Disease profiles

Question 1

Pathophysiology of Lambert-Eaton myasthenic syndrome (LEMS)?

Answer 1

Autoantibodies against presynaptic voltage-gated calcium channels

Question 2

What is LEMS?

Answer 2

LEMS is a rare autoimmune disorder characterised by the production of autoantibodies that target pre-synaptic voltage-gated calcium channels, leading to impaired neurotransmission at the neuromuscular junction.

Question 3

Non-small cell lung cancer is an underlying cause of LEMS. True/false?

Answer 3

False. Small cell lung cancer.

Question 4

Management of LEMS?

Answer 4

Management of LEMS focuses on treating the underlying cause, typically small cell lung cancer, and alleviating symptoms:

Underlying cause management: Cancer treatment options (chemotherapy, radiation, surgery) are required if LEMS is associated with a malignancy.

Symptom management: Amifampridine can be used, which blocks pre-synaptic potassium channels in the nerve terminals, augmenting the release of acetylcholine.

Severe respiratory or bulbar weakness: Management includes intubation and ventilation, along with plasma exchange or intravenous immunoglobulin (IVIG).

Question 5

Key distinguishing features of migraines?

Answer 5

Unilateral throbbing headache, potentially preceded by an aura (visual or sensory)

Headache duration of 4-72 hours

Association with photophobia (light sensitivity) and phonophobia (sound sensitivity)

Possible triggers such as oral contraceptives or specific foods (e.g., chocolate)

Question 6

Management of migraines?

Answer 6

Management strategies include avoiding triggers, prophylaxis with Propranolol (contraindicated in asthma) or Topiramate, and managing acute attacks with oral triptans like Sumatriptan (contraindicated in ischaemic heart disease) in addition to Paracetamol or an NSAID.

Question 7

Tension headaches are more likely in men. True/false?

Answer 7

False, more likely in women.

Question 8

Management of cluster headaches?

Answer 8

Management strategies involve avoiding triggers, prophylaxis with Verapamil, and treating acute attacks with 100% oxygen via a non-rebreathable mask (contraindicated in COPD) and a subcutaneous or nasal Triptan (contraindicated in ischaemic heart disease).

Question 9

What is a cluster headache?

Answer 9

Pain around the eyes presenting as a “cluster”

Tearing

Red eye

Question 10

What is trigeminal neuralgia?

Answer 10

Trigeminal neuralgia, also known as tic douloureux, is a chronic pain condition characterized by severe, sudden, and brief bouts of shooting or stabbing pain that follow the distribution of one or more divisions of the trigeminal nerve, affecting the patient’s facial region.

Question 11

Trigeminal neuralgia epidemiology?

Answer 11

Trigeminal neuralgia typically affects adults over the age of 50, with a higher prevalence in women.

Question 12

Trigeminal neuralgia aetiology?

Answer 12

Malignancy: can lead to nerve compression or infiltration, resulting in pain

Arteriovenous malformation: abnormal, tangled blood vessels can compress the trigeminal nerve

Multiple sclerosis: demyelination in this condition can affect the trigeminal nerve

Sarcoidosis: granulomatous lesions can affect the trigeminal nerve

Lyme disease: infection and subsequent inflammation can affect the trigeminal nerve

Question 13

Signs and symptoms of trigeminal neuralgia?

Answer 13

Patients typically present with unilateral facial pain that is sudden, severe, and brief.

The pain is often described as shooting or stabbing, and can be triggered by lightly touching the affected side of the face, eating, or wind blowing on the face.

Neurological examination in these patients is typically normal.

Question 14

Investigations for trigeminal neuralgia?

Answer 14

Trigeminal neuralgia is largely a clinical diagnosis, but investigations may be performed to rule out other causes of facial pain.

Neuroimaging such as MRI can be used to exclude secondary causes, including tumors or vascular compression.

Question 15

Management of trigeminal neuralgia can be both medical and surgical. True/false?

Answer 15

True

Question 16

Medical management of trigeminal neuralgia?

Answer 16

Carbamazepine (first-line treatment)
Phenytoin
Lamotrigine
Gabapentin

Question 17

Surgical management of trigeminal neuralgia?

Answer 17

Microvascular decompression: a procedure to remove or relocate blood vessels that are in contact with the trigeminal root

Treatment of the underlying cause: such as removing a tumor or addressing an arteriovenous malformation

Alcohol or glycerol injections: used to damage the trigeminal nerve and reduce pain signals

Question 18

Each side of the forehead has lower motor neurone innervation by both sides of the brain. True/false?

