs in relation to a preexisting brain lesion or progressive nervous system disorder beyond the time interval recognized for acute symptomatic seizure .
Epilepsy if any one of following : At least two unprovoked (or reflex) seizures occurring more than 24 hours apart. Reflex seizures are seizures evoked by specific external ( eg light flashes) or internal ( eg , emotion, thoughts) stimuli . 2. One unprovoked (or reflex) seizure and a probability of further seizures that is similar to the general recurrence risk after two unprovoked seizures ( eg , ≥60 percent), occurring over the next 10 years. Examlpes a re structural lesions such as stroke, central nervous system infection, or certain types of traumatic brain injury. 3. Diagnosis of an epilepsy syndrome.
The causes of seizures and epilepsy can be broadly classified into six categories Genetic Structural Metabolic Immune Infectious Unknown
Causes of Seizures based on Age
CLASSIFICATION OF SEIZURE
FOCAL SEIZURES C aused by localised cortical activity with retained awareness. Awareness may become impaired if spread occurs to the temporal lobes. A bnormal motor movements may begin in a very restricted region such as the fingers and gradually progress (over seconds to minutes) to include a larger portion of the extremity - described by Hughlings Jackson and known as a Jacksonian march . Patients may experience a localized paresis ( Todd’s paralysis) for minutes to many hours in the involved region following the seizure
AURA subjective, “internal” events that are not directly observable by someone else are referred to as auras. Occurs before seizure, mostly seen in focal seizures. describe odd, internal feelings such as fear, a sense of impending change, detachment, depersonalization, déjá vu, or illusions that objects are growing smaller ( micropsia ) or larger ( macropsia ).
GENERALISED SEIZURES Typical absence seizures are characterized by sudden, brief lapses of consciousness without loss of postural control. The seizure usually lasts for only seconds, consciousness returns as suddenly as it was lost, and there is no postictal confusion. Atypical absence seizures have features that deviate both clinically and electrophysiologically from typical absence seizures. For example, the lapse of consciousness is usually of longer duration and less abrupt in onset and cessation, and the seizure is accompanied by more obvious motor signs that may include focal or lateralizing features.
Atonic seizures are characterized by sudden loss of postural muscle tone lasting 1–2 s. Consciousness is briefly impaired, but there is usually no postictal confusion. Myoclonus is a sudden and brief muscle contraction that may involve one part of the body or the entire body. A normal, common physiologic form of myoclonus is the sudden jerking movement observed while falling asleep.
Features that suggest seizure in older adults: Confusion, behavioral change, or unresponsiveness Sudden falls with no recall or warning Recurrent events occurring in various positions or circumstances Arousal from sleep with confusion or disorientation
Approach to Seizure
If History of Eilepsy present
If No history of Eilepsy present
ANTI EPILEPTIC DRUGS
Management of Epilepsy three main goals: controlling seizures, avoiding treatment side effects, and maintaining or restoring quality of life
Controlling seizure A ntiseizure medication therapy is usually not necessary in individuals after a single seizure, particularly if a first seizure is provoked by factors that resolve. C lassify the patient's seizure type Seizure types and epilepsy syndromes are classified primarily upon clinical grounds, assisted by laboratory, neurophysiologic, and radiographic studies.
Monitoring of therapy Regular follow-up visits should be scheduled to check drug concentrations, blood counts, and hepatic and renal function, when indicated. A ddress concerns about taking the medication and possible side effects, or psychosocial aspects of their disorder.
Discontinuation of therapy Withdrawal of medication may be considered after a patient has been seizure-free for more than 2 years Childhood-onset epilepsy, particularly classical absence seizures, carries the best prognosis for successful drug withdrawal. Other epilepsy syndromes, such as juvenile myoclonic epilepsy, have a marked tendency to recur after drug withdrawal. Patients should be advised of the risks of recurrence, to allow them to decide whether or not they wish to withdraw. If undertaken, withdrawal should be done slowly, reducing the drug dose gradually over weeks or months.
Mortality in Epilepsy R isk of death that is roughly two to three times greater than expected . Most of the increased mortality is due to the underlying etiology of epilepsy (e.g., tumors or strokes in older adults). However, a significant number of patients die from accidents, status epilepticus , and a syndrome known as sudden unexpected death in epilepsy (SUDEP ). The cause of SUDEP is unknown, it may result from brainstem-mediated effects of seizures on pulmonary, cardiac, and arousal functions.
Status Epilepticus consist of the following : ≥5 minutes of continuous seizures, or ≥2 discrete seizures between which there is incomplete recovery of consciousness. Refractory SE: Refractory status epilepticus is defined as ongoing convulsive or nonconvulsive seizures following administration of an initial benzodiazepine and a nonbenzodiazepine antiseizure medication, given in appropriate doses.
Management of SE
Complications C ardiac arrhythmias H ypoventilation and hypoxia fever, and leukocytosis Aspiration pneumonitis N eurogenic pulmonary edema R espiratory failure
References Harrison's Principles of Internal Medicine, 20th Edition Davidsons Principle and Practice of Medicine Katzungs Principles of Pharmacology. Uptodate 2020