Flashcards in Motor neurone disease Deck (15):
Signs of MND on examination
Inspection: Wasting and fasciculation, especially tongue fasciculation.
Reflexes: absent or brisk (mixed UMN and LMN signs in MND).
Sensation is Normal.
Completion of an MND exam
Speech: bulbar palsy - nasal speech. Pseudobulbar - hot potato speech.
Jaw-jerk: bulbar - absent, pseudobulbar - brisk.
Eye movements: MND does not involve the eyes.
Lesion difference between bulbar and pseudobulbar palsy
Bulbar palsy: Lower motor neurone lesion of CN9, 10 and 12.
Pseudobulbar palsy: Upper motor neurone lesion of CN9, 10 and 12.
Distinguishing bulbar versus pseudobulbar clinically
LMN (bulbar) = nasal speech + tongue fasciculating + wasting
UMN (pseudobulbar) = hot potato speech + increased jaw jerk + spastic
DDx for apparent MND
Cervical cord compression leading to myelopathy
Polio: asymmetrical LMN paralysis
Mixed UMN and LMN signs:
Investigations for MND
Brain/cord MRI to exclude structural cause (cervical cord compression or brainstem lesion)
Lumbar puncture to exclude inflammatory cause (e.g. multiple sclerosis)
Diagnostic criteria for MND
Revised El Escorial Criteria (for ALS only)
General management for MND
Discussion of end-of-life decisions, e.g. DNAR, advanced directive
Medical management of MND
Riluzole is the only drug with proven benefit - prolongs lifespan by 3 months.
Drooling - hyoscine.
Muscle cramps - baclofen, quinine, diazepam.
Respiratory distress - opiates (palliative setting).
Depression - antidepressants.
Pain - analgesia.
Prognosis in MND
Most die within 3 years due to bronchopneumonia and respiratory failure.
Worse prognosis: elderly, female, bulbar involvement.
Types of MND
50% Amyotrophic Lateral Sclerosis
30% Primary Lateral Sclerosis
10% Progressive Bulbar Palsy
10% Progressive Muscular Atrophy
Pathophysiology of Amyotrophic Lateral Sclerosis
Corticospinal tracts affected - UMN and LMN signs + fasciculation
Pathophysiology of Primary Lateral Sclerosis
Loss of Betz cells in motor cortex - mainly UMN signs. Marked spastic leg weakness and pseudobulbar palsy. No cognitive decline.
Pathophysiology of Progressive Bulbar Palsy
Only affects CN9-12 - bulbar palsy