A Healthy 18-Year-Old with a History of Remote Splenectomy
An 18-year-old woman presents to the office for a precollege medical evaluation in advance of matriculation at her state university the upcoming fall. Leading up to her visit, she and her parents had engaged in several conversations about the recent measles outbreak as well as other viral diseases that can occur in the absence of proper immunization. Their hope was that she would discuss this concern with her doctor and take any necessary precautions before heading off to college.
At the time of her visit, the patient was in excellent health, without any significant chronic diagnoses, and maintained her physical fitness as a member of her varsity high school track team. History and documentation provided by her parents shows an up-to-date immunization record, particularly for pathogens (eg, measles and mumps).
At age 8, she had undergone a splenectomy related to a sledding accident with subsequent full recovery. Her physical exam and routine complete blood count and metabolic panels are normal.
Which of the following is the least accurate statement relative to her current condition?
A. She should immediately retrieve her vaccination history and arrange for an appropriate follow-up vaccination program.
B. She should have amoxicillin 500 mg tablets in her medicine cabinet for use with onset of any febrile illness.
C. She must follow a lifelong antimicrobial pneumococcus prophylaxis program.
D. Despite the remote timing of her splenectomy and lack of underlying hematologic disease, she remains at increased risk for post-splenectomy sepsis.
(Answer and discussion on next page)
Correct Answer: C
There are several medical situations that result in asplenia which, as indicated in how this patient presented, create a number of management issues. Although certain hematological conditions, such as sickle cell anemia, can result in anatomic asplenia due to auto-infarction in the general population, surgical asplenia related to trauma or therapy for hematologic disease, such as the common immune thrombocytopenia purpura, is probably typically more common.1 Our case is an example of this.
INCIDENCE
Regardless of the etiology of asplenia, the condition presents a real risk of postsplenectomy sepsis. There are 2 important incidence figures that relate to, and define, this very serious situation.2
First and better defined is the mortality rate of such an event: Until 2000, a very solid, data-based estimate is in the 50% range.2 The syndrome is well-characterized with a prodromal finding of fever and chills followed by rapid (within 6 hours) deterioration in full-blown sepsis with shock. Bacteremia is profuse and essentially universal, with the predominant organism being S pneumonia.2
Less precise and more calculated is the incidence and risk ratio for this catastrophic complication in the asplenic population: The best recent data comes up with a 3.2% incidence of postsplenectomy sepsis during a median follow-up of 6.9 years.2 In this study, the risk in children was greater than adults. Furthermore, splenectomy or asplenia related to medical condition (eg, sickle cell) conferred more risk than splenectomy for trauma.2
TREATMENT
Two maneuvers to prevent, or at least lessen, this risk have been successfully implemented since their efficacy was confirmed in 2000. The pneumococcal conjugate vaccine (currently 13-valent or PCV13) is used to reduce the incidence of pneumococcal disease in general. Although not specifically examined in a general asplenic population, good studies have demonstrated a diminution of up to 93% in invasive pneumococcal disease in the very high-risk hemoglobin S population using these vaccines.3,4 This maneuver is thus clearly indicated and is a key management strategy in asplenia patients, such that Answer A, detailing her vaccination history and arranging for appropriate, up-to-date antipneumococcal vaccine administration, is an accurate statement here.
The second maneuver is the use of prophylactic antibiotics. The best data for their use comes from studies in the very high-risk group of sickle cell anemia. In these instances, the use of prophylactic antibiotics demonstrated an 84% reduction in invasive pneumococcal disease in children under the age of 5.1,5 This maneuver came to be less effective than anticipated after the age of 5, and is discontinued at that point. Therefore, lifelong, continuous antimicrobial prophylaxis is no longer recommended in either the sickle cell or general asplenic populations. Therefore, Answer C is the least appropriate maneuver offered and the correct answer.
Episodic, situational use of “therapeutic” antibiotics seems useful in theory and is prescribed in the guidelines for managing asplenic patients. Since the key causative organisms are known—and since the abrupt, catastrophic development of sepsis does often not allow for time to see a physician or receive adequate follow-up—asplenic patients should always have an appropriate dose of oral antibiotics against S pneumoniae (eg, amoxicillin 2 grams or levofloxacin 750 mg) on hand for use immediately with the onset of a febrile episode prior to their seeking prompt medical attention.1 Thus, Answer B is very appropriate here.
Finally, although the incidence of postsplenectomy sepsis is highest in children (more than in adults) and in the first 1 to 2 years of age, regardless of underlying cause for splenectomy, observational studies strongly suggest that risk to some degree persists for life and maneuvers discussed above need to be maintained.5 Thus, Answer D is also an appropriate statement here.
PATIENT FOLLOW-UP
After successfully obtaining her immunization records and discovering that she had never received vaccination for pneumococcal or meningococcus, an appropriate vaccination program was arranged. The patient also participated in an education program and did receive a script for amoxicillin.
TAKE-HOME MESSAGE
Patients who have had a splenectomy regardless of cause (eg, hematologic or traumatic) have a lifelong risk for sepsis, which can carry a 50% mortality rate. Any febrile episode of significance should prompt medical attention with blood cultures and empiric antibiotics. Of particular risk is pneumococcus, therefore, antibiotics (ie, amoxicillin) should be in the home and used prior to seeking medical attention. Additionally, a vigorous vaccination program for pneumococcus and meningococcus can lower infection and sepsis risk.
Ronald Rubin, MD, is a professor of medicine at Temple University School of Medicine and chief of clinical hematology in the department of medicine at Temple University Hospital, both in Philadelphia, PA.
References:
1. Rubin LG, Schaffner W. Care of the asplenic patient. N Eng J Med. 2014;
371(4):349-356.
2. Bisharat N, Omari H, Lavi I, Raz R. Risk of infection and death among post-splenectomy patients. J Infect. 2001;43(3):
182-186.
3. Halasa NB, Shankar SM, Talbot TR, et al. Incidence of invasive pneumococcal disease among individuals with sickle cell disease before and after the introduction of the pneumococcal conjugate vaccine. Clin Infect Dis. 2007;44(11):1428-1433.
4. Pilishvili T, Lexau C, Farley MM, et al. Sustained reductions in invasive pneumococcal disease in the era of conjugate vaccine. J Infect Dis. 2010;201:32-41.
5. Kristinsson SY, Gridley G, Hoover RN, Check D, Landgren O. Long-term risks after splenectomy among 8149 cancer-free American veterans: a cohort study with up to 27 years follow-up. Haematologica. 2014;99:329-398.