Neuro Flashcards
Differentials for seizure and for LOC?
Seizures: febrile convulsion, non-epileptic attack disorder (pseudoseizures), epilepsy, meningoencephalitis, infection (sepsis, abscesses, subdural empyemas), tumour, toxins, metabolic (e.g. hypoglycaemia, urea cycle defects), head injury.
LOC: breath-holding attacks or spasms, reflex anoxic seizures, vasovagal syncope, cardiac arrhythmias.
What is a febrile convulsion? Who does it affect?
6 months – 6 yrs (6 months – 3 yrs most common). ~1 in 20.
Most common presentation of seizures in ED (~5% of pre-school children).
Associated with ≥38°C, in absence of CNS infection, metabolic imbalance or neurological condition.
Aetiology not fully understood, but genetics (familial predisposition) and infection are important factors. Believed to be due to viral illness however bacterial infection should always be considered.
Often occur with tonsillitis, otitis media, herpes simplex, shigella, rotavirus gastroenteritis or roseola.
How are febrile seizures classified?
- Simple: generalised tonic-clonic seizure ≤15 mins, not recurring within 24 hours
- Complex / atypical: >15 mins, focal, or recurring within the same febrile illness
- Status: >30 mins
How are febrile convulsions diagnosed?
Management?
Clinical ∴ no specific Ix needed: initial Ix to rule out hypoglycaemia or UTI in infants should be taken as general precautions.
Simple febrile seizures: rapid + full neurological recovery. Always consider meningoencephalitis in child with fever + seizures (potentially life-threatening).
?1st presentation of epilepsy if no clear neurological focus.
Most children presenting with febrile convulsions are well by the time they attend ED + have a clear focus. In these cases, management:
- Antipyretics: paracetamol & ibuprofen ↓ discomfort, not prevent further convulsions
- Education & reassurance: parents should understand risks of recurrence & how to manage future febrile seizures (recognition and reduction of fever by undressing & giving anti-pyretic), know how to keep child safe during seizure, to seek medical advice if it lasts <5 mins, and to call an ambulance if it lasts longer
When to consider admission for febrile convulsions?
Consider admission if: • First febrile seizure • Seizure >15 mins • Focal seizure • Recurring with same febrile illness within 24 hours • Incomplete recovery after 1 hour • <18 months old • Parental anxiety • Suspected serious cause for infection (e.g. pneumonia) • No apparent focus of infection
If none of the features below: green (self-care advised)
If a febrile seizure lasts >5 mins?
Benzodiazepines (e.g. buccal midazolam, PR diazepam) can be effective
Prophylactic anti-epileptics are not routinely recommended, even if seizures are recurrent.
Prognosis of febrile convulsions?
Overall recurrence risk ~1 in 6.
associated with good neurological outcome and there is a 2% risk developing epilepsy (compared to 1% risk in those without Hx of febrile seizures).
Complex febrile seizures have a higher risk of epilepsy.
Epilepsy - aetiology?
0.05% incidence, 0.5% prevalence.
Recurrent (at least 2 unprovoked episodes, 24 hours apart) seizures thought to be of electrical origin in the brain. The term describes a predisposition to have epileptic seizures. Also possible for children who do not have epilepsy to have such seizures. Six main causes:
- Idiopathic: 70%
- Genetic: e.g. channelopathies
- Structural: e.g. tuberous sclerosis, cortical malformation, medial temporal lobe epilepsy with hippocampal sclerosis
- Metabolic: e.g. pyridoxine deficiency
- Immune: autoimmune-mediated CNS inflammation e.g. NMDAR antibody encephalitis or VG-K+ channel antibody encephalitis
- Infectious: often has a structural correlate e.g. HIV, TB, cerebral malaria or cerebral toxoplasmosis
Types of epilepsy in children?
