Pernicious anaemia is a type of anaemia caused by a lack of vitamin B12. Your body needs vitamin B12 to make healthy red blood cells. Without enough B12, red blood cells become large and fewer in number, leading to tiredness and other problems. It's often caused by an autoimmune condition where the body attacks cells needed to absorb B12.
Vitamin B12 deficiency, most commonly due to pernicious anaemia (autoimmune gastritis targeting intrinsic factor or parietal cells), leads to megaloblastic anaemia and potentially irreversible neurological damage. Diagnosis requires a combination of haematological, biochemical, and immunological investigations.
| Condition | Distinguishing Feature |
|---|---|
| Folate Deficiency | Similar megaloblastic anaemia, but typically lacks intrinsic factor antibodies and neurological symptoms are less common. Folate levels will be low. |
| Myelodysplastic Syndromes (MDS) | Can present with macrocytosis and pancytopenia. Bone marrow biopsy is crucial for diagnosis, showing dysplastic haematopoiesis. |
| Alcoholic Liver Disease | Can cause macrocytosis due to direct toxic effects on bone marrow and poor nutrition. Liver function tests and history of alcohol intake are key. |
| Hypothyroidism | Can lead to macrocytosis and anaemia. Thyroid function tests are essential for diagnosis. |
| Medication-induced Macrocytosis (e.g., phenytoin, azathioprine) | Requires careful medication history review and exclusion of other causes. |
| Other Malabsorption Syndromes (e.g., Crohn's disease, coeliac disease) | May cause B12 malabsorption but often accompanied by other nutrient deficiencies and specific gastrointestinal symptoms. |
Management involves prompt parenteral (intramuscular or subcutaneous) vitamin B12 replacement, typically hydroxocobalamin or cyanocobalamin, to replete body stores and correct anaemia. Neurological symptoms require aggressive and prolonged treatment, with ongoing monitoring for response and potential complications.