Amyotrophic Lateral Sclerosis (Case Scenarios Series 56)

https://drive.google.com/file/d/1K-B1... Amyotrophic Lateral Sclerosis (ALS) is a progressive motor syndrome characterized by the simultaneous degeneration of both upper motor neurons (UMN) and lower motor neurons (LMN). Clinical Presentation ALS is defined by a "clinical signature" of UMN and LMN signs. UMN Signs (Pyramidal Release): Include spasticity, hyperreflexia, clonus, and the Babinski sign, which occur due to the loss of descending corticospinal modulation. LMN Signs (Denervation): Include muscle atrophy, fasciculations (spontaneous firing of denervated motor units), and weakness, resulting from the failure of the final common pathway. Preserved Functions: Sensory pathways, ocular motor nuclei, autonomic sphincters, and cognition are generally spared. Anatomical Basis The disease affects two distinct motor neuron populations: Upper Motor Neurons: Located in the motor cortex, internal capsule, and the corticospinal/corticobulbar tracts. Lower Motor Neurons: Found in the anterior horn cells of the spinal cord and cranial motor nuclei in the brainstem. Diagnosis and Monitoring ALS is diagnosed by identifying a pattern of diffuse motor-neuron degeneration through history, physical examination, EMG/NCS, and the exclusion of mimics like cervical myelopathy or multifocal motor neuropathy. Clinical monitoring focuses on bulbar (speech/swallowing) and respiratory functions (vital capacity, cough strength).Pathophysiology and Treatment Cellular mechanisms involve protein aggregation (TDP-43), RNA dysregulation, excitotoxicity, mitochondrial/axonal stress, and neuroinflammation. Treatment strategies include: Disease-Modifying Therapies: Riluzole, edaravone, and tofersen for patients with SOD1 mutations. Supportive Care: Respiratory support, nutritional/speech therapy, mobility aids, and psychosocial support.