Neurology Flashcards
Define of meningitis
Inflammation of arachnoid mater, pia mater and CSF
Viral
- enteroviruses
- HSV
- VZV
- HIV
Bacterial
- neonates - Streptococcus agalactiae, Haemophilus influenzae type B
- childhood - Neisseria meningitidis, strep pneumoniae
Pathophysiology of meningitis
Increased cytokines
Increased permeability of the blood-brain barrier
Cerebral vasculature vasodilation -> reduced perfusion pressure -> ischaemia
Cerebral oedema
Raised ICP
Risk factors for meningitis
Maternal infection Splenectomy PROM Not immunised Low birthweight CSF shunt Prematurity Immunocompromised
Clinical features of meningitis
Meningeal irritation
- neck stiffness, photophobia, Brudzinski sign, Kerning sign, seizures
Raised ICP + cerebral oedema
- altered consciousness, N+V, reduced GCS, bulging fontanelles, papilloedema
Cytokine release
- rigors, headache, fever
Meningococcal septicaemia
- hypovolaemia, non-blanching rash, reduced BP, increased HR, petechiae and purpura
Brudzinski sign
Child is supine
Passively flex their neck and they have reflex flexion of their hips
Kering sign
Patient supine
Passively flex hip and knee to 90
Passively straighten knee - produce pain along the spine
Ix for meningitis
Blood cultures FBC CRP Renal profile Lumbar puncture - gold standard but contraindicated if features of raised ICP - need plasma sample to compare too
Features of CSF in meningitis
Bacterial - turbid appearance - neutrophils present - high protein content - low glucose content Viral - clear appearance - lymphocytes present - normal or slightly raised protein content - normal or slightly low glucose content
Mx of meningitis
ABCDE appearance
Empirical abx IV
IV corticosteriods - if > 3 months of age
Complications of meningitis
Ataxia Abscess DIC Epilepsy Paralysis Deafness
Pathophysiology of febrile convulsions
Seizure that is associated with fever
- unrelated to other pathology
Epidemiology of febrile convulsions
Between 1 and 5 years of age 1 in 2o will suffer febrile convulsions
- reoccur in 1/3 children
- should not happen > 5 years old
Clinical features of febrile convulsions
Preceding febrile illness must be evident
Generalised tonic-clonic seizure - lasting about 5 mins
No features of meningitis, encephalitis or sepsis
Full recovery < 1 hour
Ix for febrile convulsions
Clinical diagnosis
Mx for febrile convulsions
Manage fever Managed at home Do not restrain - fracture risk Nothing in mouth Recovery position after Call 999 is last longer than 5 mins Give rectal diazepam or oral midazolam if last longer than 5 mins
Define epilepsy
Enduring predisposition to generating unprovoked seizures
- 2+ unprovoked seizures occurring > 24 hours apart
- 1 unprovoked seizures and probability of further 2 seizures in next 10 years
- diagnosis of epilepsy syndrome
Pathophysiology of epilepsy
Increased activation or decrease inhibition of neurones can lead to imbalance creating overall net excitation -> paroxysmal discharge
Brain region affected dictates symptoms associated with seizures
Brain regions affected by epiepsy
Frontal lobe
- motor cortex - movement impairment
- frontal cortex - emotional/cognitive change
Temporal lobe
- auditory cortex - ringing or hissing/hearing music
- Wernicke’s area - dysphagia
- olfactory area - unusual taste or smell
- superior temporal gyrus - automatisms, lip smacking, chewing
Parietal
- sensory cortex - sensory disturbance
Occipital
- visual cortex - flashes, scotoma or blurring
Limbic
- amygdala, thalamus and hypothalamus - autonomic dysfunction
Types of epilepsy
Focal onset - motor - non-motor Generalised onset - awareness always impaired - motor - non-motor (absence) Unknown onset - motor - non-motor
Risk factors for epilepsy
Learning disability 1st degree relative affected Idiopathic Genetic syndromes - tuberous sclerosis Metabolic disease Mitochondrial disease Intracranial infection Post-traumatic Electrolyte disturbance
Diagnosis of epilepsy
Childhood absence
- 10% of childhood epilepsy
- frequent absence seizures with onset around 6 years
Juvenile myoclonic epilepsy
- 5%
- onset in adolescence
- characterised by myoclonic, tonic-clonic and absence seizures
Definitions of seizures
Tonic - stiffness in limbs
Clonic - sustained rhythmical jerking of limbs
Tonic-clonic - initial stiffening followed by jerking
Atonic - sudden loss of muscle tone so child falls on floor
Myoclonic - brief muscle jerk
Automatisms - repetitive, purposeless actions
Mx of epilepsy
Anti-epileptic drugs
- focal seizures - carbamazepine or lamotrigine
- generalised tonic-clonic seizures - sodium valproate or lamotrigine
- absence - ethosuximide of sodium valproate
- myoclonic - sodium valproate
- tonic or atonic - sodium valproate
Side effects of sodium valproate
Ataxia Liver failure Pancreatitis Reversible hair loss Oedema Appetite increased Teratogenic Thrombocytopenia Enzyme (CYP450) inhibitor
