Normocytic anemias Flashcards
Normal reticulocytes count
1-2%
How should bone marrow properly respond to anemia?
Increase reticulocyte count >3%
How to correct reticulocyte count
RC x (Hematocrit/45)
Clinical findings and lab findings of extravascular hemolysis
Anemia with spenomegaly
Jaundice (due to unconjugated bilirubin)
Increased risk for bilirubin gallstones
Marrow hyperplasia and corrected reticulocyte count >3%
Clinical findings and lab findings of intravascular hemolysis
Hemoglobinemia
Hemoglobinuria
Hemosiderinuria
Decreased serum haptoglobin (free haptoglobin binds Hb)
What causes hereditary spherocytosis?
inherited defect of cytoskeleton-membrane tethering proteins most commonly ankyrin, spectrin or band 3
Pathophys of hereditary spherocytosis?
membrane blebs form and are lost over time leading to loss of membrane and spherocyte formation
Sperocytes are less able to maneuver through splenic sinusoid and are consumed by spenic macrophages results in anemia
clinical and lab findings of hereditary spherocytosis
spherocytes
Increased RDW and MCHC
Splenomegaly, jaundice with unconjugated bilirubin, increased risk for bilirubin gallstones
Increased risk for aplastic crisis
Diagnosis of hereditary spherocytosis
osmotic fragility test
Treatment and subsequent findings of hereditary spherocytosis
Splenectomy - resolves anemia
Spherocytes will persists and Howell-Jolly bodies will emerge
pathophys of sickle cell anemia
Autosomal recessive mutation in Beta chain of hemoglobin - glutamic acid –> valine
HbS polymerizes when deoxygenated; polymers aggregate into sickle cells.
When does sickling occur?
hypoxemia, dehydration, acidosis
treatment of sickle cell
hydroxyurea
RBC membrane damage from sickling and recycling leads to what type of hemolysis?
BOTH extravascular and intravascular
Clinical findings of sickle cell
Massive erythroid hyperplasia – crewcut xray of skull, chipmunk facies
Hepatomegaly from intramedullary hematopoiesis
Risk of aplastic crisis with parvovirus
Complications of extensive sickling in sickle cell disease
vaso-occlusion - dactylitis
Autosplenectomy - fibrotic spleen, increases risk of infection from encapsulated organisms
increased risk of salmonella paratyphi
Acute chest syndrome - vasoocclusion in pulmonary microcirculation
Pain crisis
Renal papillary necrosis
Most common cause of death in adult patients with sickle cell anemia
Acute chest syndrome
Blood findings in sickle cell trait
<50% HbS in RBCs, about 55% HbA, 2% HbA2
No sickle cells on blood smear
Positive metabisulfite screen
What is a metabisulfite screen?
A test used to identify cells with any amount of HbS - cells with any amount will sickle - positive in both disease and trait
What is hemoglobin C?
mutation in Beta chain of hemoglobin - glutaminic acid replaced with lysine
Inheritance pattern of hemoglobin C?
autosomal recessive
Presentation of hemoglobin C
mild anemia due to extravascular hemolysic
Blood smear findings of hemoglobin C
HbC crystals
Paraxysmal nocturnal hemoglobinuria pathophys
AQUIRED defect in myeloid stem cells causing loss of GPI, thus cells are susceptible to complement mediated damage leading to intravascular hemolysis
