Splenic Abscess

Updated: Apr 15, 2016
  • Author: Julian E Losanoff, MD, MHA, MSS; Chief Editor: John Geibel, MD, DSc, MSc, AGAF  more...
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Overview

Background

Abscesses of the spleen have been reported periodically since the time of Hippocrates, who postulated that the condition would take one of the following three courses [1] :

  • The patient might die
  • The abscess might heal
  • The abscess might become chronic, and the patient might live with the disease

Splenic abscess is a rare entity, with a reported frequency of 0.05-0.7%. [2, 3] Its reported mortality is still high, up to 47%, and has the potential to reach 100% among patients who do not receive antibiotic treatment. [4] Appropriate management can lower mortality to less than 10%. [5]

Timely and widespread use of imaging methods (eg, computed tomography [CT] and ultrasonography) facilitates early diagnosis and guides treatment, thereby improving the prognosis. [6]

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Anatomy

The normal adult spleen weighs up to 150 g, measures 4 × 7 × 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 relations to 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. [7]

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Pathophysiology

Splenic abscesses occur in a variety of clinical scenarios (see the images below). Published studies suggest that preexisting splenic tissue injury and bacteremia are required to form a basis for an abscess. [2, 8] Published scenarios include the following:

  • Hematogenous embolization to a previously normal spleen - Typical examples include patients with septic endocarditis who have abused intravenous (IV) drugs and patients undergoing chemotherapy who develop fungemia, resulting in a splenic abscess; generally, such patients either are immunosuppressed or have an overwhelming bacteremia; it is expected that this patient group will expand to 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 (see the images below)
  • Contiguous spread - This includes direct involvement from a pancreatic abscess, gastric or colonic perforations, or subphrenic abscesses
This patient has a splenic abscess due to pneumoco This patient has a splenic abscess due to pneumococcal bacteremia. Note that the massively enlarged spleen is readily visible, with minimal retraction in the left upper quadrant.
Resected spleen (same as in the above image) with Resected spleen (same as in the above image) with abscesses caused by pneumococcal bacteremia. Note the discrete abscesses adjacent to normal parenchyma.
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Etiology

Splenic abscesses have diverse etiologies. [9] The most common is hematogenous spread originating from an infective focus (most commonly involving aerobes) 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. [10] Other infective sources include typhoid, paratyphoid, malaria, urinary tract infection, pneumonias, osteomyelitis, otitis, mastoiditis, and pelvic infections.

Organisms associated with splenic abscess include the following [5] :

  • Aerobes (in most published cases) - Gram-positive cocci ( Streptococcus, [11] Staphylococcus, and Enterococcus [predominant in most reports]); gram-negative bacilli ( Escherichia coli, Klebsiella pneumoniae, Proteus, Pseudomonas, and Salmonella [occasionally predominant])
  • Anaerobes - Peptostreptococcus, Bacteroides, Fusobacterium, Clostridium, and Propionibacterium acnes
  • Polymicrobial (up to 50% of cases)
  • Fungi - Candida
  • Unusual flora - Burkholderia pseudomallei (occasionally reported in melioidosis); actinomycetes and mycobacteria (most typically seen in immunosuppressed patients)

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 (see the image below), such as hemoglobinopathies (especially sickle cell disease), leukemia, polycythemia, or vasculitis, can become infected and evolve into splenic abscesses. [2, 4, 12, 13, 14, 15, 16, 17]

Splenic infarct. Selective splenic arteriogram sho Splenic infarct. Selective splenic arteriogram showing extravasation of contrast from the splenic artery at the splenic hilum prior to angioembolization.

Alcoholics, diabetics, and patients who are immunosuppressed are among the most susceptible to splenic abscesses. [6, 15] . Rarely, splenic abscess can be caused by a parasitic infection such as brucellosis [18] or umbilical catheterization in the newborn. [19]  A case of chorinic splenic abscess occurring as the initial manifestation of pancreatic tail carcinoma has been reported. [20]  Splenic abscess has been reported as a rare complication of sleeve gastreectomy. [21]

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Epidemiology

Published autopsy statistics suggest that splenic abscess is rare (0.05-0.7%); the incidence may depend on the study population. [2, 3] For example, the incidence of splenic abscesses in Denmark was 0.056% per 1000 somatic hospital discharges per year or 0.0049% per year of all hospital deaths. [3]

The literature suggests a wide variability of causative pathogens, demography, and clinical material. [2]

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Prognosis

The natural history of untreated splenic abscess has not been studied prospectively. No prospective, randomized study is available to determine the most effective treatment for splenic abscess. 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. The diversity of the patient population suggests the importance of patient selection to improve outcome.

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. [22]

Available results from the use of laparoscopic splenectomy for splenic abscess have been promising, suggesting that there is significant opportunity for further development of this method. [23] Surgical splenectomy must currently be considered the most reliable treatment for this condition and must be considered if the available less-invasive treatment methods fail.

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