Neurology

Question 1

GBS

Answer 1

• Acute inflammatory demyelinating polyneuropathy
• Progressive symmetrical ascending weakness with sensory and autonomic instability
• Inx - vasculitic screen, Abs, CXR, MRI, LP for normal WCC and oligoclonal bands, Nerve conduction studies
• search for prodromal infection - bld, stool MC&S
• Mx - steroids, IVIG, PLEX

Question 2

Plasmapheresis and PLEX

Answer 2

Extracorporeal removal of plasma by membrane filtration or centrifugation.
PLEX - replacement with albumin or FFP
30-40mls/kg removed per exchange

Used in:

• GBS
• Myasthenia
• TTP
• Myeloma
• ANCA/Anti-GBM
• Severe SLE

Complications

• Related to vascular access - Infection, haemorrhage, local structures, air embolus
• Related to replacement fluid - Tx reactions, hypothermia, coagulopathy, low Ca

Question 3

CT Heads

Answer 3

DAI - loss of grey-white, loss of sulci, small haemorrhages

Acute subdural - comment on midline shift, ventricle effacement

MCA infarct - MCA syndrome - numerous RCTs show improved mortality but significant morbidity

Question 4

Stroke - thrombectomy

Answer 4

NHS England - 20% improved chance of being functionally independent at 90 days.

Generally treatment best within 6 hrs of onset but with evidence of salvageable brain tissue on imaging this can be done up to 12 hrs or 24hrs in extreme.

Criteria:
1 - Timings as above
2 - Either inadequate response to thrombolysis or thrombolysis contraindicated
3 - Proximal occlusion
4 - NIHSS > 5
5 - Prev idependent (Mod Rankin score < 3)

Question 5

NIHSS

Answer 5

Areas scored: consciousness, vision, sensation, movement, speech and language

Scored 0-42

0 - no stroke
5-15 - moderate stroke
16-20 - mod/severe stroke
21-42 - severe stroke

Question 6

Myasthenia Gravis

Answer 6

Fatiguable weakness
Diff Dx: stroke, ICH, GBS, MND, malignancy
Precipitatants: Surgery, infection, stress events, Meds - macrolides, anminoglyc., BBB, CBB, ketamine

Question 7

Myasthenia Gravis

Answer 7

Fatiguable weakness
Diff Dx: stroke, ICH, GBS, MND, malignancy
Precipitatants: Surgery, infection, stress events, Meds - macrolides, anminoglyc., BBB, CBB, ketamine

Question 8

ICP monitoring

Answer 8

Normal ICP 5-15mmHg
20mmHg - escalate treatment

Causes:
1 - Brain volume - Tumour, oedema
2 - CSF - hydrocephalus
3 - Blood vol - drug induced vasodilation, venous hypertension

Indications ICP monitoring in trauma:
1 - any abnormal CT scan with GCS < 8
2 - GCS < 8 with a normal CT scan if > 40 yrs, SBP < 90, or motor posturing
3 - Mod TBI who need to stay anaesthetised
4 - Multiply injury patient

Contraindications:
All relative - severe coagulopathy, plts < 10, INR >1.3, infection over target area

Methods:
1 - EVD - surgically into ventricle (gold standard, can be calibrated, cheap, therapeutic - infection, traumatic)
2 - Intraparenchymal catheter (less invasive and easier to place, can’t be calibrated, may only measure local ICP, not always MR safe)
3 - ICP bolt - enters subdural space
4 - Transcranial Doppler - poor AUROC

ICP waveform
3 pulse waves P1 = arterial pulse, P2 = cerebral compliance, P3 = aortic valve closure
ICP high then P2 increases

Lundberg A waves - steep increases lasting 10 mins - critically high ICP
Lubbers B waves - oscillations 1-2 every min - unstable ICP
Lundberg C wave - oscillations 4-8 waves/min - healthy

Mx: Osmotherapy - expand plasma, increases CO, improves microcirc, reduces plasma viscosity, secondary osmotic effect with fluid moving from intracelluar to intravascular space

HHS - 1-2mls/kg 3% or 5%
Rpt is Na < 155 and osmol < 320

Ventriculitis
5 - 20%
Reduced with silver impregnated catheters
Intraventricular Abx - sys abx - ceftriaxone/vancomycin
RFs: CSF leak, poor infection control, repeated access

Question 9

Neuroprognostication

Answer 9

Difficult

At 72 hrs, unconscious with M = 1 or 2 and:
1 - Bilateral absent pupils and corneal reflexes
Or
2 - Bilateral absent SSEP N20 ——————————- Poor outcome

Wait 24hrs then:

2 out of the following
 1 - Status myoclonus at < 48 hrs
 2 - High NSE level
 3 - Burst suppression or status on EEG
 4 - CT/MRI showing diffuse anoxic brain injury ———— Poor outcome

Question 10

Disorders or consciousness

Answer 10

Coma - absent wakefulness and absent awareness

Persistent vegetative state - some wakefulness but no awareness

Minimally conscious state - wakefulness with some minimal signs of awareness

Locked-in - wakefulness and awareness but no movement due to brain stem pathology

Question 11

SAH

Answer 11

WFNS classification:
1 - GCS 15, no motor 
2 - GCS 13-14, no motor 
3 - GCS 13-14, motor
4 - GCS 7-12
5 - GCS 3-6

Fisher - based on CT findings - vol blood - correlates with DCI

Complications:
Rebleed
Seizures
DCI - peaks at 4-10 day - nimodipine, hypertension, avoid hypovolaemia 
Hydrocephalus
Adrenergic storm/myocardial dysfunction
Sodium issues

Mx:
Airway control
Ventilation optimised
CVS - BP <160
CT, normothermia, normoglycaemia
Clipping, coiling

ISAT trial - coiling vs clipping - death or dependence less in coiling group at 1 year but long term have an increased risk of re-bleed