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PassPMR - 05 Neurology > 5- Motor Neuron Diseases > Flashcards

5- Motor Neuron Diseases Flashcards

Motor Neuron Diseases - Classification - Clinical Presentation & Differentials - EDX Study - Spinal Muscular Atrophy (SMA) - Poliomyelitis & Post Polio Syndrome - Rule of Rehabilitation

1
Q

Classification of Motor Neuron Diseases 🔑🔑

Which is the best prognosis? worst prognosis?

High mortality in MND is related to …

A

UMN Syndromes

  • Progressive Lateral Sclerosis (PLS)
  • Hereditary spastic paraplegia (HSP)

Mixed Syndromes

  • Amyotrophic lateral sclerosis (ALS)

LMN Syndromes

  • Spinal Muscle Atrophy (SMA)
  • Poliomyelitis, postpolio syndrome
  • ALS Variants:
    • Progressive Muscle Atrophy (PMA) → Best prognosis
    • Progressive Bulbar Palsy (PSP) → Worst prognosis → Pnuemonia & Resp Failure
    • Brachial Amyotrophic Diplegia (BAD)
    • Leg Amyotrophic Diplegia (LAD)

High mortality rate in MND is due to

  1. Pneumonia
  2. Respiratory failure 3-5 years (improve with ventilation & PEG tube)

Cuccurollo 4th Edition Chapter 5 EDX pg445 Table5-57

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2
Q

Lower Versus Upper Motor Neuron Signs 🔑🔑

A

UMN

  • Look → Atrophy (long term)
  • Tone → Spasticity
  • MP & Reflexes → Weakness, Hyperreflexia, Upgoing plantar response

LMN

  • Look → Atrophy, Fasciculations, Muscle cramps
  • Tone → Tone: Flaccidity
  • MP → Weakness, Hyporeflexia

Cuccurollo 4th Edition Chapter 5 EDX pg445 Table 5-58

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3
Q

List 4 affected areas and 4 spared areas in MND/ALS 🔑🔑

A

Affected Areas

  1. Bulbar muscles → swallowing, speech, breathing
  2. Cervical → Upper limb weakness
  3. Thoracic → Respiratory and spine stabilization
  4. Lumbar → Paraparesis

Spared Areas

  1. Sensation
  2. Cerebellar
  3. Extraocular muscles
  4. Bowel and bladder
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4
Q

List 4 risk factors for pneumonia in MND 🔑

A
  1. Sialorrhea
  2. Aspiration
  3. Impaired clearance of mucus
  4. Atelectasis
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5
Q

List 4 DDx for MND 🔑

A

Bulbar

UMN: Syrinx, mass, stroke, and Multiple Sclerosis

LMN: Cranial nerve palsies, Myasthenia Gravis

Limb

UMN: Myelopathy, syrinx, cord tumor, hereditary spastic paraparesis, HIV-related myelopathy, Multiple Sclerosis

LMN: Plexopathy, motor neuropathy, Myasthenia Gravis

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6
Q

EDX Criteria for MND 🔑🔑 MOCK

A
  • Active denervation with reinnervation must be found in three of four body segments (craniobulbar, cervical, thoracic, and lumbosacral)
  • At least two muscles with different innervations should be abnormal

Cuccurollo 4th Edition Chapter 5 EDX pg445

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7
Q

List 4 Workups for SMA. Blood - Something to See - EDX 🔑🔑 - Special Test

A
  1. Blood
    • Increase CPK levels (muscle break down)
  2. Muscle Biopsy
    • Hyper/atrophic fibers
  3. NCS = NMJ & Myopathy
    • Normal Sensory Study SNAP, except for hereditary spastic paraplegia and spinobulbar muscular atrophy.
    • Abnormal Motor Study CMAP: decreased CV & conduction velocity
    • F-wave: Abnormal latency
  4. EMG = NMJ & Myopathy
    • Abnormal Activities: Fibs, PSWs, CRDs (de-innervation)
    • Delayed/Decreased recruitment (Weak motor unit)
    • SDSA Short duration, small amplitude (de-innervation, acute)
    • LDLA Long duration, large amplitude (re-innervation via collateral sprouting)
    • SFEMG: Abnormal fiber density, jitter, and blocking.
  5. Genetic testing (Confirm diagnosis)

Cuccurollo 4th Edition Chapter 5 EDX pg445

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8
Q

Multifocal motor neuropathy (MMN) vs MND in EDX? 🔑🔑

A

💡 From its name: Multifocal → focal blocking

In MMN we see conduction block and temporal dispersion, which are not seen in MND.

