Neurology - Epilepsy Flashcards
Definition of epilepsy
Paroxysmal electrical discharge of cerebral neurons causing a variety of clinical seizure patterns
Single seizure is NOT epilepsy - diagnosis requires recurrent seizures
How are epileptic seizures classified?
2 types of seizure:
- Focal (partial) - seizures that start locally
- Generalized - no evidence of focal onset
Can focal (partial) seizures be sub-classified?
Yes
- ) Simple partial seizures - consciousness retained throughout the attack
- ) Complex partial seizures - consciousness is impaired at any stage
Secondary generalization
Partial seizure becomes generalized
Patient loses consciousness with clinical evidence of spread across the cerebral cortex
Aetiology
- ) Idiopathic - majority of patients
- includes patients who have suffered intrauterine, perinatal or neonatal insults or genetic
2.) Symptomatic - cause can be found
Causes of symptomatic epilepsy in neonates
(Cerebral disorders, metabolic, drug intake)
- ) Birth trauma
- ) Intracranial haemorrhage
- ) Hypoxia
- ) Hypoglycaemia
- ) Hypocalcaemia or hypomagnesaemia
Causes of symptomatic epilepsy in children
(Cerebral disorders, metabolic, drug intake)
- ) Congenital anomalies - e.g. hippocampal sclerosis
- ) Tuberous sclerosis
- ) Metabolic storage disease
Causes of symptomatic epilepsy in young adults
- ) Post- traumatic (e.g. head injury)
- ) Drugs - amphetamines, TCAs, phenothiazines
- ) Alcohol - head injury whilst intoxicated, severe intoxication
Causes of symptomatic epilepsy in middle aged adults
Cerebral tumour
Causes of symptomatic epilepsy in the elderly
Cerebrovascular disease
Degenerative diseases - e.g. Alzheimer’s, Huntington’s
What infections can cause epilepsy?
- what should you especially consider in AIDs patients and travelers?
Encephalitis
Bacterial meningitis
Cerebral abscess
Toxoplasmosis (consider in AIDs)
Cysticercosis (parasitic tapeworm infection)
Syphilis
Falciparum malaria (consider in travellers)
What are the differential diagnosis to exclude in epilepsy?
Consider other causes of loss of consciousness - “CRASH”
- ) Cardiac - bradycardia (e.g heart block - Stokes-Adams attack), tachycardia (e.g. AF, WPW), structural (i.e. causing low cardiac output states - LVF, Aortic stenosis, HOCM, myxoma, PE)
- ) Reflexes - either vagal overactivity or sympathetic under activity
- ) Arterial - e.g. vertebrobasilar insufficiency (TIA, CVA, subclavian steal); Shock; hypertension
- ) Systemic - e.g. metabolic (hypoglycaemia), respiratory (hypoxia or hypercapnia), blood (anaemia or hyper viscosity)
- ) Head - e.g. epileptic attacks, non epileptic attacks, drop attacks
Distinguishing faints from seizures
Epileptics are:
- stiff, not floppy
- staring open eyes rather than half open
- no memory of the fall
- tongue biting
- take over 30s to recover
How many people die from epilepsy per year?
2 per 100,000
Most common cause of death is status or accidental head injury following a seizure
Primary generalized epilepsy - features
- what is the most common type of seizure in this syndrome?
Adult epileptic syndrome
Tonic-clonic or grand mal is most typical seizure type
- 50% cases preceded by aura
- Loss of consciousness and tonic phase (approx 30s)
- Clonic phase follows in all limbs (micturition and tongue biting)
- Patients normally sleep for 1-2 hours after
Temporal lobe epilepsy - features
Partial epilepsy (adult epileptic syndrome) Aura may consist of psychic symptoms (e.g. fear or deja vu), hallucinations, or rising sensation in epigastrium
Patient may be confused and anxious and exhibit automatisms (organised stereotyped movements) - e.g. chewing, lip smacking
Jacksonian epilepsy - features
- what is this type of epilepsy normally associated with?
Focal motor attacks
Begin in corner of mouth, toe or index finger and spread to the face or ascend the limb (Jacksonian march)
Normally associated with organic brain disease - e.g. tumour
What is Todd’s paralysis?
Muscles affected by Jacksonian seizure may be weak for several hours after
Epilepsia partialis continua
Rare form of Jacksonian epilepsy where seizures persist for prolonged periods of time - e.g. days or weeks
Key features of febrile convulsions
Usually brief and generalized (last less than 15 minutes)
Occur as an isolated attack without recurrence in 70% of cases
Carry a risk of subsequent epilepsy in 5% of cases
Generally do NOT require treatment with prophylactic anti convulsants
Absence seizures (petit mal)
Generalized seizure (childhood epilepsy)
Features are “ABSENCES”
- ABrupt onset and offset
- Short
Do absence seizures progress beyond puberty?
Most stop during puberty
5-10% develop adult seizures
Infantile spasms (West’s syndrome)
Childhood epilepsy
Brief spasms ("shock like" - arm flexion, drawing up of knees) associated with progressive learning difficultiesJuvenille myoclonic epilepsy
Childhood primary generalized epilepsy
Typical onset in teenagers
Infrequent generalised seizures, daytime absences and myoclonus (sudden limb, face or trunk jerk)
Investigations in epilepsy
Bloods - U&E’s (alcohol, sodium, calcium)
Urine toxicology
ECG
Imaging
Indications for an EEG in epilepsy
Use to support the diagnosis (cannot exclude or prove)
Helps classification and prognosis
Indications for neuroimaging in epilepsy
Not routine for idiopathic epilepsy
Adult onset seizures
Any evidence of focal onset (localizing features)
Seizures continuing despite 1st line Rx
Localised functions of the frontal lobe
- Higher intellectual function
- Personality, mood
- Social conduct
- Motor areas (primary motor area)
- Frontal eye fields (conjugate eye movements)
- Language, dominant hemisphere (Broca’s area/ expressive)
What are the functions of the temporal lobe?
- Memory
- Language (dominant hemisphere)
- Visual pathway (optic radiation)
Localised functions of the occipital lobe
- Visual cortex and visual association areas
What are the functions of the parietal lobe?
Dominant hemisphere:
- Language, dominant hemisphere (Wernike’s area/ receptive)
- Calculation
- Praxis (complex motor tasks)
Non dominant hemisphere:
- Visuo-spatial function
Both hemispheres:
- Higher sensory function
- Visual pathway (optic radiation)
