Subacute combined degeneration of spinal cord
|Subacute combined degeneration of spinal cord|
|Classification and external resources|
Subacute combined degeneration of spinal cord, also known as Lichtheim's disease, refers to degeneration of the posterior and lateral columns of the spinal cord as a result of vitamin B12 deficiency (most common), copper deficiency or vitamin E deficiency. It is usually associated with pernicious anemia.
This condition can be due to a dietary deficiency of B12, malabsorption of B12 in the terminal ileum, lack of intrinsic factor secreted from gastric parietal cells, low gastric pH inhibiting attachment of intrinsic factor to ileal receptors.
The onset is gradual and uniform. The pathological findings of subacute combined degeneration consist of patchy losses of myelin in the dorsal and lateral columns. Patients present with weakness of legs, arms, trunk, tingling and numbness that progressively worsens. Vision changes and change of mental state may also be present. Bilateral spastic paresis may develop and pressure, vibration and touch sense are diminished. A positive Babinski sign may be seen. Prolonged deficiency of vitamin B12 leads to irreversible nervous system damage. HIV-associated vacuolar myelopathy can present with a similar pattern of dorsal column and corticospinal tract demyelination.
If someone is deficient in vitamin B12 and folic acid, the vitamin B12 deficiency must be treated first to avoid precipitating subacute combined degeneration of the cord (giving folic acid first will turn the remaining B12 into methylcobalamin which will not be able to participate in fatty acid metabolism).
Administration of nitrous oxide anesthesia can precipitate subacute combined degeneration in people with subclinical vitamin B12 deficiency, while chronic nitrous oxide exposure can cause it even in persons with normal B12 levels.
Serum B12, Malonic Acid, Methylmalonic Acid, Schilling Test, Complete Blood Count- looking for megaloblastic anemia if there is also folic acid deficiency or macrocytic anemia
MRI- T2 images may reveal increased signal within the white matter of the spinal cord predominately in the posterior columns but also may be in the spinothalamic tracts.
Therapy with vitamin B12 results in partial to full recovery, depending on the duration and extent of neurodegeneration.
- synd/492 at Who Named It?
- L. Lichtheim. Zur Kenntnis der perniciösen Anämie. Verhandlungen des Deutschen Kongress für innere Medizin, 1889, 6: 84-96. 42: 1887.
- Kumar N, Gross JB Jr, Ahlskog JE. Copper deficiency myelopathy produces a clinical picture like subacute combined degeneration. Neurology. 2004 Jul 13;63(1):33-9.
- Greenburg, Mark (2010). Handbook of Neurosurgery 7th Edition. New York: Thieme Publishers. pp. 1187–1188. ISBN 978-1-60406-326-4.