Answer 18

False

UMN = from both sides of brain.

LMN = from one side of the brain.

Question 19

In an upper motor neurone lesion, is the forehead spared?

Answer 19

Yes

In UMN lesion (i.e. stroke, tumour), forehead is spared and patient can move forehead on affected side.

In LMN lesion (i.e. Bell’s palsy, Ramsay - Hunt syndrome), forehead will NOT be spared and patient cannot move forehead on affected side.

Question 20

Aetiology and clinical presentation of Bell’s palsy?

Answer 20

Aetiology: idiopathic

Clinical presentation: Unilateral lower motor neurone facial nerve palsy

Question 21

If patient with Bell’s palsy presents within 72 hours of developing symptoms. What is the medication provided?

Answer 21

Prednisolone

Question 22

Most patients of Bell’s palsy usually recover over several weeks but recovery can take up to 12 months. True/false?

Answer 22

True

Question 23

Aetiology of Ramsay-hunt syndrome?

Answer 23

Varicella zoster virus (VZV)

Question 24

Clinical presentation of Ramsay-hunt syndrome?

Answer 24

• Unilateral lower motor neurone facial nerve palsy.
• Patients stereotypically have a painful and tender vesicular rash in the ear canal, pinna and around the ear of the affected side.
  • Rash can extend to anterior 2/3rd of the tongue and hard palate

Question 25

Management of Ramsay-hunt syndrome?

Answer 25

Prednisolone + aciclovir

Patients also require lubricating eye drops

Question 26

What is myasthenia gravis?

Answer 26

an autoimmune condition affecting the neuromuscular junction.

It causes muscle weakness that progressively worsens with activity and improves with rest.

Question 27

Typically ages affected by myasthenia gravis?

Answer 27

affects men and women at different ages, typically affecting women under 40 and men over 60.

Question 28

What tumour type does myasthenia gravis have a link to?

Answer 28

thymomas (thymus gland tumours). 10-20% of patients with myasthenia gravis have a thymoma. 30% of patients with a thymoma develop myasthenia gravis.

Question 29

Name of the neurotransmitter released by the axons from the presynaptic membrane?

Answer 29

Acetylcholine

Question 30

Acetylcholine travels across the synapse and attaches to receptors on the postsynaptic membrane, simulating muscle contraction. True/false?

Answer 30

True

Question 31

What autoantibody is commonly found in myasthenia gravis?

Answer 31

Anti-AChR (anti-acetylcholine) antibodies

Question 32

How do the anti-AChR antibodies play a role in myasthenia gravis?

Answer 32

These antibodies bind to the postsynaptic acetylcholine receptors, blocking them and preventing acetylcholine stimulation

Question 33

What 2 other autoantibodies can cause myasthenia gravis?

Answer 33

Muscle-specific kinase (MuSK) antibodies
Low-density lipoprotein receptor-related protein 4 (LRP4) antibodies

Question 34

MuSK and LRP4 are important proteins for the creation and organisation of the acetylcholine receptor. Destruction of these proteins leads to inadequate acetylcholine receptors. true/false?

Answer 34

True

Question 35

Typical features of myasthenia gravis?

Answer 35

Weakness that worsens with muscle use and improves at rest.

Symptoms typically best in morning and worsen throughout the day

Question 36

What muscles are usually affected in myasthenia gravis?

Answer 36

proximal muscles of the limbs and small muscles of the head and neck

Question 37

Symptoms of myasthenia gravis?

Answer 37

Difficulty climbing stairs, standing from a seat or raising their hands above their head

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

Question 38

What scar on the patients body could indicate the presence of myasthenia gravis?

Answer 38

Thymectomy scar

Question 39

Blood testing can look for what antibodies?

Answer 39

AChR antibodies (around 85%)
MuSK antibodies (less than 10%)
LRP4 antibodies (less than 5%)

AChR antibodies are most commonly found and have the largest association with myasthenia gravis.

Question 40

What can a CT or MRI scan look for in myasthenia gravis?

Answer 40

Views the thymus gland in order to look for presence of thymoma

Question 41

Most common treatment options for myasthenia gravis?

Answer 41

Pyridostigmine is a cholinesterase inhibitor that prolongs the action of acetylcholine and improves symptoms

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

Question 42

Thymectomy can only be carried out in the presence of a thymoma. true/false?

Answer 42

False

Can be carried out to improve symptoms, even in patients without a thymoma.

Question 43

What treatment option can be used for myasthenia gravis if other treatment options fail?

Answer 43

Rituximab (a monoclonal antibody against B cells)