Neurology Quiz: Motor Neuron Lesions and Palsy

Study Notes

Associated with fasciculations
Not associated with spasticity, clonus, or preserved reflexes in atrophic muscles

Characterized by progressive atrophy and weakness of hands and forearms, spasticity of legs, brisk jaw jerk
Neuroimaging shows increased signal in corticospinal tracts on T2-weighted MRI
Also known as Lou Gehrig's disease
Primary lateral sclerosis is a progressive isolated UMN disorder
Familial ALS is caused by genetic mutations of superoxide dismutase
Involves anterior horn cell and corticospinal tract
Features include split-hand syndrome, frontotemporal dementia, dropped head syndrome, tongue fasciculations, and spastic dysarthria
Confirmatory test of choice is none of the above
Riluzole is the only drug known to improve survival in ALS
Mechanism of action of riluzole includes inhibition of glutamate release, but not inhibition of GABA reuptake, NMDA glutamate receptor antagonism, or kainate glutamate receptor antagonism
Edaravone is a novel free-radical scavenger approved for use in ALS

Cerebellar ataxia characterized by dysdiadochokinesis, ataxia, and hypotonia, but not resting tremor
Paraneoplastic cerebellar ataxia associated with carcinoma breast, Hodgkin's lymphoma, and non-small-cell lung cancer, but not carcinoma ovary
Most common inherited ataxia is Friedreich's ataxia
Vitamin B12 deficiency can give rise to paresthesia, optic atrophy, peripheral neuropathy, but not myopathy
Subacute combined degeneration of spinal cord due to Vitamin B12 deficiency, involves posterior column and corticospinal tracts, and characterized by brisk deep tendon reflexes
Tabes dorsalis characterized by ataxia, Argyll Robertson pupil, bladder dysfunction, but not hyperreflexia
Ataxia telangiectasia presents in childhood, shows autosomal recessive mode of inheritance, and is characterized by ataxia, telangiectasia, and immunodeficiency