Generalised epileptic seizures (both hemispheres + accompanied by LOC)
- Tonic clonic: most common: sudden rigidity, stiffening + muscle contraction followed by rhythmic twitching or muscle jerking: usually last for 1 minute, and EEG shows generalised symmetrical waveform
• Tonic: generalised increased tone
• Atonic: jerk follows sudden loss of tone
• Clonic: rhythmical muscle contraction + subsequent relaxation
• Absence: sudden loss of motor activity which spontaneously recovers – flickering of eyelids, staring, and transient LOC may occur
• Myoclonic: one or several brief arrhythmic muscle jerks, often localised to one body part: neck, trunk or limb, repetitive and spontaneously recovers. Sometimes visible movement of affected region not seen but child can feel shock-like sensation in muscles
Partial epileptic seizures (one hemisphere, do not always cause LOC)
• Focal / simple partial: can be motor, sensory or autonomic (sweating, nausea), or psychic (déjà vu altered mood)
• Complex partial (temporal lobe epilepsy): starts in one region but also affects other regions controlling consciousness – characterised by reduced consciousness and often preceded by aura including automatisms e.g. lip smacking
• Temporal: auditory or sensory disturbances, déjà vu (feeling of familiarity) and jamais vu (feeling of unfamiliarity)
• Occipital: visual disturbance associated with oculomotor signs
• Focal seizure with secondary generalisation
Also: Epilepsy Syndromes: epilepsies presenting with ‘electro-clinical’ pattern of clinical features + characteristic EEGs
Outline West syndrome
Infantile spasms: uncommon but serious form of epilepsy, typically 3-8 months old: ‘salaam attacks’: sudden flexor spasms, bending at waist + nodding head > subsequent arm extension.
Movements last 1-2 secs, often occur in clusters. EEG diagnostic: hypsarrhythmia - chaotic, irregular high amplitude waves + spikes, with background of disorganised + chaotic electrical activity.
Developmental delay or even regression often associated. Also associated with tuberous sclerosis.
Tx options: corticosteroids, ACTH + vigabatrin.
Outline absence epilepsy
Childhood absence epilepsy usually present 4-9 years, girls > boys.
Typical seizure lasts 5-20s, usually involves arrest of movement + awareness, staring into space blankly without loss of tone. Can occur multiple times a day + sometimes associated with purposeless movements of mouth + eyes (eyelid flickering, lip smacking), called automatisms.
Development usually normal but learning may be impaired due to the episodes. Ictal EEG typically shows generalised + bilaterally synchronous 3-per-second spike + wave discharges.
Spontaneous remission often occurs in adolescence.
Ix for epilepsy?
Clinical diagnosis (detailed history, eyewitnesses), but may be supported by:
• Home video recordings
• EEG (support diagnosis + define syndrome)
- sleep deprived EEG or telemetry may be indicated to increase sensitivity (if high clinical suspicion of focal or generalised epilepsies).
- Intracranial EEG gold standard for identifying neuronal activity (+ if surgery being considered, can be used to localise exact epileptogenic zone)
• Imaging
- MRI recommended if epilepsy <2 years + for focal epilepsy, myoclonic epilepsy, intractable seizures, loss of previous good control, continuing seizures despite 1st line medication, associated neurological deficits / evolving neurological signs, developmental regression or infantile spasms
- CT: to identify focal structural defect if focal neurological signs are identified
- fMRI, PET & SPECT not used except in specialist cases – identifies areas of hyperactivity and metabolism in the brain – used to assess brain involvement and plan neurosurgical resections
• Genetic studies: to identify known epilepsy syndromes e.g. gene deletions related to ion channels
Management of epilepsy?
- Education: diagnosis, action plan + emergency plan with relatives + school: recognising + managing seizures, supervision (bathing, swimming, outdoor activities) – driving and future careers important in adolescents
- MDT: always needed for complex epilepsy regardless of developmental needs e.g. epilepsy specialist nurse, consultant neurologist, local paediatrician, educational psychologist, physiotherapist, OT. Successful therapeutic relationships important – adherence often an issue especially in adolescent patients
- AEDs: likely to initiate by specialist after 2nd seizure: depends on type of epilepsy, tolerability of side effects and treatment goal (eliminating vs reducing seizures) > Sodium inhibition, calcium inhibition, GABA effects
Surgical intervention: potential to benefit selected patients e.g. clearly identified focus of activity, mass triggering the seizure, or recurrent seizures causing significant morbidity despite maximal medication therapy o Resection (remove epileptogenic focus) o Multiple subpial transection (cutting nerves in outer layers of brain, preserving vital function concentrated in deeper layers of brain) o Corpus callosotomy: surgery to corpus callosum - contain any seizure in ½ brain
Ketogenic diet: high fat & low carb – intractable epilepsy although mechanism unclear – careful supervision of consultant paediatric neurologist + dietician – can be difficult for children to be adherent
Vagus nerve stimulation: generator implanted under skin below clavicle – connected to thin wire which stimulates vagus nerve at regular intervals to prevent seizures
Deep brain stimulation: fitting a device with neurostimulator that stimulates part of the brain where seizures originate
Outline which AEDs are used for which seizures?