Cuccurollo 4th Edition Chapter 5 EDX pg445

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9
Q

What causes spinal muscular atrophy (SMA)? Inheretance?

A

SMA is an autosomal recessive disorder most commonly caused by deletions in the survival motor neuron gene 1 (SMN1) on chromosome 5q13

Neurology Secrets 6th Edition Chapter 6 MND pg93

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10
Q

Spinal muscular atrophy type 1: Coarse - Affected/Spared - Labs - EDX - Tx

A

💡 Acute infantile: 3–6 months, death by 2–3 years due to respiratory failure.

Affected Areas (LMN)

  1. Bulbar: Difficulty feeding, Weak cry, Tongue fasciculations
  2. Thoracic: Floppy baby/hypotonia, Paradoxical breathing
  3. Legs: Frog-legged position
  4. Reflexes: Absent MSR

💡 Never sits independently

Spared Areas

  • Facial Muscles
  • Extraocular muscles
  • Sphincter Muscle

Labs

  • Blood: Increase CPK levels → Muscle loss and break down
  • M Bx: Hyper/atrophic fibers

NCS of Motor Neuron Disease, Just like NMJ

  • SNAP: Normal
  • CMAP: ± Abnormal

EMG of Motor Neuron Disease, Just like NMJ

  • Abnormal Activities: Fibs, PSWs, CRDs (de-innervation)
  • Delayed recruitment (Weak motor unit)
  • SDSA Short duration, small amplitude (de-innervation, acute)
  • LDLA Long duration, large amplitude (re-innervation via collateral sprouting)

Treatment

  • Supportive

Cuccurollo 4th Edition Chapetr 5 EDX pg446-447 Table5-60

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11
Q

Spinal muscular atrophy type 2: Coarse - Affected/Spared - Labs - EDX - Tx

A

💡 Chronic infantile: 2–12 months, wheelchair by 2–3 years of age and death by 10 years old

MND Regions with LMN features:

  1. Bulbar: ± Tongue fasciculations
  2. Thoracic: Floppy baby/hypotonia, Kyphoscoliosis, Progressive pulmonary involvement
  3. Limbs: Gradual progressive limb weakness, Equinus deformity of the feet
  4. Reflex: Absent MSR

💡 Independent sitting, Assistive devices for standing and walking

Labs:

  • Blood: Increase CPK levels
  • M Bx: Hyper/atrophic fibers

NCS of Motor Neuron Disease, Just Like NMJ

  • SNAP: Normal
  • CMAP: ± Abnormal

EMG of Motor Neuron Disease, Just Like NMJ

  • Abnormal Activities: Fibs, PSWs, CRDs (de-innervation)
  • Delayed recruitment (Weak motor unit)
  • SDSA Short duration, small amplitude (de-innervation, acute)
  • LDLA Long duration, large amplitude (re-innervation via collateral sprouting)

Treatment

  • Supportive
  • Rehabilitation

Cuccurollo 4th Edition Chapetr 5 EDX pg446-447 Table5-60

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12
Q

Spinal muscular atrophy type 3: Coarse - Affected/Spared - Labs - EDX - Tx

A

💡 Chronic juvenile: 2-15 years old, wheelchair by 30 years of age with normal life expectancy & normal intelligence

MND Regions with LMN features:

  1. Bulbar ± Dysphagia ± Dysarthria, Tongue fasciculations
  2. Limbs: Symmetric weakness: Lower > upper
  3. Reflexes: Abnormal MSR

💡 Independent standing/walking, Gowers’ sign & Calf pseudohypertrophy

Labs:

  • Blood: Increase CPK levels
  • M Bx: Hyper/atrophic fibers

NCS of Motor Neuron Disease

  • SNAP: Normal
  • CMAP: ± Abnormal

EMG of Motor Neuron Disease, Just Like NMJ

  • Abnormal Activities: Fibs, PSWs, CRDs (de-innervation)
  • Delayed recruitment (Weak motor unit)
  • SDSA Short duration, small amplitude (de-innervation, acute)
  • LDLA Long duration, large amplitude (re-innervation via collateral sprouting)

