Epilepsy & Status Epilepticus PDF

# Epilepsy The document describes epilepsy in detail, including its definition, pathophysiology, epidemiology, etiology, classification and treatment. ## Definition Epilepsy is defined as: - A chronic neurologic disorder manifesting by repeated epileptic seizures (attacks or fits) which result fro...

# Epilepsy The document describes epilepsy in detail, including its definition, pathophysiology, epidemiology, etiology, classification and treatment. ## Definition Epilepsy is defined as: - A chronic neurologic disorder manifesting by repeated epileptic seizures (attacks or fits) which result from paroxysmal uncontrolled discharges of neurons within the central nervous system (grey matter disease). - The tendency to have recurrent attacks is known as epilepsy. ## Pathophysiology - Epilepsy differs from most neurological conditions as it has no pathognomonic lesion. - A variety of different electrical or chemical stimuli can easily give rise to a seizure in any normal brain. - The hallmark of epilepsy is a rather rhythmic and repetitive hyper-synchronous discharge of neurons, either localized in an area of the cerebral cortex or generalized throughout the cortex, which can be observed on electroencephalogram (EEG). - Recent studies in animal models of focal epilepsy suggest a central role for the excitatory neurotransmitter glutamate (increased in epi) and inhibitory gamma amino butyric acid (GABA) (decreased). ## Epidemiology - 5% of the population suffer a single sz at some time. - 0.5-1% of the population have recurrent sz = EPILEPSY. - 70-80% are well controlled with drugs (prolonged remissions), and about half will successfully withdraw their medications. - 20-30% of epilepsy at least partially resistant to drug treatments = INTRACTABLE (FARMACORESISTANT) EPILEPSY. - 20-30% will develop chronic epilepsy. ## Etiology ### Infancy and childhood - Prenatal or birth injury - Inborn error of metabolism - Congenital malformation - Febrile seizure ### Childhood and adolescence - Idiopathic/genetic syndrome - CNS infection - Trauma ### Adolescence and young adult - Head Trauma - Drug intoxication and withdrawal* * causes of acute symptomatic seizures, not epilepsy ### Older adult - Stroke - Brain tumor - Acute metabolic disturbances* * causes of acute symptomatic seizures, not epilepsy - Neurodegenerative ## Epilepsy - Classification The modern classification of the epilepsies is based on the nature of the seizures rather than the presence or absence of an underlying cause. ### Types of Seizures - **Focal (partial) seizures** - account for 80% of adult epilepsies - Simple partial seizures - Complex partial seizures - Partial seizures secondary generalised - **Generalised seizures** - **Unclassified seizures** #### Partial Seizures - **Simple** - **Complex** - **Secondary generalized** ### Epilepsy and Seizures | Seizure Type | Description | |---|---| | Simple Partial | Remains conscious, aura | | Complex Partial | Lose consciousness, secondarily generalised seizure | | Generalized | Tonic clonic seizure with unconsciousness | #### Simple Partial Seizure - In these seizures, the discharge remains localized and consciousness is fully preserved. - What actually happens during a simple partial seizure depends on the area of the discharge and may vary widely from person to person but will always be stereotyped in one person. - Localized jerking of a limb or the face, stiffness or twitching of one part of the body, numbness or abnormal sensations are examples of what may occur during a simple partial seizure. - If the seizure progresses with impairment of consciousness, it is termed a complex partial seizure. - If it develops further and a convulsive seizure occurs, it is then called a partial seizure with secondary generalization. #### Simple Partial Seizures - Full awareness maintained - Rhythmic movements (isolated twitching of arms, face, legs) - Sensory symptoms (tingling, weakness, sounds, smells, tastes, feeling of upset stomach, visual distortions) - Psychic symptoms (déjà vu, hallucinations, feeling of fear or anxiety, or a feeling they can’t explain) - Usually lasts less than one minute - May be confused with: acting out, mystical experience, psychosomatic illness #### Complex Partial Seizures - Impaired consciousness - Clinical manifestations vary with site of origin and degree of spread - Presence and nature of aura - Automatisms (set of brief unconscious behaviors, in which the subject is unaware of his/her actions) - Other motor activity - Lip smacking or chewing movements, undressing, performing aimless activities. - Duration (typically 1 minute) #### Secondarily Generalized Seizures - These are partial seizures, either simple or complex, in which the discharge spreads to the entire brain. - The person may have a warning, but this is not always the case. - The spread of the discharge can occur so quickly that no feature of the localized onset is apparent to the person or an observer, and only an EEG can demonstrate the partial nature of the seizure. - The involvement of the entire brain leads to a convulsive attack with the same characteristics as a generalized tonic clonic convulsion. - Typical duration up to 1-2 minutes. - Confusion, somnolence, with or without transient focal deficit ## Generalized seizures (convulsive or non-convulsive) | Seizure Type | Description | |---|---| | Tonic Clonic | | | Absences | | | Myoclonic | | | Atonic | | | Tonic | | | Clonic | | #### Tonic-clonic convulsions - Often called 'grand mal' attacks. - These are the commonest of all epileptic seizures. - Without warning, the patient suddenly goes stiff, falls and convulses, with laboured breathing and salivation. - Cyanosis, incontinence and tongue biting may occur. - The convulsion ceases after a few minutes and may often be followed by a period of drowsiness, confusion, headache and sleep. #### Absence attacks - Often called 'petit mal', these are a much rarer form of generalized seizure. - They happen almost exclusively in childhood and early adolescence. - The child goes blank and stares; fluttering of the eyelids