Clinical reasoning: A young woman with rapid mental deterioration and leukoencephalopathy: a treatable cause

A case of subacute combined spinal cord degeneration and suspected leukoencephalopathy associated with vitamin B12 deficiency showing improved imaging findings after vitamin B12 administration

We report a case of subacute combined spinal cord degeneration (SCD) caused by vegetarianism and autoimmune gastritis, which is rarely reported in Japan, and which showed improvement in symptoms and imaging findings after vitamin B₁₂ administration. As delayed treatment can lead to irreversible damage, we suggest that patients with characteristic abnormal signals in the posterior cervical cord should be examined while considering the possibility that SCD may occur even in the absence of a history of gastrectomy or heavy drinking. We also describe the patient's reversible abnormal signals in the cerebral white matter on magnetic resonance imaging, indicative of an early sign of leukoencephalopathy associated with vitamin B₁₂ deficiency. J. Med. Invest. 69 : 299-301, August, 2022.

Guidelines for diagnosis and management of the cobalamin-related remethylation disorders cblC, cblD, cblE, cblF, cblG, cblJ and MTHFR deficiency

BACKGROUND

Remethylation defects are rare inherited disorders in which impaired remethylation of homocysteine to methionine leads to accumulation of homocysteine and perturbation of numerous methylation reactions.

OBJECTIVE

To summarise clinical and biochemical characteristics of these severe disorders and to provide guidelines on diagnosis and management.

DATA SOURCES

Review, evaluation and discussion of the medical literature (Medline, Cochrane databases) by a panel of experts on these rare diseases following the GRADE approach.

KEY RECOMMENDATIONS

We strongly recommend measuring plasma total homocysteine in any patient presenting with the combination of neurological and/or visual and/or haematological symptoms, subacute spinal cord degeneration, atypical haemolytic uraemic syndrome or unexplained vascular thrombosis. We strongly recommend to initiate treatment with parenteral hydroxocobalamin without delay in any suspected remethylation disorder; it significantly improves survival and incidence of severe complications. We strongly recommend betaine treatment in individuals with MTHFR deficiency; it improves the outcome and prevents disease when given early.