Detection, Education and Management of the Asplenic or Hyposplenic Patient

Author: Malcolm L. Brigden
Date: Feb 1, 2001

Fulminant, potentially life-threatening infection is a major long-term risk after splenectomy or in persons who are functionally hyposplenic as a result of various systemic conditions. Most of these infections are caused by encapsulated organisms such as pneumococci, Haemophilus influenzae and meningococci. A splenectomized patient is also more susceptible to infections with intraerythrocytic organisms such as Babesia microti and those that seldom affect healthy people, such as Capnocytophaga canimorsus. Most patients who have lost their spleens because of trauma are aware of their asplenic condition, but some older patients do not know that they are asplenic. Other patients may have functional hyposplenism secondary to a variety of systemic diseases ranging from celiac disease to hemoglobinopathies. The identification of Howell-Jolly bodies on peripheral blood film is an important clue to the diagnosis of asplenia or hyposplenia. Management of patients with these conditions includes a combination of immunization, antibiotic prophylaxis and patient education. With the increasing prevalence of antibiotic-resistant pneumococci, appropriate use of the pneumococcal vaccine has become especially important. (Am Fam Physician 2001;63:499-506,508.)

Patients who are asplenic or who have functional hyposplenism are at lifelong risk for a variety of serious infections, especially with encapsulated organisms such as Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.(1-3) With the growing concern about antibiotic-resistant pneumococci, the appropriate management of asplenic and hyposplenic patients has become increasingly important.(4-6)

Infection in Asplenic or Hyposplenic Patients

Splenic macrophages have a major role in phagocytosing bacteria and aging blood cells from the circulation.(1,2) The spleen is also a major producer of antibodies.(3) Although most serious infections in asplenic persons are due to encapsulated bacteria,(2-4) other pathogens, such as gram-negative organisms and Capnocytophaga canimorsus (formerly DF-2 bacillus), which is associated with dog bites, may also be responsible.(7) A splenectomized person also has an increased susceptibility to infections with intraerythrocytic parasites such as Plasmodia falciparum and Babesia microti, which is endemic on Cape Cod and Nantucket Island in Massachusetts.(2,3) More rarely involved organisms include group B streptococci; Enterococcus, Bacteroides, Salmonella and Bartonella species; Plesiomonas shigelloides, Eubacterium plauti and Pseudomonas pseudomallei.(1,3)

Although the risk for fulminant infection is low (probably in the range of 1 per 500 person-years of observation), in one large study the overall cumulative risk of infection severe enough to require hospitalization was 33 percent at the end of a 10-year follow-up period.(1,3) Children are especially susceptible because they often have lower levels of specific antibodies against encapsulated organisms.(8)

Overall immune status is also an important consideration. Patients who have conditions associated with defective cellular immunity, such as Hodgkin's disease or hypogammaglobulinemia, those who are undergoing chemotherapy or radiation therapy, and those who have had bone marrow transplantation, all have impaired ability to mount an effective antibody response.(5,9)

The majority (50 to 70 percent) of serious infections occur within the first two years following splenectomy. However, patients have had serious infections more than 40 years after a splenectomy, indicating that the increased risk is lifelong.(1-3)

The most dreaded infectious complication is overwhelming postsplenectomy infection (OPSI).(1-3) The typical clinical features of OPSI are listed in Table 1. Initial symptoms are often mild, with an influenza-like presentation that includes fever, malaise, myalgias, headache, vomiting, diarrhea and abdominal pain. The infection may then rapidly progress to full-blown bacteremic septic shock, accompanied by hypotension, anuria, disseminated intravascular coagulation and hypoglycemia.(7) Bacterial proliferation in OPSI is often so extreme that bacteria are noted in buffy-coat preparations or even in the neutrophils present on a peripheral blood film.(3) Despite appropriate antibiotic therapy and other intensive intervention, the reported mortality has ranged from 50 to 80 percent.(2,3,7) If patients are educated to seek medical attention immediately, the mortality may be reduced to about 10 percent.(9) More than one half of the patients who die do so within 48 hours of admission to the hospital.(7)

Detection of Patients at Risk

Most patients who have had a splenectomy are aware of it. Partial splenectomy with retention of some splenic tissue has been increasingly performed in patients with splenic trauma.(10) Another approach involves autotransplantation of splenic tissue within the mesentery.(11) Splenic implants or accessory spleens may be found in the peritoneum of 50 percent of patients who undergo traumatic splenectomy.(3) Unfortunately, the degree of protection provided by splenosis or accessory spleens appears to be variable and unpredictable. Because of the uncertainty about how much splenic function persists following partial splenectomy or autotransplantation of splenic tissue, such patients should undergo protective measures similar to those provided for patients known to be asplenic.(1-3)

In the past, many patients undergoing hiatal hernia surgery or partial gastric resection for peptic ulcer disease had incidental removal of the spleen. Unfortunately, some of these patients were never informed about their asplenic state.(2) In addition, splenic dysfunction may occur as a consequence of various gastrointestinal, immunologic, inflammatory, infiltrative and hematologic diseases, many of which have been linked to cases of OPSI (Table 2).(2,3,12,13) Virtually all adult patients with sickle cell disease are functionally asplenic.(12)

In clinical practice, severe liver disease and celiac disease are probably the two most common causes of functional hyposplenism.(12) Although most liver-related cases are the result of cirrhosis and portal hypertension, functional hyposplenism occasionally occurs in persons with acute alcoholism, perhaps because of a direct toxic effect of alcohol on the spleen.(13)

The presence of Howell-Jolly bodies in the erythrocytes on a peripheral blood film is an important clue to the diagnosis of asplenia or functional hyposplenism (Figure 1).(2,3) These small round remnants of the original erythrocyte nucleus should be readily apparent on microscopic examination of the peripheral blood film, a procedure that usually must be specifically requested. Other, rarer causes of Howell-Jolly bodies include myelodysplasia and hemolysis.

