Which gross findings are characteristic of amyotrophic lateral sclerosis (ALS) (Lou Gehrig disease)?

Updated: Apr 28, 2014
  • Author: Hidehiro Takei, MD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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In amyotrophic lateral sclerosis (ALS), the anterior nerve roots in the spinal cord are gray and thin or atrophic as compared with the posterior sensory roots (see the image below); this finding is more pronounced in the cervical and lumbar enlargements. The hypoglossal nerves are also affected. The bilateral pyramids in the medulla oblongata may be flattened.

Amyotrophic lateral sclerosis. Grossly, spinal cor Amyotrophic lateral sclerosis. Grossly, spinal cord shows gray and thin or atrophic anterior nerve roots.

The brain is usually unremarkable; however, the precentral gyrus (primary motor cortex) may be atrophic, especially in severe cases. In ALS cases with accompanying dementia, the brain may exhibit frontal (and temporal) lobe atrophy.

At autopsy, widespread muscle atrophy and wasting affecting the proximal and distal extremities, tongue, intercostal muscles, and diaphragm are noted. The skeletal muscle is grossly pale. Because of the loss of muscle bulk through atrophy, rigor mortis is usually absent in advanced stages of ALS disease.

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