Neuro emergencies

Question 1

What is Guillain-barre syndrome

Answer 1

Disorder causing demyelination and axonal degeneration resulting in acute, ascending and progressive neuropathy, characterised by weakness, paraesthesiae and hyporeflexia.

Question 2

What is GBS usually preceded by

Answer 2

75% of patients have a history of preceding infection, usually of the respiratory and gastrointestinal tract.

A large number of infections have been linked, including Campylobacter jejuni, Epstein Barr virus, cytomegalovirus, mycoplasma and human immunodeficiency virus

Question 3

Risk factors for GBS

Answer 3

History of gastrointestinal or respiratory infection from 1-3 weeks prior to the onset of weakness.
Recently, an association has been suggested with the Zika virus

Vaccinations: live and dead vaccines have been implicated.

Malignancies - eg, lymphomas, especially Hodgkin’s disease.

Pregnancy: incidence decreases during pregnancy but increases in the months after delivery.

Question 4

Presentation of GBS

Answer 4

Weakness 
Pain 
Areflexia 
sensory symptoms 
autonomic symptoms

Question 5

Weakness in GBS

Answer 5

In 60% of cases, onset occurs approximately three weeks after a viral illness.

The condition usually presents with an ascending pattern of progressive symmetrical weakness, starting in the lower extremities.

This reaches a level of maximum severity two weeks after initial onset of symptoms and usually stops progressing after five weeks.

Facial weakness, dysphasia or dysarthria may develop.

In severe cases, muscle weakness may lead to respiratory failure.

Question 6

Pain in GBS

Answer 6

neuropathic pain may develop, particularly in the legs. Back pain may be another feature.

Question 7

Sensory symptoms in GBS

Answer 7

These can include paraesthesiae and sensory loss, starting in the lower extremities.

Question 8

Autonomic symptoms in GBS

Answer 8

Involvement of the autonomic system may present, with reduced sweating, reduced heat tolerance, paralytic ileus and urinary hesitancy.

Severe autonomic dysfunction may occur.

Question 9

Features of GBS on examination

Answer 9

Hypotonia.
Demonstrable altered sensation or numbness.
Reduced or absent reflexes.
Fasciculation may occasionally be noted.
Facial weakness - may be asymmetrical.
Autonomic dysfunction - fluctuations of heart rate and arrhythmias, labile blood pressure and variable temperature.
Respiratory muscle paralysis.

Question 10

What might a lumbar puncture show in GBS

Answer 10

Most patients have an elevated level of cerebrospinal fluid (CSF) protein, with no elevation in CSF cell counts. The rise in the CSF protein may not be seen until 1-2 weeks after the onset of weakness.

Question 11

What is a major determinant of need for admission to ITU in GBS

Answer 11

Spirometry - forced vital capacity

Question 12

Management of GBS

Answer 12

Plasma exchange
IV immunoglobulins
Corticosteroids
DVT prophylaxis

Question 13

Complications of GBS

Answer 13

Persistent paralysis 
Respiratory failure requiring mechanical ventilation 
Hypotension or hypertension 
Thromboembolism 
Cardiac arrhythmia 
Ileus

Question 14

What is myasthenia gravis

Answer 14

Autoimmune condition that causes muscle weakness that gets progressively worse with activity and improves with rest

Question 15

Which tumours are associated with myasthenia gravis

Answer 15

Strong link between thymoma

10-20% of patients with myasthenia gravis have a thymoma. 20-40% of patients with a thymoma develop myasthenia gravis.

Question 16

Pathophys of myasthenia gravis

Answer 16

In around 85% of patients with myasthenia gravis, acetylcholine receptor antibodies are produced by the immune system.

These bind to the postsynaptic neuromuscular junction receptors which blocks the receptor and prevents the acetylcholine from triggering muscle contraction. As the receptors are used more during muscle activity, more of them become blocked up.

This leads to less effective stimulation of the muscle with increased activity. There is more muscle weakness the more the muscles are used. This improves with rest as more receptors are freed up for use again.

