A person affected by hypersplenism may experience symptoms related to the organ's enlargement, such as discomfort and abdominal pain in the region that corresponds to the spleen's location. The distended spleen often exerts pressure on the gastric walls, leading to decreased appetite. Pancytopenia or selective leukopenia, erythropenia and thrombocytopenia will also produce symptoms and signs. Erythropenia will lead to the typical anemic symptoms (fatigue, pallor), leukopenia renders the individual susceptible to various kinds of infections and decreased platelet levels result in coagulation disorders, which can be observed during the clinical examination (bruising, etc). The presence of sharp, intense pain in the left upper abdominal quadrant may be an indicator of a splenic infarction.
A detailed clinical examination, complete with medical history, will direct suspicion towards hypersplenism. The physical examination may reveal an enlarged spleen, which, if accompanied by decreased levels of blood components in the blood test, strongly suggests hypersplenism. The patient will most of the times report symptoms consistent with cytopenia: weakness and fatigue due to anemia, frequent infections and bleeding disorders. Other significant findings include a splenic friction rub to detect an infarction of the spleen and the presence of bruits, heard over the splenic artery, which suggests congestion-induced splenomegaly. Enlarged lymph nodes can also be observed and may point towards autoimmune causes or a myeloproliferative condition.
Concerning the blood tests, a complete blood count should be performed, in order to measure white blood cells, red blood cells and platelets. Levels are usually decreased but not profoundly and may produce no prominent symptomatology. As for cellular morphology, spherocytosis and reticulocytosis are frequently observed.
Splenomegaly is often moderate or not palpable; should the need arise, an ultrasonographic scan (US) or a computerized tomography scan (CT) be used to diagnose the enlargement, with the US being the first option. A magnetic resonance imaging scan can help to illustrate soft tissue structure and identify a potential splenic vein occlusion or other vascular irregularities.
The underlying cause should also be identified and treated, depending on the characteristics of each case. An occult infection should be eliminated as a first step if there is no indication towards to another possible cause. Infection is also a cause that should be suspected in areas with a known infectious disease prevalence, especially tropical regions. Thorough testing, including a complete blood count, bone marrow biopsy and a blood culture should be obtained for further diagnostic purposes. Liver function tests can be conducted supplementally and the presence of a lymphoma can be investigated with the aid of flow cytometry as well.
An appropriate treatment plan is drawn after the underlying condition has been diagnosed. The first step is always a therapy plan involving medications, as many conditions causing hypersplenism can be reversed with drugs and the patient can avoid surgery.
The avoidance of surgical intervention is crucial given the importance of the spleen and the multitude of its functions. Except for the destruction of the old and abnormal blood components, the spleen is responsible for the production of antibodies (eg. IgG) against pathogens that the organism has never in the past been exposed to  . It is the largest lymphoid organ in the body and cannot be restored once severely damaged or resected.
However, if the underlying cause cannot be adequately managed or treated in a conservative manner, splenectomy may be unavoidable. The same applies to cases of patients exhibiting solely hypersplenism as a symptom and those affected by chronic hypersplenism. Total splenectomy is a surgical procedure that retains, up to this day, considerable infection risks and morbidity , and is therefore viewed as the last resort . Complications following total splenectomy include various infections (frequently affecting the respiratory tract) and severe septicemia, which is also referred to as the "post splenectomy sepsis syndrome". The spleen possesses the ability to neutralize encapsulated bacterial strains, such as pneumococci or H. influenzae; patients are extremely vulnerable to such pathogens once the spleen has been excised and immunocompromised people, children and senior citizens are at greater risk. Furthermore, patients who undergo a splenectomy often need daily antibiotic intake for the rest of their lives to avoid septic phenomena and mandatory vaccination against various encapsulated pathogens. Patients should learn to be cautious and follow a vaccination schedule against pneumococcus, H. influenza and other pathogens.
Patients who present with fever or a diagnosed infection should receive empiric antibiotic treatment, which will be adjusted if the examinations reveal a specific pathogen. Ceftriaxone is the drug of choice; if there is a strong possibility of resistance to penicillin and cephalosporins, vancomycin should be introduced instead .
An alternative approach to total splenectomy is the partial splenic embolization: a part of the splenic tissue is ablated and rendered inactive. Patients seem to respond well to this type of treatment with a corresponding correction of pancytopenia. The embolization process involves only a part of the spleen and it is therefore not followed by the same complications as a total splenectomy.
Mortality and morbidity rates greatly vary, depending on the underlying condition that has lead to the occurrence of hypersplenism. Coexistent diseases, old age and severe pancytopenia are all poor prognostic factors. Failure to administer proper treatment and recognize the cause of hypersplenism can result in severe complications or even death.
Hypersplenism occurs as a result of splenomegaly, in a variety of ways. The conditions that cause splenomegaly and subsequent hypersplenism can be infectious diseases, hyperplastic conditions, congestion, infiltrative diseases and various other causes. As far as infectious diseases are concerned, any type of pathogen can potentially lead to hypersplenism. Bacteria which cause endocarditis and tuberculosis, fungal and parasitic infections (malaria, schistosomiasis) are all possible causes of a hyperactive spleen. A plethora of viruses can also cause hypersplenism, such as the HIV virus, Epstein-Barr virus and others. The condition can also be a result of abdominal circulatory congestion, as is the case in portal hypertension, portal or hepatic vein occlusion, cirrhosis and congestive heart failure. In the category of infiltrative conditions fall Gaucher disease, Niemann-Pick disease, amyloidosis, histiocytosis, Waldenstrom macroglobulinemia and metastatic cancer.
