ALS Flashcards
what does the Amyotrophic Lateral Sclerosis mean?
- A - no/without
- Myo - muscle
- Trophic - nourishmen
- lateral - defines the areas in a person’s spinal cord where portions of the nerve cells that signal and control the muscles are located
- as this area degenerates, it leads to scarring or hardening (sclerosis) in the region
Epidemiology of ALS
- most common and devastating fatal of all motor neuron diseases
- mortality typically in 2-5 years; highly variable symptoms
- onset is often >50 years old but can occur in younger people
- men are slightly more affected than women (1.5:1)
what is ALS characterized by?
- progressive degeneration and loss of motor neurons in the spinal cord, brain stem, and motor cortex
- destruction of upper and lower motor neurons
- degeneration of anterior horn cells and descending corticobulbar and corticospinal tract
pathophysiology of ALS
- demyelination and gliosis of the motor cortex, corticospinal and corticobulbar tracts resulting from degeneration of UMN cell bodies in the motor cortex
describe the etiology of ALS
- unknown
- viral/autoimmune/toxic?
- glutamate excitotoxicity
- increased levels in CSF, plasma, post-mortem tissue
- 5-10% genetic (autosomal dominant)
Risk factors for ALS
- Male > Female
- Caucasian, non-Hispanic minorities
- Geographical clusters
- Family History
- Age (55-75)
- Prior trauma or TBI
ALS Diagnosis
- Diagnosis is very difficult
- misdiagnosis is not uncomon
- Largely diagnosis by exclusion
- Clinical examination
- EMG/NCV
- MRI
- CSF, blood and urine tests
- creatine phosphokinase levels higher in ~70% cases
- ID of biomarkers to rule out other neurological diseases
clinical diagnosis of ALS requires what criteria?
- a pattern of observed and reported symptoms of both UMN and LMN as well as persistent decline in physical function that cannot be attributed to other disorders
- El Escorial criteria
what is included in the El Escorial criteria for diagnosis of ALS?
- exclusion of all other Dx + Progressive Functional Decline +
- progressive UMN and LMN deficits in at least one limb or region of the human body or
- LMN deficits in at least one region by clinical exam and/or by EMG in two body regions (defined as bulbar, cervical, thoracic, lumbosacral)
- the EMG findings consist of neurogenic potentials and fibrillation potentials and/or sharp waves
General Clinical Presentations of ALS
- cardinal sign → progressive muscle weakness
- UMN impairments
- LMN impairments
- Bulbar impairments
- Respiratory impairments
- Cognitive impairments
- Additional impairments
ALS S/S: Progressive Muscle Weakness
- most common impairment focal, asymmetrical muscle weakness beginning in LE or UE or Bulbar weakness
- Can be due to UMN and/or LMN involvement
- LMN weakness >> UMN weakness
- Eye, bowel and bladder muscle normally spared until terminal stages
- Progresses to entire body involvement
ALS UMN Impairments
- spasticity
- hyperreflexia
- clonus
- pathological reflexes
- weakness
ALS LMN Impairments
- hyporeflexia
- hypotonicity
- atrophy
- fasciculations
- weakness
ALS Bulbar Impairments
- spastic bulbar palsy or flaccid bulbar palsy
- dysarthria
- sialorrhea
ALS Respiratory Impairments
- decreased respiratory muscle strength
- reduction of VC up to 50% typically when symptoms arise
ALS Cognitive Impairments
- variable evidence on prevalence
- verbal fluency
- language comprehensive
- memory
- abstract reasoning
ALS Additional impairments
- pain
- fatigue
- ANS symptoms (1/3 cases)
Clinical subtypes of ALS
- Classic ALS
- limb-onset
- bulbar-onset
- Primary Lateral Sclerosis (PLS)
- Progressive Spinal Muscular Atrophy (SMA)
- ALS with Frontotemporal Dementia (FTD)
- Familial ALS
early signs of classic ALS
- progressive limb weakness
- reduced dexterity
- wasting of hands
- muscle fasciculations
- with additional bulbar involvement, there is wasting of the tongue, and muscles for speech and swallowing
describe Limb-Onset Classic ALS
- ~70-80% of cases (most common presentation of ALS)
- first symptoms are a result from damage to motor neurons in motor cortex, specifically corticospinal tracts
- distal → proximal
- fasciculations
- atrophy
- weakness
- spasticity
describe bulbar-onset classic ALS
- ~20-30% of cases. Progresses faster than limb-onset
- first symptoms are a result of damage to motor neurons in brainstem, specifically corticobulbar tracts (face, head, neck, muscles)
- affects CN IX and XII causing dysarthria and dysphagia
- tongue atrophy, tongue fasciculations
- vocal cord spasms
- more common in older female with male:female (2:3)
describe Primary Lateral Sclerosis
- rare condition (5% of those with ALS)
- Upper motor neuron signs and symptoms ONLY
- can progress to classical ALS
- key exam findings can include spasticity, upper motor neuron pattern weakness, and pseudobulbar findings
- VERY different prognostic story → relatively good with life expectancy comparable to normal!
