Amyotrophic Lateral Sclerosis Flashcards
1
Q
Describe the ALS Functional Rating Scale (ALSFRS-R)
A
- Minimum detectable change = 6.74 points
- Minimum clinically important differences = a 20% decline in ALSFRS-R is generally considered clinically significant
2
Q
Epidemiology of ALS
A
- Most physically devastating of the neurodegenerative diseases
- Cause unknown
- Slightly more common in men than women
- Average age of onset is mid 50s
3
Q
How does Jean Martin Charcot describe ALS
A
- Disorder of muscle wasting and gliotic hardening sclerosis of the anterior & lateral corticospinal tracts involving both upper and lower motor neurons
4
Q
Describe motor neuron diseases
A
- Only upper motor neurons damaged = primary lateral sclerosis
- Only lower motor neurons damaged = spinal muscular atrophy or progressive muscular atrophy
- Both upper and lower motor neurons damaged = amyotrophic lateral sclerosis (ALS)
5
Q
Decisions regarding care across the continuum are influenced by
A
- Stage of disease
- Availability of disease modifying agents
- Time of disease onset
- Patient factors: goals, psychosocial factors, social and financial resources
- Nature & course of the disease
- Individual variability through course of disease
6
Q
Different signs for suspected, probable, and definite ALS
A
- Suspected ALS: LMN only in one region or UMN only in one region
- Probable ALS: LMN + UMN in one region (identify gene defect); LMN + UMN in 2 regions; LMN + UMN in 1 region or UMN only in 1 region
- Definite ALS: LMN + UMN in 3 regions
7
Q
Describe ALS
A
- Affects both UMN and LMN
- Generally accepted that sensory nerves are normal
- Distal motor latencies & slowing of conduction velocity worsened as the severity of muscle weakness increased
- Will not show up on imaging
8
Q
Diagnosis of ALS requires the presence of
A
- Signs of LMN degeneration: electrophysiological or neuropatholgic exam
- Signs of UMN degeneration: clinical exam
- Progressive spread of signs within a region or to other regions with absence of electrophysiological evidence of other disease processes and absence of neuroimaging evidence of other disease processes
- Overall diagnosis is a combination of clinical presentation & EMG
9
Q
EMG criteria for diagnosis of ALS
A
- Fibrillations
- Positive waveforms
- Fasciculations
- Motor unit potential changes in multiple nerve root distributions in at least 3 limbs & the paraspinal muscles
- These changes occur without change in sensory response
10
Q
Time to diagnosis of ALS differs according to 1st presenting symptoms
A
- UE onset: 15 mo
- LE onset: 21 mo
- Bulbar onset (UMN/speech, breathing, swallowing functions impacted): 17 mo
11
Q
Steps in the Dx of ALS
A
- Hx, physical & appropriate neurological exams to ascertain clinical finding
- Electrophysiological exams to ascertain findings which confirm LMN degeneration
- Neuroimaging exams to ascertain findings which may exclude other disease processes
- Clinical laboratory exams determined by clinical judgement
- Neuropathologic exams
- Repetition of clinical & electrophysiological exams at least 6 mo apart to certain evidence of progression
12
Q
Risk factors for ALS
A
- Family Hx: heritability is estimated 61%
- Genetic risk factors: C9ORF72 gene, SOD1 gene, & TARDBP gene
- Viruses
- Occupational/environmental risk factors: military service & environmental exposure
- Lifestyle: smoking, lower risk with higher intake of antioxidants & polyunsaturated fatty acids, lower BMI & increased physical fitness, professional athletes
13
Q
Describe the inflammation.infection theory of development of ALS
A
- Whether inflammatory mechanisms are one of the primary causes of ALS or secondary to other pathological mechanisms is unclear.
- Inflammation can be triggered by invading microbes such as viruses or bacteria; injurious chemicals, or by physical injury.
- The trigger may come from within the organism such as a disease affecting the immune system or nervous system
14
Q
Describe the excess glutamate theory of development of ALS
A
- You need a certain amount of glutamate for motor nerves to communicate, but too much can be toxic to nerve cell bodies.
- People with ALS have too much glutamate in their spine and the excess glutamate damages the motor neurons.
- A major area of ALS research has been aimed at finding drugs that will reduce the amount of glutamate in the synaptic area between neurons
15
Q
Slides 23-26
A
16
Q
Clinical presentation fo ALS
A
- Most frequent initial symptom is focal weakness beginning in the leg, arm, or bulbar muscles
- Absence of sensory symptoms and findings
- Cognition, extra ocular eye movements, & autonomic, bowel, bladder, & sexual functions usually remain intact
- Muscle weakness progresses over time
- Pts must cope with continual, multiple functional losses f speech, swallowing, ability, ADLs
17
Q
Death from ALS usually result from _______________ with 50% of patients surviving only _________ after onset of symptoms unless mechanical ventilation is used to sustain breathing
A
- Respiratory failure; 3-4 years
18
Q
Patients with Bulbar Palsy generally have a ________ rapidly progressive clinical course
A
- More
19
Q
Describe the pathogenesis of ALS
A
- Speculates overstimulation of nerve cells by excessive amounts of glutamate could lead to cell death
- Immune system may be involved
- Pathogenesis is complex & remains unknown
- No cure exists but medications have beneficial effects: Riluzol (Rilutec) provides modest survival benefit and Myotrophin (insulin like growth factor-I) moderately lessens noter dysfunction
20
Q
UMN signs
A
- Spasticity: clonus
- Hyperreflexia
- Pathologic reflexes: Hoffman and Babinski
