Neurology Flashcards
Define epileptic seizure
Sudden synchronous discharge of cerebral neurons causing symptoms or signs that are apparent either to patient or observer.
Classification of seizures
General:
- Absence seizures with 3Hz spike-and-wave discharge (petit mal)
- Generalised tonic-clonic seizures (grand mal)
- Myoclonic seizures
- Tonic and Atonic seizures
Partial seizures or Focal seizures (location related epilepsy)
- Simple partial seizures (without impaired awareness e.g. Jacksonian seizures)
- Complex partial seizures (with impaired awareness e.g. temporal lobe seizures)
- Partial seizures with secondary generalisation
Unclassified seizures: any that don’t fit in the above categories.
What is syncope?
Transient loss of consciousness due to transient global cerebral hypoperfusion. Rapid onset, short duration and spontaneous complete recovery.
Causes of syncope
- Neurally mediated: vasovagal, carotid sinus, situational
- Orthostatic: drug induced, ANS failure
- Cardiac Arrhythmia: Brady(sick sinus) tachy(VT/SVT) Long QT
- Structural cardio-pulmonary: aortic stenosis, HOCUM
- Non-cardiovascular: psychogenic, metabolic, neurological
Red flag signs for pathological cause of syncope
ECG abnormalities
Heart failure or previous MI
TLoC during exercise
Family history of sudden cardiac death
Dangerous ECG signs
Long or short QTc Pre-excited QRS complex Brugada syndrome: RBBB with ST elevation V1-V3 Abnormal T wave inversion Negative T waves in right precordial leads, epsilon waves suggest ARVC Pathological Q waves Conduction abnormality Inappropriate persistent bradycardia
What is an epsilon wave on ECG?
Small positive deflection ‘blip’ buried in end of QRS
Characteristic of ARVD- arrhythmogenic right ventricular dysplasia. (Seen often with T wave inversion in ; prolonged S wave upstroke (55ms); local QRS widening 110ms; all in V1-V3)
Classification of cardiovascular causes of syncope
Vascular
Obstructive
Arrhythmias
Vascular causes of syncope
AKA neurally mediated reflex syncope (NMS)
Neurocardiogenic (vasovagal: if no features of other diagnosis and features suggesting uncomplicated faint)
Postural hypotension
Postprandial hypotension
Micturition syncope
Carotid sinus syndrome
Situational syncope
Structural cardiovascular causes of syncope
Ventricular arrhythmia 2a to structural disease - HCM - DCM - ARVD (arrhythmogenic right ventricular cardiomyopathy) - Ischaemic cardiomyopathy Obstructive - HOCM (hypertrophic obstructive cardiomyopathy) - Severe AS (aortic stenosis) - Atrial myxoma or thrombus - Pulmonary hypertension/emboli - defective prosthetic valve - Pulmonary stenosis - Tetralogy of Fallot
Arrhythmic causes of syncope
Brady:
- sinus arrest, exit block (significant pauses)
- high grade or acute complete AV block e.g. Stoke-Adams attacks
- artificial pacemaker failure
Tachy (rarely due to SVT)
- ventricular: VT and VF
How useful is EEG to investigate seizures
Single awake EEG -> 29-56% show changes
Repeat inc sleep EEG -> 59-92% show changes
Types of epilepsy
Provoked seizure
Unprovoked seizure: generalised or focal… Etc
Provocation of seizures
In those not prone to epilepsy: drug OD, hypoglycaemia
In epileptics: sleep deprivation; stress; alcohol; TV/strobe lighting; menstruation.
Common types of epilepsy in childhood
Absence seizures ‘petit mal’
Febrile convulsions
Infantile spasms
Juvenile myoclonic epilepsy
Common causes of epilepsy in neonates and childhood
Neonatal:
- hypoxia: perinatal hypoxic ischaemic encephalopathy (HIE)
- vascular insufficiency (or intracranial haemorrhage)
- birth trauma;
- acute infection
- metabolic
- congenital malformation
- genetic
Childhood: (most idiopathic)
- acute infection
- trauma
- febrile convulsion
OR: congenital abnormality; tuberous sclerosis; metabolic storage disorders
Any age: Metabolic; infection; tumour; AVM; Inflammation.
Secondary causes of epilepsy in adulthood/elderly
Any age: metabolic, infection, tumour, AVM, inflammation.
Adult:
- head injury
- drug and/or alcohol intoxication/withdrawal
Elderly:
- cerebrovascular disease
- degenerative disease e.g. Alzheimer’s, huntington’s
Secondary causes of epilepsy in any age
- Metabolic e.g. Hypoglycaemia, hypocalcaemia, hyponatraemia
- Cerebral infection e.g. Meningitis, encephalitis, abscess
- cerebral tumour or AVM
- Inflammation e.g. Vasculitis, SLE, rarely demyelination.