and flopping of the head may occur. - The attacks last only a few seconds and often go unrecognized even by the child experiencing them. #### Myoclonic seizures - These are abrupt, very brief involuntary shock-like jerks, which may involve the whole body, or the arms or the head. - They usually happen in the morning, shortly after waking. - They may sometimes cause the person to fall, but recovery is immediate #### Atonic seizures - These comprise a sudden loss of muscle tone, causing the person to collapse to the ground. Recovery afterwards is quick. - They are rare, accounting for less than 1% of the epileptic seizures seen in the general population, but much commoner in patients with severe epilepsy starting in infancy. #### Tonic seizures - The patient will quickly lose consciousness. - The skeletal muscles will suddenly tense, often causing the extremities to be pulled towards the body or rigidly pushed away from it. - This will cause the patient to fall if standing or sitting. - The tonic phase is usually the shortest part of the seizure, usually lasting only a few seconds. #### Clonic seizures - Is a series of involuntary, rhythmic, muscular contractions and relaxations, causing convulsions. - These may range from exaggerated twitches of the limbs to stiffened extremities. - The eyes typically roll back or close and the tongue often suffers bruising or crushing injuries sustained by strong jaw contractions. - The lips or extremities may turn slightly bluish (cyanosis) and incontinence is seen in some cases. - May last a few seconds to several minutes depending on the patient's condition. ## Generalized Seizures (induced by the entire brain) | Seizure Type | Description | |---|---| | al" or Generalized tonic-clonic | Unconsciousness, continuing muscle rigidity | | | Brief loss of consciousness | | | Sporadic (isolated), jerky movements | | | Repetitive, jerking movements | | | Muscle stiffness, rigidity | | | Loss of muscle tone | ## Non-Drug Treatment/Lifestyle Modifications - Adequate sleep - Avoidance of alcohol, stimulants, etc. - Avoidance of known precipitants - Stress reduction - specific techniques ## Epilepsy - Treatment - The majority of pts respond to drug therapy (anticonvulsants). - In intractable cases surgery may be necessary. The treatment target is seizure-freedom and improvement in quality of life. - The commonest drugs used in clinical practice are: Carbamazepine, Sodium valproate, Lamotrigine, phenytoin, Ethosuximide, clobazam, clonazepam (first line drugs) Levetiracetam, Topiramate, Vegabatrin, Phenobarbital (second line drugs), Gabapentin, Felbamate, Zonisamide, (new AEDs) ## Epilepsy - Treatment | Drug | Seizure Type | |---|---| | Carbamazepine | | | Lamotrigine | | | Oxcarbazepine | | | Levetiracetam | | | Topiramate | | | Valproate | | | Clobazam | | | Zonisamide | | | Pregabalin | | | Phenytoin | | | Gabapentin | | | Lacosamide | | | Eslicarbazepine | | ## Generalised seizures | Seizure Type | Drug | |---|---| | Tonic clonic | Valproate sodium | | | Carbamazepine | | | Lamotrigine | | Tonic | Lamotrigine | | | Phenobarbital | | Clonic | Ethosuximide | | | Clonazepam | | Absence | Sodium valproate | | | Lamotrigine | | Atypical absences | Sodium valproate | | | Carbamazepine | | Atonic | Clonazepam | | | Lamotrigine | | | Clobazam | ## Epilepsy - Treatment - Basic rules for drug treatment: Drug treatment should be simple, preferably using one anticonvulsant (monotherapy): "Start low, go slow“. - Add-on therapy is necessary in some patients... - If patient is seizure-free for three years, withdrawal of pharmacotherapy should be considered. Withdrawal should be carried out only if pt is satisfied that a further attack would not ruin employment etc. (e.g. driving licence). - It should be performed very carefully and slowly! 20% of pts will suffer a further sz within 2 yrs. ## Epilepsy - Treatment - The risk of teratogenicity is well known (~5%), especially with valproates, but withdrawing drug therapy in pregnancy is more risky than continuation. - Epileptic females must be aware of this problem and thorough family planning should be recommended. - Over 90% of pregnant women with epilepsy will deliver a normal child. ## Newer AEDs - The newer AEDs are generally used as second-line drugs when treatment with established first-line drugs has failed. - However, lamotrigine, levetiracetam, topiramate and oxcarbazepine, have indications for first-line use in the UK. - Guidance has been issued that covers the use of the newer AEDs in adults (NICE 2004): - Newer drugs, for example, lamotrigine, oxcarbazepine and topiramate, suitable for the type of epilepsy to be treated can be used in patients where older drugs, for example, sodium valproate or carbamazepine, do not provide effective clinical control or cause intolerable side effects. - Gabapentin, levetiracetam, tiagabine and vigabatrin’ are generally used in combination with another drug. - Newer drugs can be used where older drugs are unsuitable for the person, for example, liver disease, or where unwanted effects cannot be tolerated. - The aim should be to treat people with just one AED where possible. ## Epilepsy – Surgical Treatment - A proportion of patients with intractable epilepsy will benefit from surgery. - Evaluation before surgery: - History and Exam: consistency, localization of seizure onset and progression - MRI & EEG: by special electrodes - Neuropsychological battery - Psychosocial evaluation ## Status Epilepticus - A condition when consciousness does not return between seizures for more than 30 min. This state may be life-threatening with the development of pyrexia, deepening coma and circulatory collapse. Death occurs in 5-10%. - Positioning the patient to avoid injury - Supporting respiration - Maintaining blood pressure - Correcting hypoglycemia (autonomic symptoms) ## Status Epilepticus - Treatment - I.V. Lorazepam or diazepam - Alternative medicines include midazolam (I.V. or buccal) - In sever cases; phenytoin, clonazepam, phenobarbital, and paraldehyde may be required. ## Homework - Drug- and Toxin-Induced Seizures? - Epilepsy Complications?