The spleen is an organ located in the upper left part of the abdomen, functioning primarily as a filter for the blood and a reservoir for certain immune cells. It removes old or damaged red blood cells and aids in fighting off specific types of infection. A splenic infarct, or splenic infarction, occurs when the blood supply to a segment or the entirety of this organ is blocked. This sudden interruption causes the deprived tissue to suffer from a lack of oxygen and nutrients, leading to localized cell death, known as necrosis. The severity depends on the size of the affected area and the underlying cause of the blockage.
Identifying the Symptoms
The presentation of a splenic infarct varies significantly, ranging from a complete lack of symptoms to severe distress. The most common sign is the sudden onset of intense pain localized to the left upper quadrant of the abdomen. This discomfort results from tissue death and subsequent inflammation of the splenic capsule. The pain is often made worse by taking a deep breath or applying pressure to the area.
This abdominal pain may sometimes radiate to the left shoulder, a phenomenon known as referred pain. This occurs because the spleen is situated near the diaphragm, and the nerves serving both areas share similar pathways, confusing the brain about the pain’s true origin. Patients may also experience systemic symptoms such as fever, which can indicate inflammation or infection, and digestive issues like nausea and vomiting. However, many splenic infarcts are discovered incidentally during imaging for other conditions, as a significant portion of patients experience no symptoms at all.
Underlying Causes
The primary mechanism leading to a splenic infarct is the occlusion of the splenic artery or one of its branches, categorized into thromboembolic events, hematological disorders, and vascular compromise.
Thromboembolic Events
Thromboembolic causes involve a mobile clot or foreign material, known as an embolus, that travels through the bloodstream until it lodges in a splenic vessel too small for it to pass. The most frequent source of these emboli is the heart, often resulting from conditions like atrial fibrillation, where irregular heart rhythm allows blood to pool and clot. Another cause is infective endocarditis, where bacterial growths (vegetations) can break off and travel to distant organs.
Hematological Disorders
This group relates to disorders that increase the blood’s tendency to clot or alter the shape of blood cells. Sickle cell disease is a common example, especially in younger patients, where abnormally shaped red blood cells obstruct the small vessels of the spleen. Other hematological conditions, such as myeloproliferative disorders (e.g., chronic myelogenous leukemia or polycythemia vera), cause an overproduction of blood cells. This excess leads to congestion and sluggish blood flow within the spleen, making the organ susceptible to infarction.
Vascular and Structural Compromise
The blood supply can also be compromised by direct issues affecting the splenic vasculature or the organ’s structure. Blunt abdominal trauma can directly damage the splenic artery, leading to a blockage. Rarely, a wandering spleen, which is not tethered in its normal position, can twist upon its blood supply (torsion), effectively cutting off circulation. Other contributors include vasculitis, which causes inflammation of blood vessel walls, or external compression of the splenic artery by tumors.
Confirmation and Diagnosis
Confirming a splenic infarct requires clinical evaluation, laboratory testing, and medical imaging to visualize the damaged tissue and identify the underlying cause. Initial laboratory work may reveal generalized markers of inflammation, such as an elevated white blood cell count or an increase in lactate dehydrogenase (LDH), an enzyme released when cells are damaged. These blood test results are not specific to the spleen and must be interpreted alongside imaging studies.
Computed Tomography (CT) scanning with intravenous contrast is the most reliable method for definitive diagnosis in a stable patient. The contrast dye highlights areas receiving blood flow, clearly outlining the infarcted region. This area characteristically appears as a peripheral, wedge-shaped area that does not absorb the contrast, a pattern corresponding to the segmental nature of the splenic artery’s branching.
While CT is preferred, other imaging techniques play a role. Ultrasound, sometimes supplemented with Doppler technology to assess blood flow, provides an initial, non-invasive view. Magnetic Resonance Imaging (MRI) is another option offering high-resolution images, especially when a CT scan is contraindicated. The diagnostic process focuses not only on confirming the infarct but also on subsequent testing, such as echocardiography, to investigate potential cardiac sources for emboli.
Treatment and Management
The standard approach to treating a splenic infarct is conservative management, focusing on supportive care and addressing the primary cause of the vascular blockage. Supportive care includes pain control using analgesic medications, hydration, and monitoring the patient for any signs of worsening.
Therapy must be targeted at the root problem, as the infarct is a consequence of an underlying systemic condition. For example, if the infarct was caused by an embolic event from atrial fibrillation, the patient will likely require anticoagulation medication. In most cases, the damaged splenic tissue heals over time without surgical intervention, scarring down and becoming fibrotic.
Surgical removal of the spleen (splenectomy) is generally reserved for rare instances where complications arise. These complications include a severe infection leading to a splenic abscess, rupture of the spleen, or uncontrolled bleeding. Since the spleen plays a significant role in immune function, patients who undergo a splenectomy face a lifelong increased risk of infection, necessitating specific vaccinations.