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General Surgery > Abdomen
Splenic Abscess
Article Last Updated: May 21, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Julian E Losanoff, MD, Associate Professor of Surgery, Wayne State University School of Medicine; Clinical Surgeon, Surgery Service, John D Dingell Veterans Affairs Medical Center
Julian E Losanoff is a member of the following medical societies: American Society of Transplant Surgeons, American Society of Transplantation, and Southern Medical Association
Coauthor(s):
Marc D Basson, MD, PhD, Chief of Surgery, John D Dingell VA Medical Center; Professor, Department of Surgery, Wayne State University School of Medicine
Editors: Lewis J Kaplan, MD, FACS, Director, Emergency General Surgery, Associate Professor, Department of Surgery, Division of Trauma and Critical Care, Yale University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; David L Morris, MD, PhD, Professor, Department of Surgery, St George Hospital, University of New South Wales, Australia; Paolo Zamboni, MD, Professor of Surgery, Chief of Day Surgery Unit, Chair of Vascular Diseases Center, University of Ferrara, Italy; John Geibel, MD, DSc, MA, Professor, Department of Surgery, Section of Gastrointestinal Medicine and Department of Cellular and Molecular Physiology, Yale University School of Medicine; Director of Surgical Research, Department of Surgery, Yale-New Haven Hospital
Author and Editor Disclosure
Synonyms and related keywords:
splenic abscess, immunosuppression, bacterial endocarditis, sepsis, bacteremia, chemotherapy, transplantation, tuberculosis, actinomycosis, interventional radiology, surgery, splenectomy, splenotomy
Abscesses of the spleen have been reported periodically since the time of Hippocrates. He postulated that 1 of 3 courses was followed by a patient with a splenic abscess: (1) the patient might die; (2) the abscess might heal; or (3) the abscess might become chronic, and the patient lives with the disease.
Splenic abscess is a rare entity, with a reported frequency of 0.14-0.7% in autopsy series. Its reported mortality rate is still high, up to 47%, and can potentially reach 100% among patients who do not receive antibiotic treatment. Appropriate management can decrease the mortality to 14%.
The timely and widespread use of imaging methods (eg, CT scanning, ultrasound) facilitates early diagnosis and guides treatment, thus improving the prognosis.
Frequency
Published autopsy statistics suggest that splenic abscess is rare (0.14-0.7%). The incidence may depend on the study population. For example, the incidence of splenic abscesses in Denmark was 0.056% per 1,000 somatic hospital discharges per year or 0.0049% per year of all hospital deaths. The literature suggests a male predominance. All age groups can be affected, most typically after the fourth decade.
Etiology
Splenic abscesses have diverse etiologies. The most common is hematogenous spread originating from an infective focus elsewhere in the body. Infective endocarditis, a condition associated with systemic embolization in 22-50% of cases, has a 10-20% incidence of associated splenic abscess. Other infective sources include typhoid, paratyphoid, malaria, urinary tract infection, pneumonias, osteomyelitis, otitis, mastoiditis, and pelvic infections. Pancreatic, other retroperitoneal, and subphrenic abscesses, as well as diverticulitis, may contiguously involve the spleen. Splenic trauma is another well-recognized etiologic factor. Splenic infarction resulting from systemic disorders, such as hemoglobinopathies (especially sickle cell disease), leukemia, polycythemia, or vasculitis, can become infected and evolve into splenic abscesses. Alcoholics, diabetics, and patients who are immunosuppressed are among the most susceptible to splenic abscesses.
Pathophysiology
Splenic abscesses occur in a variety of clinical scenarios. Published studies suggest that preexisting splenic tissue injury and bacteremia are required to form a basis for an abscess. Published scenarios are grouped below:
- Hematogenous embolization to a previously normal spleen: Typical examples include patients with septic endocarditis who have abused IV drugs and patients undergoing chemotherapy who develop fungemia resulting in a splenic abscess. Typically, patients in this category either are immunosuppressed or have an overwhelming bacteremia. This group of patients is expected to expand and include analogous groups from the domains of transplantation and HIV/AIDS.
- Hematogenous spread in the presence of previously altered splenic architecture: This group includes patients with single splenic infarcts (from trauma) or multiple splenic infarcts (from sickle cell disease or vasculitis). Bacteremia from an intercurrent infection (eg, pneumonia, cholecystitis, central line sepsis) can colonize a splenic avascular area and form an abscess.
- Contiguous spread: This includes direct involvement from a pancreatic abscess, gastric or colonic perforations, or subphrenic abscesses.
