Splenectomy, Hyposplenism and Asplenia

The spleen is involved in producing protective humoral antibodies, the production and maturation of B and T cells and plasma cells, removal of unwanted particulate matter (e.g. bacteria) and also acts as a reservoir for blood cells, especially white cells and platelets.

Splenectomy may occur in three different ways:

• Planned, where prophylactic measures can be used to prevent later complications
• Traumatic, due to an accident or during surgery
• Autosplenectomy, which refers to the physiological loss of spleen function (hyposplenism), e.g. associated with sickle cell anaemia (chronic damage to the spleen results in atrophy), coeliac disease, dermatitis herpetiformis, essential thrombocythaemia and ulcerative colitis

Indications for splenectomy

• Trauma: 25% of injuries are iatrogenic
• Spontaneous rupture: usually occurs in patients with massive splenomegaly (e.g. infectious mononucleosis) and is often precipitated by minor trauma
• Hypersplenism: hereditary spherocytosis or elliptocytosis, idiopathic thrombocytopenic purpura
• Neoplasia: lymphoma or leukaemic infiltration
• With other viscera: total gastrectomy, distal pancreatectomy
• Other indications: splenic cysts, hydatid cysts, splenic abscesses

Complications of splenectomy

• Thrombocytosis: platelet count usually peaks after 7-10 days. There is no evidence of an increased risk of thromboembolic disease but prophylactic aspirin may be considered for very high platelet counts.
• Overwhelming post splenectomy infection:
  • Due to encapsulated bacteria such as Strep. pneumoniae, Haemophilus influenzae and Neisseria meningitidis
  • Occurs post splenectomy in 4% patients without prophylaxis
  • Mortality is approximately 50%
  • Greatest risk is in first 2 years after splenectomy and the mortality is about 50%
  • Management: immunisation and antibiotic prophylaxis as outlined below

• Operative splenectomy: for severe splenic trauma, splenic cysts, or as part of a resective procedure for abdominal tumour.
• Functional hyposplenism: sickle cell anaemia (HbSS, HbSC), thalassaemia major, essential thrombocythaemia, and lymphoproliferative diseases (Hodgkin's and non-Hodgkin's Lymphoma, CLL), Coeliac disease, inflammatory bowel disease. Often Howell-Jolly bodies on peripheral blood film give an important clue to diagnosing hyposplenism.
• Bone marrow transplantation: (splenic irradiation or chronic graft versus host disease).
• Congenital asplenia: (associated with cardiac abnormalities and biliary atresia).

• Blood film: features of hyposplenism include Howell-Jolly bodies, Pappenheimer bodies, target cells and irregular contracted red blood cells.
• Imaging techniques: ultrasound, CT, MRI.
• Other investigations will depend on the clinical context.

• Fulminant, potentially life-threatening infection is a major long-term risk of hyposplenism yet such infection is largely preventable.
• Most common infection is pneumococcal infection (mortality up to 60%), followed by H. influenzae type b (less common but significant in children), and N. meningitidis.
• Other infections include E. coli, malaria, babesiosis, and Capnocytophaga canimorsus (associated with dog bites).
• Asplenic patients should be strongly advised of the increased risk of severe falciparum malaria, should take all anti-malarial precautions/prophylaxis and ideally avoid holidays in malaria endemic areas.

• Recently updated guidelines recommend the following:¹
  • All splenectomised patients and those with functional hyposplenism should receive pneumococcal immunisation and patients not previously immunised should receive Haemophilus Influenza type b vaccine.
  • Patients not previously immunised should receive Meningococcal Group C conjugate vaccine. Influenza immunisation should be given.
  • Life long prophylactic antibiotics are recommended (oral phenoxymethylpenicillin or erythromycin). Patients developing infection, despite measures, must be given systemic antibiotics and admitted urgently to hospital.
  • Patients should be given written information and carry a card to alert health professionals to the risk of overwhelming infection. Patients should wear an alert bracelet or pendant.
  • Patients should be aware of the potential risks of overseas travel, particularly with regards malaria and unusual infections, e.g. those resulting from animal bites.
  • Patient records should be clearly labelled to indicate the underlying risk of infection. Vaccination and re-vaccination status should be clearly and adequately documented.
• Suggest patient wears Med-alert bracelet or similar to warn of hyposplenia.
• All vaccines (including live vaccines) can be given safely to children or adults with an absent or dysfunctional spleen.

Pneumococcal vaccination

• The current pneumococcal vaccine should be given at least two weeks before splenectomy.
• Following splenectomy functional antibody responses are better with delayed (14 day) vaccination. All other non-immunised patients at risk should be immunised at the first opportunity.
• Immunisation should be delayed at least three months after immunosuppressive chemotherapy or radiotherapy.
• Re-immunisation of asplenic patients is currently recommended every 5 years. However, antibody levels may decline more rapidly, particularly in patients with Sickle cell anaemia and lymphoproliferative disorders. Re-immunisation in these patients may be made on the basis of antibody levels.
• Children under two years of age have a reduced ability to mount an antibody response to polysaccharide antigens and are, therefore, at particular risk of vaccine failure. The newer conjugate 7-valent vaccine produces better response in the under 2's so should be used where available in this age group and in other individuals at particularly high risk.²

HIB vaccination

All unimmunised patients should receive Haemophilus Influenza Type B vaccine (re-vaccination is not currently recommended).

Meningococcal vaccination

• All unimmunised patients should receive Meningococcal C conjugate vaccine, a course of 3 doses for infants, 2 for children (4-12 months) and single dose for older children and adults (further re-vaccination of Meningococcal C is not currently recommended).
• Vaccine should be given pre-splenectomy in the unimmunised.
• In UK prevalence of type A is low. In other parts of the world cover for Group A would be wise (so patients will need additional Meningococcal A & C combined vaccine prior to foreign travel).
• Protection afforded by plain polysaccharide A and C vaccine is short lived. Immunisation of hyposplenic individuals who have previously received the plain polysaccharide A and C vaccine with Meningococcal C conjugate vaccine is, therefore, recommended.

Influenza vaccination

Annual Influenza vaccination is recommended.

Antibiotics

• Lifelong prophylactic oral antibiotics are recommended.
• Risk is greatest in the first 2 years post splenectomy but continues throughout life (certainly doesn't stop at age 16).
• Use Penicillin V (adult 250-500 mg bd - although 500 mg od may be more realistic if compliance is a particular problem), amoxicillin (adult 250-500 mg daily), erythromycin (adult 250-500 mg daily) orally. Reduce dose for children. Antibiotics may need to be altered due differing local antibiotic sensitivities - on the advice of local public health department.
• Consider recommending patient take a full therapeutic dose of antibiotics if they develop infective symptoms such as pyrexia, malaise, shivering etc. and seek medical advice immediately.
• Allowing patients a reserve supply of antibiotics at home or on holiday may also seem appropriate.
• Pneumococcal resistance to penicillins remains low in the United Kingdom. Knowledge of local resistance patterns should be used to guide the choice of antibiotic.

UK Primary Care seems rather bad at implementing these guidelines.^3,4 Only 54% of a sample of 974 post-splenectomy patients had received pneumococcal and Hib vaccinations and were taking antibiotic prophylaxis.³ A case can therefore be made for the establishment of a disease register of hyposplenic patients and regular audit.