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Age / Sex : 42 / M
Chief complaint: tingling sensation of bilateral limbs
(7 years ago, subtotal gastrectomy due to ulcer perforation)
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)
Courtesy: 이재혁(Yi Jae Hyuck), 경북대병원(Kyungpook National University Hospital)
Diagnosis: Subacute combined degeneration of the spinal cord
Discussion
Findings:
High singal intensity on T2WI, involving the cervical and
the thoracic spinal cord in bilateral dorsolateral columns
Diagnosis: Subacute combined degeneration of the spinal cord
Discussion:
Subacute
combined degeneration of spinal cord is a result of myelin damage caused by
deficiency of vitamin B12 (cyanocobalamin). Decreased B12 levels impair
function of Methionine Synthetase and Methylmalonyl CoA mutase. This leads to
production of abnormal fatty acids and elevated levels of Methylmalonic acid,
which are toxic to myelin. Swelling of myelin sheaths is followed by astrocytic
gliosis. Similar impairment of Methionine synthetase is also seen in cases
where NO (nitrous oxide) has been used for anesthesia, possible cause being
preexisting subclinical B12 deficiency.
B12
deficiency is mostly caused by GI malabsorption (pernicious anemia,
post-gastrectomy state, Crohn disease, and celiac disease) and malnutrition.
Clinical
presentation is with paresthesia, loss of position and vibration sense and
progressive spastic and ataxic weakness. Optic atrophy and disturbed mental
function (megaloblastic madness) may also be associated. Visual disturbance due
to optic neuritis may also be seen.
On
MRI, hyperintensity of the Cervical &/or Dorsal cord is seen involving the posterior columns.
Similar changes may be seen in the cerebellum and brain stem. Cord expansion
due to edema may also be seen. MRI also shows multi-segment cord involvement.
Chronic cases may show signal change on T1 images and segmental atrophy of the
cord. Lateral column involvement,
even if clinically present, is not demonstrable on imaging.
References:
1. MR findings in subacute combined
degeneration of the spinal cord: a case of reversible cervical myelopathy, AJR 2000;174:863-865
2. Subacute combined degeneration of
cord (SCD) – case report and review of literature, Neuroradiology 2003;13(4):431-432
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