Misc Neurosurgery

Question 1

Approach to VP shunt malfunction:

Answer 1

PROXIMAL
- Infection (most)
- Obstruction with parenchyma, choroid, cells etc.
DISTAL
- Malposition
- Disconnection
- Fracture

Approach:
- Sit up 30 deg, other neuroprotective
- CTB
- Shunt series XR
- Maintain CPP
- NSx for shunt revision

If coning:
- USUAL raised ICP management
- Can try draining (not aspirating) reservoir, but won’t work if proximal occlusion

Question 2

Types of cerebral herniation:

Answer 2

SUBFALCINE
- Cingulate gyrus
through
- Falx cerebri

UNCAL
- Temporal lobe
through
- Tentorium
Either laterally (uncal, 3rd nerve palsy) or centrally

TONSILLAR
- Cerebellar tonsils
through
- Foramen Magnum
—> Compresses brainstem + CSF flow

Question 3

Cushing’s Triad

Answer 3

1- Bradycardia
2- Irregular resps
3- WIDENED PULSE PRESSURE
–> Systolic hypertension, while diastolic drops

Question 4

Signs of brain herniation:

Answer 4

Cushing triad

+
3rd nerve palsy (uncal)
Coma
Respiratory arrest
Fixed, dilated pupils

Question 5

Central venous sinus thrombosis (CVST)

Answer 5

Clots in VEINS (incl jugular) or DURAL SINUSES of brain
–> Raised ICP
–> Venous infarct
–> Haemorrhagic transformation

Rare, with nonspecific symptoms.
Need high index of suspicion

CLINICAL
- Young women
- Headache- variable ++ in nature!
- Focal deficits
- Non-specific, raised ICP stuff
–> incl. blurred vision, weakness, diplopia. seizure, ALOC etc.

Dx
- MR venogram best
- CT venogram good

Tx
- Anticoagulate (heparin –> warf/NOAC) even when transformation

+- catheter lysis, thrombectomy, craniotomy

Question 6

Normal ICP:

Answer 6

5-15
>20 needs Tx
>40 urgent + life threat

<7 in child <8yo

Question 7

CT signs of cerebral oedema:

Answer 7

Loss of grey/white diff

If 2 raised ICP:
Effacement of:
- Cisterns (ext)
- Ventricles (int)
Midline shift

Specify: local or diffuse

Question 8

Clinical features raised ICP:

Answer 8

Rapid change in GCS (>2)
Anisicoria
Headache (worse head-down)
Seizure
Cranial nerve signs
(Papilloedema)

Question 9

Evolution of blood appearance on CT over time:

Answer 9

HYPERdense
—> 2 days - 2weeks: ISOdense
—> HYPOdense

Question 10

DDx ring-enhancing brain lesion:

Answer 10

Non-enhancing: oedema, post-stroke

Abscess
Cyst
Malignancy
Tuberculoma
Cryptococcoma
Granuloma
CNS lymphoma (HIV)
Cerebral toxoplasmosis (HIV)
Radiation necrosis