The spleen is a secondary lymphoid organ that lies in intraperitoneally in the left hypochondrium, abuting the diaphragm. It spans from the 9th to 11th rib and weighs between 150-200g. Spleen is supplied by the splenic artery and drains into portal circulation via the splenic vein. It is a part of reticuloendothelial system, immune system and is a site of in utero haematopoiesis. The spleen is enlarged in a diverse set of disease of the above mentioned systems and in portal hypertension.
Normal Functions of the Spleen
The normal functions of the spleen include
- Reticuloendothelial functions: The spleen as a component of the reticuloendothelial system is involved in clearing the blood of ageing or damaged erythrocytes, antibody coated cells and opsonised bacteria. It also removes particles from red cells. The spleen ensures that the red cell in circulation have adequate deformability for passage through microcirculation.
- Immune Functions: The spleen is a part of the immune system and plays a role in mounting the immune response . Splenectomy increases the risk of infections particularly with capsulated organisms (see Overwhelming Post-Splenectomy Infection (OPSI)).
- Haematopoiesis: Spleen is the site for haematopoiesis in utero. In extrauterine life spleen can become a site of haematopoiesis in disease.
Palpating the Spleen
- Palpation of the spleen should start from the right iliac fossa. If this is not done there is a risk of missing a massively enlarged spleen.
- Move towards the left costal margin in a direction perpendicular to the margin. Move with each breath. At every position ask the patient to take a deep breath. The tip of the spleen will hit your palpating finger.
- If the spleen does not hit your finger move your palpating finger to a position closer to coastal margin, ask the patient to take a deep breath and repeat the procedure described above till your finger hits the costal margin.
- If the spleen is felt measure the perpendicular distance between the tip and the left coastal margin. Also note the texture and presence of tenderness.
- If the spleen is not felt repeat the procedure with patients lying on right side.
- Large spleen can rupture with aggressive palpation. The spleen lies directly under the anterior abdominal wall. One does not need to be aggressive.
Causes of Splenomegaly
The spleen enlarges from the left coastal margin in the direction of the umbilicus. It needs to enlarge 2-3 times before it is palpable. Splenomegaly may be caused be increase in portal venous pressure, infiltrative conditions or when the spleen function needs to increase. Clinically it is useful to classify splenomegaly by size. Massive splenomegaly is enlargement of the spleen beyond the umbilicus. The causes of massive splenomegaly include
- Malignant: Chronic myeloid leukaemia, Idiopathic myelofibrois, hairy cell leukaemia, splenic marginal zone lymphoma, chronic lymphocytic leukaemia, prolymphocytic leukaemia
- Infections: Tropical splenomegaly, AIDS with Mycobacterium avium complex infections, Kala-azar (visceral leishmaniasis)
- Others: β-Thalassaemia major and intermedia, Extrahepatic portal venous obstructions,megaloblastic anaemia, diffuse splenic haemagiosis
The causes of splenomegaly include the above and the following
- Portal Hypertension: Cirrhosis, Budd-Chairy syndrome, splenic vein thosmbosis, congestive heart failure, hepatic schistosomiasis
- Increased splenic function:
- Increased functional demands: Haemolytic anaemia commonly hereditary spherocytosis, autoimmune haemolytic anaemia, β-thalassaemia, early sickle cell anaemia, sickle cell β-thalassaemia,
- Bacterial: Septicaemia, bacterial endocarditis, splenic abscess, brucellosis, tuberculosis, AIDS with Mycobacterium avium complex infections, secondary syphilis
- Viral: Viral hepatitis, infectious mononucleosis, cytomegalovirus,
- Parasitic: Malaria , Kala-azar (visceral leishmaniasis), Trypanosomiasis,
- Fungal: Histoplasmosis
- Immune Disorders:
- Autoimmune diseases: Rhumatoid arthritis (Felty’s syndrome), systemic lupus erythrmatosis
- Other immune disorders: Immune haemolytic anaemia, immune neutropenia, drug reaction, serum sickness, sarcoidosis
- Haemophgocytic lymphohistiocytosis
- Haematological Malignancy:
- Myeloid: Chronic myeloid leukaemia, myeloproliferative disease, idiopathic myelofibrosis, polycythaemia vera
- Lymphoid: Acute lymphoblastic leukaemia, hairy cell leukaemia, chronic lymphocytic leukaemia, prolymphocytic leukaemia, splenic marginal zone lymphoma, angioimmnoblastic T cell lymphoma
- Other: Histiocytosis X, eosinophilic granuloma
- Storage disorders:Gaucher disease, Niemann-Pick, Tangier disease, mucopolysachroidosis
- Other Infiltrations: Amyloid
- Haematological Malignancy:
- Others: Iron deficiency anaemia
History and Physical Examination
- Fever: Fever is a feature of splenomegaly due to infections, inflammations or malignancy, particularly haematological malignancy. Usually the fever is low grade. High grade fever suggests splenic abscess.