Focal:
- 1st: Carbamazepine or lamotrigine
- Adjunctive: levetiracetam, oxcarbazepine or sodium valproate
Absence
- 1st: ethosuximide or sodium valproate
- 2nd: lamotrigine
Tonic or atonic
- 1st: sodium valproate
- 2nd: lamotrigine
Generalised tonic-clonic
- 1st: sodium valproate
- 2nd: lamotrigine
Myoclonic
- 1st: sodium valproate
- 2nd: levetiracetam or topiramate
Infantile spasms: refer to tertiary paediatric specialist, 1st: corticosteroid or vigabatrin
Complications of epilepsy?
Acute: prolonged, uncontrolled seizure – emergency as can lead to cardiac or respiratory arrest – as seizure becomes more prolonged, increased risk of cerebral damage – seizures also put a child at risk of physical injury from trauma e.g. haematomas, bruising, abrasions, burns
Long-term: small increased risk in mortality, usually related to impaired consciousness – sudden unexpected death in epilepsy (SUDEP) is a risk, particularly in context of uncontrolled seizures or poor compliance – exact mechanism unclear but may relate to cardiac arrhythmias, respiratory arrests or neurogenic pulmonary oedema: anti-epileptic medications come with significant side effects and school absences may be frequent
Prognosis: can depend on type, underlying conditions and structural abnormalities – most children well-controlled seizures and mainstream school, some more complex needs – may require involvement from epilepsy nurse specialist, educational support and support from extended MDT – some childhood epilepsies abate by adulthood.
What is status epilepticus?
Seizure or repeated seizures which last >30 minutes without regaining consciousness. Risk of serious brain injury and respiratory arrest are very high. Senior assistance should be sought immediately and treatment should be escalated.
Management of status epilepticus?
- High flow oxygen, check glucose, ensure patent airway
- IV lorazepam (can give 2nd dose after 10 mins), if no IV access: buccal midazolam
- If persists IV phenytoin (or phenobarbitone if already on), paraldehyde can be given if available while preparing phenytoin
- Rapid sequence induction with thiopentone and intubation
What are breath-holding attacks?
Usually <3 years, (can be age 1-6), provoked by temper or frustration, on getting upset, may hold breathe, go cyanotic and then go limp > loss and regaining of consciousness.
Eyes are closed during episodes (if tonic-clonic seizure, eyes are open). Episodes resolve spontaneously and no intervention is required.
- Cyanotic = most common type (goes blue) – caused by change in breathing usually in response to feeling angry
- Pallid = goes pale, caused by slowing of heart rate often in response to pain
What are reflex anoxic seizures?
vasovagal syncope?
cardiac arrhythmias?
Any age but peak incidence 6 months – 2 years, usually triggered by event e.g. pain, minor head trauma, cold or fever), causing child to have vagal-induced brief cardiac asystole or bradycardia > syncopal episode where turn pale and fall to floor. Subsequent hypoxia may lead to a seizure, which resolves spontaneously.
Children often have a first degree relative with history of fainting.
Vasovagal Syncope
Inadequate cardiac output to brain may lead to brief LOC – often occurs in warm environments or after standing for long periods – seizure can also occur as part of the syncope
Cardiac arrhythmias: may cause collapse or cardiac syncope – prolonged QT may be present on resting ECG, predisposing to ventricular arrhythmia
Infective causes of meningitis?
Spontaneous or with risk factors: immunosuppression (cancer, chemo, HIV, congenital T-cell deficiency, splenic disease), intracranial foreign bodies (cochlear implants, CSF shunts), trauma (may lead to basal skull fracture)
Viral (2/3rds of all cases) - most enteroviruses (self-limiting).
• Others: EBV, adenovirus, varicella zoster virus (VZV), cytomegalovirus (CMV), measles + mumps.