Differential diagnoses for epilepsy
- syncope e.g. Vasovagal, micturition, cough
- cerebrovascular disease e.g. Transient ischaemic attack; critical carotid artery stenosis; vertebrobasilar ischaemia
- vestibular disorders
- low cardiac output states
- metabolic e.g. Hypoglycaemia
- postural hypotension
- narcolepsy
- psychiatric disorders e.g. Conversion hysteria
Characteristics of infantile spasms
- brief shock-like spasms, flexion of arms, head and neck, drawing up knees
- asn with progressive learning difficulties
- causes: perinatal asphyxia/metabolic disorders/encephalitis/cerebral malformations
Prognosis of absence seizures and febrile convulsions
Absence seizures: (4-10y, F>M) no post-ictal period; few continue after puberty, 5-10% have adult seizures
Febrile convulsions (
Common causes of adolescent seizures
Teenage: - Idiopathic - Trauma - drug/EtOH withdrawal - Arteriovenous malformation Young adult 18-35 - trauma - alcoholism - brain tumour
Common causes of seizure in >35
- tumour
- stroke
- Metabolic: ureamia; liver failure; electrolyte disturbance; hypoglycaemia
- alcohol
Teenage onset infrequent general seizure and daytime absences
=juvenile myoclonic epilepsy
- asn with myoclonus
Common Types of epilepsy seen in adults
- Primary generalised epilepsy (tonic-clonic/grand mal)
Prodrome/aura of dizziness/irritable/etc -> LoC
->tonic phase (generalised muscle spasms clonic phase (sharp repetitive muscular jerks in all limbs)
->unconscious for about 30min and Post-ictal for hours
Asn with tongue biting/involuntary micturition - Temporal lobe epilepsy
Typical aura of fear/deja-vu/hallucinations(visual/olfactory/gustatory)/rising sensation in epigastrium
Confusion and anxiety (+automatism/organised stereotyped movements e.g. Chew/lip smacking) - Jacksonian (focal) epilepsy (parallel to sensory epilepsy)
From 1 area of motor cortex= 1 body part-> entire side->whole body
Temporary paresis of originally affected limb post-attack (Todd’s paresis)
Define status epilepticus and management
Recurring or continuous seizures without regaining consciousness between attacks. Medical emergency.
- basic life support/resus
- seizure control
- ID and correct predisposing cause
Nursed in HDU/ICU (+restart anticonvulsant meds ASAP if known epilepsy)
Drugs used for partial seizures (+/- secondary generalisation)
1st line: Carbamazepine Lamotrigine Oxcarbazepine Sodium valproate 2nd line Clobazam Gabapentin Levetiracetam Pregabalin Topiramate
Drugs for generalised tonic-clonic epilepsy
1st line Carbamazepine Lamotrigine Sodium valproate 2nd line Clobazam Levetiracetam Phenytoin Topiramate
Drugs for absence seizure epilepsy
1st line: Ethosuximide Sodium valproate Alternatives: Clonazepam Lamotrigine
Drugs used for myoclonic epilepsy
1st line: sodium valproate
2nd line: clonazepam, levetiracetam, Topiramate
Drugs used for status epilepticus
- IV lorazepam 4mg (or clonazepam, diazepam). Can repeat dose after 10mins if seizures recur/continue
- IV phenytoin 15mg/kg, max: 50mg/min (or fosphenytoin- prodrug). Both need ECG monitoring. OR phenobarbitone 10mg/kg, max 100mg/min, when established status epilepticus
- IV thiopentone, bolus then infusion, AND ventilation/NMJ block = if seizures >30-60min. OR midazolam and propofol. EEG monitoring to confirm termination of seizure.
Problems of epilepsy in pregnancy
Uncontrolled seizures: risk to mother and foetus
Sodium valproate/carbamazepine: screen for neural tube defects and folic acid supplements (preconception and pregnancy)
Carbamazepine/phenobarbitone/phenytoin- Vit K before delivery and for newborn (due to enzyme induction- hepatic microsomal enzymes increasing metabolism of oestrogens/progestagens = OC pill ineffective!)
Signs of optic neuropathy?
Pale disc Loss of visual acuity Loss of red colour vision Central Scotsman Afferent pupillary defect: pupil dilates to light in swinging torch test (Marcus Gunn pupil)
Signs of background diabetic retinopathy
Microaneurysms and hard exudates
What is maculopathy? Differentials? Causes?
Reduction in visual acuity either due to cataracts or maculopathy. Check visual acuity. Commonly due to diabetes (macular oedema
Features of pre-proliferative diabetic retinopathy?
Cotton wool spots (infarct of nerve cell layer on retina); venous beeding and looping; intra-retinal microvascular abnormalities
Features of proliferative diabetic retinopathy?
New vessels
Features of end stage diabetic retinopathy?
Scarring with white bands of scar tissue and retinal traction
Management of status?
Oh My Lord Fetch the Anaesthetist! Oxygen Midazolam buccal Lorazepam IV Phenytoin Get the anaesthetist for Rapid sequence induction
