Splenomegaly

Splenomegaly
Classification and external resources
CT scan showing splenomegaly in a patient with chronic lymphoid leukemia
ICD-10	Q89.0, R16.1
ICD-9	759.0, 789.2
DiseasesDB	12375
MedlinePlus	003276
eMedicine	ped/2139 med/2156
MeSH	D013163

Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. It is one of the four cardinal signs of hypersplenism, some reduction in the number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any combination; a compensatory proliferative response in the bone marrow; and the potential for correction of these abnormalities by 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. Thus, the finding of an enlarged spleen, along with caput medusa, is an important sign of portal hypertension.^[1]

Normal spleen

Definition

Poulin et al.^[2] classify splenomegaly as:

• Moderate splenomegaly, if the largest dimension is between 11–20 cm
• Severe splenomegaly, if the largest dimension is greater than 20 cm
• Splenomegaly refers strictly to spleen enlargement, and is distinct from hypersplenism, which connotes overactive function by a spleen of any size. Splenomegaly and hypersplenism should not be confused. Each may be found separately, or they may coexist.
• Clinically if a spleen is palpable, it means it is enlarged as it has to undergo enlargement by at least twofolds to become palpable. However, the tip of the spleen may be palpable in a newborn baby up to 3 months of age.

Symptoms and signs

Symptoms may include abdominal pain, chest pain, chest pain similar to pleuritic pain when stomach, bladder or bowels are full, back 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. In patients where the likelihood of splenomegaly is high, the physical exam is not sufficiently sensitive to detect it; abdominal imaging is indicated in such patients.^[3]

Causes

The most common causes of splenomegaly in developed countries are infectious mononucleosis, splenic infiltration with cancer cells from a hematological malignancy and portal hypertension (most commonly secondary to liver disease, and Sarcoidosis). Splenomegaly may also come from bacterial infections, such as syphilis or an infection of the heart's inner lining (endocarditis).^[4]
The possible causes of moderate splenomegaly (spleen <1000 g) are many, and include:

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,[5] viral hepatitis subacute bacterial endocarditis, bacterial septicemia splenic abscess, typhoid fever brucellosis, leptospirosis, tuberculosis histoplasmosis malaria, leishmaniasis, trypanosomiasis ehrlichiosis[6] Disordered immunoregulation rheumatoid arthritis Systemic lupus erythematosus serum sickness autoimmune hemolytic anemia sarcoidosis drug reactions Extramedullary hematopoiesis myelofibrosis marrow infiltration by tumors, leukemias marrow damage by radiation, toxins	Organ Failure cirrhosis 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 alpha-mannosidosis Hurler syndrome and other mucopolysaccharidoses[7] amyloidosis Tangier disease Benign and malignant “infiltrations” leukemias (acute, chronic, lymphoid, and myeloid) lymphomas (Hodgkins and non-Hodgkins) myeloproliferative disease metastatic tumors (commonly melanoma) histiocytosis X hemangioma, lymphangioma splenic cysts hamartomas eosinophilic granuloma littoral cell angioma[8][9][10]

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

• visceral leishmaniasis (kala-azar)
• chronic myelogenous leukemia
• myelofibrosis
• malaria
• primary lymphoma of spleen

Treatment

If the splenomegaly underlies hypersplenism, a splenectomy is indicated and will correct the hypersplenism. However, the underlying cause of the hypersplenism will most likely remain; consequently, a thorough diagnostic workup is still indicated, as, leukemia, lymphoma and other serious disorders can cause hypersplenism and splenomegaly. After splenectomy, however, patients have an increased risk for infectious diseases.
Patients undergoing splenectomy should be vaccinated against Haemophilus influenzae, Streptococcus pneumoniae, and Meningococcus. They should also receive annual influenza vaccinations. Long-term prophylactic antibiotics may be given in certain cases.
In cases of infectious mononucleosis splenomegaly is a common symptom and health care providers may consider using abdominal ultrasonography to get insight into a person's condition.^[11] However, because spleen size varies greatly, ultrasonography is not a valid technique for assessing spleen enlargement and should not be used in typical circumstances.