Anaemia, haemolytic

D55–59

ANAEMIA, HAEMOLYTIC

DESCRIPTION

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

  • Corpuscular defects:
    • abnormalities of the cell membrane (e.g. hereditary spherocytosis),
    • enzyme abnormalities (e.g. G6PD deficiency), or
    • abnormal haemoglobin (e.g. sickle cell anaemia, thalassaemia).
  • Extra-corpuscular defects:
    • Autoimmune or isoimmune:
      idiopathic warm or cold antibodies,
      infection triggered e.g. Mycoplasma pneumonia,
      medicine related e.g. penicillin,
      secondary to autoimmune disorders e.g. SLE, juvenile arthritis,
      secondary to tumours e.g. lymphoma, thymoma.
    • Non-immune:
      secondary to microangiopathy e.g.: haemolytic uraemic syndrome,
      infections causing haemolysis e.g. malaria,
      miscellaneous causes, including hypersplenism.

DIAGNOSTIC CRITERIA

Clinical

  • Pallor, jaundice, fatigue.
  • Splenomegaly.

Investigations (before transfusion)

  • Full blood count.
  • Evidence of haemolysis:
    • anaemia,
    • decreased haptoglobin,
    • reticulocytosis,
    • unconjugated hyperbilirubinaemia,
    • increased lactate dehydrogenase (LDH),
    • urobilinogen in the urine.
  • Direct Coombs test (direct antiglobulin) is positive with autoimmune haemolysis.
  • Haemoglobin electrophoresis.
  • Renal function is abnormal in haemolytic uraemic syndrome.
  • Exclude other autoimmune disorders.
  • Consider underlying neoplasms.
  • In patients receiving recurrent transfusions (e.g. thalassaemia), monitor ferritin levels 3-monthly and discuss with your referral centre if elevated > 1000 mcg/L.

GENERAL AND SUPPORTIVE MEASURES

  • After appropriate investigations, transfuse the patient and then discuss with a paediatrician or paediatric haematologist.
  • Coombs-positive autoimmune haemolytic anaemia may require transfusion with the least incompatible blood (if cross-matching yields no compatible units).
  • In G6PD deficiency, avoid medicines known to cause haemolysis (e.g. aspirin, sulphonamides and primaquine) and be sure to give the patient a list of such medicines at discharge.

MEDICINE TREATMENT

Warm antibody autoimmune haemolytic anaemia
Under specialist supervision:

  • Prednisone, oral, 2 mg/kg/24 hours until a satisfactory response is obtained.
    • Continue treatment for a minimum of 4 weeks.
    • Taper dose slowly over several weeks while monitoring for relapse.

Chronic haemolytic anaemia
All patients indefinitely:

  • Folic acid, oral, 2.5 mg daily between birth and 6 months and 5 mg daily for > 5 kg and/or 6 months to 5 years.

SURGICAL TREATMENT

Splenectomy for hereditary spherocytosis with Hb < 10 g/dL and transfusion dependent but only after the child’s fifth birthday.

Pre-splenectomy immunization
2 weeks prior to surgery

  • Pneumococcus conjugate vaccine (PCV) 13, IMI, 0.5 mL followed by pneumococcus polysccharide (PPV) 23, IMI, 0.5 mL 8 weeks later.
  • Haemophilus influenza, type B (Hib) booster, IMI, 0.5 mL.
  • Meningococcal conjugate vaccine (MCV), IMI, 0.5mL.

Post splenectomy

  • Phenoxymethylpenicillin, oral, 12 hourly.
    • If < 5 years: 125 mg.
    • If > 5 years: 250 mg.
    • Give indefinitely until at least 18 years of age.
  • Annual influenza vaccine, IMI, 0.5 mL.
  • After splenectomy:
    • Pneumococcus conjugate vaccine (PCV) 13, IMI, followed by pneumococcus polysccharide (PPV)23, IMI (a month later).
    • Haemophilus influenza, type B (Hib) and meningococcal conjugate vaccine (MCV) booster.

Note: For catch up of routine conjugate pneumococcal vaccination

  • < 12 months of age: 3 dose series.
  • 12 months of age and older: 2 doses 8 weeks apart. (See Primary Healthcare Standard Treatment Guidelines,Immunisation ).

