Splenic Abscess Drainage
Introduction
Splenic abscess is an uncommon but potentially life-threatening condition characterized by a localized collection of infected material — pus, necrotic debris, and inflammatory exudate — within the splenic parenchyma. Despite its relatively low incidence in the general population, it carries a disproportionately high mortality risk when diagnosis is delayed or management is inadequate, with historical reports citing fatality rates approaching one hundred percent in untreated cases. The advent of cross-sectional imaging, principally computed tomography has significantly improved the timelines and accuracy of diagnosis, while advances in interventional radiology have transformed the therapeutic landscape by offering percutaneous drainage as a definitive and minimally invasive alternative to surgical splenectomy in appropriately selected patients.
Percutaneous splenic abscess drainage is an image-guided procedure in which a drainage catheter or needle is introduced through the skin into the splenic abscess cavity under real-time imaging control, allowing evacuation of the infected collection, reduction of systemic septic burden and restoration of local tissue architecture without the morbidity and immunological consequences associated with operative splenectomy. The procedure is performed by interventional radiologists with expertise in abdominal intervention and represents a paradigm shift in the management of this historically surgically dominated condition. Its clinical importance extends beyond technical efficacy — by preserving the spleen in a significant proportion of patients, percutaneous drainage avoids the lifelong susceptibility to overwhelming post-splenectomy infection that surgical removal entails, a consideration of substantial relevance in younger patients and those with underlying immunocompromise.
Understanding Splenic Anatomy, Pathophysiology, and Abscess Formation
The spleen is a highly vascularized, encapsulated lymphoid organ situated in the left upper quadrant of the abdomen, occupying the space between the gastric fundus medially, the left hemidiaphragm superiorly, the left kidney posteriorly, and the splenic flexure of the colon inferiorly. It is invested by a dense fibrous capsule, which provides structural support but also limits the capacity of the organ to expand under conditions of acute inflammatory or infectious pathology without generating significant capsular tension and pain. The splenic parenchyma is divided into red pulp, responsible for filtering senescent erythrocytes and serving as a vascular reservoir and white pulp, comprising organized lymphoid follicles that constitute the immunological core of the organ’s function.
The spleen’s rich vascular supply — receiving approximately five percent of resting cardiac output through the splenic artery — makes it an organ vulnerable to hematogenous seeding during bacteremic episodes. The reticuloendothelial cells lining the splenic sinusoids phagocytose circulating pathogens under normal circumstances, but when this defense mechanism is overwhelmed or when local factors such as infarction, trauma or pre-existing structural abnormality create a nidus of devitalized tissue, bacterial colonization and subsequent abscess formation may occur.
Splenic abscess formation follows several well-characterized pathogenic pathways. Hematogenous seeding during bacteremia is the most common mechanism, accounting for the majority of cases and explaining the strong clinical association with infective endocarditis, intravenous drug use, urinary tract infection, dental sepsis and other distant infectious foci. The immunocompromised patient — whether due to human immunodeficiency virus infection, prolonged corticosteroid therapy, chemotherapy-induced neutropenia, diabetes mellitus or hematological malignancy — is at substantially elevated risk, as the splenic immune surveillance function is already compromised. Splenic infarction, occurring in the context of hemoglobinopathies such as sickle cell disease, thromboembolic events or hematological malignancies with massive splenomegaly and vascular occlusion, creates devitalized parenchyma susceptible to superinfection. Direct extension from contiguous infection — including subphrenic abscess, perinephric collection or infected pancreatic pseudocyst in the context of pancreatitis — represents an additional pathway. Penetrating abdominal trauma with splenic parenchymal injury and subsequent secondary infection constitutes a less common but recognized etiology.
The causative microbiology of splenic abscess is broad and reflects the underlying pathogenic mechanism. Gram-positive organisms, particularly Streptococcus species and Staphylococcus aureus, predominate in hematogenous cases. Gram-negative enteric organisms including Escherichia coli, Klebsiella pneumoniae — notably in the context of Klebsiella liver and splenic abscess syndrome seen in diabetic patients of Southeast Asian descent — and Salmonella species are frequently implicated. Fungal abscesses, particularly due to Candida species, occur predominantly in profoundly immunocompromised patients, including those receiving intensive chemotherapy for hematological malignancie, and carry a distinct clinical course and therapeutic requirement. Polymicrobial infections reflect hematogenous spread from polymicrobial bacteremic sources or contiguous extension from abdominal sepsis.
