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absite spleen
Question | Answer |
---|---|
2 key roles of spleen | Ag processing center for macrophages, producer of IgM |
2 types of tissue in spleen and their roles | 85% red pulp, removes abnlties in RBC membrane (pitting) and less deformable RBC/senescent (culling); 15% white pulp w immunologic fxn (lymphocyte, macrophages) |
what does spleen remove from RBC membrane | Howell Jowell bodies (nuclear remnants), Heinz bodies (Hb) |
what does white pulp do | bacterial clearance that lacks pre-existing Abs; removal of poorly opsonized bac particles and cellular debris |
what is tuftsin, fxn and where produced | an opsonin, facilitates phagocytosis, made in spleen |
what is properdin, fxn and where produced | activates alternate complement path, made in spleen |
when does hematopiesis occur in spleen | before birth and in conditions myeloid dysplasia |
where is accessory spleen | splenic hilum |
indications for splenectomy | ITP>TTP, trauma |
spleen reservoir for | plts, granulocytes |
where does Ab production occur within spleen | germinal follicles |
immune function of spleen | filtration/trapping of circulating Ag, lymphocyte stimulation and proliferation; Ab production, production of opsonins (tuftsin and properdin) |
etiology of ITP, tx | anti plt Ig, in kids <10 present w thrombocytopenia, petichae, gingival bldg; tx=steroids, if resistant plasmophoresis and gammaglobulin (splenectomy only if fail) |
etiology TTP, s/s | assoc w Rx, infxns, inflamm, autoimmun, loss of plt inhibition leads to thrombosis and infarction w decrsd plt#; purpura, F, AMS, renal dysfxn, hematuria, hemolytic anemia |
tx TTP | plasmophoresis, 2ry tx steroid and ASA…rarely splenectomy |
post splenectomy sepsis, MC bugs, timing, who's at risk | <2yr s/p splenectomy, try to wait till kids >5yo, incrsd in kids and splenectomy for hemolytic dz or malignancy; MC bug Spenu, also Hflu and N Mening [should get vaccines for all those beforehand) |
how bld work changes s/p splenectomy | incrsd RBCs, WBCs, plts |
MC splenic tumor | hemangioma |
when remove splenic cyst | if sympt of >10cm |
bld labwork hypersplenism | decrsd plts, RBCs, WBCs w splenomegaly; resolves w splenectomy |
2ry hypersplenism | more common than 1ry, usu w incrsd venous P (portal HTN, CHF), malignancy, chronic inflamm dz (Feltys RA), hemo anemias, polycythemia vera; splenectomy if symptomatic |
how to tell if intravascular v extravascular hemo anemia | intravascular=schistocytes, decrsd haptoglobin, hemoglobulinuria; extravascular (spleen)=spherocytes, helmet |
MC congenital hemo anemia requiring splenectomy | spherocytosis |
cause of spherocytosis | spectrin defect (deforms RBC leading to sequestration) |
tx spherocytosis | splenectomy, chole |
pyruvate kinase defic | altered glu metabolism, RBC survival incrsd w splenectomy |
blood smear indicating G6PD | bite cells (where Heinz bodies bitten out by spleen), Heinz bodies |
auto immune hemo anemia, lab tests, types | MC extracellular from destruction fo cells in spleen or Kupffer cells in liver, can look like hereditary spherocytosis but coombs +; MC Warm AIHA w IgG extravascular (spleen), #2 cold IgM->complement->intravascular in liver |
if + direct coombs think | warm AIHA |
what is the test for cold AIHA | cold agglutin |
tx warm AIHA | if severe steroids, splenectomy if not responsive |
tx cold AIHA | avoid cold, steroids don't help and neither does splenectomy |
why isn't splenectomy needed in sickle cell | spleen autoinfarcts |
MC type thalassemia is | beta |
blood smear thalassemia | micro anemia, nml Fe studies and nml RDW (all same size), target cells |
causes of spont splenic rx | mono, malaria, sepsis, sarcoid polycythemia vera |
who gets splenic artery aneur | females, 2/2 fibromuscular dysplasia |
what will a blood smear show w RBCs s/p splenectomy | howell jowell (nuclear fragment), Heinz (Hb deposits), Papneheimer bodies (Fe deposits), target cells, spur cells (acanthocytes |
what happens to cell lines plts and wbcs s/p splenectomy | transient decrs in plt and WBC |