Chapter 34 - Spleen Flashcards
Where is the splenic v in relation to splenic a?
Posterior and inferior
Spleen is the largest producer of what antibody?
IgM
What % of the spleen is red pulp? Function?
85%; acts as filter for aged or damaged RBCs
What is pitting?
Removal of abnormalities in RBC membrane
What are Howell-Jolly bodies?
Nuclear remnants
What are Heinz bodies?
Hemoglobin
What is culling?
Removal of less deformable RBCs
What % of the spleen is white pulp? Function?
15%; immunologic function, contains lymphocytes and macrophages; major site of bacterial clearance that lacks preexisting abs; site of removal of poorly opsonized bacteria/debris
What is tuftsin?
An opsonin; facilitates phagocytosis (produced in spleen)
What is properidin?
Activates alternate complement pathway (produced in spleen)
When does hematopoiesis occur in the spleen?
Before birth and in conditions such as myeloid dysplasia
Where is the most common location of accessory spleen?
Splenic hilum (20%)
What is the most common nontraumatic condition requiring splenectomy?
ITP
What happens in ITP?
Antiplatelet IgG binds platelets, cause dec. platelet count –> gingival bleeding, petechiae, bruising, soft tissue ecchymosis
Treatment for ITP in children? Adults?
Children <10, usually resolves spontaneously; steroids (primary therapy), plasmapheresis, gammaglobulin for steroid-resistant disease, splenectomy for those who fail steroids
Why does splenectomy fix ITP?
Spleen is normal; removes IgG production and source of phagocytosis (80% respond)
TTP associated with what conditions?
Medial reactions, infections, inflammation, autoimmune disease
What happens in TTP?
Loss of platelet inhibition leads to thrombosis and infarction, profound thrombocytopenia; purpura, fever, AMS, renal dysfunction, hematuria, hemolytic anemia
Treatment for TTP?
Plasmapheresis (primary), steroids, ASA - 80% respond to medical therapy
Most common cause of death due to TTP?
Due to ICH or acute renal failure
Risk of postsplenectomy sepsis?
0.1%, increased risk in children; highest in pts with splenectomy due to hemolytic disorders or malignancy
Most common bacteria causing OPSS?
S. pneumonia, N. meningitidis, H. flu