Makindo Medical Notes.com

Related Subjects: |Neurological History taking |Motor Neuron Disease (MND-ALS) |Miller-Fisher syndrome |Guillain Barre Syndrome |Multifocal Motor Neuropathy with Conduction block | Multiple Sclerosis (MS) Demyelination | Inclusion Body Myositis |Cervical spondylosis |Anterior Spinal Cord syndrome |Central Spinal Cord syndrome |Brown-Sequard Spinal Cord syndrome |Spinal Cord Compression |Spinal Cord Haematoma |Spinal Cord Infarction

Important as it may mimic Motor neurone disease and is treatable

About

• An acquired immune-mediated demyelinating neuropathy
• Slowly progressive weakness that can mimic Motor neuron disease
• Is much rarer than MND - seen in younger men

Aetiology

• Demyelination of predominantly motor nerves.

Clinical

• A patient may present with limb weakness and fasciculation
• Affects the young - mean age is 41 years old
• Generally involving arms > legs.
• Commoner in men x3.
• Reduced reflexes, No sensory symptoms
• Cranial nerves/bulbar generally not affected

Investigations

• Blood tests show ? titres of anti-GM1 antibodies in 80%
• Nerve conduction studies: Motor conduction block is seen in ulnar and median nerves would be compatible with the diagnosis. Sensory studies are normal.
• CSF analysis is normal

Differential

• MND, CIDP, Lead poisoning
• Hexosaminidase A deficiency

Management

• Treatment with IVIG 0.4 g/kg/day is first-line choice and can cause substantial improvement
• Second line treatment with Oral or IV Cyclophosphamide
• Paradoxically steroids can cause worsening
• Treatment can produce useful functional improvement in patients with MMN.