Reducing sepsis risk in patients who are asplenic
Management has been reappraised and should be viewed as best practice rather than evidence-based Dr Gavin Spickett explains
It was once thought the risk of overwhelming sepsis from asplenia lasted just two years after surgery. There is now reasonable evidence that the risk is lifelong. There is a 7 per cent risk in 10 years and the fatality rate for overwhelming sepsis in this group of patients is 50-80 per cent. Key organisms include the pneumococcus, haemophilus and meningococcus. Others include
E. coli, Staphylococcus aureus and other streptococci.
This has forced us to reappraise our approach to management, with a recommendation that all asplenic and hyposplenic patients should be on long-term prophylaxis with antibiotics and be immunised regularly. To do this it is highly desirable to identify these patients and organise a practice register for recall on an annual basis. Much advice on management is not based on robust clinical trials, but it is unlikely such trials will ever be conducted. Management should therefore be viewed as best practice, rather than evidence-based.
The main causes of asplenia and hyposplenia are shown on page 22. They are much more common than previously thought when efforts are made to identify such patients. Unfortunately it is sometimes unclear from surgical discharge letters whether the spleen has been removed. Examination of a blood film for the presence of Howell-Jolly bodies can be helpful, particularly in patients with coeliac disease.
Patients about to undergo elective splenectomy
These patients should ideally be immunised at least one week, and preferably longer, before surgery. Antibiotic prophylaxis is required post-surgery and continued lifelong.
Patients undergoing emergency splenectomy
These should have been immunised before leaving hospital and started on antibiotics. GPs should check this has happened, and if it has not been done, should organise it as soon as possible.
· Hyposplenic patients
There is no absolute advice on these patients but if Howell-Jolly bodies are seen on a blood film then immunisation and antibiotics are required.
· Pneumococcus: either pure pneumococcal polysaccharide or the new conjugated pneumococcal vaccine. Blood levels of antibodies fall more quickly in asplenic patients, especially those
with underlying malignancy, so it is important to check blood levels annually and re-immunise if the levels fall below the protective level (consult your immunology laboratory for advice).
· Haemophilus influenzae type b: use the conjugate vaccine, as used in children, in a single dose for adults. Check blood levels annually, as above.
· Meningococcus: there is no consensus on the best vaccine to use. If the conjugated meningococcal C vaccine is used, remember the protection is strain specific. Monitoring blood levels is less helpful here as lab assays are not robust.
· Influenza: asplenic patients are not at increased risk of influenza but influenza infection itself increases the risk of bacterial lung infection and increases the risk of overwhelming sepsis. Annual flu vaccine is therefore advised.
The only evidence for benefit relates to antibiotic prophylaxis in children with sickle cell disease, but this has been extrapolated to all asplenic patients. The preferred antibiotic is penicillin V 500mg bd; erythromycin 250mg bd is an alternative. Young children with congenital asplenia may require alternatives and it is prudent to seek advice from a specialist in paediatric infectious disease or immunology.
· Malaria: asplenic patients are at serious risk from overwhelming malaria. Malarial prophylaxis and use of anti-mosquito precautions are essential, and it is preferable that asplenic patients avoid malarial areas. Advice should be sought from an infectious disease specialist.
· Babesiosis: there is an increased risk of severe babesiosis, an intra-erythrocytic parasite, transmitted by tick bites. Again avoidance of areas where this organism occurs is desirable. This includes the north-eastern seaboard of the USA, but also parts of the UK and Europe. Camping and hiking increase risks.
· Penicillin-resistant pneumococci: Spain and other areas around the Mediterranean have a markedly increased risk of penicillin-resistant pneumococci; switching antibiotics to amoxicillin 250mg bd is advisable.
Asplenic patients are at risk from dog bites, as these may become infected with Capnocytophaga canimorsus. This is usually sensitive to amoxicillin and treatment with this antibiotic should be started immediately, while seeking advice from a microbiologist or infectious disease specialist, as long as the patient is not allergic.
Fever in an asplenic patients
This must always be taken seriously as patients with the overwhelming post-splenectomy sepsis syndrome can progress from being well to moribund in septicaemic shock within a few hours. If they are unwell, it is advisable for them to take an additional double dose of their antibiotic while seeking immediate medical help.
If a febrile asplenic patient is seen in general practice it is highly desirable that a parenteral antibiotic be administered, as for suspected meningitis, before transfer to hospital.
Information to Patients
All patients should have some sort of warning card (the Department of Health has produced one) or Medic-Alert bracelet. They should have an information sheet giving advice on what to do if unwell, travelling abroad or have a dog bite. The information must advise urgent medical attention if they develop a febrile illness.
This is best carried out in primary care. The need for an annual flu vaccine means patients should be recalled each autumn. An opportunity should be taken to check antibody levels to pneumococcus and haemophilus, reinforce advice about antibiotic prophylaxis and ensure counselling about other risks.
Causes of asplenia and hyposplenia
Congenital (rare) Coeliac disease
Staging for lymphoma
rarely done now) Splenic infarction
Malignancy of stomach,
colon (spleen removed
because of adherence
to tumour or
local extension) Splenic irradiation
anaemia, CML) Sickle cell disease