Epilepsy is not a disease entity but a chronic manifestation of brain damage that results in abnormal electrical brain activity and electrical discharges. It may manifest as -
- Changes in consciousness
- Altered or lost muscle control
- Seizures and convulsions - predominantly violent muscular contractions preceded by hallucinations, changes in mood or behaviour (aura), disorientation, slurring of speech and blinking.
What causes epilepsy?
Some neuropathological factors may underlie epilepsy, including-
- Increased neuronal excitability
- Decreased inhibition of the motor cortex
- Metabolic disorders of cerebral neurones.
- Idiopathic epilepsy
- Symptomatic or secondary epilepsy
- Febrile convulsions - FEVER
- Intracranial causes: space-occupying lesions, trauma, vascular defects, infections, cerebral palsy, rubella syndrome, phakomatoses (neurofibromatosis, epiloia), AIDS, meningitis
- Systemic causes: hypoxia, hypoglycaemia, inborn errors of metabolism, drug withdrawal (anticonvulsants, barbiturates, alcohol, opioids, benzodiazepines).
Classification and diagnosis
The diagnosis and classification of seizures and epilepsy syndrome follow the guidelines suggested by the International League against Epilepsy. Epilepsy may be classified in three main groups:
- Generalised seizures
- Partial seizures
Generalised seizures: Occur due to abnormal electrical brain activity and electrical discharge that involves both sides of the brain at once.
Partial seizures: Occur due to electrical discharge in one limited area of the brain. Head injury, brain infection, stroke, tumor are the causes of partial seizures.
Epilepsy usually begins in the preschool child, or occasionally at puberty. It manifests with a warning (aura), followed by loss of consciousness, tonic and clonic convulsions, and finally a variably prolonged recovery.
- Mood change, irritability, brief hallucination or headache or even the sensation of a strong smell (e.g. burning rubber)
- The attack then begins suddenly with total body tonic spasm and loss of consciousness
- Falls to the ground - danger of injury
- Pale face, dilated pupils
- The head and spine are thrown into extension (opisthotonus)
- Glottic and respiratory muscle spasm - initial brief cry and cyanosis
- Incontinence and biting of the tongue or lips
- The tonic phase passes, after less than a minute, into the clonic phase
- Repetitive jerking movements of trunk, limbs, tongue and lips
- Profuse Salivation
- Bruxism, tongue-biting, occasionally vomiting
- There may be urinary or faecal incontinence
- Tachycardia, hypertension and flushing
- Clonus is followed by a state of flaccid semi-coma for a further 10-15 minutes, and then recovery.
- Confusion and headaches are common afterwards and the patient may sleep for up to 12 hours or more before full recovery.
- The attack may occasionally be followed by a transient residual paralysis or by automatic or aggressive behaviour.
This full sequence is, however, not always completed.
Factors precipitating a seizure
Various factors can precipitate attacks including -
- Withdrawal of anticonvulsant medication
- Epileptogenic drugs
- Flickering lights (television, strobe lights)
Complications of major convulsions
- Respiratory embarrassment
- Brain damage
- Status epilepticus
Convulsions may have craniofacial sequelae, from trauma that frequently results from a grand mal attack when the patient falls unconscious, or from the muscle spasm. Such injuries can include:
- Periorbital subcutaneous haematomas in the absence or presence of facial fractures
- Injuries to the face from falling (lacerations, haematomas, fractures of the facial skeleton)
- Fractures, devitalisation, subluxation or loss of teeth
- Subluxation of the TMJ
- Lacerations of lips, tongue or buccal mucosa.
- Skull Radiographs
- CT (Computed Tomography) Scan
- EEG (electroencephalogram)
- Blood Investigations - Complete Blood Count, Blood Culture, Electrolytes
- Urine Analysis
- Anticonvulsants are the treatment of choice
- Gamma Aminobutyric acid (GABA) potentiators and neuronal inhibitors
- Carbamazepine and sodium valproate are the most widely used
Anticonvulsants but newer drugs are being used more frequently either in monotherapy (lamotrigine) or as an adjunct (gabapentin).
- Phenytoin and phenobarbitone less commonly used.
- In severe cases, protective headgear may be worn to limit injury to the CNS during seizures
- Surgical treatment - Surgical intervention by neurosurgeon is required.
- People with epilepsy face some legal restrictions, notably in the areas of driving and employment.
- They are prohibited from entering specific occupations, such as becoming an aircraft pilot, ambulance driver or soldier.
