Miscellaneous Neurological Conditions

Question 1

What is Hydrocephalus?

Answer 1

Accumulation of CSF is due to an imbalance between production and absorption of CSF with subsequent enlargement of brain ventricles.

Question 2

How is hydrocephalus classified?

Answer 2

Non-communicating/Obstructive – CSF is obstructed within the ventricles or between the ventricles and the subarachnoid space. Most commonly due to tumours e.g. meningioma, haemorrhage (subarachnoid or intraventricular) and developmental abnormalities e.g. aqueduct stenosis.

Communicating - there is communication between the ventricles and the subarachnoid space. The problem lies outside of the ventricular system. Due to reduced absorption or blockage of the venous drainage system. It may also be due to increased CSF production. Causes include choroid plexus tumours (very rare) or failure of absorption due to meningitis or post-haemorrhagic.

Question 3

What are the clinical features of hydrocephalus?

Answer 3

Present with symptoms of raised ICP 
Headache, worst when lying down, in the morning, bending over or coughing/sneezing
Nausea and Vomiting 
Papilloedema 
Comatose

In children
Increase in skull size/bulging fontanelles
Sunsetting eyes due to compression of the midbrain

Question 4

What investigations should be done in patients with suspected hydrocephalus

Answer 4

CT head
MRI if more detail required
Lumbar puncture and opening pressure (also therapeutic if pressure is high in the column). Note LP is contraindicated if there is obstructive hydrocephalus as it could cause herniation.

Question 5

How can hydrocephalus be managed?

Answer 5

External ventricular drain (EVD) in acute severe hydrocephalus – inserted into the right lateral ventricle and drains into a bag at the bedside 
Ventriculoperitoneal shunt (VPS) – long term CSF diversion technique draining CSF from the ventricles into the peritoneum
Treating cause if there is an obstruction

Question 6

What is CJD?

Answer 6

Prion disease – misfolded protein that self-propagates other properly folded proteins. These misfolded proteins lead to spongiform changes (tiny cavities and tubulovesicular structures).

Question 7

Describe the different types of CJD

Answer 7

Sporadic – most common

Variant – 225 cases worldwide which is transmitted via contaminated CNS tissue affected by bovine spongiform encephalopathy

Inherited forms – Gerstmann-Straussler-Scheinker syndrome due to a mutation in the PRNP gene causing the protein to be so unstable it readily transforms into PrPSc.

Iatrogenic causes – CJD can be passed on via contaminated surgical instruments, corneal transplants, growth hormone from human pituitaries, and in variant CJD blood products because the prion resists sterilisation.

Question 8

What are the clinical features of CJD?

Answer 8

Progressive dementia with focal CNS signs
Myoclonus (95% of cases)
Depression
Eye signs (diplopia, supranuclear palsies, complex visual disturbances, homonymous field defects, hallucinations, cortical blindness)

Question 9

How is sporadic CJD distinguished from variant CJD?

Answer 9

Distinguishing Varied form Sporadic
Earlier age at presentation 29yrs for varied vs 60 in sporadic
Longer survival and later dementia 14months for varied vs 4 months for sporadic
More normal EEG – sporadic has a characteristic EEG - high amplitude sharp waves
Mean CSFtaupT181/Tau protein ratio is 10 fold higher in vCJD than sCJD

Question 10

What investigations are required in CJD?

Answer 10

Tonsil/olfactory mucosal biopsy
CSF gel electrophoresis
MRI showing hyperintense signals in the basal ganglia and thalamus

Question 11

How is CJD managed?

Answer 11

No proven treatment, death usually occurs within 6 months in sporadic and a little slower in variant

Question 12

What is spontenous intracranial hypotension (SIH)?

Answer 12

Sudden leak of cerebral spinal fluid

Question 13

Who does SIH occur in?

Answer 13

Usually occurs around the age of 40 and women are twice as likely then men to develop it.

Unless iatrogenic then the cause is unknown, but the leak usually occurs from the thoracic nerve root sleeves. The main risk factor is Marfan’s syndrome.

Question 14

What are the clinical features of SIH?

Answer 14

Orthostatic headache (only present when stood upright) so often bed bound
Neck pain and stiffness
Nausea and vomiting
Dizziness
Fatigue
Metalic taste in the mouth (indicating a cranial leak)

Question 15

How should SIH be investigated?

Answer 15

CT and MRI with gadolinium

Question 16

How is SIH managed?

Answer 16

Epidural blood patch – (insertion of blood into the leak which clots preventing the leak.
Surgical procedures such as fibrin glue or Lumbar drain

Question 17

What complications can occur from spontaneous intracranial hypotension?

Answer 17

Brain herniation
Infection
Coma

Question 18

What is normal pressure hydrocephalus?

Answer 18

This is a unique form of non-obstructive hydrocephalus characterised by large ventricles but normal intracranial pressure. The classic triad of symptoms is dementia, incontinence, and disturbed gait.

It is thought around 60% of patients will have all 3 features at the time of diagnosis. Symptoms typically develop over a few months.

Question 19

What is seen on CT imagine in normal pressure hydrocephalus?

Answer 19

Hydrocephalus with an enlarged fourth ventricle in addition to the ventriculomegaly there is typically an absence of substantial sulcal atrophy

Question 20

How is normal pressure hydrocephalus managed?

Answer 20

Ventriculoperitoneal shunting
Around 10% of patients who have shunts experience significant complications such as Seizures, infection, and intracerebral haemorrhages