13.1 Assess and Analyze the Impact of Nutrition on the Pulmonary System

Epilepsy is a neurological disorder characterized by recurrent seizures. These seizures result from abnormal electrical activity in the brain, caused by an imbalance between excitatory and inhibitory neurotransmitters.

Anticonvulsant drugs are the primary treatment for epilepsy. They work by reducing neuronal excitability and raising the seizure threshold. Different classes of anticonvulsants target various mechanisms in the brain to control seizures and improve quality of life for people with epilepsy.

Pathophysiology and Diagnosis of Epilepsy

Mechanisms and manifestations of epilepsy

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• Abnormal neuronal activity in the brain results from excessive and synchronous firing of neurons due to an imbalance between excitatory neurotransmitters like glutamate and inhibitory neurotransmitters like GABA
• Clinical manifestations include seizures which can be generalized involving both hemispheres (tonic-clonic, absence, myoclonic, atonic) or focal and localized to one area of the brain (simple focal without loss of consciousness, complex focal with altered consciousness)
• Non-seizure symptoms may include aura (sensory, motor, or psychological symptoms before a seizure) and postictal state (confusion, fatigue, or headache after a seizure)

Causes and diagnosis of epilepsy

• Common causes include genetic factors, structural brain abnormalities (traumatic brain injury, stroke, brain tumors, congenital malformations), metabolic disorders, and infections (meningitis, encephalitis)
• Diagnostic methods involve a neurological examination, electroencephalogram (EEG) to record electrical activity in the brain and identify abnormal patterns associated with seizures, neuroimaging like MRI or CT scan, and blood tests to rule out metabolic causes

Neuronal excitability and seizure threshold

• Neuronal excitability refers to the ease with which neurons generate action potentials
• Seizure threshold is the level of stimulation required to trigger a seizure, influenced by factors such as genetics, brain injury, and medication
• Anticonvulsant drugs aim to reduce neuronal excitability and raise the seizure threshold

Anticonvulsant Drugs and Treatment Strategies

Classes of anticonvulsant drugs

• Sodium channel blockers like phenytoin, carbamazepine, and lamotrigine stabilize neuronal membranes and reduce excitability
• GABA enhancers such as benzodiazepines (diazepam, lorazepam), barbiturates, and valproic acid increase inhibitory GABA activity
• Calcium channel blockers including ethosuximide and gabapentin reduce calcium influx and neurotransmitter release
• Glutamate antagonists like topiramate and perampanel block excitatory glutamate receptors
• Other mechanisms involve levetiracetam binding to synaptic vesicle protein SV2A and zonisamide having multiple mechanisms (sodium and calcium channel blockade, GABA enhancement)

Effects and interactions of anticonvulsants

• Therapeutic effects aim for seizure control and reduction in frequency and severity
• Common side effects include drowsiness, dizziness, ataxia, cognitive impairment (memory, concentration), gastrointestinal upset (nausea, vomiting), weight changes, and potentially serious skin rash (Stevens-Johnson syndrome)
• Drug interactions can occur with enzyme inducers (phenytoin, carbamazepine) decreasing levels of other drugs, enzyme inhibitors (valproic acid) increasing levels of other drugs, and oral contraceptives being less effective with enzyme-inducing anticonvulsants

Nursing considerations for anticonvulsants

• Assess for allergies and contraindications before administering anticonvulsants
• Monitor therapeutic drug levels (phenytoin, carbamazepine, valproic acid) and assess for side effects, adverse reactions, and signs of toxicity (nystagmus, ataxia, slurred speech)
• Educate patients on the importance of adherence, not stopping medications abruptly, and having regular follow-up with their healthcare provider
• Administer with food if gastrointestinal upset occurs
• Perform antiepileptic drug monitoring to ensure therapeutic levels and adjust dosages as needed

Patient education for epilepsy medications

• Emphasize the importance of taking medications as prescribed and discuss potential side effects and when to seek medical attention
• Advise on maintaining a consistent sleep schedule, keeping a seizure diary to track triggers and medication effectiveness, and the impact of epilepsy on daily activities (driving, swimming, working)
• Provide information on support groups and resources and emphasize the need for regular follow-up with healthcare providers

Treatment approaches for seizure types

• Generalized tonic-clonic seizures use first-line treatments like valproic acid, lamotrigine, levetiracetam and second-line options such as phenytoin, carbamazepine, topiramate
• Absence seizures are treated with first-line ethosuximide, valproic acid, lamotrigine while avoiding carbamazepine and gabapentin which may worsen absence seizures
• Focal seizures use first-line carbamazepine, lamotrigine, levetiracetam and second-line phenytoin, zonisamide, topiramate
• Status epilepticus (prolonged or repetitive seizures) requires emergency treatment with benzodiazepines (diazepam, lorazepam), phenytoin, phenobarbital and refractory cases may need anesthesia (propofol, midazolam)
• Non-pharmacological treatments include ketogenic diet (high-fat, low-carbohydrate) for refractory epilepsy in children, vagus nerve stimulation (VNS) for refractory focal seizures, and surgical resection of seizure focus in selected cases
• For drug-resistant epilepsy, combination therapy or alternative treatment options may be considered