Question 17

Presentation of myasthenia gravis

Answer 17

Most affect proximal muscles and small muscles of head/neck

Extraocular muscle weakness causing double vision (diplopia)

Eyelid weakness causing drooping of the eyelids (ptosis)

Weakness in facial movements

Difficulty with swallowing

Fatigue in the jaw when chewing

Slurred speech

Progressive weakness with repetitive movements

Question 18

How can fatiguability of muscles be elicited on examination

Answer 18

Repeated blinking will exacerbate ptosis

Prolonged upward gazing will exacerbate diplopia on further eye movement testing

Repeated abduction of one arm 20 times will result in unilateral weakness when comparing both sides

Question 19

Diagnosis of myasthenia gravis

Answer 19

Acetylcholine receptor (ACh-R) antibodies (85% of patients)
Muscle-specific kinase (MuSK) antibodies (10% of patients)
LRP4 (low-density lipoprotein receptor-related protein 4) antibodies

Question 20

What is the edrophonium test

Answer 20

Patients are given an IV dose of edrophonium chloride (or neostigmine).

Normally, cholinesterase enzymes in the neuromuscular junction break down acetylcholine.

Edrophonium block these enzymes and stop the breakdown of acetylcholine.

As a result the level of acetylcholine at the neuromuscular junction increases. It briefly and temporarily relieves the weakness. This establishes a diagnosis of myasthenia gravis.

Question 21

Treatment of myasthenia gravis

Answer 21

Reversible acetylcholinesterase inhibitors (usually pyridostigmine or neostigmine) increases the amount of acetylcholine in the neuromuscular junction and improve symptoms

Immunosuppression (e.g. prednisolone or azathioprine) suppresses the production of antibodies

Thymectomy can improve symptoms even in patients without a thymoma

Question 22

Use of monoclonal antibodies in myasthenia gravis

Answer 22

Rituximab is a monoclonal antibody that targets B cells and reduces the production of antibodies. It is available on the NHS if standard treatment is not effective and certain criteria are met.

Eculizumab is a monoclonal antibody that targets complement protein C5. This could potentially prevent the complement activation and destruction of acetylcholine receptors. There is ongoing research and debate about whether the evidence is strong enough to offer it on the NHS. It is currently not recommended by NICE.

Question 23

What is a myasthenic crisis

Answer 23

Severe complication of myasthenia gravis. It can be life threatening. It causes an acute worsening of symptoms, often triggered by another illness such as a respiratory tract infection. This can lead to respiratory failure as a result of weakness in the muscle of respiration.

Question 24

Management of myasthenic crisis

Answer 24

Non-invasive ventilation with BiPAP or full intubation and ventilation

Medical treatment is with immunomodulatory therapies such as IV immunoglobulins and plasma exchange

Question 25

Definition of TIA

Answer 25

A transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.

Question 26

Clinical features of TIA

Answer 26

The clinical features are similar to those of a stroke, i.e. sudden onset, focal neurological deficit but, rather than persisting, the features resolve, typically within 1 hour. ``` unilateral weakness or sensory loss. aphasia or dysarthria ataxia, vertigo, or loss of balance visual problems sudden transient loss of vision in one eye (amaurosis fugax) diplopia homonymous hemianopia ```

Question 27

Immediate pharmacological management of TIA

Answer 27

give aspirin 300 mg immediately, unless 1. the patient has a bleeding disorder or is taking an anticoagulant (needs immediate admission for imaging to exclude a haemorrhage) 2. the patient is already taking low-dose aspirin regularly: continue the current dose of aspirin until reviewed by a specialist 3. Aspirin is contraindicated: discuss management urgently with the specialist team

Question 28

Advice regarding specialist review for TIA

Answer 28

if the patient has had more than 1 TIA ('crescendo TIA') or has a suspected cardioembolic source or severe carotid stenosis: discuss the need for admission or observation urgently with a stroke specialist If the patient has had a suspected TIA in the last 7 days: arrange urgent assessment (within 24 hours) by a specialist stroke physician if the patient has had a suspected TIA which occurred more than a week previously: refer for specialist assessment as soon as possible within 7 days

Question 29

IX for TIA

Answer 29

CT brains should not be done 'unless there is clinical suspicion of an alternative diagnosis that CT could detect' MRI (including diffusion-weighted and blood-sensitive sequences) is preferred to determine the territory of ischaemia, or to detect haemorrhage or alternative pathologies it should be done on the same day as specialist assessment if possible Carotid doppler

Question 30

1st line antithrombotic therapy for patients who have had a stroke

Answer 30

Clopidogrel otherwise aspirin + dipyridamole

Question 31

When should carotid endarterectomy be considered in TIA/Stroke management

Answer 31

recommend if patient has suffered stroke or TIA in the carotid territory and are not severely disabled should only be considered if carotid stenosis > 70% according ECST* criteria or > 50% according to NASCET** criteria

