Anaemia of renal disease refers to an anaemia that precipitates due chronic kidney disease. It occurs due to a deficiency in erythropoietin (EPO) as the GFR declines.
Pathophysiology
It is a hypoproliferative anaemia as it results from EPO deficiency. EPO stimulates the production of the protein hormone erythroferrone which has been identified as an inhibitor of hepicidin. A lack of EPO results in a lack of erythroferrone, increasing hepcidin activity. Hepcidin disables ferroportin on the basolateral surface of enterocytes which allows iron to pass from enterocytes → bloodstream. This decrease in iron reduces haem production and thus RBC production and RBC survival.
The red blood cells tend to be normochromic and normocytic.
It tends to occur in stage 3a or 3b CKD.
😷 Presentation
- ⭐️ Fatigue and lethargy
- Dyspnoea
- Anorexia
- Pallor
- Signs and symptoms of CKD
🔍 Investigations
- A full blood count can be done, primarily looking at the haemoglobin value:
- Haemoglobin - <130g/L in men, <120g/L in non-pregnant women, and <110g/L in pregnant women.
- MCV should be normal as it is a normocytic anaemia (as with most anaemias of chronic disease).
- Peripheral blood smear will show normocytic and normochromic RBCs. RBC fragmentation may be seen.
- U&Es will show a reduced GFR (normally 90-120). Anaemia of renal disease tends to happen at stage 3a (45-59) or stage 3b (30-44).
Patients should be screened every 6-12 months with an FBC.
It is important to remember that the causes of anaemia are numerous and we need to assess for other causes (such as iron deficiency, vitamin B12 or folate deficiency for example) before simply attributing it to anaemia of renal disease.
🧰 Management
- 🥇 Treat underlying CKD.
- If the Hb falls <100g/L and there are symptoms of anaemia, we can consider an erythropoietin-stimulating agent.
- Epoetin alfa
- Darbepoeitin alfa
If they are iron-deficient as well, oral or IV iron supplementation should be provided.
🚨 Complications
Patients with CKD on EPO-stimualting agents have a higher risk of death and CVS complications if the Hb is normalised.