Muscle + Nerve disease Flashcards
What is the common presentation of Muscle disorders?
- Skeletal muscle weakness:
- > resp and swallowing muscles important
- Cardiac symptoms
- > cardiomyopathy, arrhythmias
- Cramps/muscle pain, stiffness
- Myoglobulinuria
- > (muscle breakdown product in the urine)
- > “coca-cola” urine
- Babies
- > floppy, poor suck/feeding/failure to thrive
What is the classification of muscle disorders?
- Congenital/Genetic:
- > contractile: congenital myopathies
- > structural: muscular dystrophies
- > coupling: channelopathies
- > energy: metabolic myopathies
- Acquired:
- > Electrolyte disturbance: esp. K+
- > Endocrine: thyroid, adrenal, vit D)
- > Autoimmune inflammatory disease
- > Iatrogenic: meds (steroids/statins)
What is the investigation of muscle disorders?
- History and examination
- Bloods: esp. CK
- Electromyography (EMG)
- Muscle biopsy: structure, biochemistry, inflammation
- Genetic Testing
What is the clinical presentation of Myasthenia Gravis?
- Fatiguable weakness
- > ie. weakness gets worse with repetitive movements
- Ocular:
- > eyelids (ptosis)
- > muscles of eye movement (diplopia)
- Generalised:
- > lips
- > bulbar (CNs of medulla (IX, X, XI, XII) -> ie. chew, swallow, talk)
- > breathing
What is the treatment of Myasthenia Gravis?
- Symptomatic:
- > cholinesterase inhibitors (pyridostigmine)
- > (less cholinesterase -> more Ach overcomes the blockage from the Ab)
- > (does not remove the Ab though, so may need DMTs)
- Disease-modifying therapies (DMTs):
- > immunoglobulin / plasma exchange
- > steroids
- > steroids-sparing immunosuppression
- > thymectomy
What is the investigation of Myasthenia Gravis?
- Ach receptor or anti-MuSK antibodies (if u can’t see anti-Ach antibodies in blood)
- Neurophysiology
- CT chest (Thymoma)
What is the investigation of Myasthenia Gravis?
- Ach receptor or anti-MuSK antibodies (if u can’t see anti-Ach antibodies in blood)
- Neurophysiology
- CT chest (Thymoma)
What are the different types of Peripheral Nerve disease?
- Root disease:
- > commonly Degenerative Disc disease
- Lesion of individual peripheral nerve:
- > compressive/entrapment neuropathy
- > vasculitic (mononeuritis multiplex)
- Generalised Peripheral Neuropathy:
- > motor, sensory, both
- > +/- autonomic features
What is the aetiology of Peripheral Nerve disease?
- Hereditary
- Metabolic:
- > diabetes, alcohol, renal failure, vitamin deficiency
- Toxic: drugs
- Infectious: Lyme, HIV
- Malignancy: paraneoplastic
- Inflammatory: autoimmune, usually demyelinating
- > Acute: Guillain-Barre syndrome
- > Chronic: chronic inflammatory demyelinating polyneuropathy
What are the clinical features of Peripheral Nerve disease?
- Sensory:
- Motor:
- Autonomic:
What is the aetiology of Peripheral Nerve disease?
- Hereditary
- Metabolic:
- > diabetes, alcohol, renal failure, vitamin deficiency
- Toxic: drugs
- Infectious: Lyme, HIV
- Malignancy: paraneoplastic
- Inflammatory: autoimmune, usually demyelinating
- > Acute: Guillain-Barre syndrome
- > Chronic: chronic inflammatory demyelinating polyneuropathy
What are the clinical features of Peripheral Nerve disease?
- Sensory: loss of sensation, abnormal sensation, pain
- Motor: muscle thinning, weakness (LMN)
- Autonomic: skin changes, blood pressure, bowel, bladder
- > Root: myotome/dermatome
- > Single nerve
- > Generalised nerve: distal first (ie. feet, then hands if progressive)
What is the investigation of Peripheral Nerve disease?
- Blood tests: ?diabetes, ?alcohol XS
- Nerve conduction studies/EMG
- Lumbar puncture: CSF analysis (GB syndrome)
- Nerve biopsy
- > only for sensory nerves (don’t want to biopsy motor nerves and cause damage!)
- Genetic analysis
What is the treatment of Peripheral Nerve disease?
Treat the cause!
ie. stop the drug (if due to drug), surgery (if due to spinal root disease or nerve entrapment), immunoglobulins (ie. in GBS, can also do plasma exchange)
What are the clinical features of MND/ALS?
- Usually limb -> bulbar -> respiratory
- combo of UMN and LMN signs:
- > LMN = muscle fasciculations, wasting, weakness
- > UMN = spasticity, brisk reflexes, extensor plantars
- no sensory involvement
- > a pure motor condition
- 10%+ have cognitive decline
- > Frontotemporal Dementia
