6 - Hemolytic Anemia - General and Acquired Causes Flashcards
key lab value that is increased across most forms of hemolytic anemia
retic count is usually up
normal RBC lifespan
120 d
how short does the average RBC lifespan have to be for increased hemolysis to cause anemia?
30 d
only process in the body that makes CO
RBC destruction
normal RBC destruction is extravascular/intravascular/both?
Extravascular only
____ is converted to bilirubin when RBCs die
protoporphyrin
cycle of bilirubin after being formed from RBC destruction
unconjugated bilirubin binds albumin (not soluble in this stage) > to liver
hepatocytes convert it to conjugated w/ glucuronyl transferase (now soluble)
excreted in bile
bacteria convert to stercobilinogen, can be resorbed and excreted in urine as urobilinogen
____ hemolysis is assoc w/ hemoglobinemia, hemoglobinuria, and hemosidinuria
intravascular
LDH and haptoglobin levels in intravascular hemolysis?
inc LDH
low haptoglobin
hemolytic anemia will cause high direct or indirect bilirubin in the blood?
indirect
what is the main consequence in terms of treatment of a hemolytic anemia having an intrinsic vs extrinsic cause?
intrinsic cause will mean that transfused cells will have a normal lifespan usually
causes of reticulocytosis (4)
recovery from hypo-proliferative anemia
bleeding
myelophthisis (fibrosis or tumor)
hemolytic anemia
3 categories of disorders that are congenital causes of hemolysis
membrane abnormalities
enzymopathies
hemoglobinopathies
acute intravascular hemolytic events - examples
ABO incompatible transfusion
clostridial sepsis
PNH crisis
acute intravascular hemolytic event symptoms
chills, fever
dark/red urine
back / abd pain
severe cases can lead to shock, DIC, acute renal failure
complications of chronic hemolytic anemia
anemia cholelithiasis (pigmented stones) splenomegaly leg ulcers folate deficiency worsened anemia with illnesses iron deficiency growth retardation in children venous thromboembolic disease aplastic crises w/ parvo B19 infection
spherocytosis - give a acquired and congenital cause for hemolytic anemia
acquired - most auto-immune hemolytic anemias will show spherocytes
congenital - hereditary spherocytosis
4 immune hemolytic anemias
warm-antibody induced
cold agglutinin dz
allo-immune hemolytic anemia
paroxysmal cold hemoglobinuria
test to confirm warm antibody autoimmune hemolytic anemia
DAT (Coombs)
how do you distinguish between Warm AIHA and cold agglutinin disease with lab tests?
Warm: DAT + IgG + C3 +/-
Cold: DAT + IgG - C3 +
3 main causes of AIHA
idiopathic, lymphoproliferative disorders, SLE
Tx of warm AIHA
corticosteroids (only about 60% respond)
splenectomy (effective in about 2/3)
immunosuppression/modulation (cyclophosphamide, IVIG, rituximab)
RBC transfusion (w/ caution - already prone to reacting to blood)
what pathogen is cold agglutinin dz associated with for unknown reasons?
mycoplasma pneumoniae
warm AIHA is an Ig_ response, cold AIHA is an Ig_ response
IgG
IgM
tx of cold agglutinin dz
if 2/2 infection - usually transient, just try to keep warm (mittens, earmuffs)
corticosteroids and splenectomy not usually helpful
immunomodulation - cyclophosphamide, IVIG, anti CD20
signs of hemolytic anemia + absence of platelets on PBS >
fragmentation syndrome - affects both RBCs and platelets
causes of microangiopathic HA
TTP HUS DIC disseminated carcinomatosis obstetric complications vasculitis vascular malformations inc shear stress malignant hypertension
paroxysmal nocturnal hemoglobinuria - general
rare acquired disorder characterized by episodic intravascular hemolysis
most morbidity/mortality related to thromboembolic complications