Microbiology
- Aerobes (in most published cases)
- Gram-positive cocci - Streptococcus, Staphylococcus, Enterococcus (predominant in most reports)
- Gram-negative bacilli - Escherichia coli, Klebsiella pneumoniae, Proteus, Pseudomonas species, Salmonella species (occasionally predominant)
- Anaerobes - Peptostreptococcus, Bacteroides, Fusobacterium, Clostridium, Propionibacterium acnes
- Polymicrobial (up to 50% of cases)
- Fungal - Candida
- Unusual flora - Burkholderia pseudomallei (occasionally reported in melioidosis), actinomycotic and mycobacterial abscesses
Clinical
The history and physical examination are not sufficiently reliable to make the diagnosis of splenic abscess. However, information derived from the history and physical examination can suggest this diagnosis. Therefore, the clinician must maintain a high index of suspicion, particularly in the higher risk clinical scenarios and patient groups listed above. History
The signs and symptoms of splenic abscess have been well described but are not very specific. Therefore, splenic abscess remains a substantial diagnostic challenge. The classical triad of fever, left upper quadrant pain, and splenomegaly is seen in only about one third of patients.
The symptoms of splenic abscess can be variable and depend on the location, size, and progression of the process. They can also be acute, subacute, or chronic. Deep-seated, small abscesses can be painless and accompanied by septic symptoms. - Fever (>90%) can be moderate, continuous, intermittent, or even absent.
- Abdominal pain (>60%) typically occurs suddenly, with a punctum maximum in the left hypochondrium (>39%). Remember that pain usually signifies perisplenitis.
- Involvement of the diaphragmatic pleura can cause shoulder pain. The associated eponym is the Kehr sign, although there is no clear demonstration that Kehr either described it or suffered from it.
- Pleuritic chest pain around the left lung base (>15%) is aggravated by coughing or forced expiration.
- General malaise and other constitutional and dyspeptic symptoms can be included, all of which can also be seen in a variety of other septic conditions.
Physical examination
- Abdominal tenderness (>50%) may or may not be accompanied by muscle guarding in the left upper quadrant. There may be edema of the soft tissues overlying the spleen. Costovertebral tenderness may also be noted.
- Splenomegaly (<50%) is less frequently observed, probably because of early diagnosis resulting from the widespread use of imaging methods.
- Chest findings are nonspecific and reportedly include dullness at the left lung base (>30%), left basilar rales (>21%), or elevation of the left hemidiaphragm (>15%).
Once the diagnosis of a splenic abscess has been made, the patient must be admitted to the hospital and treated. Treatment depends upon the patient's overall condition, comorbidities, and primary disorder (if any), as well as the size and topography of the abscess.
Empiric broad-spectrum antibiotics have a primary role in the initial management of splenic abscesses. The success of antibiotic therapy is not affected by the presence of multiple abscesses or by a polymicrobial flora. The choice of antibiotics is tailored to the culture results. Percutaneous drainage has gained acceptance as an effective and less invasive treatment method than surgical intervention in selected patients. The reported success rate of percutaneous drainage is 67-100%. Such drainage preserves the spleen and avoids the risk of overwhelming postsplenectomy infections. Percutaneous drainage can also be used as a bridge to elective surgery in patients who are clinically unstable or in patients who have multiple comorbidities.
Percutaneous drainage is likely to be useful in patients who have unilocular or bilocular collections and if the character of the abscess content permits a minimally invasive drainage. Multilocular abscesses, ill-defined cavities, septations, and necrotic debris typically do not respond to percutaneous drainage. Surgery is reserved for patients who are stable and not amenable to percutaneous drainage. Depending on available expertise, laparoscopic or open procedures can be considered.
The normal adult spleen weighs up to 150 grams, measures 4 X 7 X 11 cm, and represents the largest single accumulation of lymphoid tissue in the body. The spleen lies beneath the left hemidiaphragm and is attached to the stomach, left kidney, and diaphragm by the gastrosplenic, lienorenal, and phrenolienal ligaments. The gastrosplenic ligament contains the short gastric vessels, which can be injured easily during interventions in the area.
Anomalies of the spleen must always be considered, including wandering spleen, polysplenia, asplenia, or accessory spleen. Accessory spleen is the most common of the splenic anomalies (>1% of all patients). Solitary or multiple accessory spleens can be found in the splenic hilum, pancreas, lesser sac, retroperitoneum, liver, or gut mesentery.
The size and location of a splenic abscess determines its relationship with the surrounding organs and the possible routes for extension or fistulization. Small solitary or multiple abscesses tend to remain contained by the splenic capsule. Advanced abscesses in the spleen's upper pole can fistulize into the pleura. Abscesses originating from the lower pole can involve the splenic flexure and communicate with the colonic lumen. The stomach and pancreas can be affected in an analogous way.
