Neuromuscular Disorders Flashcards
Why do neuromuscular disorders occur?
Abnormal or deficient motor neurone signals to skeletal muscle
What may be the potential reasons for a neuromuscular disorder to develop?
- Defect in the brain
- Defect in the spinal cord
- Defect in the peripheral nerve
- Defect in the NMJ
- Defect in the muscle
Any defect which causes abnormal or deficient motor neuron signal to skeletal muscle
What do upper motor neurone causes of neuromuscular disorders give rise to?
- Weakness
- Spasticity
- Hyperreflexia
- Extensor plantar response (Babinski)
What is Babinksi’s sign?
In involves using a blunt object to firmly stroke down the sole of the foot.
The normal response is flexion of the toes.
In patients with an upper motor neurone disorder, the toes will extend
What do lower motor neurone causes of neuromuscular disorders give rise to?
- Weakness
- Reduced tone
- Areflexia (Hyporeflexia - reduced or absent reflexes)
What is cerebral palsy?
A neuromuscular disorder caused by insult to the immature brain before, during or after birth.
It usually has an onset before 2-3 years
What are some possible causes of CP?
- Genetic problems
- Brain malformation
- Intrauterine infection in early pregancy
- Prematurity
- Intra-cranial haemorrhage
- Hypoxia during birth
- Meningitis
What is the commonest expression of CP?
Spastic CP
(due to insult to the motor cortex, UMNs or corticospinal tract)
Which expression of CP involves insult to the cerebellum?
Ataxic CP
(this reduces coordination and balance)
Which type of CP results in an uncontrolled writhing motion?
Athetoid CP
(affects the extrapyramidal motor system, the pyramidal tract and basal ganglia)
Athetoid CP presents in what way?
- Uncontrolled writhing motion
- Sudden changes in tone
- Difficulties controlling speech
What is the most common form of CP in terms of the limbs affected?
Hemiplegic (on ipsilateral upper and lower limb)
Which type of musculoskeletal problems can develop as a result of CP?
- Joint contractures
- Scoliosis
- Hip dislocations
Which types of non-surgical treatment are there for the MSK problems associated with CP?
- Physiotherapy
- Splintage (to prevent contractures)
- Intrathecal Baclofen injections (reduces spasticity)
- Botox injection into spastic muscles
What is selective dorsal rhizotomy?
A surgical procedure involving sectioning overfiring motor nerve rootlets which are chosen by intra-operative EMG
What is spina bifida?
A congenital disorder where two halves of the vertebral arch fail to join
What are the two types of spina bifida?
- Spina bifida occulta
- Spina bifida cystica (2 subtypes - meningocele and myelomeningocele)
Describe spina bifida occulta
- Most mild form
- May be no associated problems
- Spinal cord and roots may tether to vertebral defects causing pes cavus (high arched foot) and clawing of toes
- Neurological issues can develop at any age
- Dimple or tuft of hair in the skin overlying the defect may be present
Describe spina bifida cystica
- Most severe form
- Contents of vertebral canal can herniate through the defect
- This may be the meninges alone (meningocele) or the spinal cord and or cauda equina (myelomeningocele)
- Neurological defects below the lesion are commonly associated with a myelomeningocele
Spina bifida cystica is associated with hydrocephalus, what is this?
Excess CSF around the brain causing raised intracranial pressure
What is the treatment for spina bifida cystica?
The defect is usally closed within 48 hours of birth
Hydrocephalus can be treated via a shunt from the brain to either the right atrium of the heart, pleural cavity or peritoneal cavity
Associated spinal deformities and hip dislocations can be treated othropaedically
Polio is known by which other name?
Poliomyelitis
What is polio?
A viral infection which affects motor anterior horn cells which can cause lower motor neurone issues
Why is polio rarely seen in the UK?
It is vaccinated against
Which virus causes polio?
Poliovirus
How does poliovirus enter the body?
GI tract
(causes a flu-like illness and variable degree of paralysis)
As well as limb paralysis, what other symptoms are associated with polio?
- Joint deformites
- Growth defects
- Shortening of the limbs
How can a shortening of a leg be treated in polio?
Shoe raise
How can deformities especially in the foot or ankle be treated in patients with polio?
Fusion (arthrodesis) to allow maximal function
