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Background: Overwhelming post-splenectomy infection (OPSI) is a serious complication of asplenia. Clinical guidelines recommend numerous measures to reduce the risk of OPSI, but awareness and adherence to preventative measures are generally poor. We aimed to determine whether a registry for asplenic/hyposplenic patients was associated with a reduction in the incidence of infection with encapsulated bacteria., Methods: We performed a retrospective cohort study of asplenic/hyposplenic patients in the state of Victoria, Australia, who registered with Spleen Australia from 2003 through 2014. Spleen Australia provides education, clinical guidance, and annual vaccination reminders to registrants and their healthcare providers. We compared the incidence of infection with Streptococcus pneumoniae, Haemophilus influenzae type B (Hib), and Neisseria meningitidis before and after registration. Registry data were linked with Victorian notifiable disease data on invasive pneumococcal disease (IPD), invasive meningococcal disease (IMD), and Hib between 2000 and 2014., Results: Twenty-seven cases of IPD and 1 of IMD occurred among 3221 registrants. No cases of Hib were reported. The rate of IPD/IMD was 150 per 100000 patient-years prior to registration and 36 per 100000 patient-years after registration; registration was associated with a 69% reduction in the risk of infection (incidence rate ratio, 0.31; 95% confidence interval, 0.12 to 0.83; P = .019). Based on the absolute reduction in incidence, we estimate that Spleen Australia prevents 5-6 invasive infections with encapsulated organisms annually among registrants., Conclusions: Systematic, long-term approaches to post-splenectomy care can significantly reduce the risk of infection with encapsulated organisms among individuals with asplenia/hyposplenism.

People with asplenia/hyposplenism are at increased risk of fulminant sepsis, which carries a high mortality rate. A range of preventive measures is recommended although there is ongoing evidence that knowledge of and adherence to these strategies is poor. There have been significant changes in recommended vaccinations since the previously published recommendations in 2008. We provide current recommendations to help Australian and New Zealand clinicians in the prevention of sepsis in patients with asplenia and hyposplenia. The guideline includes Australian epidemiological data, preferred diagnostic techniques and recommendations for optimal antimicrobial prophylaxis and vaccination protocols., (© 2017 Royal Australasian College of Physicians.)

Overwhelming post-splenectomy infection (OPSI) is a serious complication of asplenia and is associated with encapsulated organisms, most commonly Streptococcus pneumoniae, but also Haemophilus influenzae and Neisseria meningitidis. We aimed to estimate the risk of infection in this patient group. We reviewed data collected by the Victorian Spleen Registry in Australia. On registration, all patients are asked about significant infections requiring admission to hospital for intravenous antibiotics; those requiring admission to ICU were defined as OPSI. In the 3274 asplenic patients registered 492 patients reported at least one episode of infection. There were 47 episodes of OPSI requiring intensive care (incidence rate 1·11/1000 patient-years). The risk of OPSI was highest in older patients, and there were no statistically significant differences in incidence by reason for splenectomy except for a higher rate in patients with medical hyposplenia. This study reinforces that post-splenectomy infection is a clinically significant but uncommon complication, and that fulminant infection requiring intensive care is a minority of all infections.

Asplenic patients have a lifelong risk of overwhelming post-splenectomy infection and have been reported to have low numbers of peripheral blood IgM memory B cells. The clinical value of quantitation of memory B cells as an indicator of splenic abnormality or risk of infection has been unclear. To assess changes in B cell sub-populations after splenectomy we studied patients recruited to a spleen registry (n = 591). A subset of 209 adult asplenic or hyposplenic subjects, and normal controls (n = 140) were tested for IgM memory B cells. We also determined a) changes in IgM memory B cells with time after splenectomy using the cross-sectional data from patients on the registry and b) the kinetics of changes in haematological markers associated with splenectomy(n = 45). Total B cells in splenectomy patients did not differ from controls, but memory B cells, IgM memory B cells and switched B cells were significantly (p<0.001) reduced. The reduction was similar for different indications for splenectomy. Changes of asplenia in routine blood films including presence of Howell-Jolly bodies (HJB), occurred early (median 25 days) and splenectomy associated thrombocytosis and lymphocytosis peaked by 50 days. There was a more gradual decrease in IgM memory B cells reaching a stable level within 6 months after splenectomy. IgM memory B cells as proportion of B cells was the best discriminator between splenectomized patients and normal controls and at the optimal cut-off of 4.53, showed a true positive rate of 95% and false positive rate of 20%. In a survey of 152 registry patients stratified by IgM memory B cells around this cut-off there was no association with minor infections and no registry patients experienced OPSI during the study. Despite significant changes after splenectomy, conventional measures of IgM memory cells have limited clinical utility in this population.

Background: The spleen plays a crucial role in human defence against infection. Patients who are asplenic or hyposplenic are at increased risk of severe sepsis due to specific organisms. Overwhelming postsplenectomy infection (OPSI) has a mortality rate of up to 50%., Objective: This article describes the causes of OPSI and provides strategies to reduce it., Discussion: Streptococcus pneumoniae is responsible for over 50% of cases of OPSI. Strategies to prevent OPSI include education; vaccination against S. pneumoniae, Haemophilus influenzae type b, Neisseria meningitidis and influenza (annually); and daily antibiotics for at least 2 years postsplenectomy and emergency antibiotics in case of infection. Asplenic patients should carry a medical alert and an up-to-date vaccination card. Asplenic patients require specific advice around travel and animal handling as they are at increased risk of severe malaria, and OPSI (due to Capnocytophaga canimorsus) may result from dog, cat or other animal bites. The Victorian Spleen Registry was established to improve adherence to best practice preventive guidelines and thereby reduce the incidence of OPSI.

