Subacute combined degeneration of the cord
Updates to Article Attributes
Subacute combined degeneration of the cord (SCD) is caused by a vitamin B12 deficiency.
Epidemiology
Most common in patients older than 40 and especially older than 60 7.
Clinical presentation
The clinical presentation of SCD is usually paresthesia in the hands and feet, with progression to sensory loss, gait ataxia, and distal weakness, especially in the legs.
Pathology
Aetiology
In the developed world where nutrition is good, it tends to result most commonly frompernicious anaemia. Other possible causes includeCrohn's disease and other causes ofterminal ileitis. Strict vegetarians or those who are undernourished may develop sufficient deficiencies to develop SCD. SCD can be initiated and exacerbated in these groups by nitrous oxide anaesthesia and abusers of nitrous oxide have also been reported to develop SCD3.
Radiographic features
MRI
Most commonly there is symmetric bilateral high signal within the dorsal columns. This appearance has been described as the "inverted V sign" 4. The signal changes typically begin in the upper thoracic region, with ascending or descending progression 5. The lateral corticospinal tracts, and sometimes lateral spinothalamic tract may also be involved. Although very unusual, there has been at least one described case of anterior cord involvement 6. Usually no enhancement. Often there is cerebral white matter change also. Both spinal and cerebral changes resolve after correction of B12 deficiency.
Treatment and management
- diagnosis may be confirmed by serum vitamin B12 levels
- patient needs to be evaluated for pernicious anaemia
- therapy is vitamin B12 replacement
- approximately half will completely recover7
Differential diagnosis
Clinical differential diagnosis can be broad.
On imaging the differential includes:
-
demyelination
- multiple sclerosis: also affects dorsal columns but usually over a shorter length
- transverse myelitis: although longer length, usually not restricted to dorsal columns
- infectious causes
- HIV vacuolar myelopathy: may appear very similar.
- herpes viruses myelitis
- syphilis (tabes dorsalis)
- inflammatory processes
- ischaemia
- neoplasms
-
astrocytoma: not particularly of dorsal columns. usually, more cord expansion
. often; often enhance. -
ependymoma: not particularly of dorsal columns. usually, more cord expansion
. often; often enhance
-
astrocytoma: not particularly of dorsal columns. usually, more cord expansion
-<p><strong>Subacute combined degeneration of the cord (SCD) </strong>is caused by a <a href="/articles/vitamin-b12">vitamin B12</a> deficiency.</p><h4>Epidemiology</h4><p>Most common in patients older than 40 and especially older than 60 <sup>7</sup>. </p><h4>Clinical presentation</h4><p>The clinical presentation of SCD is usually paresthesia in the hands and feet, with progression to sensory loss, gait ataxia, and distal weakness, especially in the legs.</p><h4>Pathology</h4><h5>Aetiology</h5><p>In the developed world where nutrition is good, it tends to result most commonly from <a href="/articles/pernicious-anaemia">pernicious anaemia</a>. Other possible causes include <a href="/articles/crohn-disease-1">Crohn's disease</a> and other causes of <a href="/articles/terminal-ilitis">terminal ileitis</a>. Strict vegetarians or those who are undernourished may develop sufficient deficiencies to develop SCD. SCD can be initiated and exacerbated in these groups by nitrous oxide anaesthesia and abusers of nitrous oxide have also been reported to develop SCD <sup>3</sup>. </p><h4>Radiographic features</h4><h5>MRI</h5><p>Most commonly there is symmetric bilateral high signal within the dorsal columns. This appearance has been described as the "inverted V sign <sup>4</sup>. The signal changes typically begin in the upper thoracic region, with ascending or descending progression <sup>5</sup>. The lateral corticospinal tracts, and sometimes lateral spinothalamic tract may also be involved. Although very unusual, there has been at least one described case of anterior cord involvement <sup>6</sup>. Usually no enhancement. Often there is cerebral white matter change also. Both spinal and cerebral changes resolve after correction of B12 deficiency.</p><h4>Treatment and management</h4><ul>- +<p><strong>Subacute combined degeneration of the cord (SCD) </strong>is caused by a <a href="/articles/vitamin-b12">vitamin B12</a> deficiency.</p><h4>Epidemiology</h4><p>Most common in patients older than 40 and especially older than 60 <sup>7</sup>. </p><h4>Clinical presentation</h4><p>The clinical presentation of SCD is usually paresthesia in the hands and feet, with progression to sensory loss, gait ataxia, and distal weakness, especially in the legs.</p><h4>Pathology</h4><h5>Aetiology</h5><p>In the developed world where nutrition is good, it tends to result most commonly from <a href="/articles/pernicious-anaemia">pernicious anaemia</a>. Other possible causes include <a href="/articles/crohn-disease-1">Crohn disease</a> and other causes of <a href="/articles/terminal-ilitis">terminal ileitis</a>. Strict vegetarians or those who are undernourished may develop sufficient deficiencies to develop SCD. SCD can be initiated and exacerbated in these groups by nitrous oxide anaesthesia and abusers of nitrous oxide have also been reported to develop SCD <sup>3</sup>. </p><h4>Radiographic features</h4><h5>MRI</h5><p>Most commonly there is symmetric bilateral high signal within the dorsal columns. This appearance has been described as the "inverted V sign" <sup>4</sup>. The signal changes typically begin in the upper thoracic region, with ascending or descending progression <sup>5</sup>. The lateral corticospinal tracts, and sometimes lateral spinothalamic tract may also be involved. Although very unusual, there has been at least one described case of anterior cord involvement <sup>6</sup>. Usually no enhancement. Often there is cerebral white matter change also. Both spinal and cerebral changes resolve after correction of B12 deficiency.</p><h4>Treatment and management</h4><ul>
-<li>approximately half will completely recover <sup>7</sup>- +<li>approximately half will completely recover <sup>7</sup>
-<a href="/articles/astrocytic-tumours">astrocytoma</a>: not particularly of dorsal columns. usually, more cord expansion. often enhance.</li>- +<a href="/articles/astrocytic-tumours">astrocytoma</a>: not particularly of dorsal columns. usually, more cord expansion; often enhance</li>
-<a href="/articles/ependymoma">ependymoma</a>: not particularly of dorsal columns. usually, more cord expansion. often enhance</li>- +<a href="/articles/ependymoma">ependymoma</a>: not particularly of dorsal columns. usually, more cord expansion; often enhance</li>
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