splenomegaly

Splenomegaly is an enlargement of the spleen, which usually lies in the left upper quadrant (LUQ) of the human abdomen. It is one of the four cardinal signs of hypersplenism, the other three being cytopenia(s), normal or hyperplastic bone marrow, and a response to splenectomy. Splenomegaly is usually associated with increased workload (such as in hemolytic anemias), which suggests that it is a response to hyperfunction. It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas.

Symptoms and signs

Symptoms may include abdominal pain, early satiety due to splenic encroachment, or the symptoms of anemia due to accompanying cytopenia.

Signs of splenomegaly may include a palpable left upper quadrant abdominal mass or splenic rub. It can be detected on physical examination by using Castell's sign or Traube's space, but an ultrasound can be used to confirm diagnosis.

Causes

Splenomegaly grouped on the basis of the pathogenic mechanism

Increased function	Abnormal blood flow	Infiltration
Removal of defective RBCs spherocytosis thalassemia hemoglobinopathies nutritional anemias early sickle cell anemia Immune hyperplasia Response to infection (viral,bacterial,fungal,parasitic) mononucleosis, AIDS, viral hepatitis subacute bacterial endocarditis, bacterial septicemia splenic abscess, typhoid fever brucellosis, leptospirosis, tuberculosis histoplasmosis malaria, leishmaniasis, trypanosomiasis ehrlichiosis Disordered immunoregulation rheumatoid arthritis SLE Serum sickness Autoimmune hemolytic anemia Immune thrombocytopenia sarcoidosis drug reactions Extramedullary hematopoiesis Myelofibrosis Marrow infiltration by tumors, leukemias marrow damage by radiation, toxins	Organ Failure cirrhosis congestive heart failure Vascular hepatic vein obstruction portal vein obstruction Budd-Chiari syndrome splenic vein obstruction Infections hepatic schistosomiasis hepatic echinococcosis	Metabolic diseases Gauchers disease Niemann-Pick disease Hurler syndrome and other Mucopolysaccharidoses Amyloidosis Tangier disease Benign and malignant infiltrations L eukemias(acute,chronic,lymphoid and myeloid) lymphomas(Hodgkins and non-hodgkins) myeloproliferative disorders metastatic tumors(commonly melanoma) histiocytosis X Hemangioma,lymphangioma splenic cysts hamartomas eosinophilic granuloma

The causes of massive splenomegaly (>1000 g) are much fewer and include:

• thalassemia
• visceral leishmaniasis (Kala Azar)
• schistosomiasis
  
• chronic myelogenous leukemia
• chronic lymphocytic leukemia
• lymphomashairy cell leukemia
• myelofibrosis
• polycythemia vera
• Gauchers disease
• Niemann Pick disease
• sarcoidosis
• autoimmune hemolytic anemia
• malaria

Treatment

If the splenomegaly underlies hypersplenism, a splenectomy is indicated and will correct the problem. After splenectomy, however, patients have an increased risk for infectious diseases.

After splenectomy, patients should be vaccinated against Haemophilus influenzae and Streptococcus pneumoniae. They should receive annual influenza vaccinations. Long-term prophylactic antibiotics should be given.