24.2 Epilepsy Flashcards
What are the 3 different diagnostic criteria for epilepsy?
1) At least 2 unprovoked seizures occurring more than 24 hours apart
2) One unprovoked seizure with a probability of further seizures similar to the general recurrence risk (at least 60%) after 2 unprovoked seizures, occurring over the next 10 years
3) Diagnosis of an epilepsy syndrome
What is a seizure?
A temporary disruption of brain function due to hypersynchronous, abnormal firing of cortical neurons.
Sudden burst of uncontrolled electrical acitivity in the brain which causes disruption to the pt’s ability to function.
What may cause a seizure?
- Stroke
- Brain tumour
- Head injury
- Infection
- Metabolic disturbance (high fever, hypoglycaemia, alcohol or drug use or withdrawal)
What are the types of seizures?
Focal onset:
- Focal aware (systems depend on area of abnormal acitivity e.g. motor cortex will cause rhythmic movements, sensory regions will cause hallucinations
- Focal impaired awarenss (post-ictal afterwards)
Generalised onset:
- Myoclonic (muscle jerk, may be precusor to tonic-clonic)
- Absence seizure (blank and unresponsive)
- Tonic-clonic
- Atonic (muscles relax, pt floppy) and tonic (stiff and fall)
Unknown onset
Describe a tonic-clonic seizure.
- Tonic phase: epileptic cry, body goes stiff, fall to the floor
- Clonic phase: clonic jerks of limbs, may become incontinent, breathing may be affected
What seizure type has a high risk of facial/tooth injury?
Atonic (generalised onset): also known as drop seizure, pt normally falls
What might a patient have before their seizure?
An aura, an awareness/feeling that a seizure is about to occur.
What are the causes of epilepsy?
- Genetic: benign familial neonatal epilepsy, Dravet syndrome
- Infection: refers to a patient with an epilepsy diagnosis who experiences an infection (e.g. neurocysticercosis, TB, HIV, cerebral malaria, Zika virus). Not referring to people who have a one-off seizure as a consequence of infection e.g. meningitis.
- Metabolic: e.g. porphyria, uraemia, cerebral folate deficiency
- Immune: refers to immune disorders in which seizures are a core symptom e.g. autoimmune epilepsy
- Structural: abnormalities which are visible on structural imaging. May be acquired e.g. stroke, trauma, infection or genetic such as malformations of the brain.
- Co-morbidities: children with learning disabilities may have epilepsy, psychological problems such as depression, behavioural problems
Name some common epilepsy drugs.
- Sodium valproate
- Lamotrigine
- Gabapentin
- Carbamazepine
- Oxcarbamazepine
- Phenytoin
- Pregablin
- Clobazam (adjunctive)
Around 50% of pts have their seizures managed with 1 medicine alone.
Around 30% of pts will continue to have seizures when taking multiple medicines.
What treatment options are there for pts who don’t respond to epilepsy medication? (Aka medically refractory epilepsy)
- Surgical resection: removing a small portion of the brain
- Deep brain stimulation
- Vagus nerve stimulation
- Responsive neurostimulation
What are the side effects of sodium valproate?
- Can cause thrombocytopaenia (low platelets) which may cause drug induceed gingival enlargement
- Can cause liver impairement which affects amounts of LA used
- Drowsiness
What are the side effects of phenytoin?
- Drug induced gingival enlargement (50% risk)
- Altered taste
- Thrombocytopaenia
- Teratogenic potential
- Dental anomalies
- Ulcers
- Cervical lymphadenopathy
What are the side effects of gabapentin?
- Dry mouth
- Vomiting
What are the side effects of lamotrigine?
- Dry mouth
- Vomiting
What are the side effects of carbamazepine?
- Glossitis
- Ulceration
- Dry mouth
- Stomatitis