Splenic abscess is not a frequent clinical problem. However, if the diagnosis is missed, splenic abscess does carry very high mortality reaching more than 70% with appropriate treatment, the mortality can be reduced to less than 1%. Today with the availability of a CT scan, the condition is not only rapidly diagnosed, but it also helps with treatment by aspirating the collection.
Abscesses of the spleen usually result from bacteremia, particularly in the setting of abnormalities caused by trauma, embolization, or hemoglobinopathy. Immunocompromised states that from human immunodeficiency virus infection, may also be a risk factor. Some reports indicate that splenic abscesses have occurred from a contiguous focus of infection. Other recognized risk factors are neoplasms, metastatic infection, splenic infarction, and diabetes. Splenic abscesses have also been found to be associated with parasitic infection of the spleen.
In some cases, an abscess elsewhere in the abdomen may communicate and involve the spleen. It is known as pancreatic abscesses, and diverticulitis may sometimes extend and involve the spleen.
Organisms commonly associated with a splenic abscess include the following:
Splenic abscesses are relatively uncommon. Autopsy series have estimated the incidence of splenic abscess between 0.2% to 0.07%. Associated mortality is still high, especially in the immunocompromised. There is evidence that the rate may be increasing due to improved detection, increased illicit intravenous drug use, and the increased number of immunocompromised individuals. Splenic abscess has a bimodal age distribution with peaks in the third and sixth decade of life. Approximately two-thirds of splenic abscesses in adults are solitary, and one-third are multiple.
Splenic abscesses are most regularly seen as a complication of infective endocarditis, which occurs in about 5% of patients. Frequently, isolated pathogens include Streptococcus, Staphylococcus, (due to endocarditis being the most common cause of splenic abscess), Mycobacterium, fungi, and parasites. Burkholderia pseudomallei is a cause of splenic abscesses in predisposed individuals in some parts of the world. Mortality rates are high and fluctuate with immune status and the type of abscess. There is up to an 80% mortality in immunocompromised patients with multilocular abscesses and 15% mortality in immunocompetent patients with unilocular abscesses.
Fever is the most common symptom, followed by abdominal pain and tender mass on palpation of the left upper quadrant of the abdomen. The common signs and symptoms described of a splenic abscess include the triad of fever, left upper quadrant tenderness, and leukocytosis is present only in one-third of the cases.
The physical exam will reveal the following:
Blood work will reveal leucocytosis with a left shift, and the blood cultures may be positive.
Plain radiographs of the chest can reveal many findings indicative of splenic abscesses such as an elevated left hemidiaphragm and left-sided pleural effusion with or without left basal atelectasis. An ultrasonogram typically demonstrates an area of decreased or absent echogenicity and splenomegaly. An ultrasonogram is quick and can be done at the bedside. A CT scan is the gold standard for diagnosis. The scan also helps doctors to plan treatment by delineating the details of the abscess and the topography of the surrounding structures.
In many cases, a diagnostic aspiration guided by ultrasound or CT scan can help confirm the diagnosis.
High-dose parenteral broad-spectrum antibiotics are of paramount importance while further diagnostic and therapeutic arrangements are made. The culture results guide the choice of antibiotics.
The gold standard for treatment of splenic abscess is splenectomy; however, recent studies have shown success using different approaches based on abscess characteristics. Percutaneous aspiration may be a less invasive option in patients who are at high risk for surgery, or a temporary solution used as a bridge to surgery, avoiding the risk of a fulminant and potentially life-threatening infection. A percutaneous aspiration is a successful approach when the abscess collection is unilocular or bilocular, with a complete and thick wall and no internal septations. Aspiration is easier to achieve when the content is liquid enough to be drained. If there are multiple collections, or there is associated coagulopathy, either laparoscopic or open surgical treatment is preferred.
Percutaneous drainage is less likely to be successful in patients with multilocular abscess, ill-defined cavities, necrotic debris, and thick, viscous fluid. Contraindications for percutaneous drainage include the following:
Medical treatment alone is not recommended and remains a controversial subject. Mortality rates of more than 50% have been reported in patients only managed with antibiotics. In patients who do not respond, one should consider fungi, actinomycetes or Mycobacterium as a cause.
Fungi are known to respond well to antifungal treatment alone. One study also noted that corticosteroid therapy in these patients could be beneficial.
Open drainage is sometimes required when percutaneous drainage fails. The routes for open drainage include:
Unlike the past, the prognosis of a splenic abscess today is markedly improved. The availability of percutaneous CT guided drainage is not only safe and less invasive, but it also avoids the morbidity of open surgery. Furthermore, laparoscopic splenectomy has been a promising alternative to the open method, with faster recovery and short hospital stays. Surgical splenectomy is the treatment of last choice since most cases can be managed with percutaneous guided drainage and antibiotics.
Complications of a splenic abscess include the following:
The respiratory complications can be minimized by advocating incentive spirometry, pain control, and aggressive chest physical therapy.
If a subphrenic abscess develops, it usually requires prompt drainage.
Post-splenectomy sepsis is always a risk, especially in young people who have had the spleen removed. These patients should undergo immunization against Meningococcus, Streptococcus pneumoniae and Haemophilus influenzae.
Follow up is essential after treatment of a splenic abscess
Late complications are not unusual and close monitoring is required.
With new advances in ultrasonography, computed tomography (CT), improved diagnosis, and aggressive antibiotic therapy, the prognosis in patients with a splenic abscess has improved.
Splenic abscess is not a common disease and hence the natural history has not been well studied in controlled clinical trials. The lack of trials and evidence-based medicine makes it difficult to make recommendations on diagnosis and management. However, expert opinion suggests that an interdisciplinary approach may help with prompt diagnosis and earlier treatment. One study revealed that a stratified approach in the emergency room led to an earlier diagnosis with improved outcomes. (Level III)
Both the surgeon and the radiologist must be involved in the care of the patient. Recent data indicate that CT guided drainage is safe and an effective way to treat a splenic abscess. If surgery is taken then a laparoscopic approach is preferred over an open approach. (Level III)
If the spleen is removed then both the nurse and pharmacist play a vital role in educating the patient on post-splenectomy sepsis and the need for vaccination. In the absence of guidelines it is imperative that the healthcare workers communicate and integrate their strategies so that the patient gets the best care possible. (Level III).