Absolute contraindications to percutaneous drainage include the following:
- Multiloculated or debris-filled abscess
- Multiple small abscesses
- Uncontrollable coagulopathy
- Poorly defined abscess on CT scan or ultrasound
- Diffuse ascites
- No safe route for drainage
Relative contraindications to percutaneous drainage include the following:
- Splenic abscesses secondary to spread from a contiguous process, such as other large primary abscesses (eg, pancreatitis, perforated colon cancer) that cannot be eradicated by this method
- Abscess rupture
- A phlegmonous or poorly characterized lesion on CT scan or ultrasound
Lab Studies
- A CBC demonstrates leukocytosis (WBC count, >20,000/mm3) with a left shift in most patients. Patients who are immunologically compromised may deviate from this rule.
- Recurrent positive blood cultures can further suggest the diagnosis.
Imaging Studies
- A chest radiograph is typically the first step in the preoperative evaluation. However, a chest roentgenogram will reveal nonspecific changes typical for a septic process in the region rather than diagnostic findings for a splenic abscess in particular.
- Abnormal chest radiograph findings in most patients
- Elevated left hemidiaphragm (>30%)
- Pleural effusion (>20%)
- Plain x-ray films of the abdomen are notoriously nonspecific in patients with a splenic abscess. Findings on abdominal x-ray films can include abnormal soft tissue density or a gas collection in the left upper quadrant.
- Radioisotope scanning is of little value because most tests require more than 24 hours to perform and interpret.
- Ultrasound
- Ultrasound is cost-effective, noninvasive, and readily available at the bedside around the clock.
- However, the evaluation is nonspecific and operator dependent.
- CT scan
- CT scan is presently the criterion standard in helping to establish the diagnosis of splenic abscess.
- Reported sensitivity of the CT scan for this purpose typically approaches 100%.
- The characteristic image of splenic abscess reveals low-density lesions that fail to enhance after intravenous contrast.
- CT scan best delineates the size, topography, and access routes to the spleen and surrounding structures.
- CT-guided drainage can be performed during the examination.
Diagnostic Procedures
- Ultrasound- or CT-guided diagnostic percutaneous aspiration is useful in helping to confirm the diagnosis and in providing a specimen for bacteriology.
Staging
No universally accepted staging system for splenic abscess exists.
Medical therapy
Early supportive care and parenteral broad-spectrum antibiotics are of paramount importance while further diagnostic and therapeutic arrangements are made. Antibiotic coverage should target the presumed bacterial strains. Medical management as the only treatment of selected splenic abscesses has been advocated in several studies but remains controversial. The published literature suggests that most patients in this category have contiguous infections in the abdomen. The mortality rate in this group is 50% or greater. Besides the more common organisms isolated from splenic abscesses, mycobacteria, Candida, and Aspergillus should also be considered; these organisms account for 8% of the splenic abscesses in patients who are immunocompromised. Fungal abscesses are known to respond more favorably to antifungal treatment because they result more often from a disseminated infection. The mortality rate with antifungal therapy alone is 6%.
Surgical therapy
The invasive treatment of splenic abscess includes 3 options: percutaneous drainage, open or laparoscopic surgery (splenectomy), and open drainage.
Percutaneous drainage Percutaneous drainage is indicated for easily accessible uniloculated or biloculated abscesses with otherwise favorable features, as described previously, and also for very high-risk surgical patients who cannot tolerate general anesthesia or surgery.
The procedure includes a risk of iatrogenic injury of the spleen, colon (splenic flexure), stomach, left kidney, and diaphragm.
Calcified walls of the abscess, the presence of other intra-abdominal cysts with intra-luminal daughter cysts, and an origin from endemic areas (eg, Mediterranean basin, Eastern Europe) should raise a suspicion for Echinococcus granulosus. Percutaneous drainage of such suppurative cysts increases the risk of hydatid seeding and anaphylaxis and is therefore contraindicated.
Other iatrogenic complications resulting from percutaneous drainage include hemorrhage, pleural empyema, pneumothorax, and enteric fistula. Splenectomy Splenectomy has long been considered the standard treatment of splenic abscess. Depending on the patient population, open splenectomy has a mortality rate of 0-17% and a morbidity rate of 28-43%. The method removes the septic source and the diseased organ. The surgeon can explore and manage coexisting septic collections.
Laparoscopic splenectomy is safe and effective in selected patients. It can be performed with no morbidity or mortality. Patients reported so far have had a shorter hospital stay.
Very infrequently, the perisplenic adhesions are so severe that safe dissection between the spleen and the surrounding structures is impossible. The only choice in this scenario is to perform an open splenotomy and drain the collection.