Lastly, hyperplastic splenomegaly and hypersplenism can be caused by thalassemia, myelofibrosis, lymphoma, chronic lymphocytic leukemia and other conditions. In some cases, hypersplenism remains uncategorized with reference to its cause and is deemed idiopathic. It can also arise as a result of vitamin deficiency (B12) and as a part of the clinical picture of thyrotoxicosis .
A comprehensive study of the incidence of hypersplenism or splenomegaly has yet to be conducted. The rate lies between 2-6% according to two studies carried out in the USA. It is , however, generally accepted that individuals living in the African tropical zone and visitors to these regions run frequently exhibit the tropical splenomegaly syndrome, due to malaria infection.
The pathophysiological mechanisms leading to a hyperactive spleen depend on the underlying cause. In a healthy individual, macrophages located in the spleen are responsible for identifying deformed or aged blood cellular components, pathogens or any type of foreign body. Patients who suffer from conditions leading to an altered cellular morphology or autoimmune disorders, exhibit decreased numbers of those blood components, precisely because they are destroyed in the spleen, despite being functional. In these cases, hypersplenism occurs due to overload-induced hyperplasia and splenomegaly is a subsequent finding.
On the other hand, splenomegaly itself may lead to hypersplenism, via various other mechanisms. Conditions such as portal hypertension, amyloidosis or myelofibrosis may be responsible for the distention of the spleen; the organ enlargement leads to an increase in the volume of the blood that is filtered by the spleen. Thus, a greater number of blood components are destroyed, compared to a healthy individual.
The spleen is a unique organ located in the upper left quadrant of the abdomen and its contribution is vital for the physiological function of the human body. It is the largest lymphoid organ of the body and mediates the destruction of old or abnormal red cells, produces immunoglobulin G (IgG) and properdin, filters the blood in order to remove pathogens and foreign bodies and maintains a hemopoietic role, although secondary in an adult .
Hypersplenism involves a given hyperactivity of the spleen. It can be accompanied by splenomegaly, which is usually not extremely prominent. It is important to keep in mind that hypersplenism is, as a definition, distinguished from splenomegaly; the first refers to a functional disorder and the latter refers to an augmentation of the organ's dimensions. Even though the conditions occur at the same time, the terms are not used interchangeably.
As a disorder, hypersplenism typically involves a distended spleen (splenomegaly), decreased levels of leukocytes, erythrocytes and platelets, shorter platelet and erythrocyte lifespan, as well as the "maturation arrest phenomenon". The latter features an increased production of bone marrow precursor cells, with a decline in the levels of mature erythrocytes, leukocytes and platelets; this indicates that the cells are destroyed by the spleen prematurely . All cell lines may be increasingly discarded by the spleen in a case of hypersplenism, but the most common abnormality is anemia (partly dilutional)  and thrombocytopenia.
The spleen is an organ located in the abdomen, specifically under the left rib cage. It cannot be felt with the fingertips under normal circumstances and has multiple important functions. Firstly, the spleen is responsible for the production of blood cellular components in an embryo, although the function is undertaken by the bone marrow in adults. Secondly, old and abnormally shaped red blood cells and other blood components are destroyed in the spleen, which is thus able to regulate the consistency of the blood and ensure that only normal and functional components are circulating. The spleen is also responsible for filtering the blood from various microorganisms and produces antibodies against such germs.
Various conditions cause the spleen to enlarge; the more it enlarges, the more blood components it destroys and therefore causes low levels of red blood cells, white blood cells and platelets. In other cases, the spleen destroys otherwise functional blood components, only because they are structurally different than the others, eg. due to an autoimmune disorder.
Hypersplenism means precisely this: the spleen functions hyperactively, exaggerating every function, so that abnormally large numbers of red and white blood cells, as well as platelets, are sequestered. It can occur as a result of infection, autoimmune disorders, and various other causes. The spleen also becomes distended in order to better accommodate the overload (splenomegaly).
Patients who are affected by hypersplenism may complain of a feeling of discomfort in the left side of the abdomen, of fullness, weakness or fatigue. They may be more susceptible to infections because of the low levels of white blood cells and bruise easily. Fever may also be present in more acute cases. An enlarged spleen may put extra pressure on the stomach; as a result, patients feel full even after consuming normal or small quantities of food. Pain in the location just below the left rib cage is not uncommon either. A doctor will diagnose hypersplenism based on the medical history and findings such as a spleen that can be palpated and low levels of blood cellular components revealed by blood tests. A US, CT or MRI scan can also help to diagnose the condition.
Doctors always try to treat the underlying condition first, because many cases of hypersplenism regress after the cause has been eliminated or controlled. In some occasions, chronic hypersplenism or the failure to diagnose any underlying condition, accompanied by the persistence of splenic hyperactivity require a total splenectomy to be performed. A total splenectomy is the complete removal of the spleen and is a procedure that is seen as the last resort to correct hypersplenism. People who have had their spleen removed are naturally more susceptible to infection, may need to take daily antibiotics to prevent infection and also require annual vaccination against some pathogens.