Page 473 - Medicine and Surgery

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Chapter 12: Haemoglobin disorders and anaemia 469

Aetiology/pathophysiology Table 12.3 Conditions that may cause anaemia of chronic
Haem synthesis is abnormal with a failure of iron incor- disease
poration.Thereisaccumulationofironinthemitochon- Infections Subacute infective endocarditis,
dria of erythroblasts, which stain as a ring around the tuberculosis, osteomyelitis
nucleus (ring sideroblasts). Sideroblastic anaemia may Inflammation Rheumatoid arthritis, systemic
be congenital or acquired: lupus, erythematosus,
connective tissue disease
Congenital X-linked disease.

Chronic renal failure
Primary acquired sideroblastic anaemia is one of the Malignancy

myelodysplastic syndromes.
Secondary acquired sideroblastic anaemia may be

caused by drugs (e.g. isoniazid) or toxins such as lead Aetiology/pathophysiology
or alcohol. Anaemia may result from any chronic disease, see Ta-
ble 12.3. The exact mechanisms are unknown but may
Clinical features include the following:
Patients initially present with symptoms and signs of Bone marrow iron stores are not incorporated into
anaemia. As sideroblastic anaemia results in a microcytic developing erythrocytes.
hypochromic anaemia, it may be misdiagnosed as iron There is a relative resistance to erythropoetin.
deficiency. The anaemia is however refractory to iron Circulating red cells have a reduced life span.
supplementation. These changes may be mediated by cytokines such as
IL-1, TNF and interferon.
Investigations
The full blood count and film may reveal diamor-
Clinical features
phic red cells, i.e. there are two populations of cells Symptoms and signs of anaemia (see page 467).
–one normal sized and a population of microcytic
hypochromic cells. Investigations
Serum iron and ferritin are normal or raised. The anaemia is usually normocytic but may be slightly

Perl’s staining of bone marrow samples shows a microcytic. Serum iron is low but ferritin is normal or

ring of iron around the nucleus in erythrocyte pre- high. The total iron binding capacity is low. The ESR is
cursors. The presence of these ring sideroblasts are usually raised.
diagnostic.
Management
Management Treating the underlying cause may result in a resolution
Congenital sideroblastic anaemia may respond to pyri- of the anaemia. Erythropoeitin may be of benefit.
doxine. Primary acquired sideroblastic anaemia is
treated as for myelodysplastic syndrome (see page Macrocytic anaemia
481). In secondary acquired sideroblastic anaemia any
causative agent should be removed where possible.
Macrocytic normoblastic anaemia

Definition
Normocytic anaemia
Macrocytosis (large circulating red blood cells) are seen
with normal erythrocyte progenitor cells in the bone
Anaemia of chronic disease marrow (normoblasts).
Definition
Anaemia of chronic disease is a condition of impaired Aetiology/pathophysiology
iron use where haemoglobin is reduced but iron stores Macrocytic normoblastic anaemia may be physiologi-
are normal or high. cal (in pregnancy and in neonates), pathological, e.g.