Cord Syndromes & Myopathies

Question 1

Dorsal column, Spinothalamic tract, Corticospinal tract info:

Answer 1

Dorsal Column:
- Ascending + Sensory
- Carries proprioception, fine touch, vibration
- Decussates in the medulla after leaving cord.
Spinothalamic tract:
- Ascending + Sensory
- Carries pain, temperature and crude touch
- Decussated almost immediately after entering cord
Corticospinal tract:
- Descending Upper Motor Neurone
- Decussation occurs in medulla and descents contralaterally

Question 2

Anterior cord syndrome aetiology, PPx:

Answer 2

• Damage to the anterior 2/3rds of the spinal cord usually as a result of reduced blood flow or occlusion to the anterior spinal artery.
• Aetiology: Trauma/Occlusion of anterior spinal artery
• Tracts affected: Corticospinal and spinothalamic tracts

Question 3

Clinical presentation of anterior cord syndrome?

Dx and Tx?

Answer 3

1) Bilateral motor paralysis
2) Loss of pain and temperature sensations
3) Autonomic dysfunction below the level of the lesion (badder, bowel, sexual dysfunction)
4) Dorsal columns (proprioception and vibration sense) are preserved.
Dx - Spinal MRI
Tx - Treat underlying cause

Question 4

Brown-Sequard Syndrome?

Answer 4

1) Hemi-section of the spinal cord
2) Ipsilateral and contralateral are in relation to the lesion
3) Ipsilateral weakness below lesion - corticospinal tract decussated already
4) Ipsilateral loss of proprioception + fine touch - dorsal column yet to decussate in medulla
5) Contralateral loss of pain and temperature below lesion - Spinothalamic decussated immediately after entering cord.
- Ipsilateral loss of proprioception, motor and fine touch.
- Contralateral loss of pain, temperature + crude touch
- Flaccid/Spastic paralysis depends on where lesion is.

Question 5

What is a myopathy?

Answer 5

• Disease of the muscle in which the muscle fibres do not function properly.
• Usually affect muscle without involving the nervous system - various aetiologies .
• Presentation - 1) muscle weakness, fatiguability
  2) Pain at rest indicates - inflammatory myopathy
  3) Pain on exercise indicates ischaemia or metabolic myopathy

Question 6

Toxic myopathies:

Answer 6

1) Alcohol
2) Steroids
3) Ciclosporin
4) Statins
Tx - stop drug immediately

Question 7

Polymyositis (Inflammatory myopathy) pathophys:

Answer 7

• Insidious, symmetrical proximal muscle weakness due to muscle inflammation.
• Auto-immune mediated striated muscle inflammation

Question 8

Polymyositis Presentation?

Answer 8

1) Dysphagia
2) Dysphonia
3) Respiratory weakness
4) Extra-muscular: Arthralgia, Raynaud’s (myocardial involvement)

Question 9

Polymyositis Diagnosis?

Answer 9

1) Muscle enzymes: ALT, AST, CK all raised
2) EMG - fibrillation potentials
3) Muscle biopsy DIAGNOSTIC

Question 10

Polymyositis Treatment?

Answer 10

1) Oral prednisolone

2) Immunosuppressives e.g. Azathioprine or cytotoxics (Cyclophosphomide in resistant cases)

Question 11

Poliomyelitis (inflammatory myopathy) pathophys?

Answer 11

1) Caused by polio (eradicated in UK due to vaccine)

2) Polio spread via droplet or faecal-oral (7 day incubation)

Question 12

Poliomyelitis presentation?

Answer 12

1) 2-day history of flu-like prodrome with fever then pre-paralytic stage
2) Pre-paralytic - fever, tachycardia, headache, vomiting, stiff neck, unilateral tremor. In 50% cases this progresses to paralytic stage.
3) Paryletic stage: myalgia, LMN signs +/- respiratory failure

Question 13

Poliomyelitis treatment?

Answer 13

1) Supportive - less than 10% who develop paralysis die

2) Permanent disability may result

Question 14

Metabolic/acquired myopathy of late onset?

Answer 14

Often part of systemic disease: 
1) Thyroid disease
2) Carcinoma
3) Cushing's
4) Hypo/hypercalcaemia
TREAT CAUSE!!!!

Question 15

Muscular dystrophy aetiology and PPx?

Answer 15

• Group of genetic diseases with progressive degeneration and weakness of specific genetic groups.
• Primary abnormality may be in the muscle membrane
• Secondary effects are marked variation in the size of individual muscle fibres and deposition of fat and connective tissue.
• Duchenne’s: Duchenne gene produces non-functional dystrophin, X-linked recessive and only affects males (3/1000 male births), Beck’s (milder and better prognosis but rarer) produced partially functional dystrophin.

Question 16

Duchenne’s Muscular Dystrophy presentation?

Dx and Tx?

Answer 16

1) By 4 years there is clumsy walking, then difficulty standing and respiratory failure
2) Pseudohypertrophy - due to fat & connective tissue deposition is seen in calves - look muscular but filled with fat and connective tissue

Dx -

1) Creatine Kinase is raised 40-fold
2) Genetic testing
3) Muscle biopsy - diagnostic

Tx - No cure (some survive beyond 2 years), supportive - physiotherapy and occupational therapy.

Question 17

Dystrophia myotonica? PPx, Sx + Tx?

Answer 17

1) Tonic muscle spasm - myotonia
2) Autosomal dominant CI - channelopathy (1 in 20000)
3) Onset at 25 years
Sx:
1) Distal onset weakness - hand/foot drop
2) Weak sternomastoids
3) Myotonia (tonic spasms)
4) Facial weakness and muscle wasting give long haggard appearance
5) Cataracts, male frontal baldness, diabetes, testis/ovary atrophy, reduced cognition
Tx:
Supportive - managing symptoms
Physio to maintain muscle strength

Question 18

Myopathy or Neuropathy?

Answer 18

Myopathy:

• Gradual onset of symmetrical proximal weakness - difficulty combing hair and climbing stairs
• Dystrophies - affect specific muscle groups (specific weakness on first presentation)
• Preserved tendon reflexes

Neuropathy:

• Paraesthesia
• Bladder problems
• Distal weakness
• Rapid onset suggests neuropathy or a toxic/metabolic myopathy
• Excess fatiguability (increased weakness with exercise) - Myasthenia Gravis
• Spontaneous pain at rest and local tenderness occurs in inflammatory myopathies
• Pain on exercise suggests ischaemia or metabolic myopathy (McArdle’s disease)
• Firm muscles (oddly) suggest pseudohypertrophic muscular dystrophies (e.g. Duchenne’s) due to infiltrations with fat or connective tissue.