Paediatric neurology (Neuromuscular disorders)

Question 1

Note - Differentials for a child presenting with weakness covers both upper and lower MN disease - this lecture/deck only covers Lower motor neuron disease

Answer 1

:3

Question 2

Where do lower motor neurones begin?

Answer 2

Ventral (anterior) horn of Gray mater of spinal cord

Exit via ventral root

Question 3

What (features of a history) would alert you to a possible neuromuscular disease?

(from post-birth to young child age)

Answer 3

Baby ‘floppy’ from birth

Baby often slips from hands

Paucity of limb movements

Alert - but less motor activity

Delayed motor milestones

Frequent falls (if able to walk) & clumsiness

Question 4

Shown below is a test you would do to check Neuromuscular activity in a baby

What feature may indicate Neuromuscular disease?

Answer 4

This is lifting a baby into the seated position by lifting up their arms

Inability for the baby to hold up its head may indicate NMD

Question 5

If a baby has NMD - what would happen if you lifted them up by the abdomen?

Answer 5

Infant hangs like ragdoll

Question 6

What is Gower’s sign?

Answer 6

Medical sign which indicates weakness of the lower limb muscles and muscles of pelvic girdle

It can indicate many NMD conditions but mainly Muscular dystrophy

Child is asked to lie down on back - then is timed to roll on their front and stand up

Slow time & using arms to stand up = +ve Gower’s sign

See photo below

Question 7

What is Duchenne muscular dystrophy?

Answer 7

X linked recessive condition - in which there is a mutated Dystrophin gene (Xp21)

Characterised by:

• delayed gross motor skills
• progressive, symmetrical, proximal muscle weakness from 4/5 years
• intellectual impairment (30%)

Question 8

Describe the epidemiology of Duchenne muscular dystrophy?

Answer 8

1/3500 boys

X-linked recessive

Question 9

What are the signs of Duchenne muscular dystrophy?

Answer 9

Calf pseudohypertrophy _{- due to fat, not muscle}

Waddling gait

Gower’s sign

Charcot-Marie-Tooth disease (arched foot)

Intellectual disability (not a sign but commonly seen with DMD)

+ below

Question 10

What blood test would be very abnormal in somoene with Duchenne muscular dystrophy?

Answer 10

Creatine Kinase

>1000

(lecture says creatinine kinase but that simply does not exist)

Question 11

What are the main complications of Duchenne muscular dystrophy?

Answer 11

Cardiomyopathy

Respiratory involvement by teens

Question 12

What is the other main type of muscular dystrophy and how does its presentation differ from duchenne?

Answer 12

Becker muscular dystrophy

Presents later - >10 years old

Question 13

What are the different neuromuscular diseases that affect:

a) Muscle
b) NMJ
c) Nerve
d) Anterior horn cells

Answer 13

a) affecting the Muscle itself:

• muscular dystrophies (Duchenne & Becker)
• myopathies (congenital & acquired)
• myotonic syndromes

b) affecting the neuromuscular junction:

• myasthenic syndromes

c) affecting the nerves:

• neuropathies (heridtary & acquired)

d) affecting anterior horn cells:

• spinal muscular atrophy

Question 14

A child presents with weakness

Through clinical examination - how would you differentiate between neuropathies and myopathies?

Describe what you would examine, and what findings would be in keeping with each

Answer 14

Site of weakness:

• Neuropathy - distal
• Myopathy - proximal

Sensation:

• Neuropathy - usually concomitant sensory loss/dysfunction
• Myopathy - pure motor

Reflexes:

• Neuropathy - reflexes lost early
• Myopathy - lost late

Fasciculations:

• Neuropathy - may be present
• Myopathy - nope

Contractures:

• Neuropathy - nah
• Myopathy - yah

Myocardial dysfunction:

• Neuropathy - nah
• Myopathy - may be present