Drug side effects
- Phenytoin-induced gingival swelling and/or ulcers secondary to folic acid
- Deficiency anaemia
- Palatal petechiae, as a consequence of platelet aggregation inhibition due to valproic acid
- Ulcers due to agranulocytosis from carbamazepine
- Depression of the bone marrow
Drugs that can be epileptogenic (can precipitate epilepsy) and therefore are contraindicated
- Lidocaine (large doses)
- Tricyclic antidepressants
- Aspirin and other NSAIDs - can interfere with phenytoin, can increase the bleeding tendency induced by valproate
- Azole antifungals - can interfere with phenytoin
- Erythromycin - can interfere with carbamazepine, can increase the bleeding tendency induced by valproate
- Metronidazole - can interfere with phenytoin
- Propoxyphene - can interfere with carbamazepine
Appropriate management of a patient undergoing tonic-clonic seizure includes:
- Summon help
- Lay the patient flat turned to one side
- Do not try to move the patient while they are actively fitting
- Protect the patient from injury
- Do not attempt to force a spoon or tongue depressor or other hard object between the teeth
- Clear the area of equipment, furniture or other objects that may cause injury during the seizure
- Do not attempt to restrain or hold the person down during the seizure
- If the patient is having difficulty breathing or becoming cyanosed, maintain the airway by gently extending the neck
- CPR or mouth-to-mouth breathing cannot be performed during the seizure and is rarely needed after seizures. In an uncomplicated seizure no other treatment is necessary
- However, if the fit continues for longer than normal, or >10 minutes, midazolam 10mg should be given intramuscularly
- While waiting, the airway should be protected where possible, with suction to remove excess saliva, and high flow oxygen 10-15 L/min administered
- If the fit does not resolve within the next 5 minutes, an ambulance should be called, as status epilepticus may develop and is a medical emergency
Status epilepticus is defined as a seizure lasting for more than 30 minutes, or repeated seizures over the same period without intervening periods of consciousness. This is a particularly dangerous form of epilepsy and is a MEDICAL EMERGENCY. Status epilepticus may result in aspiration of material into the lungs, and cerebral hypoxia, and has a mortality rate of 5–20%.
- Maintaining patency of the airway
- Adequacy of oxygenation and ventilation
- Venous access is secured as soon as possible
- Head positioning, using the chin lift and jaw thrust, may open the airway, and an oral or nasal airway can be inserted
- Oral suctioning may be required, so this should be available
- High-flow oxygen is administered to all patients via mask or bag-valve-mask ventilation
- Cardiac status and pulse oximetry are monitored continuously
- Intubation may be necessary to oxygenate and ventilate the patient adequately
- After intravenous access is obtained, a bedside glucose determination is performed, and blood is drawn for complete blood count, electrolytes, BUN, glucose, calcium, and magnesium
- For patients on anticonvulsant therapy, drug levels are obtained and in some patients a toxicology screen may be indicated.
- If the glucose is <60 mg/dL, 0.5 to 1.0 g/kg of dextrose is given
- Drug therapy requires a clear plan, prompt administration of anticonvulsants in adequate doses, and with attention to side effects, such as hypoventilation or apnea.
- Benzodiazepines are effective for treatment of an actively seizing patient.
- Diazepam (Valium) is useful for control of seizures. It has an onset of action of 1 to 3 minutes- dose is 0.1 to 0.3 mg/kg, administered slowly by intravenous push.
These are seizures that occur during the first 28 days of life, although most occur shortly after birth. Because the cerebral cortex is immature, seizures in neonates can be extremely subtle, consisting only of lip smacking, eye deviation, or apnea. Motor activity can appear normal. They manifest as lethargy, vomiting, and poor feeding.
- Perinatal asphyxia
- Metabolic abnormalities - hypoglycemia and hypocalcemia
- Central nervous system infections
- Perinatal hemorrhage
- Urea cycle defects and abnormalities in amino acid metabolism
- Inherited pyridoxine deficiency - an autosomal recessive trait
- Airway patency and adequate oxygenation
- Anticonvulsant drugs
- Correction of metabolic abnormalities with adequate supplements
A febrile seizure is a seizure accompanied by a fever without evidence of intracranial infection, intracranial abnormality and toxins.
- Febrile seizures usually occur between 6 months and 5 years of age.
- Most febrile seizures are self-limited, generalized, and last for <15 minutes, in which case they are classified as simple.
- A complex or atypical febrile seizure lasts more than 15 minutes, occurs more than once in a 24-hour period, or has a focal component.
- Following a febrile seizure, children will usually have a postictal period during which they are lethargic, irritable, or confused.
- Any illness that causes fever can provoke a febrile seizure.
- The seizure usually occurs during the early phase of the infectious illness.
- Commonly implicated etiologies include upper respiratory tract infections, pharyngitis, otitis, pneumonia, gastroenteritis, urinary tract infections, and roseola.
- Febrile seizures can also occur after immunizations.
- The initial management of the patient with a febrile seizure includes stabilizing the airway and ensuring adequate oxygenation.
- If the seizure persists for more than 10 minutes, anticonvulsant therapy is indicated.
- Acetaminophen 15 mg/kg or ibuprofen 10 mg/kg is administered to reduce the fever.
Prognosis in epilepsy
Prognosis in epilepsy is influenced by
- The underlying disease,
- Extent of brain damage,
- Severity and frequency of seizures.
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