Motor Neuron Diseases Flashcards
Possible locations of motor neuron diseases?
Motor neurons, motor axons, and muscle fibers they innervate
Spinal muscular atrophy in an infant? a juvenile? Adult?
Werdnig-Hoffman - infantile spinal muscular atrophy
Wolfart-Kugelberg-Welander - Juvenile proximal chronic spinal muscular atrophy
Adult onset spinal muscular atrophy
Characteristics of Werdnig-Hoffman (infantile spinal muscular atrophy?
AR Hypotonicity Hyporeflexia Fatal Tongue fasciculations Poor suck reflex Abdominal respirations
Characteristics of Wolfart-Kugelberg-Welander (juvenile proximal chronic spinal muscular atrophy)?
AR Slowly progressive Fasciculations Proximal Weakness Resembles myopathy
Characteristics of adult onset spinal muscular atrophy?
Sporadic (some familial)
Proximal, distal weakness
Hypotonicity
Hyporeflexia
Mutation in Werdnig-Hoffman?
‘Survival motor neuron gene’ on chromosome 5q
When and how do patients with Werdnig-Hoffman die?
Early in life
Respiratory failure
Frog leg posture?
Hips abducted due to weakness
Seen in Werdnig-Hoffman
When does Juvenile spinal muscular atrophy (Kugelberg-Welander)present? What does it resemble?
Childhood
Muscular dystrophy
What does the EMG show in patients with Kugelberg Welander?
Serum CK?
Denervation changes
Normal
Mutation in Kugelberg Welander?
‘Survival Motor Neuron gene’ on chromosome 5q
What is absent both infantile and juvenile spinal muscular atrophy? What separates the two?
SMN1
SMN2 is longer in juvenile compared to infantile
Characteristic of progressive bulbar palsy?
Sporadic Fasciculations Bulbar (innervated by neurons of the medulla) muscles weakness Rapidly progressive --> classic ALS Tongue and palate atrophy
Characteristics of Amyotrophic Lateral Sclerosis?
Mostly sporadic (some familial) Hyperreflexia Spasticity Muscle atrophy Fasciculations Tongue atrophy Rapidly progressive
Characteristics of Progressive Lateral sclerosis?
Sporadic Involves ONLY the UMNs Spasticity Hyperreflexia Benign course
Characteristics of Progressive spinal muscular atrophy?
Mostly sporadic Progressive weakness Muscle atrophy Fasciculations Arflexia
Signs/Symptoms of motor neuron disease?
Symmetrical or asymmetrical weakness Atrophy Increase/decrease reflexes - dependent upon corticospinal tract involvement (ALS) Fasciculations Normal sensation Normal nerve conduction velocities Denervation on EMG Increase # of motor units Muscle biopsy shows atrophic fibers & fiber grouping
What is the root cause of ALS?
Degeneration of the upper and lower motor neurons
What are bunina bodies?
Eosinophilic inclusions in anterior horn cell neurons. Ubiquitin accumulations
Possible genetic defects seen in ALS?
SOD gene mutations in chromosome 21 in AD familial ALS
Juvenile ALS: in chromosome 2q33 (9q34, 15q15, 8q21)
Mutation of 9q21, Xp
Expanded section of DNA on chromosome 9 in the gene C90RF72 is the most common cause of familial ALS with or without FTD
Increase in what can cause neuronal degeneration that can possible cause ALS?
Glutamate mediated excitotoxicity
In an EMG, what is the F wave? H wave? M wave
Delayed response to stimuli
Muscle stretch reflex to stimuli
Immediate response to stimuli
