Neurology Flashcards
Stroke Mimics (10)
- Structural
- ICH - subdural or Extra-dural
- Brian tumour
- Brain abscess
- Vascular
- Aortic dissection
- Carotid/vertebral artery dissection
- Migraine - Vestibular
- Giant cell arteritis
- Polyarteritis nodosa
- Lupus / vasculitis
- Cerebral Venous sinus thrombosis
- AGE
- Infectious
- Bell’s Palsy
- Labrynthitis
- Vestibular neuronitis
- Demyelination/Peripheral Neuropathy
- Peripheral nerve palsy
- Demyelinating disease - MS
- Meniere’s disease
- Metabolic
- Hypoglycaemia
- Hyponatraemia
- Wernicke’s encephalopathy
- Todd’s paresis
- Toxicological
- Intoxicated states
- Methanol → blindness
Seizure differential
ALWAYS CONSIDER PRE-ECLAMPSIA IN FEMALE!
- Drugs - abuse / accidental / acquired / TOX / intoxication or withdrawal
- Infection - Febrile rigors
- Metabolic - Hypoxia, BSL, Electrolytes, Encephalopathy, Uraemia, TSH
- Environmental - heat stroke, dysbarism,
- Structural - Epilepsy, SOL, SAH, ICH
- Other - pre-eclampsia, syncope, pseudoseizure
HINTS EXAM
PERIPHERAL
- Head impulse abnormal
- Nystagmus unidirectional
- No veritcal skew
- No new hearing loss
CENTRAL
- Head impulse normal
- Nystagmus bidirectional
- Veritcal skew
- May have new hearing loss
Rinne vs Weber
- Weber test: Place the base of a struck tuning fork on the bridge of the forehead, nose, or teeth. In a normal test, there is no lateralization of sound. With unilateral conductive loss, sound lateralizes toward affected ear. With unilateral sensorineural loss, sound lateralizes to the normal or better-hearing side.
- Rinne test: Place the base of a struck tuning fork on the mastoid bone behind the ear. Have the patient indicate when sound is no longer heard. Move fork (held at base) beside ear and ask if now audible. In a normal test, AC > BC; patient can hear fork at ear. With conductive loss, BC > AC; patient will not hear fork at ear.
Bulbar Palsy (7)
LMN lesion - IX, X, XII
- MND
- Syringobulbia
- GBS
- Polio
- Subacute meningitis
- Neurosyphilis
- Brainstem CVA
Pseudobulbar Palsy (5)
UMN lesion - IX, X, XII
- Bilateral Internal Capsul CVA
- MS
- MND
- High brainstem tumour
- Head injury
Bulbar vs Pseudobulbar Palsy
Compare and contrast (14)
BP Targets for CVA
- AIS / TIA <220/120
- AIS with tPA <185/110
- ICH <180/90
- SAH <160/90
Stroke Syndromes
Complete Cord Transection
Total loss of sensory, autnomic and motor function below level of spinal cord injury
Acute or subacute process
Trauma, infarction, haemorrhage and extrinsic compression
Flaccid paralyis
Loss of sensation with sensory level - NO sacral sparing - no perianal sensation, rectal pshincter tone or gt toe movement)
Autonomic dyfsunction
Reflexes can still occur as they are mediated by spinal levels
DTRs - may be lost, present or AbN
Autonomic dysfunction - neurogenic shock, priapism
Urinary retention
Bradycardia, hypotension, hypothermia, ileus
Multiple Sclerosis
Auto-immune demyelinating disorder of brain and spinal cord (CNS)
Relatively sparing of axons
25-30yrs, F:M 2:1, latitude
Very variable clinical presentation
- CN - optic/trigeminal neuraliga
- Spinal cord - transverse myelitis
- Paraesthesia/weakness of limbs
- Bladder urgency, constipation
- Sexual difficulties
- Cerebellar
- Cerebral
- Hemiplegia
- Seizures
- Neuropsych
Dx
- 2 or more discrete episodes evolving over days to weeks
- CSF - Oligoclonal bands (IgG)
- MRI - demyleinating lesions
- Nerve conduction studies
Rx
- Acute exacerbation - IV methylpred 1g daily for optic neuritis / paraplegia / brainstem lesions
- Inhibit progression
- Immunosuppression - methotrexate, azathioprine, mitozantrone
- Immunomodulators - B-interferons, glatiramer, natalizumab
- Rx complications
- Depression / bladder dysfunction, spasticity, tremors
Raised ICP
Normal 5-15mmHg
Raised >20mmHg
CPP = MAP - ICP
When ICP > MAP - brain doesnt get O2
Causes
- Trauma - HI, NAI (kids and elderly)
- Haemorrhage
- Tumours
- Infections
- Extra CSF - ICH
- CVA
Signs/Sx
- GCS < 9
- Fixed dilated pupils
- Cushing’s reflex - SNS activation
- HTN / ↑ widened pulse pressure
- ↓ HR - bradycardia
- ↓ RR
Mx
- Osmotherapy
- Mannitiol 0.5-1g/kg - target 300-320mOsmol/kg
- Hypertonic saline - target 145-155mmol/L
- Surgical
