45 year old Polish male with a past medical history of hyperthyroidism who presented to the emergency room complaining of two weeks history of upper and lower extremity numbness and stiffness involving his palms up to the arms and his feet. He reported fatigue and muscular pain all over his body for the last two months, and yellowish discoloration of his eyes that noticed few days ago. He denied any dietary restrictions. Physical examination reveals impaired position sense, impaired vibration sense and ‘glove and stocking’ peripheral paresthesia. Lab findings were significant for macrocytic anemia (with hemoglobin of 9, MCV of 109), indirect hyperbilirubinemia 5.1, high LDH (1630), high retic count (3.7 %) and low level of vitamin B12 (159). Antibodies profile showed positive anti intrinsic factor antibody, high thyroid peroxidase antibody (270) and high thyroglobulin antibody (2). Cervical Spine MRI showed heterogeneous T2 hyperintensity with scattered enhancement in the bilateral posterior dorsal columns of the cervical cord with an inverted “V” appearance extending from C2-T1. Thoracic cord MRI demonstrates mild posterior column hyperintensity without enhancement.
Subacute combined degeneration of spinal cord refers to degeneration of the posterior and lateral columns of the spinal cord as a result of vitamin B12 deficiency which is the most common cause and usually it is associated with pernicious anemia. It also can be caused by vitamin E deficiency and copper deficiency.
In the stomach, cobalamine is bound to intrinsic factor, a glycoprotein produced by the parietal cells of the stomach. The cobalamine-intrinsic factor complex is transported to the terminal ileum, where it binds to receptors on the brush border of enterocytes and is absorbed. The common setting of vitamin B12 deficiency is pernicious anemia, an autoimmune disorder caused by antibodies against gastric parietal cells and the intrinsic factor. Vitamin B12 deficiency may also result from Helicobacter pylori gastritis, surgical resection, tumors, and other conditions involving large parts of the stomach or the lower ileum.
Pernicious anemia can present with severe hematologic conditions and even neuropsychiatric illness known as megaloblastic madness.
Our patient has neurologic abnormalities that are consistent with vitamin B12 deficiency, which was confirmed with a low level of vitamin B12. In the absence of dietary restriction or a known cause of malabsorption, further evaluation is warranted; testing for pernicious anemia (anti–intrinsic factor antibodies) was positive. Parenteral vitamin B12 treatment (8 to 10 loading injections of 1000 μg each, followed by monthly 1000-μg injections) is an effective therapy. Effective vitamin replacement will correct blood counts in two months and correct or improve neurologic signs and symptoms within six months. After three months of parenteral injections the patient reported significant improvement in his symptoms, with almost complete resolution in six months. Early identification of vitamin B12 deficiency and prompt diagnosis of SCD could avoid any irreversible neurologic damages and prevent disability by early parenteral vitamin B12 treatment.