The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes from Ancient Greek σπλήν (splḗn).
Infectious mononucleosis, also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adults, the disease often results in fever, sore throat, enlarged lymph nodes in the neck, and fatigue. Most people recover in two to four weeks; however, feeling tired may last for months. The liver or spleen may also become swollen, and in less than one percent of cases splenic rupture may occur.
Lymphocytosis is an increase in the number or proportion of lymphocytes in the blood. Absolute lymphocytosis is the condition where there is an increase in the lymphocyte count beyond the normal range while relative lymphocytosis refers to the condition where the proportion of lymphocytes relative to white blood cell count is above the normal range. In adults, absolute lymphocytosis is present when the lymphocyte count is greater than 5000 per microliter (5.0 x 109/L), in older children greater than 7000 per microliter and in infants greater than 9000 per microliter. Lymphocytes normally represent 20% to 40% of circulating white blood cells. When the percentage of lymphocytes exceeds 40%, it is recognized as relative lymphocytosis.
A splenectomy is the surgical procedure that partially or completely removes the spleen. The spleen is an important organ in regard to immunological function due to its ability to efficiently destroy encapsulated bacteria. Therefore, removal of the spleen runs the risk of overwhelming post-splenectomy infection, a medical emergency and rapidly fatal disease caused by the inability of the body's immune system to properly fight infection following splenectomy or asplenia.
Hereditary spherocytosis (HS) is a congenital hemolytic disorder wherein a genetic mutation coding for a structural membrane protein phenotype causes the red blood cells to be sphere-shaped (spherocytosis), rather than the normal biconcave disk shape. This abnormal shape interferes with the cells' ability to flex during blood circulation, and also makes them more prone to rupture under osmotic stress, mechanical stress, or both. Cells with the dysfunctional proteins are degraded in the spleen, which leads to a shortage of erythrocytes and results in hemolytic anemia.
Portal hypertension is defined as increased portal venous pressure, with a hepatic venous pressure gradient greater than 5 mmHg. Normal portal pressure is 1–4 mmHg; clinically insignificant portal hypertension is present at portal pressures 5–9 mmHg; clinically significant portal hypertension is present at portal pressures greater than 10 mmHg. The portal vein and its branches supply most of the blood and nutrients from the intestine to the liver.
Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced ('hypo-') splenic functioning, but not as severely affected as with asplenism.
Hepatosplenomegaly is the simultaneous enlargement of both the liver (hepatomegaly) and the spleen (splenomegaly). Hepatosplenomegaly can occur as the result of acute viral hepatitis, infectious mononucleosis, and histoplasmosis or it can be the sign of a serious and life-threatening lysosomal storage disease. Systemic venous hypertension can also increase the risk for developing hepatosplenomegaly, which may be seen in those patients with right-sided heart failure.
Primary myelofibrosis (PMF) is a rare bone marrow blood cancer. It is classified by the World Health Organization (WHO) as a type of myeloproliferative neoplasm, a group of cancers in which there is activation and growth of mutated cells in the bone marrow. This is most often associated with a somatic mutation in the JAK2, CALR, or MPL genes. In PMF, the bony aspects of bone marrow are remodeled in a process called osteosclerosis; in addition, fibroblast secrete collagen and reticulin proteins that are collectively referred to as (fibrosis). These two pathological processes compromise the normal function of bone marrow resulting in decreased production of blood cells such as erythrocytes, granulocytes and megakaryocytes, the latter cells responsible for the production of platelets.
Organomegaly is the abnormal enlargement of organs. For example, cardiomegaly is enlargement of the heart. Visceromegaly is the enlargement of abdominal organs. Examples of visceromegaly are enlarged liver (hepatomegaly), spleen (splenomegaly), stomach, kidneys, and pancreas.
A splenic injury, which includes a ruptured spleen, is any injury to the spleen. The rupture of a normal spleen can be caused by trauma, such as a traffic collision.
Castell's sign is a medical sign assessed to evaluate splenomegaly and typically part of an abdominal examination. It is an alternative physical examination maneuver to percussion over Traube's space.
Felty's syndrome (FS), also called Felty syndrome, is a rare autoimmune disease characterized by the triad of rheumatoid arthritis, enlargement of the spleen and low neutrophil count. The condition is more common in those aged 50–70 years, specifically more prevalent in females than males, and more so in Caucasians than those of African descent. It is a deforming disease that causes many complications for the individual.
Splenic infarction is a condition in which blood flow supply to the spleen is compromised, leading to partial or complete infarction in the organ. Splenic infarction occurs when the splenic artery or one of its branches are occluded, for example by a blood clot.
Splenic marginal zone lymphoma (SMZL) is a type of marginal zone lymphoma, a cancer made up of B-cells that replace the normal architecture of the white pulp of the spleen. The neoplastic cells are both small lymphocytes and larger, transformed lymphoblasts, and they invade the mantle zone of splenic follicles and erode the marginal zone, ultimately invading the red pulp of the spleen. Frequently, the bone marrow and splenic hilar lymph nodes are involved along with the peripheral blood. The neoplastic cells circulating in the peripheral blood are termed villous lymphocytes due to their characteristic appearance.
An accessory spleen is a small nodule of splenic tissue found apart from the main body of the spleen. Accessory spleens are found in approximately 10 percent of the population and are typically around 1 centimetre in diameter. They may resemble a lymph node or a small spleen. They form either by the result of developmental anomalies or trauma. They are medically significant in that they may result in interpretation errors in diagnostic imaging or continued symptoms after therapeutic splenectomy. Polysplenia is the presence of multiple accessory spleens rather than one normal spleen.
Wandering spleen is a rare medical disease caused by the loss or weakening of the ligaments that help to hold the spleen stationary.
Abdominal ultrasonography is a form of medical ultrasonography to visualise abdominal anatomical structures. It uses transmission and reflection of ultrasound waves to visualise internal organs through the abdominal wall. For this reason, the procedure is also called a transabdominal ultrasound, in contrast to endoscopic ultrasound, the latter combining ultrasound with endoscopy through visualize internal structures from within hollow organs.
Littoral cell angioma, abbreviated LCA, and formally known as littoral cell angioma of the spleen, is a benign tumour of the spleen that arises from the cells that line the red pulp.
Spleen pain is a pain felt from the left upper quadrant of the abdomen or epigastrium where the human spleen is located or neighboring.