Indications for the Procedure
Percutaneous drainage of splenic abscess is indicated in patients presenting with a confirmed or radiologically suspected unilocular or paucilocular splenic abscess who are hemodynamically stable and lack contraindications to the percutaneous approach. The procedure is the preferred first-line interventional strategy for unilocular abscesses of sufficient size — generally greater than three to four centimeters in diameter — that are amenable to safe needle or catheter access along a trajectory that avoids major vascular structures, pleural space transgression or adjacent hollow viscera.
Patients presenting with systemic sepsis attributable to splenic abscess, including persistent fever, leukocytosis and bacteremia refractory to antibiotic therapy alone, represent the most urgent indication for drainage, as source control through evacuation of the infected collection is fundamental to resolving the septic state. In clinically stable patients with smaller abscesses detected incidentally or in early evolution, a trial of targeted intravenous antibiotic therapy may be appropriate in carefully selected circumstances, but clinical and radiological reassessment must be rigorous and drainage should not be delayed if there is evidence of clinical deterioration or abscess enlargement.
Percutaneous drainage is particularly valuable in patients for whom splenectomy carries elevated operative risk — including those with severe comorbidities, coagulopathy, malnutrition or markedly immunocompromised states — and in patients in whom splenic preservation is clinically desirable to avoid the immunological consequences of asplenia. Complex, multilocular abscesses with thick internal septations, fungal abscesses with their characteristically viscous content, abscesses associated with underlying splenic neoplasm and situations in which a safe percutaneous access route cannot be defined represent clinical scenarios where surgical consultation for splenectomy or laparoscopic drainage is more appropriate. Rupture of the splenic abscess with peritonitis or hemodynamic instability mandates emergency surgical intervention rather than percutaneous approach.
Pre-Procedure Preparation
Thorough pre-procedure preparation is essential to ensure procedural safety and optimize the likelihood of clinical success. Cross-sectional imaging, primarily contrast-enhanced computed tomography of the abdomen and pelvis, serves as the definitive diagnostic and planning modality. Computed tomography characterizes the number, size, location and internal architecture of the abscess or abscesses within the splenic parenchyma, defines the relationship of the collection to the splenic capsule and adjacent structures including the stomach, left kidney, pancreatic tail, left hemidiaphragm , left pleural space and identifies the vascularity of the surrounding parenchyma to anticipate hemorrhagic risk. It further facilitates identification of the optimal access route — typically a direct transsplenic or a perisplenic subcostal trajectory — that maximizes catheter placement accuracy while minimizing traversal of non-target structures.
Laboratory evaluation includes a full blood count, coagulation profile including prothrombin time, activated partial thromboplastin tim, and international normalized ratio, platelet count, serum creatinine, electrolytes, liver function tests and blood cultures drawn prior to procedure. Coagulopathy is corrected prior to intervention; an international normalized ratio below 1.5 and a platelet count above 50,000 per microliter are generally accepted thresholds for proceeding with catheter drainage, though individual clinical urgency may necessitate procedural intervention with pharmacological correction occurring concurrently. Blood group and crossmatch are obtained given the hemorrhagic risk associated with splenic intervention.
Broad-spectrum intravenous antibiotics are commenced upon diagnosis and prior to the procedure, selected empirically to cover the anticipated microbiological spectrum and tailored once culture and sensitivity results become available. Anticoagulant and antiplatelet medications are withheld according to standard pre-procedural protocols commensurate with the thrombotic risk profile of the individual patient. The patient is fasted for a minimum of four to six hours prior to the procedure in anticipation of sedation or analgesia requirements. Informed consent is obtained following a detailed discussion of the procedural rationale, technique, expected benefits and risk profile, including the possibility of conversion to surgical management if percutaneous drainage is unsuccessful or complications arise.
How the Procedure is Performed
Percutaneous splenic abscess drainage is performed in an interventional radiology suite equipped with real-time imaging capability, resuscitation equipment and the capacity for procedural sedation and analgesia monitoring. The procedure is most commonly performed under computed tomography guidance, which affords superior visualization of the splenic parenchyma, abscess morphology and adjacent structures, particularly in cases where the access window is anatomically constrained. Ultrasound guidance may be employed for superficially situated, clearly defined abscesses accessible via a subcostal or intercostal approach, offering the advantage of real-time needle visualization without ionizing radiation, though its utility is limited by overlying ribs, bowel gas and the depth of the spleen in certain patient habitus types. Combined ultrasound and fluoroscopic guidance may be employed during catheter exchange and manipulation steps following initial computed tomography-guided access.
The patient is positioned on the computed tomography table in a supine, right lateral decubitus or oblique position depending on the planned access trajectory determined from pre-procedure imaging review. The skin overlying the planned entry site — typically the left lateral flank, subcostal margin or an intercostal space below the left costal margin — is sterilely prepared with antiseptic solution and draped appropriately. Local anesthetic, generally one percent lidocaine, is infiltrated generously from the skin surface through the subcutaneous tissue and, where the access route traverses the splenic capsule, down to and including the capsular surface.
