Anaemia of Chronic Disease
Definition
Anaemia of chronic disease (also known as anaemia of inflammation), refers to anaemia that develops in the context of chronic systemic inflammation, such as
- Infection
- IBD
- Autoimmune disease (e.g. RA, SLE, vasculitis, sarcoidosis)
- Malignancy
- Chronic organ failure
Pathophysiology
In chronic systemic inflammation, inflammatory cytokines (notably IL-6) stimulates hepatic production of hepcidin: [Ref]
- Hepcidin binds to and degrade ferroportin (iron channel on enterocytes and macrophages)
- ↓ GI iron absorption and prevent macrophages from releasing iron
- Functional iron deficiency (despite normal total body iron stores)
Additionally, inflammatory mediators suppress erythropoietin production and blunt the marrow response to erythropoietin. [Ref]
Clinical Features
There are no unique clinical features that distinguish anemia of chronic disease from other anemias based solely on symptoms. [Ref]
Anaemia of chronic disease typically presents with features of underlying cause of systemic inflammation, and non-specific features of anaemia: [Ref]
| Symptoms |
|
| Signs |
|
Investigation and Diagnosis
Key laboratory findings: [Ref]
- Normocytic, normochromic anaemia
- ↓ Hb
- Normal MCV (mean corpuscular volume)
- Normal MCH (mean corpuscular haemoglobin)
- Normal / ↓ reticulocyte count
- ↑ Ferritin (or normal)
- ↓ Iron
- ↓ TIBC and ↓ transferrin
- ↓ Transferrin saturation
Anaemia of chronic disease is usually normocytic at onset and may become microcytic if iron deficiency develops or co-exists [Ref]
It is common to confuse anaemia of chronic disease with iron deficiency anaemia, as both can cause microcytic / normocytic anaemia.
| Test | Iron deficiency anaemia | Anaemia of chronic disease |
|---|---|---|
| Serum iron | ↓ | ↓ |
| Ferritin | ↓ | ↑ (or normal) |
| TIBC | ↑ | ↓ |
| Transferrin | ↑ | ↓ |
| Transferrin saturation | ↓ | ↓ |
Note that ferritin can be normal or ↑ in iron deficiency anaemia, if there are concurrent infection / inflammation. In such cases, interpreting the TIBC, transferrin, and transferrin saturation becomes important.
Management
Treating the underlying cause is the cornerstone of management. [Ref]
Conditional management (not routinely offered to all patients): [Ref]
- Iron supplementation – reserved for those with confirmed absolute iron deficiency
- Erythropoiesis-stimulating agents – generally not recommended except in select cases (e.g. CKD, cancer)
- Red cell transfusion for severe symptomatic anaemia (typically haemoglobilin <7-8 g/dL)
Management is not clean-cut and straight forward, it should be individualised, taking into account anemia severity, symptoms, comorbidities, and risk factors.