Muscle and Nerve Disease Flashcards
Muscle and nerve diseases can result from disorders in which parts of the pathway?
Muscle itself
NMJ
Peripheral nerve
Anterior horn cell
What are the signs/symptoms of a muscle disease?
Weakness of muscle Shortness of breath (resp muscles) Poor swallow Cardiomyopathy Cramp, pain, myoglobinuria Poor suck, feeding, failure to thrive, floppy Wasting/hypertrophy Normal/reduced tone and reflexes Motor weakness - not sensory
What investigations might be done in suspected muscle disease?
Creatinine Kinase
Electromyography
Muscle biopsy - structure, biochemistry, inflammation
Genetic testing
What are the different types of muscle disease?
Muscular dystrophy Channelopathies Metabolic muscle disease Inflammatory muscle disease Congenital myopathies Iatrogenic
How might NMJ disorders present? What is an example of one?
Fatiguable weakness
- limbs
- eyelids
- muscles of mastication
- talking
- SOB
- diplopia
E.g. myasthenia gravis
What investigations might be done in suspected NMJ disorder?
AChR Ab
Anti Muscle-specific kinase AB
Neurophysiology - repetitive nerve stimulation and single-fibre EMG
CT chest - thymoma
How are NMJ disorders treated?
Symptomatic e.g. AChEIs
Immunosuppressants - prednisolone, steroid saving agent (azatioprine)
Ig/Plasma exchange
Thymectomy
What are the types of peripheral nerve disorders?
Root disease
- degenerative spine disease
- inflammation
- infiltration
Lesion of individual peripheral nerve
- compressive/entrapment
- vasculitic
Generalised peripheral neuropathy
- motor/sensory/both
- +/- autonomic features
What are some causes of peripheral nerve disorders?
Metabolic - diabetes, alcohol, renal, B12 Toxic - drugs Hereditary Infectious - Lyme, HIV, leprosy Malignancy Inflammatory demyelinating - acute = Guillain Barre syndrome - chronic = chronic inflammatory demyelinating polyneuropathy
What are the symptoms/signs of a peripheral nerve disorder?
If nerve root
- myotomal wasting/weakness
- reflex change
- dermatomal sensory change
Individual nerve
- wasting and weakness of specific muscle
- specific sensory change
Generalised peripheral neuropathy
- sensory and motor symptoms starting distally and moving proximally
What investigations might be done in suspected peripheral nerve disorders?
Blood tests Genetic analysis Nerve conduction studies LP - CSF analysis Nerve biopsy
What are the clinical features of Guillain-Barre syndrome?
Weakness of distal limb muscles and/or distal numbness
Low back pain frequent early feature
Proximal progression of neuropathy
Loss of tendon reflexes
Give IV Ig
Clinical features of lower vs upper motor neuron lesion?
LMN
- muscle fasciculations
- wasting
- weakness
UMN
- increased tone
- brisk reflexes
- no sensory involvement
What are the definitions of myelopathy and radiculopathy?
Radiculopathy is the term used to describe pinching of the nerve roots as they exit the spinal cord or cross the intervertebral disc, rather than the compression of the cord itself (myelopathy)
How might motor neuron disease present?
Usually limb onset, later bulbar and respiratory involvement
Combination of LMN and UMN signs
50% die within 14 months of diagnosis
