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Amyotrophic Lateral Sclerosis

- See: - El Escorial Revisited: Revised Criteria for the Diagnosis of Amyotrophic Lateral Sclerosis

- Disorders of Nerves:
- Anterior Horn Cell Disorders:
- ALS Society Homepage

- Discussion:
- amyotrophic lateral sclerosis is a syndrome characterized by both upper and lower motor neuron disease;
- destruction of anterior horn cells & descending corticospinal tracts;
- some patients will demonstrate more upper motor neuron disease where as others show more lower motor dz;
- disease is generally acquired and etiology is unknown;
- most common in middle & later life & rarely occurs in childhood;
- clinical course:
- symptoms include progressive muscle wasting, weakness, & fasciculations;
- symptoms may begin in arms or legs or may begin with slurred speech;
- muscles are affected randomly, but eventually respirator failure develops;
- in 25% of pts the dz is slowly progressive, however, most pts follow a more fulminant course to early death;
- diff dx: it is important to consider other conditions since these can be successfully treated;
- multifocal motor neuropathy
- can be treated with cyclophosphamide or IV immune globulin;
- cervical spondylotic myelopathy
- X-linked spinobulbar muscular atrophy
- (Kennedy's disease): slowly progressive lower motor neuron disease of the proximal limbs, usually affecting the upper extremities and bulbar muscles;
- myasthenia gravis
- lead intoxication
- lyme disease


- Exam:
- clinical presentation is often painless weakness of the arms or legs;
- manifests with lower motor neuron symptoms of muscle wasting, weakness, and fasciculation;
- contralateral limb may have hyperreflexia;
- the ocular muscles and voluntary muscles to the bladder and bowel are often spared;
- sensation is always normal;
- clonus:
- Clonus after a Stroke


- Biopsy:
- muscle bx is particularly useful in dx of spinal muscular atrophy or amyotrophic lateral sclerosis.
- degeneration occurs in small clusters of fibers (small group atrophy).
- later on, larger numbers of axons degenerate;
- those fibers supplied by axons not yet involved remain normal;

- EMG Findings:
- normal or low compound motor action potentials
- normal sensory-nerve action potentials
- evidence of both active (fibrillation potentials, positive sharp waves, and fasciculation potentials)
- chronic (large-amplitude, large-duration motor-unit action potentials) denervation in multiple sites without conduction block


References

Amyotrophic Lateral Sclerosis.

Case records of the Massachusetts General Hospital. Case 22-2006--a 77-year-old man with a rapidly progressive gait disorder.

Study Says Brain Trauma Can Mimic A.L.S.