Sickle Cell Splenic Sequestration

Splenic sequestration crisis is acute pooling of red cells in the spleen with sudden splenic enlargement and falling haemoglobin.

• Occurs in HbSS between ages 6 months and 5 years (before autoinfarction), and in HbSC or sickle thalassaemia in older children and adults.
• Defined by haemoglobin drop of 2 g/dL or more from baseline with enlarged spleen, and reticulocytosis and thrombocytopenia.
• Recurs in about 50% of cases; mortality 10 to 15% of first episodes in children.
• Triggers: infection (often viral).

• Sudden pallor, weakness, abdominal pain and distension, tachycardia, hypotension, shock.
• Massively enlarged tender spleen.
• Hypovolaemic shock may progress to death within hours.

• Sudden fall in haemoglobin (often below 6 g/dL), reticulocytosis, thrombocytopenia, raised nucleated red cells.
• Ultrasound: splenomegaly.
• Blood cultures, infection screen, group and cross match.
• Exclude aplastic crisis (low reticulocytes), haemolytic crisis, hepatic sequestration.

• Urgent resuscitation: IV isotonic saline 10 to 20 mL/kg, oxygen.
• Careful red cell transfusion 5 to 10 mL/kg of packed cells (not to normal haemoglobin as trapped cells are released with recovery causing hyperviscosity); aim haemoglobin about 8 to 9 g/dL.
• Antibiotics if febrile (ceftriaxone 50 to 75 mg/kg).
• Prevention of recurrence: splenectomy after first life threatening episode or second episode (children over 1 year), or chronic transfusion until splenectomy age; partial splenectomy.
• Parental education to palpate spleen; penicillin prophylaxis and vaccination; hydroxyurea may reduce recurrence.
• Post splenectomy: vaccines (pneumococcal conjugate and polysaccharide, meningococcal ACWY and B, Hib), penicillin V 125 to 250 mg twice daily.