This patient's presentation of progressive neurologic deterioration after ileal resection is most suggestive of subacute combined degeneration due to vitamin B12 deficiency.
Vitamin B12 functions as a cofactor for both homocysteine methyltransferase and methylmalonyl-CoA mutase. It is found only in animal products (meat and dairy); however B12 may be stored in the liver, with reserves often lasting many years. Deficiency may be caused by pernicious anemia, gastric bypass surgery, terminal ileum resection, malabsorption, bacterial overgrowth of the bowel, or a vegan diet. Deficiency of vitamin B12 presents as a macrocytic, megaloblastic anemia with hypersegmented neutrophils as well as peripheral and central neurologic symptoms, paresthesias and suabacute combined degeneration.
Langan et al. review the screening, diagnosis, and management of vitamin B12 deficiency. Initial workup in a patient with suspected vitamin B12 deficiency should include a complete blood count, serum B12 level, homocysteine level, and methlymalonic acid level. A grossly low B12 level is diagnostic of deficiency; however, in cases of a low-normal or borderline serum B12 level, increased homocysteine and methylmalonic acid levels can be used to confirm a deficiency.
Briani et al. discuss the clinical and radiographic manifestations of subacute combined degeneration. It is characterized by symmetrically distributed abnormal sensation to light touch, temperature, and vibration. Additionally, subacute combined degeneration manifests with distorted proprioception and spastic weakness of the limbs. MRI shows a symmetric increase in T2 signal intensity in the posterior and lateral columns in the thoracic and cervical spinal cord.
Illustration A is a spinal cord specimen showing myelin degeneration/lesions in the dorsal columns and lateral corticospinal tracts. Illustration B shows a hypersegmented neutrophil, a common finding in vitamin B12 deficiency.
Answer 1: Vitamin B1 deficiency, most commonly caused by alcoholism or malnutrition, presents with Wernicke-Korsakoff syndrome or beriberi.
Answer 2: Vitamin B2 deficiency presents with cheilosis, corneal vascularization, and a magenta colored tongue.
Answer 3: Vitamin B3 deficiency presents with glossitis and pellagra (diarrhea, dermatitis, dementia).
Answer 4: Vitamin B6 deficiency manifests with convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemias, and cheilosis.
Langan RC, Zawistoski KJ. Update on vitamin B12 deficiency. Am Fam Physician. 2011 Jun 15;83(12):1425-30.
PMID:21671542 (Link to Abstract)
Briani C, Dalla Torre C, Citton V, Manara R, Pompanin S, Binotto G, Adami F. Cobalamin deficiency: clinical picture and radiological findings. Nutrients. 2013 Nov 15;5(11):4521-39. doi: 10.3390/nu5114521.
PMID:24248213 (Link to Abstract)