• Herpes simplex: rare but devastating cause of meningoencephalitis, neonates usually acquire during delivery > maternal secretions). Hallmarks: seizures + liver dysfunction.
Bacterial: dramatic changes: Hib, Men C + PCV vaccines
- <3 months: GBS, Escherichia coli, Listeria
- 3 months – 16 years: streptococcus pneumoniae, Neisseria meningitis (meningococcus), Hib
GBS most common cause of bacterial meningitis, septicaemia + infectious death in <3 months. Usually vertically transmitted + can occur up to 6 months. If mother colonised, low threshold to Tx baby prophylactically/
Strep. pneumoniae: any age but usually <5, higher mortality + neurological sequelae
Meningococcus: usually nasopharyngeal mucosa > bloodstream > CNS. If also septicaemia, associated with non-blanching rash (can consist of petechiae and/or purpura).
TB meningitis: rare in countries with low TB incidence + good BCG uptake, higher risk in some UK inner city areas. Can be difficult to diagnose as children often present with vague non-specific symptoms (generally unwell, aches/pains, low grade fever for up to 8 weeks. Usually poorer prognosis because of the late diagnosis).
Fungal: rare, more common in immunocompromised. Cryptococcus most common cause.
Symptoms of meningitis?
All ages: seizures, lethargy, irritability, ↓feeding / off food, ↓ urine output, vomiting / diarrhoea, respiratory distress, Fever not always present, especially in neonates..
Children < 1: high-pitched cry, tense fontanelle, ↓ tone, apnoeas, bradycardias, temperature instability
Older children: headache, neck stiffness, photophobia, confusion, muscle pains, positive Kernig’s sign (knee and hip at 90°, extension of knee is painful), Brudzinski sign (less common – neck flexion causes hip flexion)
Non-infective causes of meningitis?
Rare but often missed and can result in significant morbidity. Symptoms tend to be milder, develop more slowly and fail to respond to antimicrobials.
- Malignancies e.g. leukaemia, lymphoma, CNS tumours
- Chemotherapy
- Autoimmune diseases e.g. Kawasaki’s, SLE, vasculitis + connective tissue disease
Blood tests in meningitis?
FBC (elevated WCC and altered platelets in infection)
U+Es: renal function may be compromised from shock with associated electrolyte disturbances. Low sodium may be secondary to SiADH
LFTs: may have hypoxic injury from shock or be directly infected as classically seen in HSV infection
CRP: elevated indicates infection, may not immediately rise, can also be low as a result of liver dysfunction.
Blood culture • Viral PCR • Meningococcal PCR • Enterovirus can be isolated from stool • Lactate: if >2, can indicate compromised end organ perfusion (note: sepsis and meningitis can occur both separately and concurrently)
- Glucose: sepsis may be associated with hypoglycaemia or hyperglycaemia – aids interpretation of CSF glucose
- Blood gas: low arterial pH with low bicarbonate may show a metabolic acidosis
Ix in meningitis (apart from bloods)?
- CT: always if focal neurological signs or evidence of raised ICP (+ normal CT does not exclude raised ICP). Perform in child with closed fontanelles before LP, but not necessary to exclude raised ICP in neonates as raised ICP is generally prevented by open fontanelles
- Cranial USS: considered in neonates as it may identify any intracranial bleeds – as the fontanelles are open, USS can access the brain
LP: indicated in suspected meningitis to confirm diagnosis, determine Abx sensitivities to any bacteria cultured + length of Tx according to organism.
- Absolute contraindications to LP: signs of raised ICP (relative HTN + bradycardia, focal neurological signs, papilloedema, doll’s eyes or fluctuating level of consciousness). Cardiopulmonary compromise, infection overlying the skin, coagulopathy or thrombocytopaenia.
- WCC, protein level, glucose level + opening pressure give an indication of the aetiology. CSF samples can be sent for bacterial culture, meningococcal and viral PCR. Paired glucose from serum and CSF are necessary to help accurately interpret results.
Additional tests: throat swabs, urine culture (UTI can present very non-specifically, particularly in neonates), sputum culture (if possible respiratory focus), stool culture (if possible GI focus), CXR (if any signs of respiratory distress), ECG (not as frequent in children – may be helpful is suspected arrhythmia e.g. irregular rhythm or persistent tachycardia not responding to fluid resuscitation), EEG if associated seizures
