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 cardinal signs of hypersplenism (This is a pancytopenia occurring in patients with an enlarged spleen - due to large numbers of cells being pooled and destroyed in the spleen's reticuloendothelial system, and haemodilution because of an increased plasma volume). 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 infitration by leukemias and lymphomas.
Signs of splenomegaly may include a palpable left upper quadrant abdominal mass or splenic rub. Patients may also be cytopenic. Patients with splenomegaly may present with abdominal pain, early satiety due to splenic encroachment, and may complain of the symptoms of anemia due to accompanying cytopenia. It can be detected by physicians on physical examination, but an ultrasound can be used to confirm diagnosis.
Causes
Splenomegaly grouped on the basis of the pathogenic mechanism
| Increased function |
Abnormal blood flow |
Infitration |
| 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
Immune 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
Hurlers syndrome and other Mucopolysaccharidoses
Amyloidosis
Tangiers disease
Benign and malignant infiltrations
Leukemias(acute,chronic,lymphoid and myeloid)
lymphomas(Hodgkins and non-hodgkins)
myeloproliferative disorders
metastatic tumors(commonly melanoma)
histiocytosis X
hemangiomas,lymphangiomas
splenic cysts
hamartomas
eosinophilic granuloma |
The causes of massive splenomegaly (>1000gms) are much fewer and include:
Chronic myelogenous leukemia
lymphomas
hairy cell leukemia
myelofibrosis
polycythemia vera
Gauchers disease
chronic lymphocytic leukemia
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.
M.W. Vance