Spleen Flashcards
What are the major functions of the spleen?
Removal of elements in the blood:
- clearing blood cells and bacteria
- recycling iron and globins
Secondary lymphoid organ
- Ab production
- Ag capture and presentation to T/B cells
Hematopoiesis
- normal during fetal development
- compensatory extramedullary site in adults
Stores formed elements:
- stores 30-40% of platelets
- stores lymphocytes
What effects can be seen as result of splenomegaly/hypersplenism?
- pressure/pain in LUQ
- risk of rupture
Hypersplenism:
- anemia (sequestration of RBCs)
- leukopenia (sequestration of leukocytes)
- thrombocytopenia (sequestration of platelets, up to 80-90% of total)
What are common causes of splenomegaly?
- infection
- portal hypertension
- blood cell disorders (neoplasms and anemias)
- autoimmune/inflammatory conditions
- IEM (Gaucher, Neimann-Pick, etc.)
- amyloidosis
- cancer of the spleen/metastasis to the spleen
What are causes of congestive splenomegaly?
- cardiac decompensation/right heart failure
- liver cirrhosis
- obstruction of portal or splenic vein
What are causes of splenic infarcts?
Occlusion of splenic artery (lack of collateral blood supply):
- cardiac emboli
- infectious endocarditis
- splenomegaly
- myeloproliferative disorders (MPD)
What are common effects of splenic infarcts?
-dramatic increased risk of infection by encapsulated bacteria (pneumococcus, H. influenzae, meningococcus)
What are the most common primary and secondary neoplasms of the spleen?
Primary:
-rare; lymphagiomas and hemangioma
Secondary:
-lymphoid/myeloid neoplasms
What conginital abnormalities of the spleen exist?
What is their significance if any?
Splenic aplasia:
-rare, typically associated with other abnormalities
Splenic hypoplasia:
-more common that aplasia
Accessory spleens:
- common (20-35%)
- splenectomy is used as treatment in immune thrombocytopenia and hereditary shperocytosis; if an accessory spleen is not removed, theraputic benefit is diminished
What are common causes of splenic rupture?
Trauma, especially to an acutely enlarged spleen
Uncommon in chronically enlarged spleens (fibrosis)
Especially in the setting of:
- mononucleosis
- malaria
- typhoid fever
- neoplasms of the spleen
What are the effects of splenic rupture?
massive intraperitoneal hemorrhage resulting in death if not treated with emergent splenectomy
What are signs of splenic rupture?
Can present with:
- LUQ pain
- left shoulder pain (Kehr sign)
- peritonitis
- hemodynamic instability
What is a possible post-splenectomy complication?
Overwhelming post-splenectomy infection (OPSI)
-
encapsulated bacteria are mainly eliminated by the spleen
- Streptococcus pneumoniae
- Neisseria meningitidis
- Haemophilus influenae B
- highest risk first 3 years following splenectomy
