Anaemia, haemolytic

D59.0-1

DESCRIPTION

Anaemia due to destruction of red blood cells. Destruction may be due to:

  • Extracellular factors such as auto-immunity or mechanical factors, e.g. disseminated intravascular coagulation (DIC), hypersplenism, mechanical heart valves.
  • Abnormalities of the cell membrane, e.g. hereditary spherocytosis.
  • Enzymes, e.g. G6PD deficiency.
  • Haemoglobin abnormalities, e.g. sickle cell anaemia, thalassaemia.
  • Thrombotic thrombocytopenic purpura is a life-threatening emergency, if treated early. Immediate referral to specialist unit for plasma infusion or exchange is necessary (see : Thrombotic thrombocytopenic purpura-Haemolytic uraemic syndrome).

Investigations

  • Evidence of haemolysis: anaemia, reticulocytosis, decreased haptoglobin, increased lactate dehydrogenase (LDH) and unconjugated hyperbilirubinaemia.
  • FBC smear: Spherocytes often reported
  • Coombs’ test (direct antiglobulin) is usually positive with autoimmune haemolysis.
  • HIV status.

GENERAL MEASURES

Treat the underlying cause.
Do not transfuse prior to appropriate investigations, unless anaemia is severe.
In situations of life-threatening anaemia, transfuse the most compatible unit of red blood cells and get specialist advice urgently. Coombs-positive haemolytic anaemia may be technically difficult to cross match.
Efficacy of transfusion is limited by the shortened red cell survival due to haemolysis.
In G6PD deficiency, avoid drugs known to cause haemolysis, including aspirin, sulphonamides (including cotrimoxazole), dapsone and primaquine.
In patients with cold agglutinins all transfusions must be given through a blood warmer to avoid cold-induced haemolysis.

MEDICINE TREATMENT

All patients:
Because of high red cell turnover, supplement with:

  • Folic acid, oral, 5 mg daily.

Autoimmune haemolytic anaemia

Treat under specialist supervision.

  • Prednisone, oral.
    • Initial dose:1 mg/kg daily, until Hb stable and >10 g/dL.
    • Taper slowly and monitor Hb at least once weekly. (Refer to PREDNISONE, ORAL for an example of a dose reduction regimen).
    • Glucocorticoids should be tapered slowly, when there is normalization of the haemoglobin and LDH. The patient should be monitored for recurrence following cessation of treatment.
    • As these conditions can often be life-threatening, specialist advice should be sought as early as possible after diagnosis.

LoEIII [6]

REFERRAL/CONSULTATION

If inadequate response:

  • haemolysis remains severe for 3 weeks at prednisone doses of 1 mg/kg, if remission cannot be maintained on low doses of prednisone, or if the patient has intolerable adverse effects or contraindications to glucocorticoids.

Refer to specialist for second-line treatment:

Immunosuppresive therapy is needed in some cases, initiated by specialists.

LoEIII [7]