describe Progressive SMA
- 5-10% of cases
- LMN involvement ONLY
- flaccid weakness
- atrophy
- fasciculation
- hyporeflexia or areflexia
- Mainly limb involvement
- bulbar palsy can develop later
- Mainly affects men (male > female, 2:1)
- May be limited to one region
- Progression highly variable, can be slow or very rapid
what regions may AMS be limited to?
- Flail arm syndrome (cervical) → Man-in barrel syndrome
- Flail leg syndrome (lumbosacral)
describe ALS with FTD
- cognitive symptoms and dementia once thought to be uncommon ALS symptom. Recent studies suggest that:
- roughly 30% of pts with ALS demonstrate mild to moderate cog and/or behavioral impairments w/o dementia
- 20% of individuals with ALS with develop FTD
- Common deficits invovle executive function, either language or personality. Causes problems with judgement, impulsivity, decreased ability to handle routine tasks
describe Familial ALS
- Affects 5-10% of pts with ALS
- Genetic risk for ALS prob represents combined effects of multiple genes that establish a person’s overall genetic susceptibility, acting with environmental and random effects leading to disease onset
- pattern of inheritance varies depending on gene involved; most cases are inherited in an autosomal dominant pattern
- Onset: late 40s or early 50s
- No difference between familial and sporadic ALS on neuro exam
stage 1 of ALS
- early disease
- mild focal weakness
- asymmetrical distribution
- symptoms of hand cramping and fasciculations
stage 2 of ALS
- moderate weakness in groups of muscles
- some wasting (atrophy) of muscles
- modified independence with AD
stage 3 of ALS
- severe weakness of specific muscles
- increasing fatigue
- mild to moderate functional limitations
- ambulatory
stage 4 of ALS
- severe weakness and wasting of LEs
- mild weakness of UEs
- moderate assistive and AD
- wheelchair user
stage 5 of ALS
- progressive weakness with deterioriation of mobility and endurance
- increased fatigue
- moderate to severe weakness of whole limbs and trunk
- spasiticty
- hyperreflexia
- loss of head control
- maximal assist
stage 6 of ALS
- bedridden
- dependent ADLs
- FMS
- progressive respiratory distress
medical management of ALS
- no effective treatment for disease
- disease-modifying
- riluzole → glutamate antagonist
- symptomatic treatment
- cramps
- spasticity
- sialorrhea
- depression
- excessive laughing and crying
Outcome measure for ALS
ALS Functional Rating Scale (ALSFRS-R)
describe the ALSFRS-R
- measures ADL and global function across 12 functional categories
- used to assess response to treatment or disease progression
- total possible score 48 with higher scores reflecting worse performance
ALSFRS-R items
- speech
- salivation
- swallowing
- handwriting
- cutting food
- dressing and hygiene
- turning in bed
- walking
- climbing stairs
- dyspnea
- orthopnea
- respiratory insufficiency
ALS prognosis
- terminal diagnosis
- average mortality rate 2-5 years
- small % live 15-20 years
- EXCEPTION → Stephen Hawking
- ultimately progresses to respiratory failure
- average mortality rate 2-5 years
ALS Negative Prognostic factors
- Bulbar onset
- Early respiratory signs
ALS Positive Prognostic factors
- according to the American Academy of Neurology, pts who participate in multidisciplinary clinics live longer and have an improved QOL
How can mortality be delayed in ALS pts?
by initating home-based mechanical ventilation as opposed to palliative or comfort care only