B12 folate deficiency
| Headline | |
|---|---|
| Etiology | Folate absorbed in jejunum → ↓ supply, ↑ demand (pregnancy, haemolysis), antifolates (MTX, phenytoin). Malabsorption: pernicious anaemia (autoimmune atrophic gastritis) Functional B12 deficiency - from nitrous oxide misuse |
| Epidemiology | |
| Clinical presentation | - peripheral neuropathy, symmetrical sensory/LMN loss + symmetrical motor/UMN signs (B12>folate) - Classically: extensor plantars, absent knee jerk, absent ankle jerk. Ddx: |
| Pathogenesis | |
| Diagnostic investigations | FBC: ↓ Hb, ↑ MCV, retics ↓/N Blood film: megaloblastic anaemia |
| Management | Urgent referral if neurological symptoms present NICE. B12 before folic acid 5mg/day PO 4/12 - if B12 insufficient, ⚠ subacute combined cord degeneration - Oral B12 or IM hydroxycobalamin - Consider diet change Complications: |
| Prevention |