Treatment

  • Supportive
  • Rehabilitation

Cuccurollo 4th Edition Chapetr 5 EDX pg446-447 Table5-60

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13
Q

SMA. Compare age of diagnosis, ability to sit & age of death. 🔑🔑

A

Cuccurollo 4th Edition Chapter 10 Pediatrics

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14
Q

Two important respiratory complications in SMA, and two ways to prevent them. 🔑🔑

A
  1. Respiratory Failure → non-invasive or invasive ventilation
  2. Aspiration Pneumonia → PEG tube lowers the risk, doesn’t prevent it.
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15
Q

Diagnostic Criteria for Post Polio Syndrome

(a) What is post-polio syndrome? 🔑🔑 MOCK 🟦
(b) Cause of death - Rule of EDX & Findings - Rehab

A

Diagnostic Criteria for Post Polio Syndrome:

  1. Previous confirm diagnosis of paralytic poliomyelitis
  2. Partial or complete neurologic and functional recovery
  3. Neurological and functional stability for approximately 15 years
  4. Abrupt or gradual onset of new weakness and fatigue > pain
  5. No other medical problems to explain new symptoms

PMR Secrets 3rd Edition Chapter 58 MND pg491 Q13

Mortality

Higher with bulbar and respiratory involvement

Rule of EDX study

  • Post poliomyelitis syndrome findings resembles old stable poliomyelitis.
  • Its diagnosis is not based on EMG/NCS but on clinical presentation.
  • It can be used to rule out suspected neuropathy or myopathy.

EDX of POLIO = NEUROGENIC + SFEMG

NCS

  • Normal Sensory Study SNAP
  • Abnormal Motor Study CMAP

EMG

  • AA: Fibs & PSW (De-innervation)
  • Neurogenic MUAP: Delayed Recruitment, LDLA
  • SFEMG: Increased jitter, fiber density, and blocking

Rehabilitation

  1. Assistive devices
  2. Energy conservation
  3. Avoid fatigue
  4. Psychological counseling

Cuccurollo 4th Edition Chapter 5 EDX pg447-448 Table 5-61

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16
Q

Pathophysiology of Poliomyelitis vs Post Polio Syndrome & Prognosis

A

Poliomyelitis

Picornavirus (Poliovirus, Enterovirus) orally enters the body and spreads via lymphoid system leading to degeneration and inflammation of the anterior horn cell.

Post-Polio Syndrome

  • Resolution of inflammatory damage to motor neurons from viral infection.
  • Reinnervation of denerved muscle fibers by collateral sprouting.
  • Later on loss of the anterior horn cell from aging and increased metabolic demand

Prognosis

  • 50%: Complete recovery
  • 25%: Mild disability
  • 25%: Severe disability

Cuccurollo 4th Edition Chapter 5 EDX pg447-448 Table 5-61

17
Q

What is the clinical presentation of pilio? clinical suspesion of polio? 🔑🔑

A

INFECTION PART

  1. Viral infection: Fever, malaise, sore throat, vomiting, headache, back and neck pain, and stiffness.
  2. Autonomic dysfunction can occur (Virus affecting BBS), unlike ALS and MSA.

MND PART

  1. Bulbar: Dysphasia, nasal voice, OSA
  2. Cervical: Weak upper limbs, poor hand dexterity and overhead activities
  3. Lumbosacral: Weak lower limb, genu recurvatum, equines
  4. Reflexes: Absent MSR
  5. Spared sensation, just like NMJ & Myopathies
18
Q

Patient came with POLIO, what is the best orthosis for him? 🔑🔑 EXAM 2020

A

💡 Goal is improve ambulation, not to add heavy orthotics that may hinder the gait.

Mild Weakness

  1. Knee Ankle Foot Orthosis (KAFO)
  2. Knee Orthosis (KO) with cane

Severe Weakness

  1. Reciprocal gait orthosis (RGO) ← Seniors Answer
  2. Hip Knee Ankle Foot Orthosis (HKAFO)

Dr. Maitham

19
Q

Explain the motor pathway to R3 resident.

A

Primary Motor Cortex

Locations:

Precentral gyrus, dorsal portion of the frontal lobe, in front of the central sulcus

Blood supply:

  1. Middle cerebral artery: Lateral aspect
  2. Anterior cerebral artery: Medial aspect

Tracts:

  1. Corticobulbar Tract → Face & Neck
  2. Corticospinal Tract → Res of the Body

PassPMR - 05 Neurology (6 decks)

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