Neuromuscular diseases

Question 1

Name the 3 classic clinical signs of motor dysfunction (R-A-T)

Answer 1

Reduced reflexes
Muscle atrophy
Reduced tone

Question 2

What causes botulism and how is it diagnosed?

Answer 2

Clostiridum botulinum exotoxins

Electrophysiology, exotoxins in feed/faeces/serum

Question 3

Which ACH synapse receptors do junctionopathies affect? Name 1 clinical sign seen with this

Answer 3

Nicotinic ACH synapses

Tetraparesis or CN dysfuncton

Question 4

Which ACH synapse receptors does dysautonomia affect? Name 3 clinical signs seen with this

Answer 4

Muscarinic ACH synapses

Urinary dysfunction, GI dysmotility, mydriasis, reduced tear production

Question 5

Brachial plexus avulsions can be caused by RTAs and other trauma. Which nerves are affected?

Answer 5

C6-T2

Question 6

An animal presents with monoparesis, an ipsilateral absent cutaneous trunci reflex, and signs of Horner’s following a recent history of trauma. What is your must likely diagnosis and which nerves are affected?

Answer 6

Brachial plexus avulsion

C6-T2

Question 7

Give an example of a brachial plexus tumour

Answer 7

Malignant peripheral nerve sheath tumour

Question 8

What are the clinical signs of a brachial plexus tumour (malignant peripheral nerve sheath tumour)?

Answer 8

Chronic progressive forelimb lameness
Pain
Muscle atrophy
WITH PALPABLE MASS

Question 9

How are brachial plexus tumours treated? What is the prognosis?

Answer 9

Surgical removal

Poor if spinal involvement

Question 10

Immune mediated polymyositis is usually idiopathic. Which dog breeds are affected?

Answer 10

Large breeds:
Newfoundland
Boxer
German Shepherd
Labrador
Golden Retriever

Question 11

A German Shepherd presents with pyrexia, stiffness, reluctance to move, lowered head carriage, muscle swelling, general weakness and fatigue and episodes of regurgitation. Give your most likely diagnosis

Answer 11

Immune mediated polymyositis

Question 12

How is immune mediated polymyositis diagnosed?

Answer 12

Muscle biopsy

Electrodiagnostics

Question 13

Give 1 haematological change and 1 biochemical change seen with immune mediated polymyositis

Answer 13

Inflammatory leukogram

Elevated CK/AST (severe)

Question 14

What is the treatment for immune-mediated polymyositis?

Answer 14

Immunosuppression

prednisolone, ciclosporin, azathioprine, mycophenalate

Question 15

What is overlap syndrome?

Answer 15

Immune mediated polymyositis

+ masticatory muscle myositis

Question 16

What are the 2 causes of myasthenia gravis?

Answer 16

Congenital (autosomal recessive)

Acquired (immune mediated or paraneoplastic)

Question 17

Myasthenia gravis can be acquired as a paraneoplastic syndrome. This is commonly see with which tumour?

Answer 17

Thymoma

Up to 50% of cats with myasthenia have thymoma

Question 18

What is the gold standard test for diagnosing myasthenia gravis?

Answer 18

Nicotonic acetylcholine receptor antibody test

nAChRAb

Question 19

What is the treatment for myasthenia gravis?

Answer 19

Anti-cholinesterase drugs- neostigmine or pyridostigmine
Immunosuppression if immune-mediated
Thymectomy if thymoma

Question 20

Myasthenia gravis may be self-limiting in some dogs, but has a general prognosis of ‘guarded to poor’. Why?

Answer 20

Risk of aspiration pneumonia

fulminant form - severe and sudden onset

Question 21

Myasthenia gravis can be fulminant or focal. Give examples of focal MG

Answer 21

Facial
Laryngeal
Pharyngeal
Oesophageal - megaoesophagus

Question 22

What breed of cats are predisposed to myasthenia gravis?

Answer 22

Abysinnian

Question 23

Masticatory myositis is in dogs with antibodies to the 2M myosin isoform. Which breed is predisposed to juvenile MM?

Answer 23

CKCS

Question 24

A CKCS presents with swollen, painful mucus membranes, exopthalmus, trismus (lockjaw) and localised muscle atrophy. What is your most likely diagnosis?

Answer 24

Masticatory muscle myositis

Juvenile form

Question 25

How is masticatory muscle myositis diagnosed?

Answer 25

Imaging of TMJ Elevated CK 2M antibodies Electromyography

Question 26

How is masticatory muscle myositis treated?

Answer 26

Immunosuppressive drugs - prednisolone | Physiotherapy - Kong

Question 27

Myositis can be a paraneoplastic syndrome associated with which 2 tumours?

Answer 27

Thymoma | Lymphoma

Question 28

Name 2 infectious causes of myositis

Answer 28

Neospora caninum | Toxoplasma gondii

Question 29

What is polyradiculoneuritis?

Answer 29

Inflammation of nerves and their roots

Question 30

What cat breed is predisposed to polyradiculoneuritis?

Answer 30

Bengal

Question 31

Polyradiculoneuritis has an acute onset and is rapidly progressive. Which spine roots are mostly affected, and does this cause mostly motor or sensory deficits?

Answer 31

Ventral spinal roots | Motor deficits

Question 32

How can polyradiculoneuritis be treated?

Answer 32

Supportive - physiotherapy, ventilation | Plasmapheresis

Question 33

Polyradiculoneuritis can be idiopathic, but can also have other causes. Name 3 examples of other causes

Answer 33

Rabies vaccine Campylobacter (raw feeding) Contact with racoons Severe axon damage (demyelination)

Question 34

Define neuropraxia. What is the prognosis?

Answer 34

Temporary nerve damage Conduction block due to pressure Prognosis good: function returns in days

Question 35

Define axonotmesis. What is the prognosis?

Answer 35

Disruption of axon but intact basal laminae and myelin sheath Due to trauma Prognosis: variable

Question 36

Define neurotmesis. What is the prognosis?

Answer 36

Partial or complete nerve transection Due to trauma Prognosis guarded/poor: complete recovery unlikely

Question 37

Name the 3 traumatic neuropathies

Answer 37

Neuropraxia Axonotmesis Neurotmesis

Question 38

Trigeminal neuritis is inflammation of the trigeminal nerves, including the bilateral ganglia. What are the symptos?

Answer 38

'Dropped jaw' - acute onset of masticatory muscle paresis/plegia Masticatory muscle atrophy Horner's, facial paralysis Sensory deficits

Question 39

What is the treatment for trigeminal neuritis?

Answer 39

Supportive - self-resolves within 3 weeks

Question 40

How is trigeminal neuritis diagnosed?

Answer 40

MRI - shows inflammed nerve

Question 41

What causes half of all unilateral temporal muscle atrophy cases?

Answer 41

Trigeminal nerve sheath tumour

Question 42

How is unilateral temporal muscle atrophy due to a trigeminal nerve sheath tumour treated?

Answer 42

Radiotherapy Prednisolone (palliative)