Neurology

Question 1

Where is CSF produced?

Answer 1

choroid plexus of ventricles

Question 2

How is CSF obtained?

Answer 2

Lumbar puncture

Question 3

What is the normal pressure for CSF?

Answer 3

Normal 10-18cmH2O if on side

20-30cmH20 if sitting up

Question 4

What investigations are carried out with CSF?

Answer 4

Biochemistry
Microscopy
Culture
PCR

Question 5

What pathologies can be identified with CSF?

Answer 5

High pressure
Infection
Inflammation
Occult Bleeding (SAH)

Question 6

What are CSF findings of bacterial meningitis?

Answer 6

Pressure: Elevated
Appearance: Turbid
Protein: Elevated
Glucose: Low

Question 7

What are CSF findings of viral meningitis?

Answer 7

Pressure: Normal
Appearance: Clear
Protein: elevated
Glucose: normal

Question 8

What are CSF findings of fundal/TB meningitis?

Answer 8

Pressure: Elevated
Appearance: Clear/fibrin web
Protein: elevated
Glucose: low

Question 9

SAH - CSF findings

Answer 9

Pressure: Elevated
Appearance: Xanthochromia, bloody, or clear
Protein: elevated
Glucose: normal

Question 10

Indications for Lumbar Puncture

Answer 10

1. Diagnosis of meningitis and encephalitis
2. Diagnosis of other neurological conditions
   - -> MS, neurosyphilis, GBS, Sarcoid etc…
3. Diagnosis of SAH
4. Measurement of CSF pressure (intracranial hypertension)
5. Therapeutic removal of CSF

Question 11

Contraindications of LP

Answer 11

1. Suspicion of mass lesion in brain or spinal cord
   - -> May cause coning
2. Raised intracranial pressure
   - -> Headache, nausea, vomiting, hypertension, low GCS, acute confusion, diplopia, unreactive pupils, papilloedema
3. Local infection near site of puncture
4. Congenital spinal problems
   - -> Spina bifida
5. Low platelets (<40), coagulopathy, anticoagulants

Question 12

Procedure of LP

Answer 12

1. Informed consent, patient prepped and toileted
2. Patient in L lateral, foetal position
3. Identify 2nd and 3rd or 3rd and 4th interlumbar spaces
4. Mark and sterilise area. Local
   anaesthetic to skin
5. Spinal needle into midline of back towards umbilicus
6. Penetrate Dura (feels a give/squish/squelch/crunch)
7. Measure opening CSF pressure (using manometer) if indicated
8. Collect 3 sequential samples (5-8 drops each)
9. Get Blood Glucose as well as
10. CSF Glucose sample
11. Needle out, Dressing
12. Lie patient flat for 1 hour

Question 13

Complications of LP

Answer 13

BAD:

• Cerebral and Spinal Herniation
• Spinal Infection
• Bleeding and spinal haematoma

NOT BAD:
Nerve irritation
Dural tap Headache
- Most common but not so bad
- Drinks lots of water and caffeine
- Epidural blood patch

Question 14

Examples of Nerve tests

Answer 14

1. Nerve Conduction Studies (NCS) – tests electrical conduction down specific nerves
2. Needle Electromyography (EMG) – measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle

These usually happen in conjunction with each other

Question 15

Indications for Nerve Tests

Answer 15

1. Carpal tunnel syndrome, Cubital Tunnel Syndrome, Guillain–Barré syndrome, Guyon’s canal syndrome, peripheral neuropathy, Peroneal neuropathy, Spinal disc herniation, Tarsal Tunnel Syndrome, Ulnar neuropathy
2. Peripheral sensory problem
3. Peripheral motor problem

Question 16

Contraindication for Nerve Test

Answer 16

Fairly low risk

- Anticoagulation

Question 17

Complication of Nerve Test

Answer 17

Risk of infection/bleeding/pain

Damaging underlying structures or the nerves

Question 18

Indications for brain radiology

Answer 18

Imaging of Bone
Imaging of Brain
Imaging of Blood vessels
Imaging of everything else

Question 19

Types of brain radiology

Answer 19

Xray – Rarely done
CT – Most common	
MRI – Most detailed
USS – In children/Optic sheath for RICP
Others
-->PET/Angio/Isotope

Question 20

What is a CT?

Answer 20

Xray beam moves in a circle forming a cross-sectional view of the body.

Different attenuation of bone, brain, blood and soft tissues.

Pictures can be manipulated and viewed in different planes.

Question 21

Types of CT

Answer 21

1. Non-contrast – no dye given. Good for bone and bleeding.
2. Contrast – Given IV dye and timed to allow dye to diffuse around tissues. Useful for distinguishing soft tissue.
3. Angiogram – Given dye and CT done at specific timing to show blood passing through arteries.

Question 22

WHAT DENSITY IS ACUTE BLOOD ON CT head?

Answer 22

Hyperdense (bright white)

Old blood - hypodense

Question 23

What is CT head good for?

Answer 23

Tumours (>1cm)
Intracerebral Haemorrhage and Infarction
Sub- and extradural haematoma
Sub arachnoid bleed
Lateral shift of structures and ventricular dilatation
Atrophy
Bones

Question 24

Risks & contraindications for CT

Answer 24

Radiation

• > Pregnancy
• > Young
• > Women

Contrast

• > Allergy
• > Renal impairment

Question 25

What is MRI?

Answer 25

Uses powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. A radiofrequency current is then pulsed through the patient and the protons are stimulated, spinning out of equilibrium, straining against the pull of the magnetic field. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. Using this information, the body can be imaged in multiple planes.

Question 26

Types of MRI

Answer 26

Non contrast Contrast (gadolinium) – generally safe (?renal problems) MR Angiogram MR Venogram

Question 27

Risks and Contraindications | of MRI

Answer 27

People with pacemakers/metalwork/foreign bodies Non compliant patient IV contrast

Question 28

How many hours post-headache starting do you perform LP?

Answer 28

12 hours

Question 29

2WW referral for Neuro

Answer 29

Consider an urgent, direct access, MRI scan of the brain (or CT scan if MRI is contraindicated; to be done within 2 weeks) to assess for brain or central nervous system cancer in adults with progressive, sub‑acute loss of central neurological function.