Anemias Flashcards
Macrocytic anemia is divided to
- Megaloblastic
2. Non-megaloblastic
Megaloblastic macrocytic anemias - types
- B12 deficiency
- Folate deficiency
- Orotic aciduria
Non-Megaloblastic macrocytic anemias
- Hypothyroidism
- Liver disease
- Alcoholism
- Reticulocytosis
- Diamond-Blackdan anemia
Normocytic anemia is divided to
- Nonhemolytic (reticulocytes normal or decreased)
2. Hemolytic (reticulocyte increased)
Nonhemolytic normocytic anemias
- Anemia of chronic disease (early)
- Iron deficiency (early)
- Chronic kidney disease
- Aplastic anemia
Hemolytic normocytic anemias are divided to
- Intrinsic
2. Extrinsic
Extrinsic Hemolytic normocytic anemias
- Autoimmune
- Macroangiopathic
- Microangiopathic
- Infections
Intrinsic Hemolytic normocytic anemias
- RBC membrane defects (hereditary spherocytosis)
- RBC enzymes deficiency (G6PD, pyruvate kinase)
- HBC defects
- Paroxysmal nocturnal hemlglobinuria
- Sickle cell anemia
Causes of iron deficiency
Chronic bleeding (gi, menorrhagia)
Malnutrition
Malabsorption
Increased demand (pregnancy)
Iron deficiency iron labs
- Decreased iron
- Decreased ferritin
- Increase TIBC
- microcytosis and hypochromasia (central pallor)
Iron deficiency symptoms
- Fatigue
- Conjunctival pallor
- Spoon nails (koilonychia)
- Macrocytosis and hypochromia
- pica (consumption of nonfood substance)
- Plummer-Vinson syndrome
Plummer-Vinson triad
- Iron deficiency anemia
- Esophageal web
- dysphagia
(also atrophic glossitis)
a Thalassemia: cis vs trans thalassemia
Cis: Asia, -/- a/a (same chromosome)
Trans: Africa, a/- a/- (separate chormosomes)
4 allele a deltion
Hb bart (4γ) Hydrops fetalis
3 allele a deletion
very little α
HbH (4β)
β-thalassemia mechanism
Point mutation in splice sites and promoters–> decreased β-globin synthesis
Β thalassemia minor (heterozygotes) - definition/ mechanism/presentation/diagnosis
heterozygote –> β chain is underproduced –> usually asymptomatic
HbA2>3,5% on electrophoresis
Major β-thalassemia major - presentation (besides anemia) and mechanism (when starts)
- marrow expansion –> skeleta deformities (Crew cut on skull x ray) + chipmunk facies
- extramedullary hematopoiesis –> hepatosplenomegaly
Until 6 months is asymptomatic (HbF)
Major β-thalassemia major - definition/lab/treatment
homozygote –> β chain is absent
severe microcytic, hypochromic anemia with target cells and increased anisopoikilocytosis, high HbF
treatment: blood transfusion (2ry hemochromatosis)
HbS/β-thalassemia heterozygote
Mild to moderate sickle cell anemia depending on amount of β-globin production
Microcytic anemias
- Iron deficiency (late)
- Thalassemias
- Anemia of chronic disease (late)
- Lead poisoning
- Sideroblastic anemia
Lead inhibits (causing)
Ferrochelatase and ALA dehydratase –> decreases heme and increase protoporphyrin
rRNA degradation –> rRNA aggregation –> basophilic stippling
Lead poisoning symptoms and signs
- Burton lines
- Metaphysis lines on x ray
- Encephalopathy
- Erythrocyte basophilic stippling
- Siderblastic anemia
- ABDOMINAL COLIC
- Drops of wrist and foot
- KIDNEY DISEASE
Used for lead chelation in kids
Succimer
Lead poisoning-first line treatment
Dimercaprol, EDTA
Sideroblastic anemia types of causes (and causes)
- Genetic –> X-linked defect in δ-ALA synthase gene
- acquired –> Myelodysplastic syndrome
- reversible –> Alcohol (MC), Lead, Vit B6 deficiency, Isoniazid, Copper deficiency
Genetic causes of sideroblastic anemia
X-linked defect in δ-ALA synthase gene
Causes of acquired sideroblastic anemia
Myelodysplastic syndrome
Causes of reversible sideroblastic anemia
- Alcohol (MC)
- Lead
- Vit B6 deficiency
- Isoniazid
- Copper deficiency
sideroblastic anemia - labs
- Prussian blue-stained mitochondria (iron) seen in bone morrow (Ringed sideroblasts)
- basophilic stippling of RBCs in peripheral smear
- increased iron, normal/low TIBC, increased ferritin
Findings of megaloblastic anemia
mechanism: impaired DNA synthesis –> maturation of nucleus of precursor cells in bone marrow delayed relative to maturation of cytoplasm
findings: 1. RBC macrocytosis 2. Hypersegmented neutrophils 3. Glossitis
