{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,27]],"date-time":"2025-08-27T08:10:04Z","timestamp":1756282204103,"version":"3.44.0"},"reference-count":13,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Reports"],"accepted":{"date-parts":[[2015,4,24]]},"abstract":"<jats:p>We report a case of a 43-year-old man presenting with a 2-week history of painless ascending sensory disturbances, suspected to be suffering from acute inflammatory polyneuropathy. On clinical examination, deep tendon reflexes were preserved and muscle strength was 5\/5 everywhere. Gait was ataxic with positive Romberg test. Lumbar puncture was normal and electroneurography demonstrated demyelination. With spinal cord involvement centred on the posterior tracts on MRI, differential diagnosis focused on cobalamin deficiency. Initial laboratory work up showed nearly normal holotranscobalamin (43\u2005pmol\/L, normal&gt;50) suggesting no vitamin B<jats:sub>12<\/jats:sub> deficiency. Surprisingly, further testing including methylmalonic acid (3732\u2005nmol\/L, normal&lt;271) and homocysteine (48.5\u2005\u00b5mol\/L, normal&lt;10) showed an impairment of vitamin B<jats:sub>12<\/jats:sub>-dependent metabolism leading to the diagnosis of subacute combined degeneration. Only after repeated history taking did the patient remember having taken tablets containing cobalamin for 3\u2005days before hospitalisation. In case of B<jats:sub>12<\/jats:sub> deficiency, holotranscobalamin can rapidly normalise during supplementation, whereas methylmalonic acid and homocysteine might help to detect B<jats:sub>12<\/jats:sub> deficiency in patients who recently started supplementation.<\/jats:p>","DOI":"10.1136\/bcr-2014-208622","type":"journal-article","created":{"date-parts":[[2015,5,14]],"date-time":"2015-05-14T10:54:52Z","timestamp":1431600892000},"page":"bcr2014208622","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":8,"title":["Pitfalls in the diagnostic evaluation of subacute combined degeneration"],"prefix":"10.1136","volume":"2015","author":[{"given":"A","family":"Ulrich","sequence":"first","affiliation":[{"name":"Department of Neurology, University Hospital Z\u00fcrich, Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D","family":"M\u00fcller","sequence":"additional","affiliation":[{"name":"Institute of Clinical Chemistry, University Hospital Z\u00fcrich, Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M","family":"Linnebank","sequence":"additional","affiliation":[{"name":"Department of Neurology, University Hospital Z\u00fcrich, Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A A","family":"Tarnutzer","sequence":"additional","affiliation":[{"name":"Department of Neurology, University Hospital Z\u00fcrich, Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2015,5,14]]},"reference":[{"key":"2025082700442284000_2015.may14_1.bcr2014208622.1","doi-asserted-by":"publisher","DOI":"10.1038\/nrneurol.2014.121"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1497.2006.00525.x"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.3","doi-asserted-by":"publisher","DOI":"10.3390\/nu5114521"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.4","unstructured":"Antony AC . Megaloblastic anemias. In: Hoffman R , Benz EJ Jr , Shattil SJ, eds . Hematology: basic principles and practice. 5th edn. Philadelphia, PA: Elsevier Churchill Livingstone, 2009:473\u2013504."},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.5","doi-asserted-by":"publisher","DOI":"10.1001\/archneur.60.9.1296"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.6","doi-asserted-by":"publisher","DOI":"10.3945\/ajcn.111.013441"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.7","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2013.280490"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.8","doi-asserted-by":"publisher","DOI":"10.1179\/1476830513Y.0000000073"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.9","first-page":"273","article-title":"Vitamin B12 deficiency: a clinical and electrophysiological profile","volume":"45","author":"Puri","year":"2005","journal-title":"Electromyogr Clin Neurophysiol"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.10","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp.65.6.822"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.11","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/23.1.39"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.12","doi-asserted-by":"publisher","DOI":"10.1007\/s00415-010-5511-x"},{"key":"2025082700442284000_2015.may14_1.bcr2014208622.13","doi-asserted-by":"publisher","DOI":"10.1111\/j.1538-7836.2005.01141.x"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2014-208622","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,27]],"date-time":"2025-08-27T07:44:33Z","timestamp":1756280673000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2014-208622"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,5,14]]},"references-count":13,"alternative-id":["10.1136\/bcr-2014-208622"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2014-208622","relation":{},"ISSN":["1757-790X"],"issn-type":[{"type":"electronic","value":"1757-790X"}],"subject":[],"published":{"date-parts":[[2015,5,14]]}}}