For smaller, unilocular abscesses amenable to single-session aspiration, a diagnostic and therapeutic needle aspiration using an 18 or 20-gauge needle may be performed. The needle is advanced under continuous imaging guidance along the pre-planned trajectory, with stepwise computed tomography acquisitions or real-time ultrasound confirming needle tip position within the abscess cavity. Aspiration of purulent material confirms intracavitary placement and the collection is evacuated as completely as possible through manual syringe aspiration. Samples are sent for Gram stain, aerobic and anaerobic bacterial culture, fungal culture, and cytological examination to exclude an underlying neoplastic process. For larger collections, abscesses with thick or viscous content or in cases where complete aspiration is not achievable, catheter drainage is the preferred approach.
Catheter drainage is performed using either the Seldinger technique or the trocar technique. In the Seldinger method, an access needle is first introduced into the abscess cavity under imaging guidance and its intracavitary position confirmed by aspiration of pus. A flexible guidewire is advanced through the needle and coiled within the abscess cavity under fluoroscopic or imaging confirmation. The access needle is withdrawn over the guidewire and the tract is progressively dilated using coaxial fascial dilators to accommodate the drainage catheter — typically an 8 to 14 French pigtail or locking loop catheter. The catheter is advanced over the guidewire into the abscess cavity, the guidewire withdrawn and the pigtail loop formed and locked within the collection. In the trocar technique, applicable to larger, more superficial abscesses, the catheter is introduced directly over a rigid trocar stylet in a single pass, avoiding the multiple exchange steps of the Seldinger approach.
Once the catheter is satisfactorily positioned within the dependent portion of the abscess cavity, the collection is evacuated by drainage and gentle irrigation with sterile saline solution to disrupt loculations, remove viscous debris and assess catheter function. The catheter is secured to the skin using sutures or a securement device and connected to a closed drainage bag system. Imaging confirmation of satisfactory catheter position and residual abscess volume is obtained prior to conclusion of the procedure. In multilocular abscesses, separate catheter placement into individual compartments may be required or vigorous irrigation may be employed to break down internal septations and establish communication between locules.
Post-Procedure Care and Recovery
Following percutaneous splenic abscess drainage, the patient is transferred to a monitored inpatient setting for close clinical observation. Vital signs are assessed at regular intervals in the immediate post-procedural period to identify early signs of hemorrhage, hemodynamic instability or septic deterioration. Complete blood count and inflammatory markers are monitored serially and the clinical trajectory — particularly fever resolution, leukocyte count normalization and improvement in systemic symptoms — serves as the primary indicator of treatment response.
The drainage catheter is managed with daily irrigation using sterile saline to maintain patency and prevent blockage by debris or inspissated material, particularly in cases involving thick or particulate content. Daily drain output is recorded and the character of the effluent — transitioning from frankly purulent to serous with progressive treatment — provides a clinical marker of abscess resolution. Targeted intravenous antibiotic therapy, guided by culture and sensitivity results, is continued throughout the drainage period and transitioned to oral agents once clinical improvement is established, the patient is tolerating oral intake, and inflammatory parameters are trending toward normalization.
Catheter removal is determined by a combination of clinical, laboratory and radiological criteria. Clinical resolution of fever and systemic sepsis, normalization of leukocytosis, reduction of drain output to less than ten to fifteen milliliters per day of serous fluid and imaging confirmation of abscess cavity collapse on follow-up ultrasound or computed tomography collectively inform the decision to remove the catheter. Premature catheter removal prior to adequate cavity resolution carries a risk of abscess recurrence and clinical relapse. The duration of catheter drainage varies considerably depending on abscess size, the viscosity of the content and the underlying microbiological etiology, ranging from several days in straightforward cases to several weeks in complex or fungal abscesses.
Patients are counseled regarding activity restrictions during the catheter indwelling period, advised to avoid physical exertion that could dislodge the catheter and instructed in catheter site care to prevent local infection. Follow-up outpatient appointments are arranged following discharge to review post-treatment imaging, assess ongoing recovery, complete the antibiotic course and confirm durable resolution of the infection.
Risks and Complications
Percutaneous splenic abscess drainage is associated with a defined risk profile that reflects both the inherent vascularity of the spleen and the anatomical complexity of the left upper quadrant. Hemorrhage represents the most significant procedural risk, arising from needle or catheter traversal of the highly vascular splenic parenchyma. Minor degrees of perisplenic hematoma detectable on post-procedural imaging are relatively common and typically self-limiting. Clinically significant hemorrhage requiring blood transfusion, angiographic embolization of a bleeding splenic arterial branch or emergency surgical intervention is less common but constitutes the most serious immediate complication of the procedure.