Causes of folate defciency
- Malnutrition (alcohol)
- Malabsorption
- Drugs (trimethoprim, phenytoin, methotrexate)
- Requirement (hemolytic anemia, pregnancy)
Causes of B12 (cobolamin) deficiency
- Insufficient intake (veganism)
- Malabsorption (crohn)
- Pernicious anemia
- Diphyllobothrium latum
- Gastrectomy
Folate deficiency vs b12 deficiency according to methylmalonic acid, homocystein, and neurologic symptoms
- Methylmalonic acid (increased only in B12)
- Neurologic symptoms (only in B12)
- Homocysteine (increased in Both)
Neurologic symptoms of B12 deficiency (and why)
Sabacute combined degeneration due to its involvement in fatty acid pathays and myelin synthesis:
- Spinocerebellar tract
- Lateral corticospinal tract
- Dorsal column dysfunction
Orotic aciduria pathophysiology
Defect in UMP synthesis (orotic acid to UMP, de novo pyrimidine synthesis pathway)
AR
Orotic aciduria symptoms
- Failure to thrive
- Developmental delay
- Megaloblastic anemia refractory to folate and B12
(NO HYPERAMMONIA)
Orotic aciduria treatment/diagnosis
UMP (to bypass)
diagnosis: Orotic acid in urine
Orotic aciduria vs ornithine trancarbamylase
Orotic aciduria has no hyperammonemia
Anemia of chronic disease pathophysiology
Inflammation–> increases hepsidin –> binds ferroportin (on intestinal mucosal and macrophages) inhibiting iron trnasport–> decreases the releasing of iron from macrophages and decrease absorption
Anemia of chronic disease - associated conditions/treatment
- RA 2. SLE 3. Neoplasia 4. Chronic kidney disease
treatment: EPO in chronic kidney
Anemia of chronic disease iron status / type of anemia
Decreased iron
Decreased TIBC
Increased ferritin
–> Normocytic, but can become microcytic
Aplastic anemia is caused by
Failure or destruction of myeloid stem cells
Causes of aplastic anemia
- Radiation 2. Drugs (benzene, chloramphenicol, alkylating agents) 3. Viral agents (parvovirus B19, EBV, HIV, HCV)
- Fanconi anemia (DNA repair defect) 5. Idiopathic (immune mediate, 1ry stem cell defect)-may follow acute hepatitis
Aplastic anemia-bone marrow appearance
Hypocellular Fatty infiltration (Dry bone marrow tap)
Aplastic anemia symptoms and findings
Fatigue, malaise, pallor, purpura, mucosal bleeding, petechiae, infections
Pancytopenia (severe anemia, leukopenia, thrombocytopenia) –> but normal cell morphology
Aplastic anemia treatment
- Withdrawal of offending agent
- Immunosuppressive regimens (antithymocyte globulin, cyclosporine)
- Bone marrow allograft
- RBC/platelets transfusion
- Bone marrow stimulation (eg. GM-CSF)
Hereditary spherocytosis - due to defect in
proteins interacting iwth RBC membrane skeleton and plasma membrane
- Ankyrin
- Band 3
- Protein 4.2
- Spectrin
Hereditary spherocytosis labs
- Osmotic fragility test (+)
- Normal to decreased MCV with abudance of cells
- Increased RDW
- Increased MCHC (no central pallor)
- round RBCs with less surface area
Hereditary spherocytosis treatment/intravascular vs extravascular/susceptible for
- Splenectomy (causes splenomegaly)
- extravascular hemolysis
- susceptible for B19
Most common enzymatic deficiency of RBCs
G6PD
XR
G6PD location of hemolysis / mechanism
Intravascular AND extravascular
defect in G6PD –> low glutathione –> high RBCs susceptibility to oxidant stress
G6PD deficiency - hemolytic anemia following
- Sulfa drugs
- Antimalarias
- Infections
- Fava beans
G6PD deficiency symptoms, beside anemia
BACK PAIN
HEMOGLOBINURIA (few days after oxidant stress)
Pyruvate deficiency anemia - presentation
Hemolytic anemia in a newborn
Pyruvate deficiency anemia pathophysiology
AR. Decreased ATP–> rigid RBCs –> extravascular hemolysis
HBC pathophysiology
Lysine instead of glutamic acid in β globin
Starting event of paroxysmal nocturnal hemoglobinuria / mechanism
Acquired mutation in hematopoietic stem cell –> impaired synsthesis of for GPI anchor for decay-accelerating factor that protects RBCs from complement –> increased C-mediated intravascular RBCs lysis
paroxysmal nocturnal hemoglobinuria increases the incidence of
ACUTE LEUKEMIAS
paroxysmal nocturnal hemoglobinuria triad
