Splenic Infarcts

Etiology

The two most common causes of splenic infarction are thromboembolic disease and infiltrative hematologic diseases. In patients under 40 years of age, the most common cause is a hematologic disease. [4]Causes of splenic infarction may be categorized as follows:

• blood-borne malignancy (leukemia, lymphoma), myelofibrosis
• hypercoagulable states (sickle cell disease, protein C and S, polycythemia vera, lupus anticoagulant, exogenous estrogen use, malignancy)
• thromboembolic disorders (atrial fibrillation, endocarditis, patent foramen ovale, prosthetic heart valves)
• blunt abdominal trauma
• pancreatic disorders (pancreatitis, compressive pancreatic masses)

Additionally, broad categories of autoimmune and collagen vascular diseases, as well as the "wandering spleen," have been noted in case reports of splenic infarcts. 

Epidemiology

Splenic infarcts are considered a rare cause of abdominal pain, although the exact prevalence is unclear. The diagnosis of splenic infarct is thought to be rising due to increased abdominal imaging, increased use of splenic embolization, and increased nonoperative management of traumatic splenic injuries. This disease may affect patients of all ages. Patients 40 years of age and younger are more likely to have underlying hematologic illness, while patients 40 years of age and older are more likely to suffer splenic infarction due to thromboembolic diseases.[5]

Pathophysiology

The splenic artery (branching off the celiac artery) supplies blood flow to the spleen in combination with the short gastric arteries (branches off of the left gastroepiploic artery).

One of the most common causes of splenic infarction is sickle hemoglobinopathies. In patients with sickle cell disease, episodes of hypoxia or acidosis cause red blood cells to transform into an abnormal shape, leading to crystallization and occlusion of the vasculature. This process can lead to multiple infarctions beginning in childhood. Over time, multiple infarctions cause scarring and contraction of the spleen. This may ultimately result in complete splenic autoinfarction by the time of adulthood.

Diseases that cause splenomegaly may place patients at risk for splenic infarction. These diseases include chronic myelogenous leukemia, myelofibrosis, Gaucher disease, malarial splenomegaly syndrome, AIDS with Mycobacterium avium complex, and lymphoma.

Rarely, abnormal splenic vascular anatomy may cause infarction. An anatomical variant known as the wandering spleen has been identified in which the spleen has an abnormal vascular attachment that predisposes to torsion.

History and Physical

Splenic infarction is a rare cause of abdominal pain. Diagnosis is often suspected based on the presence of underlying disease states most likely to cause splenic infarction. A study published in 2010 set out to better characterize the modern experience of splenic infarction. This study performed chart reviews of 26 patients admitted to the hospital with the diagnosis of splenic infarction. Their observations were as follows:

• Mean age 52 years
• 50% complained of localized left sided abdominal pain
• 36% had left sided abdominal tenderness
• 32% splenomegaly
• 31% had no signs or symptoms localized to the spleen area
• 36% had a fever temperature greater than 38 °C
• 56% had WBC >12,000
• 71% had elevated LDH level
• 32% had nausea and or vomiting

Interestingly, the authors noted that in 21 of 26 patients, the diagnosis of splenic infarct led to the diagnosis of a previously unrecognized underlying illness.

Evaluation

Abdominal pain remains the leading chief complaint in patients diagnosed with a splenic infarct. Evaluation of patients who present with abdominal pain requires a broad differential approach.[6][7][8]

Lab evaluation may help rule out other causes of abdominal pain. Elevated liver function tests, bilirubin or lipase, may suggest a hepatobiliary or pancreatic source for pain. Leukocytosis and elevated lactate dehydrogenase (LDH) may be found in splenic infarction. However, these results lack specificity to splenic infarct.

Radiographic testing is required to detect this rare illness. In the hyperacute phase of infarction, an abdominal CT scan performed with intravenous contrast is the imaging modality of choice in suspected splenic infarction. A splenic infarct appears as a wedge-shaped area of splenic tissue with the apex pointed toward the helium and the base of the splenic capsule. As the infarction matures, the affected tissue may normalize, liquefy, or become contracted or scarred. Abdominal ultrasound has also been used to detect splenic infarction. Ultrasound findings of the hypoechoic wedge-shaped region of splenic tissue indicate infarction. Evolution of infarction may appear as hyperechoic with retraction of the splenic capsule.

Treatment / Management

Treatment of splenic infarction is based primarily on the underlying causative disease state. Splenic infarction in the non-infectious setting may be treated with analgesics, hydration, anti-emetics, and other means of supportive care. Hospital admission may be required to provide supportive treatment, monitoring, and further diagnostic testing if the underlying cause is not established. In patients with sickle cell hemoglobinopathies, treatment to correct hypoxia and acidosis may be required. In the case of septic emboli, patients may require intravenous antibiotics and further cardiac evaluation. In patients with an underlying hematologic disease or autoimmune disease, consultation with hematology, oncology, or rheumatology may be indicated. Abdominal pain due to uncomplicated cases of splenic infarction resolves without intervention in 7 to 14 days.[2][9][10](B3)

In the case of traumatic splenic injury, abnormal vasculature, or hemodynamic instability, a surgical evaluation may be required. Dangerous complications of splenic infarction include pseudocyst formation, abscess, hemorrhage, splenic rupture, and aneurysm. In some instances, the infarcted splenic tissue may become infected and lead to abscess formation. Infarcted tissue may also undergo a hemorrhagic transformation. These complications warrant emergent surgical consultation. 

Differential Diagnosis

• Acute leukemias

• Cardioembolic origin

• Cytomegalovirus

• Hemoglobinopathy

• Infectious mononucleosis

• Infective endocarditis

• Myelodysplastic syndromes

• Myelofibrosis

• Wandering spleen