Howell-Jolly bodies may not occur with mild hyposplenism, but their presence is thought to identify the degree of hyposplenism that represents a risk for OPSI. Figure 2 shows an algorithm of the work-up that should be performed when Howell-Jolly bodies are detected. Patients who have their spleen but in whom functional hyposplenism is demonstrated by radionuclide spleen-liver scan should be managed the same way as those who have no spleen.(2,5)

Management of Patients at Risk

Table 3(2,3,5,6,14) outlines the principles for the management of persons at risk for postsplenectomy infection. These measures fall under the broad categories of immunoprophylaxis, antibiotic prophylaxis and patient education.(2,5,9)

IMMUNIZATION

The pneumococcal vaccine was formulated in 1983 to include the 23 serotypes responsible for about 90 percent of pneumococcal infections in North America.(4,6) Under ideal conditions in healthy, immunocompetent persons, the vaccine still fails to protect 20 to 30 percent of recipients because 10 percent of possible antibody responses to individual antigens do not occur and not all serotypes are covered.(6) Pneumococcal vaccination should be performed at least two weeks before an elective splenectomy because the vaccine's immunogenicity may be reduced when given after splenectomy or while the patient is receiving chemotherapy.(15) Unimmunized patients who have had a splenectomy or who have functional hyposplenism should be immunized as soon as their conditions are identified.

Thirty percent of patients may have minor side effects from the vaccine, including localized erythema or myalgia at the injection site. About 5 percent of patients may experience mild pyrexia for as long as 48 hours after the vaccine is given.(4,6) Vaccination is not recommended if a patient has a febrile illness or is pregnant. Occasionally a patient who had a splenectomy because of chronic immune thrombocytopenic purpura may have a transient relapse following vaccination.(16)

TABLE 1Clinical Features of Overwhelming Postsplenectomy Infection in PatientsOccurs in asplenic or functionally hyposplenic personsCryptic infection (no obvious focus)Short, nonspecific prodromeMassive bacteremia with encapsulated organismLess commonly, gram-negative bacilli are causativeSeptic shock with disseminated intravascular coagulationMarked virulence: 50 to 70 percent mortalityDeath may ensue in 24 to 48 hoursTABLE 2Medical Conditions That May Be Associated with HyposplenismCongenitalIsolated congenital anomalyCongenital cyanotic heart diseaseGastrointestinalCeliac disease with or without dermatitis herpetiformis[*]Inflammatory bowel disease (especially ulcerative colitis)Whipple's diseaseIntestinal lymphangiectasiaLiver diseaseCirrhosis with or without portal hypertension[*]Chronic active hepatitisAcute alcoholismHematologicSickle cell disease[*]Other hemoglobinopathies (Hb S-C disease, Hb S-E disease, Hb S-b-thalassemia)Primary thrombocythemiaFanconi's syndromeMalignant histiocytosisAutoimmuneVasculitis (may be associated with splenic infarct)[*]Systemic lupus erythematosus or discoid lupus[*]Rheumatoid arthritisSjogren's syndromeGraves' diseaseInfiltrativeThorium dioxide administrationAmyloidosisSarcoidosisVascularSplenic artery occlusionSplenic vein thrombosisCeliac artery thrombosisMiscellaneousHIV infectionGraft-versus-host diseaseBone marrow transplantation[*]Total parenteral nutritionHigh-dose steroid therapySplenic irradiation (Hodgkin's disease)[*]Hb = hemoglobin; HIV = human immunodeficiency virus.[*]--One of the more common causes of functional hyposplenism.Information from references 2, 3, 12 and 13.TABLE 3Checklist for the Management of Asplenic or Functionally Hyposplenic PatientsVaccination status[*]Give pneumococcal vaccine at least 14 days before surgery; repeat every three to five years, depending on age and medical condition.[]Give meningococcal vaccine at least 14 days before surgery.Give Haemophilus b conjugate vaccine at least 14 days before surgery.Document immunization status in patient records.Antibiotic prophylaxis[*]Oral penicillin prophylaxis has been replaced by administration of amoxicillin-clavulanic acid (Augmentin), trimethoprim-sulfamethoxazole (Bactrim, Septra) or cefuroxime axetil (Ceftin).Patients developing infection despite prophylactic measures (antibiotics, vaccination) should be given parenteral antibiotics (ceftriaxone [Rocephin], cefotaxime [Claforan] with or without aminoglycoside or quinolone) and promptly admitted to the hospital for investigation.[]With a decision to use "standby" antibiotics, provide an up-to-date supply of antipneumococcal antibiotics, to be taken if febrile illness develops and immediate medical attention is not available.EducationInform patient about risks and types of infection.Provide information on obtaining a MedicAlert bracelet or necklace.[sections]Instruct patient to inform all new health care professionals, including dentists, about the asplenic or hyposplenic state.Label all patient medical records regarding asplenia or functional hyposplenism.[*]--Failures of immunization and antibiotic prophylaxis have been noted.[]--See explanation in text.[]--See Table 4 for drug regimens.[sections]--MedicAlert Foundation Int. is an emergency medicalinformation service. The toll-free number is 800-432-5378.Information from references 2, 3, 5, 6 and 14.

COPYRIGHT 2001 American Academy of Family PhysiciansCOPYRIGHT 2001 Gale Group

 
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