Background: Overwhelming, sometimes fatal infections represent a lifelong risk after surgical removal of the spleen, or in patients who develop hyposplenism as a consequence of illnesses. This risk may be reduced by all or a combination of vaccination, antibiotic prophylaxis and education. We aimed to determine if a registry approach to delivering these interventions would be cost effective using our own experience and published data., Method: The decision model compared a cohort of 1,000 people covered by a registry to a cohort of 1,000 people with no registry. The impact of the registry was assessed in terms of achieved rates of vaccination, chemoprophylaxis and education, consequent outcomes of overwhelming post-splenectomy infection (OPSI) and mortality (years of life lived). The cost-effectiveness of the registry compared with no registry was estimated in terms of additional cost per case of OPSI avoided and as additional cost per life year gained., Results: In the first two years, the additional cost of the registry was dollar 152,611 per case of OPSI avoided or dollar 205,931 per life year gained. After this initial registration period the cost-effectiveness improves over time, such that over the cohort lifetime a post-splenectomy register is associated with an additional cost of dollar 105,159 per case of OPSI avoided or dollar 16,113 per life year gained., Conclusion: A registry-based approach is likely to prove cost effective in terms of mortality and rates of OPSI avoided.

Splenectomy has been reported to alter inconsistently the CD4 lymphocyte numbers in patients infected with the human immunodeficiency virus (HIV). To further assess the effect of splenectomy we have retrospectively examined the charts of 10 patients who were infected with HIV and who had undergone splenectomy. There was a significant increase in the mean CD4 numbers following splenectomy (mean increase of 326/microliters, or 2.1-fold, P = 0.0009), the total lymphocyte numbers (mean increase of 1.55/ml, or 2.2-fold, P = 0.001) and in the CD8 lymphocyte count (mean increase of 968/microliters, or 2.3-fold, P = 0.014). No significant difference was observed in the percentage CD4 lymphocytes (P = 0.95) or in the CD4:CD8 lymphocyte ratio (P = 0.76). In two patients, symptoms suggestive of impaired immune function developed post-splenectomy, at a time when their CD4 lymphocyte numbers were markedly higher than their pre-splenectomy values. One developed oral candidiasis (CD4 960/microliters, percentage CD4 32%), and in one patient a 7 kg weight loss was associated with recurrent mouth ulcers (CD4 680/microliters, percentage CD4 7%). We conclude that the total CD4 count increases significantly after splenectomy while the percentage CD4 lymphocyte count and CD4:CD8 lymphocyte ratio do not. Our data suggest that the CD4 lymphocyte count overestimates the immune function in these patients, although our findings are not conclusive.

Sarah Luu,1 Denis Spelman,2,3 Ian J Woolley3–5 1Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia; 2Department of Infectious Diseases and Microbiology, Alfred Health, Melbourne, Victoria, Australia; 3Spleen Australia, Alfred Health, Melbourne, Victoria, Australia; 4Monash Infectious Diseases, Monash Health, Clayton, Victoria, Australia; 5Centre for Inflammatory Diseases, Monash University, Clayton, Victoria, AustraliaCorrespondence: Ian J WoolleyMonash Infectious Diseases, Monash Medical Centre, Clayton Rd, Victoria 68, AustraliaTel +61 39 594 4533Fax +61 39 594 4564Email Ian.woolley@monash.eduAbstract: Removal of the spleen had already been established as a routine technique to treat splenic trauma and other diseases affecting the spleen before the anatomy, physiology, and function of the spleen were known in the mid-twentieth century. It is now widely accepted that the splenectomized individual is at increased risk for infection, in particular, overwhelming post-splenectomy infection (OPSI). OPSI is a syndrome of fulminant sepsis occurring in splenectomized (asplenic) or hyposplenic individuals that is associated with high mortality and morbidity. Poorly opsonized bacteria such as encapsulated bacteria, in particular, Streptococcus pneumoniae, are often implicated in sepsis. The spleen is a reticuloendothelial organ that facilitates opsonization and phagocytosis of pathogens, in addition to cellular maintenance. Splenectomy is associated with an impairment in immunoglobulin production, antibody-mediated clearance, and phagocytosis, leading to an increased risk of infection and sepsis. Early identification of the at-risk patient, early blood cultures prior to antibiotic administration, urgent blood smears and fast pathogen-detection tests, and sepsis bundles should be utilized in these patients. Prompt management and aggressive treatment can alter the course of disease in the at-risk splenectomized patient. Overwhelming post-splenectomy infection can be prevented through vaccination, chemoprophylaxis, and patient education. This article evaluates post-splenectomy sepsis by summarizing the anatomy and function of the spleen, physiological changes after splenectomy that predispose the splenectomized patient to infection, and current management and prevention strategies.Keywords: splenectomy, sepsis, OPSI, asplenism