Inadvertent transgression of the left pleural space during needle or catheter passage through an intercostal access route may result in pneumothorax, hemothorax or empyema, particularly when the pleural reflection is low or the access trajectory is not precisely planned. Computed tomography guidance with careful pre-procedure route planning significantly mitigates this risk. Injury to adjacent viscera — including the stomach, colon, small bowel or left kidney — is an uncommon but recognized complication of misdirected needle placement and underscores the importance of meticulous imaging guidance and pre-procedural trajectory planning.
Bacteremia and transient septic deterioration may occur immediately following manipulation of the infected collection, attributable to haematogenous translocation of organisms during aspiration or catheter placement. Administration of intravenous antibiotics prior to the procedure and maintenance of appropriate antibiotic coverage throughout the drainage period provide essential prophylactic coverage against this phenomenon. Catheter-related complications including dislodgement, blockage and catheter site infection may arise during the indwelling period and are managed through appropriate catheter care, irrigation protocols and repositioning under imaging guidance when required.
Splenic abscess recurrence following catheter removal, attributable to incomplete drainage, residual loculations, or persistence of the underlying predisposing condition, necessitates repeat imaging and consideration of re-drainage or surgical management. In the small proportion of patients in whom percutaneous drainage is technically unsuccessful, complicated by major procedural complications, or in whom clinical response is inadequate despite technically satisfactory drainage, surgical splenectomy or laparoscopic drainage represents the definitive management strategy and should not be delayed once the limitations of percutaneous management are recognized.
Clinical Outcomes and Effectiveness
Percutaneous drainage of splenic abscess achieves clinical success — defined as resolution of the abscess and systemic infection without requirement for surgical splenectomy — in the substantial majority of appropriately selected patients treated in experienced interventional radiology centers. Success rates are highest for unilocular abscesses of bacterial etiology in immunocompetent patients, reflecting the more favorable access geometry and the less viscous, more readily drainable content of these collections. Multilocular abscesses, fungal abscesses — particularly those associated with Candida species in neutropenic patients, which characteristically produce thick, paste-like material resistant to catheter drainage — and abscesses complicating underlying splenic structural pathology demonstrate lower rates of technical success with percutaneous management alone and more frequently require surgical intervention.
The clinical and survival benefit of percutaneous drainage over expectant antibiotic management alone is well-established in the literature for abscesses of sufficient size, with drainage consistently demonstrating faster resolution of systemic sepsis, shorter hospitalization duration and lower mortality compared to antibiotics without source control. Comparative data between percutaneous drainage and splenectomy indicate broadly comparable clinical outcomes in carefully selected patients, with the important additional benefit of splenic preservation in the drainage cohort — an outcome of lasting immunological significance given the risk of overwhelming post-splenectomy infection with encapsulated organisms, which carries a lifetime mortality risk and necessitates vaccination and potentially prophylactic antibiotic therapy in splenectomized patients.
Factors consistently associated with favorable outcomes following percutaneous drainage include unilocular abscess morphology, abscess diameter amenable to catheter drainage, bacterial rather than fungal etiology, patient immunocompetence and early initiation of appropriately targeted antibiotic therapy concurrent with drainage. The integration of percutaneous drainage into a multidisciplinary management framework — incorporating infectious disease consultation for antimicrobial stewardship, haematological input in patients with underlying malignancy and surgical availability for cases requiring escalation — is the clinical model most consistently associated with optimal patient outcomes across institutional series.
Conclusion
Percutaneous splenic abscess drainage has fundamentally redefined the management of this once uniformly surgically treated condition, offering a minimally invasive, highly effective route to source control and clinical resolution in appropriately selected patients. Its capacity to preserve splenic immunological function while achieving outcomes comparable to splenectomy in favorable anatomical and microbiological contexts represents a significant clinical advance, particularly meaningful for immunocompromised patients and younger individuals in whom the lifelong consequences of asplenia carry substantial health implications. The procedure demands a rigorous framework of pre-procedural planning, meticulous image-guided technique and attentive post-procedural management to realize its full therapeutic potential and to recognize early the small proportion of patients in whom surgical escalation is warranted. As the expertise and technical capabilities of interventional radiology continue to advance, the role of percutaneous drainage in splenic abscess management will only become more central, supported by an expanding evidence base that continues to validate its position as the preferred first-line interventional strategy in this challenging clinical condition.