- Painful splenemegaly: The nature of pain associated with splenomegaly varies with the cause of splenomegaly.
- An enlargement spleen from any cause can cause a dragging pain in the left upper quadrant.
- Acute pain left upper quadrant pain is a feature of is a feature of splenic infarct and splenic abscess. Sickle Cell anaemia is associated with small fibrotic spleen because of repeated splenic infarcts. Early in disease the spleen enlarges. Patients may present with acute pain from splenic infarcts. Enlarged spleen from any cause is predisposed to infarction. Acute pain in the left upper quadrant is also a feature of acute splenic abscess.
- Splenic vein thrombosis can cause splenomegly and pain in left upper quadrant or epigastric region. It may also cause generalised abdominal pain.
- Pancreatitis presents with abdominal pain and can cause painful splenomegaly secondary to splenic vein thrombosis.
- Alcohol induced pain is an uncommon but unique feature of Hodgkin lymphoma. Spleen is a common site of involvement by Hodgkin lymphoma. Such patients may have alcohol induced pain in an enlarged spleen.
- Pallor: Pallor in a patient with splenomegaly suggests a diagnosis of haemolytic anaemia, haemolymphatic malignancy and infective endocarditis.
- Clubbing: Clubbing with splenomegaly is a feature of infective endocarditis and cirrhosis of the liver.
- Skin rash: Skin rash in a patient with splenomegaly is seen in systemic lupus erthomatosis, infective endocarditis, lymphoma (angioimmuniblastic T Cell lymphoma, mycosis fungiodes, skin involvement with lymphoma) and drug reaction. Each of these conditions have a distinct type of rash.
- Skin Pigmentation: Hyperpigmantation suggests be seen in hemachromatosis or megaloblastic anaemia. The patients with megaloblastic anaemia may also have knuckle pigmentation.
- Jaundice: Jaundice with enlarged spleen is a feature of haemolytic anaemia. The jaundice is usually achloruric. Patients with haemolytic anaemia are predisposed to gallstones. Obstruction of the biliary system from a calculus dislodged from the gall bladder can cause obstructive jaundice with abdominal pain and signs of acute inflammation. Splenomegaly with jaundice is a feature of advanced cirrhosis. Patients with advanced cirrhosis almost always have ascites.
- Lymphadenopathy: The enlargement of lymph nodes and spleen is a feature of lymphoid malignancies or diseases that stimulate the lymphoid systems viz. infections and autoimmune diseases and lymphoid malignancy.
- Joint symptoms: Arthropathy with splenomegaly suggests the diagnosis of rheumatoid arthritis, systemic lypus erythrmatosis or haematochromatosis.
- Oral symptoms: infectious mononucleosis is charecterized by pharyngitis and generalised lymphadenopathy. Bleeding gums and/or gum hypertrophy suggests a diagnosis of leukaemia. Lymphoma can cause tomsillar enlargement. Amyloid is charectetized by macroglossia.
- Evidence of Portal Hypertension and Liver Cell Failure: Patients with portal hypertension often have history of haemetemesis. Examination may reveal periumbilical veins (capital medusae), anterior abdominal or flank veins. Patients with evidence liver cell failures with portal hypertension (e.g. jaundice, ascites, spider angiomas, asterxis etc. see Portal Hypertension) have cirrhosis. When the jugular venous pressure is high a diagnosis of congestive cardiac failure should be considered.
Haemogram; The haemogram is the most important laboratory test in evaluating a patient with splenomegaly. The significance of findings on haemogram is described in the table below.
|Pancytopenia||Hypersplenism, Lymphoma (splenic marginal zone lymphoma), Hairy cell leukaemia, Myelofibrosis, systemic lupus erythrmotosis|
|Neutrophilic Leucocytosis||Acute infections, inflammation|
|Leucocytosis with premature white cells||Chronic myeloid leumaemia, Myeloproliferative disease, Myeloproliferative/Myelodysplastic overlap, Acute lymphoblastic leukaemia|
|Leucoerythroblastic anaemia||Idiopathic myelofibrosis, Bone marrow infiltration|
|Atypical Lymphocytes||Infectious mononucleosis|
|Thrombocytosis||Myeloproliferative disease (Chronic myeloid leukaemia, idiopathic myelofibrosis, polycythaemia vera), chronic infections like tuberculosis|
|Parasites||Malaria, bartonelosizs, babesiosis|
Other investigations are dictated by the clinical presentations. Commonly performed investigations include biochemistry, microbiology, echocardiography, endoscopy and biopsy of any lymph node or any other mass. Other investigation may be performed as indicated
Imaging is an important aspect of evaluation of the spleen but is beyond the scope of this article. Several good reviews exist e.g Singapore Med J 56(3):133-144.