- EVD
- Evacuation of haematoma
- Supportive
- Head up 30 degrees
- Avoid hypoxia, hypercarbia, HTN
- Target PaCO2 35-45mmHg
- Target MAP approx 80
- CPP = MAP - ICP
- Aim CPP > 60mmHg
- Avoid raising ICP - prevent coughing, vomiting
- Decrease cerebral metabolic rate
- Sedation, paralysis
- Treat seizures
- Consider hypothermia
Motor Weakness
Motor Weakness Additional findings
Neuropathy vs myopathy vs NMJ weakness
Bedside Pulmonary Function Tests - GBS and MG
25% with motor weakness due to GBS or MG will need intubation
Consider 20/30/40 rule
FVC < 20mls/kg
MIP < 30cm H2O
MEP < 40cm H2O
Only FVC useful
- likely to need ETT when FVC < 10-15mls/kg
Rule out other causes of respiratory failure
Do NOT chase autonomic dysfunction
Myaesthenia Gravis
Post-synaptic autoimmune disorder
Younger females and older men (bimodal)
Sx
Descending motor power loss
Bulbar symptoms, Ptosis
Sensation, reflexes and pupillary reflexes should be spared
Fatigable and fluctuate
DDx
Lambert-Eaton Syndrome
- pre-synaptic Ca channels
- Improves with activity
Botulism
- Impaired pupillary responses
Ix
Ice test - ice pack over eye for 3 minutes improves ptosis and upward gaze
Tensilon test - IV edrophonium + monitor for improving ptosis and diplopia
Tips
Avoid sux - unpredictable response
Lower doses of roc (0.5mg.kg) due to impaired receptor response
Rx
Physostigmine
Immunosuppression
IVIG
Plasmaphoresis
Treat underlying cause
Electrolyte replacement
MG - drugs to avoid
Aminoglycosides
Fluoroquinolones
BB
MgSO4
SAH - World Federation Neurosurgeons Scale
Most important porgnosticating factors are level of consciousness + level of hemiparesis
Grade I (45%) = GCS 15 + NO motor deficit
Grade II (22%) = GCS 14-13 + NO motor deficit
Grade III (3%) = GCS 14-13 + motor deficit
Grade IV (17%) = GCS 12-7 +/- motor deficit
Grade V (14%) = GCS 6-3 +/- motor deficit
SAH - Hunt and Hess classification
SAH - Fisher Scale
Radiological
Risk of vasospasm
SAH Risk Factors and Complications
Risk Factors
HTN
Smoking
F>M
Previous SAH / Known Aneurysm
CT disorders - PKD, Marfan’s, Ehler’s Danlos
Complications
Immediate
* Neurological deficit
* MI
* APO
Delayed
* Rebleeding
* Vasospasm
* Prevented with nimodipine 60mg q4-6hr PO/NG 1/52
* Hydrocephalus
* Usually communicating
* Hyponatraemia
* Seizures
SAH sites
Seizure + fever differentials
Epilepsy
CNS - meningitis, encephalitis, cerebral abscess
Raised ICP - SOL, cerebral oedema, blocked VP shunt
Febrile seizure
Toxic ingestion
Status Epilepticus Mx Options
Def: seizure > 5 minutes duration OR 2 or more seizures without full recovery in between
1st line
Midazolam
0.15mg/kg IV/IM
2nd line
Levetiracetam 40mg/kg
Valproate 40mg/kg up to 3g
Phenytoin 20mg/kg
3rd line
Phenobarbitone 20mg/kg
Propofol 2.5mg/kg, infusion @ 1-3mg/kg/hr
Thiopentone 2-5mg/kg, infusion @ 1-4mg/kg/hr
Ketamine 1-2mg/kg
Pyridoxine 100mg IV in children < 6mo with refractory seizures
Seizure related Complications
Airway - Hypoxia, aspiration
Injury - fractures, Avulsions of bone/tendons, tongue laceration, posterior shoulder dislocation
Metabolic - hypoglycaemia, hyperthermia, lactic acidosis, rhabdomyolysis
CNS - Todd’s paresis, Neuronal damage (prolonged)
LP Contra-indications
Absolute
- GCS <8 or deteriorating/fluctuating level of consciousness
- Signs raised ICP
- A bulging fontanelle + raised ICP
Relative
- Septic shock or haemodynamic compromise
- Significant respiratory compromise (eg apnoeas in a baby)
- New focal neurological signs or seizures
- Seizure within previous 30 min +/- normal conscious level has not returned following a seizure
- INR >1.5 or platelets <50 or child on anticoagulant medication
Complications
- Failure to obtain a specimen/traumatic bloody tap (common)
- Post-dural puncture headache (uncommon) 5-15%
- Transient/persistent paraesthesia/numbness (very uncommon)
- Respiratory arrest from positioning (rare)
- Infection introduced by needle causing meningitis, epidural abscess or osteomyelitis (very rare)
- Spinal haematoma (very rare)
- Brain herniation (extremely rare in the absence of contraindications above)
CVA + Speech deficits
Speech area Left side of brain
- 99% right handed
- 70% left handed
L hemisphere → dyphasia