Question 32

Features of SCC

Answer 32

``` Back pain the earliest and most common symptom may be worse on lying down and coughing lower limb weakness sensory changes: sensory loss and numbness ```

Question 33

Type of motor neurone signs exhibited by lesions above L1 in SCC

Answer 33

Lesions above L1 usually result in upper motor neuron signs in the legs and a sensory level.

Question 34

Type of motor neurone signs exhibited by lesions below L1 in SCC

Answer 34

Lesions below L1 usually cause lower motor neuron signs in the legs and perianal numbness. Tendon reflexes tend to be increased below the level of the lesion and absent at the level of the lesion

Question 35

IX for SCC

Answer 35

Whole MRI spine within 24 hrs of presentation

Question 36

MX of SCC

Answer 36

High-dose oral dexamethasone | urgent oncological assessment for consideration of radiotherapy or surgery

Question 37

Presentation of brain tumours

Answer 37

Dependent on location | Symptoms and signs of raised ICP

Question 38

Causes of raised ICP

Answer 38

Brain tumours Intracranial haemorrhage Idiopathic intracranial hypertension Abscesses or infection

Question 39

ICP presenting features

Answer 39

Nocturnal Worse on waking Worse on coughing, straining or bending forward Vomiting ``` Altered mental state Visual field defects Seizures (particularly focal) Unilateral ptosis Third and sixth nerve palsies Papilloedema ```

Question 40

Features of papilloedema in fundoscopy

Answer 40

``` Blurring of the optic disc margin Elevated optic disc Loss of venous pulsation Engorged retinal veins Haemorrhages around optic disc Paton’s lines ```

Question 41

Most common cancers that metastasise to the brain

Answer 41

Lung Breast Renal cell carcinoma Melanoma

Question 42

What are gliomas

Answer 42

Gliomas are tumours of the glial cells in the brain or spinal cord. There are three types to remember (listed from most to least malignant): Astrocytoma (glioblastoma multiforme is the most common)

Question 43

What are the meningiomas

Answer 43

Meningiomas are tumours growing from the cells of the meninges in the brain and spinal cord. They are usually benign, however they take up space and this mass effect can lead to raised intracranial pressure and neurological symptoms.

Question 44

What are acoustic neuromas AKA vestibular shwannomas

Answer 44

Acoustic neuromas are tumours of the Schwann cells surrounding the auditory nerve that innervates the inner ear. They occur around the “cerebellopontine angle” and are sometimes referred to as cerebellopontine angle tumour

Question 45

Features of acoustic neuromas

Answer 45

slow-growing but eventually grow large enough to produce symptoms and become dangerous Acoustic neuromas are usually unilateral

Question 46

What are bilateral acoustic neuromas associated with

Answer 46

Neurofibromatosis type 2

Question 47

Symptoms of acoustic neuroma

Answer 47

Hearing loss Tinnitus Balance problems Can also be associated with a facial nerve palsy

Question 48

What is Lambert-eaton myasthenia syndrome(LEMS)

Answer 48

Causes progressive muscle weakness with increased use as a result of damage to the neuromuscular junction. The symptoms tend to be more insidious and less pronounced than in myasthenia gravis.

Question 49

In which patients does LEMS typically occur in

Answer 49

In patients with small-cell lung cancer

Question 50

Pathophys of LEMS

Answer 50

Antibodies are produced by the immune system against voltage-gated calcium channels in small cell lung cancer (SCLC) cells. These antibodies also target and damage voltage-gated calcium channels in the presynaptic terminals of the neuromuscular junction where motor nerves communicate with muscle cells.

Question 51

LEMS presentation

Answer 51

Proximal muscles notably affected Reduced tendon reflexes Intraocular muscles affected causing diplopia, levator muscles affected causing ptosis and oropharyngeal muscles affected causing slurred speech and swelling problems

Question 52

Symptoms of LEMS due to autonomic dysfunction

Answer 52

Dry mouth Blurred vision Impotence Dizziness

Question 53

What is post-titanic potentiation

Answer 53

A notable finding is that these reflexes become temporarily normal for a short period following a period of strong muscle contraction. For example, the patient can maximally contract the quadriceps muscle for a period, then have their reflexes tested immediately afterwards, and display an improvement in the response

Question 54

Treatment for LEMS

Answer 54

``` Ix for SCLC Amifampridine Immunosuppressants IV immunoglobulins Plasmapheresis ```