Learning objectives
To describe the neuroradiological syndromes that may result from cobalamine deficiency.
To provide illustrative cases of the imaging features of these different syndromes,
mainly in MRI.
To demonstrate the possible reversibility of these lesions after replacement therapy.
Background
Vitamin B12 or cobalamin is produced by bacteria in the large bowel of humans and by external bacteria and fungi.
However,
cobalamin from the former source is not absorbed,
and humans need to introduce it solely from the diet.
The major sources of cobalamin are animal proteins.
There are many conditions in which vitamin B12 deficieny may develop.
Their aetiology can be divided into three main categories: inadequate intake (vegetarians),
malabsorption; and other conditions (nitrous oxide anaesthesia,
transcobalamin II deficiency),
malabsorption being the most important....
Findings and procedure details
In the nervous system,
cobalamine deficiency results in defective myelin synthesis,
leading to several neurological dysfunctions that may affect both the central (brain,
spinal cord and optic nerve) and the peripheral nervous system.
Peripheral nerve abnormalities and optic nerve involvement are usually too subtle to be recognized by current ultrasound,
CT and MRI,
while nerve conduction studies are the preferred diagnostic tools in these cases.
Nevertheless,
neuroimaging is of choice for the remaining CNS manifestations,
including subacute combined degeneration,
decrease in total brain volume and...
Conclusion
Imaging plays an important role in the diagnosis of the central manifestations of cobalamine deficiency,
including subacute combined degeneration,
decrease in total brain volume and periventricular white matter lesions.
Radiologist should be aware of the different imaging patters that may result from this deficiency,
as an early diagnosis is crucial for starting replacement therapy and avoiding irreversible neurological damage.
References
Chiara Briani,
Chiara Dalla Torre,
Valentina Citton,
et al.
Cobalamin Deficiency: Clinical Picture and Radiological Findings.
Nutrients 2013;5:4521–4539.
V.K.
Katsaros,
F.X.
Glocker,
B.
Hemmer,
et al. MRI of spinal cord and brain lesions in subacute combined degeneration. Neuroradiology 1998;40:716-719.
C.C.
Tangney,
N.T.
Aggarwal,
H.
Li,
et al.
Vitamin B12,
cognition,
and brain MRI measures.
A cross-sectional examination.
Neurology 2011;77:1276–1282.
Nihaak Reddy,
Harpreet Singh,
V.
V.
Hattiholi,
et al.
Reversible cerebral atrophy in vitamin B12 deficient infants after treatment.
Int J Biol Med Res.
2014;5:4612–4615.
Gwenaëlle...