Contribution of spinal MRI for unsuspected cobalamin deficiency in isolated sub-acute combined degeneration

A Brief Review on Vitamin B12 Deficiency Looking at Some Case Study Reports in Adults

In the era of evidence-based medicine, the randomized clinical trial corresponds to the top step in the qualitative scale of the evidence available in the literature, while small series of cases or the description of individual cases occupy the last place. However, the latter represent an important part of clinical practice and have significantly influenced the evolution of medicine, contributing significantly to the advancement of scientific knowledge. Vitamin B₁₂ deficiency shares several common symptoms that affect several tissues and organs with health aliments, so its diagnosis could be unobvious for the broad array of its effects and investigation methods used. In this review, we focused our attention on some case reports related to the vitamin B₁₂ deficiency associated to anemia, neurologic disorders, and hyperhomocysteinemia. B₁₂ deficiency reversal is simply achieved by prompt therapy, even though it is not the same for several disorders.

Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders

PURPOSE

We summarized the clinical manifestations, laboratory and electrodiagnostic characteristics and magnetic resonance imaging (MRI) findings of nitrous oxide (N₂O) abuse-induced neurological disorders.

PATIENTS AND METHODS

We retrospectively reviewed 33 patients with N₂O abuse-induced neurological disorders and reported their demographic data, clinical manifestations, laboratory examinations, nerve conduction studies, together with spinal and brain MRI.

RESULTS

The most frequent clinical manifestations included numbness and weakness in the extremities and unspecified gait disturbance. Low serum vitamin B₁₂ levels were found in 9 patients, and high homocysteine levels were noted in 27 patients. Nerve conduction studies showed a sensory-motor neuropathy. Sixteen patients showed bilateral high-intensity T2 signal within the posterior column on spinal MRI, and four patients showed cerebral white matter lesions on brain MRI.

CONCLUSION

N₂O abuse has become a significant public health problem because of the severe neurological disorders related to chronic abuse. Clinical physicians should be aware of the toxic effects of N₂O.

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.

A retrospective study of 23 cases with subacute combined degeneration

PURPOSE

To study retrospectively the diverse presentations, ancillary tests and neuroimaging in patients with subacute combined degeneration (SCD).

METHODS

Twenty-three Chinese patients with SCD were included in this study. The clinical presentations and laboratory data including comprehensive metabolic panel, serum folic acid, vitamin B12 levels, gastroscopy and images of spinal cord on magnetic resonance imaging (MRI) were evaluated. Rating scales for localizations of lesions and functional disabilities were used to define the severity of neurological impairment.

RESULTS

No difference was found between men and women in the age of disease onset. For most of the patients, sensory symptoms, oftentimes as initial symptoms, occurred earlier than motor symptoms. The signs of the disease were more obvious than the symptoms. Six patients had sensory deficit levels mimicking transverse myelopathy. Anemia was not always detected in our patients with SCD. Normal or even elevated serum levels of vitamin B12 were found in seven patients. Spinal cord lesions on MRI were observed in six patients and the clinical and neuroimaging findings were not necessarily consistent.

CONCLUSIONS

The sensory symptoms occur earlier than the motor symptoms in SCD patients. SCD patients may have sensory deficit level. Normal or even elevated serum levels of vitamin B12 may occur in patients with SCD.

Subacute combined degeneration without nutritional anemia

Subacute combined degeneration (SCD) is a rare neurological complication of cobalamin deficiency, characterized by demyelination of the dorsal and lateral spinal cord. The diagnosis and treatment of SCD can be delayed if a patient does not present with clear clinical and laboratory signs of nutritional anemia, which has a marked effect on neurological recovery. We report a 62-year-old man with SCD with a history of gastric cancer and chronic alcoholism who presented with ataxia, gait disturbance, urinary incontinence, and limb weakness, but without other clinical or laboratory signs of cobalamin deficiency. The SCD diagnosis was confirmed by 3-Tesla MRI, which showed intramedullary signal alteration in the posterior columns of the entire spinal cord.

Cobalamin C defect: natural history, pathophysiology, and treatment

Cobalamin C (Cbl-C) defect is the most common inborn cobalamin metabolism error; it causes impaired conversion of dietary vitamin B12 into its two metabolically active forms, methylcobalamin and adenosylcobalamin. Cbl-C defect causes the accumulation of methylmalonic acid and homocysteine and decreased methionine synthesis. The gene responsible for the Cbl-C defect has been recently identified, and more than 40 mutations have been reported. MMACHC gene is located on chromosome 1p and catalyzes the reductive decyanation of CNCbl. Cbl-C patients present with a heterogeneous clinical picture and, based on their age at onset, can be categorized into two distinct clinical forms. Early-onset patients, presenting symptoms within the first year, show a multisystem disease with severe neurological, ocular, haematological, renal, gastrointestinal, cardiac, and pulmonary manifestations. Late-onset patients present a milder clinical phenotype with acute or slowly progressive neurological symptoms and behavioral disturbances. To improve clinical course and metabolic abnormalities, treatment of Cbl-C defect usually consists of a combined approach that utilizes vitamin B12 to increase intracellular cobalamin and to maximize deficient enzyme activities, betaine to provide a substrate for the conversion of homocysteine into methionine through betaine-homocysteine methyltransferase, and folic acid to enhance remethylation pathway. No proven efficacy has been demonstrated for carnitine and dietary protein restriction. Despite these measures, the long-term follow-up is unsatisfactory especially in patients with early onset, with frequent progression of neurological and ocular impairment. The unfavorable outcome suggests that better understanding of the pathophysiology of the disease is needed to improve treatment protocols and to develop new therapeutic approaches.

Cervical spondylotic myelopathy

BACKGROUND

Cervical spondylosis is part of the aging process and affects most people if they live long enough. Degenerative changes affecting the intervertebral disks, vertebrae, facet joints, and ligamentous structures encroach on the cervical spinal canal and damage the spinal cord, especially in patients with a congenitally small cervical canal. Cervical spondylotic myelopathy (CSM) is the most common cause of myelopathy in adults.

REVIEW SUMMARY

The anatomy, pathophysiology, clinical presentation, differential diagnosis, diagnostic investigation, natural history, and treatment options for CSM are summarized. Patients present with signs and symptoms of cervical spinal cord dysfunction with or without cervical nerve root injury. The condition may or may not be accompanied by pain in the neck and/or upper limb. The differential diagnosis is broad. Imaging, typically with magnetic resonance imaging, is the most useful diagnostic tool. Electrophysiologic testing can help exclude alternative diagnoses. The effectiveness of conservative treatments is unproven. Surgical decompression improves neurologic function in some patients and prevents worsening in others, but is associated with risk.

CONCLUSIONS

Neurologists should be familiar with this very common condition. Patients with mild signs and symptoms of CSM can be monitored. Surgical decompression from an anterior or posterior approach should be considered in patients with progressive and moderate to severe neurologic deficits.