34 Spleen Flashcards
anatomy and physiology: arterial supply
short gastrics and splenic artery (end arteries), also some from L gastroepiploic
anatomy and physiology: venous drainage
splenic vein is posterior and inferior to splenic artery … drains to portal vein
anatomy and physiology: spleen function
antigen processing center for macrophages, largest producer of IgM
anatomy and physiology: tissue composition
85% red pulp = filter for aged or damaged RBCs (pitting and culling) … 15% white pulp = immunologic function, contains lymphocytes and macrophages
anatomy and physiology: Howell-Jolly bodies
nuclear remnants, removed by spleen (red pulp)
anatomy and physiology: Heinz bodies
Hb, removed by spleen (red pulp)
anatomy and physiology: describe function of red pulp
filter for aged or damaged TBCs … culling = removal of less deformable RBCs …. pitting = removal of abnormalities in RBC membrane (Howell-Jolly bodies = nuclear remnants, Heinz bodies = Hb)
anatomy and physiology: describe function of white pulp
immunologic unction, contains lymphocytes and macrophages, major site of bacterial clearance that lacks preexisting antibodies, site of removal of poorly opsonized bacteria/particles/cellular debris, antigen processing occurs with interactions between macrophages and help T cells
anatomy and physiology: tuftsin
opsonin, facilitates phagocytosis, produced in spleen
anatomy and physiology: poperdin
activates alternate complement pathway, produced in spleen
anatomy and physiology: hematopoiesis
occurs in spleen before birth and in conditions such as myeloid dysplasia
anatomy and physiology: plt
spleen is reservoir
anatomy and physiology: accessory spleen
20%, MC found at splenic hilum
MC condition requiring splenectomy
ITP is the MC nontraumatic condition
indications for splenectomy
trauma, ITP, TTP (ITP much more common than TTP, ITP is MC non traumatic indication for splenectomy)
ITP: causes
drugs, viruses, etc
ITP: pathophys
anti-plt IgG –> bind plt –> decreased plt
ITP: px
petechiae, gingival bleeding, bruising, soft tissue ecchymosis
ITP: spleen abnl
spleen is normal
ITP: natural hx in kids
usually resolves spontaneously in kids <10 … AVOID splenectomy!
ITP: tx
steroids (primary therapy), gammaglobulin if steroid resistant, splenectomy indicated for those who fail steroids - removed IgG production and source of phagocytosis (80% respond after splenectomy), give platelets 1 hour preop
TTP: aka
thrombotic thrombocytopenic purpura
TTP: assoc with what?
medical reactions, infections, inflammation, autoimmune disease
TTP: pathophys
loss of plt inhibition —> thrombosis and infarction, profound thrombocytopenia
TTP: px
purpura, fever, mental status changes, renal dysfunction, hematuria, hemolytic anemia
TTP: response to tx
80% response to medical therapy
TTP: tx
plasmapheresis (primary), immunosuppression … splenectomy rarely indicated
TTP: mortality
death MC 2/2 intracerebral hemorrhage or acute renal failure