LMN disorders Flashcards
myopathies can present as ? reflexes ? wasting ? weakness? pain ?
- proximal weakness
-symmetrical weakness
-PAIN
-reflex is sparred - wasting is late
ie : inclusion body myositis
NMJ disorders ?
- fatiguability
- Extra occur muscles are involved (ophthalmoplegia, ptosis, diplopia)
- Bulbar muscles ( difficulty in chewing, swallowing, nasal speech)
- Myaesthenia graves ( younger women and older men)
the muscles mentioned above have more NMJ’S
Polyneuropathy dependant on ----- of neurones? wasting ? weakness? reflexes ? example?
length dependant ie : the longest nerves are affected first
- Early wasting
- Symmetrical
- Weakness
- REFLEXES are absent
- distal wasting
- Motor neurone disease ( lot of wasting and combination of UMN, LMN, extra ocular muscles are sparred)
investigations for the lMN diseases?
- bloods
- neurophysiology
- muscle biopsy
- MRI to exclude other causes
- genetic testing
- creatine kinase
inflammatory myopathy = dermatomyositis ? signs, antibodies
signs :
- peri-orbital oedema , heliotrope,Rash, V sing , shawl sign etc , mechanic’s hand
- Anti MI2 antibodies (20%)
Lambert eaton syndrome antibodies
myasthenic syndrome –> antibodies to the v-g ca2+ channels
Myaesthnia graves antibodies ?
- nicotinic ACHr, MuSK
- post synaptic membrane can’t be depolarised
-degeneration of the motor end plate - increase in threshold required for AP
REFLEXES aren’t affected
treatment of dermatomyositis
Treatments:
- steroids , immunosuppressants
what is dermatomyositis associated with ?
-assocaited with breast, ovarian and lymphoma cancer
how is MG diagnosed ? WHEN THE antibody test takes too long ?
- Diagnostic difficulties
- Conduct clinically ICE pack test
- Ice lowers the temp in NMJ so achetylcholinesterase is denatured , hence ACH increases , so muscle weakness is dramatically better!
- Edophonium IV ( ACHesterase inhibitor ) - monitor to see if muscle strength increases
how do we manage MG ?
- Pyridostigmine ( Acetylcholinesterase inhibitor)
- steroids to reduce antibody production
- IV immunoglobulin
- Rituximab
management of myasthenia crisis
- TYPE 2 RESPIRAOTRY FAILURE ( O2, BLOOD gases are normal !!!!)
- DO a FVC
TREATMENTS: - IVg
-Plasma exchange
-Ventilatory support
-NIL by mouth as they can’t swallow
Demyelinating neuropathy vs axonal neuropathy
- Primary demyelination => means the jumping between the nodes of ranvier isn’t there so Conduction Velocity is REDUCED
- Axonal Damage => Amplitude of the AP is reduced THINK AXONAL –>AMP
Guillain Barre syndrome ?
- triggers and peak ?
Ascending Demyelinating Inflammatory Polyneuropathy
- acute triggers: CMV, Campylobacter jejuni , mycoplasma pneumoniae
- Motor»_space;»>sensory involvement
- peak is < 4 weeks
what can be seen in the lumbar puncture result of GB syndrome
RAISED PROTEIN IN LUMBAR PUNCTURE BUT NORMAL WBC