R hemisphere → neglect, visuo-spatial + cognitive problems
Wernicke’s area = posterior first temporal gyrus →expressive dysphasia
Broca’s = posterior third frontal gyrus
→ receptive dysphasia
Diplopia
Critical
- Basilar artery thrombosis
- Botulism
- Basilar meningitis
- Aneurysm
Emergent
- Vertebral dissection
- MG
- Wernicke’s encephalopathy
- Orbital Apex syndrome / Cavernous sinus process
Urgent
- Brainstem Tumour
- Miller-Fischer syndrome
- MS
- Thyroid myopathy (Grave’s)
- Ophthalmoplegic migraine
- Ischaemic Neuropathy
- Orbital Myositis
- Orbital Apex Mass
Internuclear ophthalmoplegia
Def = inability to perform conjugate lateral gaze
Pathophysiology
Damage to the interneuron (level of MLF) between 2 nuclei of CN III and CN VI at the level of the midbrain or pons
Mechanism:
Demyelination
Ischaemia - basilar artery supply
Neoplastic
Inflammatory
CN VII Palsy
Peripheral
- Infective - HSV, HZV, CMV, EBV, AOM
- Trauma - base skull
- Neurological - MS, GBS, mononeuropathy
- Neoplastic - post fossa, parotid
- Autoimmune - Sjogren’s
- HTN + eclamplsia
- Melkersson’s syndrome
Central
- CVA
- Intra-cranial tumours
- MS
- HIV
- Vasculitides
Conus medullaris vs Cauda Equina Syndrome
Dermatomes
Myotomes
C4: shoulder shrugs
C5: shoulder abduction and external rotation; elbow flexion
C6: wrist extension
C7: elbow extension and wrist flexion
C8: thumb extension and finger flexion
T1: finger abduction
L2: hip flexion
L3: knee extension
L4: ankle dorsiflexion
L5: big toe extension
S1: ankle plantarflexion
S4: bladder and rectum motor supply
Incomplete Cord Syndromes
Sensory - Ascending Tracts
Anterolateral tract
- fibres cross at level of input
- sacral > trunk > cervical (lateral to medial)
Anterior spinothalamic tract (light touch and pressure pathway)
Lateral spinothalamic tract (pain and temperature pathway)
Dorsal Columns
Touch, pressure, vibrations, proprioception
Cross at medulla
Sacral fibres medial, cervical fibres lateral
Motor
Lateral Corticospinal tract (80%)
Distal limb muscles
Fine motor
Fibres corss in spinal cord
Cervical medial, lumbar lateral
Ventral Corticospinal Tract (20%)
Axial and proximal limb muscles
Postural and gross limb movements
Descends ipsilaterally and does not cross until level of synapse with LMN
Anterior Cord Syndrome
Common following diving injury, flexion injuries
Injury:
- bonu impaction into cord
- anterior spinal artery injury or thrombosis
Symptoms
Loss of motor, pain and tmeeprature sensation below lesion
Light touch and proprioception preserved
Prognosis: poor
Central Cord Syndrome
Brown-Sequard Syndrome
Head Injury Risk Comparison
Head injury High Risk Features
SAH CT head features
Ix SAH
Key points
CT within 6 hours effectively rules out diagnosis
LP may be useful when presentation is delayed
- CSF blood is the hallmark feature of SAH, but may be difficult to distinguish from a traumatic tap
- CSF xanthochromia is a more specific finding for SAH, however takes >12 hours to manifest
- Xanthochromia from a SAH is nearly always accompanied by more than 1000 RBCs in the CSF (usually > 10000)
Traumatic Tap vs SAH
Traumatic tap occurs in 20% of LP’s
Traumatic tap and SAH may co-exist
None of the following criteria are 100% accurate
- Normal CSF CSF pressure
- Clearing of blood in tubes 1-3 / marked decrease in RBC count in tubes 1 to 3
- Proportion of white cells to red cells the same as in blood - i.e. RBC:WBC = 500 - 1,000:1
- Clot formation
- No xanthochromia
DDx Thunderclap Headache
More common:
1. SAH (subarachnoid hemorrhage)
2. RCVS (reversible cerebral vasoconstriction syndrome)
3. Acute hypertensive crisis
4. Cervical artery dissection (carotid or vertebral)
5. CCVT (cerebral venous thrombosis)
6. ICH (intracerebral hemorrhage)
7. Benign Post Coital HA
8. Benign post exertional headache
9. Pituitary apoplexy
10. Ischemic stroke
11. Primary thunderclap headache.
Rarer causes: (LaHue 2021)
Spontaneous intracranial hypotension.
Cerebral vascultiis.
Sphenoid sinusitis.
Aqueductal stenosis.
Colloid cyst of the third ventricle.
Giant cell arteritis.
Cardiac cephalgia (pain referral related to myocardial ischemia).
Cervical Artery DIssection
Spinal vs Neurogenic Shock
Vertigo Causes
Peripheral vs Central Vertigo