REFERRAL

  • Any child with haemolytic anaemia e.g. thalassaemia, especially those who are transfusion dependent (more than 10 transfusions) for assessment for chelation therapy.
  • All cases associated with evidence of haemolysis as above should be managed in consultation with a paediatrician or paediatric haematologist.

THALASSEMIA

D56

DESCRIPTION

Hereditary single gene defect causing abnormal production or translation of beta-globin mRNA, resulting in foetal haemoglobin (HbF) production. Presents with pallor, jaundice, fever, failure to thrive, abdominal distension and hepatosplenomegaly, bossing.

DIAGNOSTIC CRITERIA

Investigations

  • Microcytic hypochromic anaemia.
  • Haemoglobin electrophoresis.
  • Genetic studies.
  • Family screening.

MEDICINE TREATMENT

B Thalassaemia major – homozygous trait:
Monthly blood transfusion to maintain Hb between 9.5 and 14 g/dL.

REFERRAL

  • All cases for confirmation of diagnosis and a comprehensive care transfusion program.
  • Iron chelation therapy.

ANAEMIA SICKLE CELL

D57

DESCRIPTION

Haemolytic anaemia due to homozygous inheritance of the sickle cell gene.
Patients may experience complications:

  • Painful vaso-occlusive crises.
  • Haemolytic crises (usually secondary to infection).
  • Aplastic crises.
  • Thrombotic crises, e.g. acute chest syndrome, priapism or stroke.
  • Splenic sequestration.
  • Severe infections.

DIAGNOSTIC CRITERIA

Clinical

  • Pallor, jaundice, fatigue all of which may worsen abruptly (sequestration crisis, aplastic crisis).
  • Features of complications:
    • painful swelling of the hands and feet (dactylitis);
    • bone pain, abdominal pain;
    • chest pain, fever, dyspnoea (acute chest syndrome);
    • convulsions, hemiparesis;
    • priapism.

Investigations

  • Laboratory features of haemolytic anaemia. See Anaemia, haemolytic .
  • Haemoglobin electrophoresis shows an SS pattern (both parents will be AS).

GENERAL AND SUPPORTIVE MEASURES

  • Avoid exposure to cold, dehydration and stress.
  • Increase fluid intake during painful crises.
  • Heat and/or massage for pain.

MEDICINE TREATMENT

For sequestration crisis or aplastic crisis:

  • Packed red cells, IV, 15 mL/kg.
    • Avoid over-transfusing patients since the increase in viscosity may aggravate the vasculopathy associated with sickle cell disease (a Hb threshold of 13 g/dL has been recommended).

If hypoxic:

  • Oxygen, by face mask.

Exchange transfusions may be used to treat severe complications (see referral criteria).

Prophylaxis against infection
Is given to all children because functional asplenia is present by 1–2 years of age.

  • Routine vaccinations during infancy.
  • Catch up conjugate pneumococcal vaccine
    • If < 12 months of age: 3 dose series.
    • If 12 months of age and older: 2 doses 8 weeks apart.
  • Pneumococcal polysaccharide vaccine at 2 years (at least 8 weeks after conjugate vaccine). Repeat vaccination as a booster 5 years after the initial dose.
  • Annual influenza vaccination.
  • Phenoxymethylpenicillin, oral, 12 hourly.
    • < 5 years: 125 mg
    • > 5 years: 250 mg
    • Give indefinitely.

Treatment
Analgesia as required:

  • Paracetamol, oral, 15 mg/kg 6 hourly.
    AND
  • Ibuprofen, oral, 10 mg/kg 8 hourly.
  • Hydroxyurea, oral, 15 mg/kg.
    • Increase by 5 mg/kg every12 weeks.
    • Maximum dose: 35 mg/kg daily.

Infections:
All children with axillary temperature ≥ 38°

  • Ceftriaxone, IV, 50–80 mg/kg/dose once daily.

Acute chest syndrome:
Consult a paediatrician.

REFERRAL

  • All children with sickle cell anaemia should be managed in consultation with a paediatric haematologist or paediatrician.
  • All children with severe complications that may benefit from exchange transfusion or intensive care, e.g. stroke, severe vaso-occlusive disease and acute chest syndrome.
  • All cases of stroke should be referred for a regular transfusion program.