Open drainage
Open drainage is used in case of an inability to drain the abscess percutaneously. Depending on the location of the abscess, 1 of 3 access routes can be used: - Transpleural - Usually requires resection of the 12th rib in the posterior axillary line and drainage of the abscess through the diaphragm
- Abdominal extraperitoneal - Accesses the abscess through the lateral abdominal wall and between the peritoneum and the flat abdominal muscles
- Retroperitoneal - Used when the abscess extends to the flank
Preoperative details
The difficult location of the spleen increases the risk of iatrogenic hemorrhage or hollow organ injury. Patients with splenic abscess must be typed and screened, and massive blood transfusion must be anticipated. Prophylactic broad-spectrum antibiotic coverage is essential. A nasogastric tube must be used to decompress the stomach. The risk of injury to the colon requires preoperative bowel preparation in nonemergency cases. Administration of polyvalent vaccines must be planned.
Intraoperative details
The operating room must be warm to decrease the risk of coagulopathy and wound infection. Blood products must be readily available.
A splenectomy can be performed through various abdominal incisions.
- A midline incision is preferred in adult patients by most surgeons because it provides easy access to all 4 quadrants.
- A left subcostal incision sparing the rectus abdominis muscle (Singleton) is preferred in pediatric patients.
- A thoracoabdominal incision is rarely required in massive pleural involvement by the abscess requiring open thoracic access.
Massive perisplenitis with adhesions carries a significant risk of iatrogenic splenic rupture. The spleen is mobilized carefully by dividing the ligamentous attachments. Special care must be taken to avoid injury to the pancreas and resulting pancreatic fistula.
In laparoscopic splenectomy, the spleen must be morselized intra-abdominally to allow retrieval of the specimen through a limited incision. Prophylactic peritoneal drainage is at the discretion of the surgeon.
Postoperative details
As stated above, interventions for splenic abscess are potentially morbid. The patients must be placed under close observation, especially during the first 24 hours when the risk of postoperative hemorrhage is high.
Follow-up
Follow-up is an essential element of the management of patients undergoing treatment of splenic abscess.
The patients must be screened for the following:
- Late iatrogenic complications, such as residual intra-abdominal abscesses, pancreatic or enteric collections, or fistulas
- Intestinal obstruction and ventral hernia
- Recurrent splenic abscess
- Overwhelming postsplenectomy sepsis
The mortality rate of untreated splenic abscess approaches 100%. The list of complications is long but most importantly includes free rupture into the peritoneal cavity with generalized peritonitis, rupture into the colon, erosion of the abscess through the diaphragm, or, more rarely, necessitation through the skin. The complications of treated splenic abscesses depend on the topography and treatment method. They can include the following:
- Life-threatening hemorrhage from the splenic parenchyma or hilar vessels
- Pneumothorax
- Left-sided pleural effusion
- Subphrenic abscess
- Perforation of the colon, stomach, or small intestine
- Pancreatic pseudocyst or fistula
- Postsplenectomy thrombocytosis
- Overwhelming postsplenectomy sepsis
- Atelectasis or pneumonia
Knowledge of the anatomy, careful preoperative planning, optimal exposure, and attention to the details of the technique can substantially reduce the incidence of iatrogenic complications.
Respiratory complications are minimized or avoided by incentive spirometry and chest physical therapy.
Subphrenic abscess, although uncommon after splenic surgery, is a recognized consequence of pancreatic or hollow organ injury. The condition requires prompt diagnosis and drainage.
In cases of splenectomy, thrombocytosis occurs in more than 50% of cases. A very high platelet count (>1,000,000/microliter) requires an intervention to minimize the incidence of thrombotic complications. Platelet apheresis or anticoagulants can be used in this regard. Overwhelming, postsplenectomy sepsis carries a significant mortality risk, especially for young patients who have undergone splenectomy. Whenever splenectomy is considered, patients should undergo immunization against Streptococcus pneumoniae, Meningococcus, and Haemophilus influenzae type b. The administration of oral antibiotics to splenectomized individuals is the mainstay of prophylaxis (and initial therapy). Two complementary strategies are commonly used: daily antibiotic prophylaxis and empiric antibiotic therapy for fever.
The natural history of untreated splenic abscess has not been studied prospectively. The lack of randomized studies does not provide a conclusive clinical algorithm for the condition. The published literature suggests that early diagnosis, individualized management, and increased experience with minimally invasive methods carry a potential for lower morbidity and mortality.
No prospective, randomized study is available to determine the most effective treatment of splenic abscess. The diversity of the patient population suggests the importance of patient selection to improve outcome. CT scan is currently considered the criterion standard in helping to establish the diagnosis of splenic abscess. Percutaneous CT-guided drainage is a safe, minimally invasive, and successful treatment option that should be used as a spleen conserving alternative to surgery in suitable patients.
The available early results of laparoscopic splenectomy for splenic abscess are appealing and suggest that there is significant opportunity to further develop this method. At the current time, surgical splenectomy must be considered as the most reliable treatment of this condition and must be considered if the other available less invasive treatment methods fail.
This material is the result of work supported with resources and facility use at the John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan.
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Splenic Abscess excerpt Article Last Updated: May 21, 2007
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