- Coombs hemolytic anemia
- Pancytopenia
- Venous thrombosis
paroxysmal nocturnal hemoglobinuria flow cytometry
CD 55/59 ( - )RBCs
paroxysmal nocturnal hemoglobinuria treatment
Eculizumab (terminal complement inhibitor)
Sickle cell anemia mutation / intravascular vs extravascular hemolysis
Valine instead of Glutamic acid
intravascular + extravascular
Sickle cell x ray
Crew cut on skull (marrow expansion)
Sickle cell complications
- Aplastic crisis (parvovirus B19)
- Autosplenectomy (howell-jolly bodies)
- Splenic infract/sequestration
- Salmonella osteomyelitis
- Renal papillary necrosis (low PO2 in papilla) –> microhematuria (medullary infracts)
- Painful crisis (vaso-occlusive): dactylitis (painful swelling of hands/feets), acute chest syndrome, avascular necrosis, stroke. priapism
Sickle cell anemia diagnosis and treatment
Diagnosis: Hb electrophoresis
Treatment: hydroxyurea, hydration
Hemolytic anemia-infections (mechanism)
Malaria and Babesia
increased destruction of RBCs
Causes of Macroangiopathic anemia
Prosthetic heart valce and Aortic stenosis –> mechanical destruction
Causes of microangiopathic anemia
DIC, SLE, MALIGNANT HYPERTENSION, TTP/HUS
Pregnancy (ocp use) - iron status
Increases the Transferin/TIBC
Decrease the transferin saturation
Autoimmune hemolytic anemia types
Warm (IgG)
Cold (IgM and complement)
Causes of Warm agglutinin
- SLE
- CLL
- Drugs (methyldopa)
- Idiopathic
- -> chronic anemia
Causes of Cold agglutinin
- CLL
- Mycoplasma pneumonia
- Infectious mononucleosis
- Idiopathic
- -> acute anemia
Megaloblastic anemia mechanism
Impaired DNA synthesis –> maturation of nucleus of precursor cells i. Bone marrow delayed relative to maturation in cytoplasm
B12 deficiency –> mechanism of neurological symptoms
Involvement of B12 in fatty acid pathway and myelin synthesis
thalassemia-a - 2 allele vs 1 allele deletion
2 –> less clinically severe anemia
1 –> no anemia (clinically silent)
β-thalassemia - prevalent in
Mediterranean populations
risk of Lead exposure is increased in
old houses with chipped paint
sideroblastic anemia - treatment
B6, cofactor for δ-ALA synthase
how to predict simple the type of anemia (macro vs micro vs normocytic)
on peripheral blood smear, a lymphocyte nucleus is approximately the same size as a normocytic RBC:
if RBC larger than lymphocyte nucleus, consider macrocytosis. If smaller, microcytosis
B12 deficiency - historically is diagnosed with (explain)
Schilling test, a 4-stage test that determines if the cause is dietary insufficiency vs malabsorption
(WITH RADIOLABELED B12)
Non-Megaloblastic macrocytic anemias - mechanism / neutrophils
- DNA synthesis is unimpaired
- not hypersegmented
Diamond-Blackfan anemia - description
Rapid-onset anemia within 1st year of life due to intrinsic defect in erythroid progenitor cells
Diamond-Blackfan anemia - lab
increased % of HbF (but low total Hb)
Diamond-Blackfan anemia - presentation
- short stature
- craniofacial abnormalities
- upper extremity malformations (triphalangeal thumbs) in up to 50% of cases
drugs that causes aplastic anemia
- benzene
- chloramphenicol
- alkylating agents
aplastic anemia - EPO?
increased
HbSC - presentation
milder thatn HbSS patients
HbC - homozygotes - blood smear
hemoglobin crystals within RBCs and target cells
Heterozygoges of SC anemia - advantage
resistance to malaria
prevelance of sickle cell in African american
8% carry an HbS allele
RBC agglutination with cold exposure - presentation
acute anemia
painful, blue fingers and toes with cold exposure
Autoimmune anemia are usually Coombs ..?
positive
Direct Coombs test - mechanism
anti-Ig antibody (Coombs reagent added to patient’s blood –> RBCs agglutinate if are coated with Ig
Indirect Coombs test - mechanism
normal RBCs added to patient serum –> if serum has anti RBC surface Ig, RBCs agglutinate whtn Coombs reagent added
The hemolytic anemias are divided according to
- the cause of hemolysis (intrinsic vs extrinsic to the RBC)
- the location of the hemolysis (intra vs extravascular)
extravascular hemolytic anemia - findings
- Spherocytes in peripheral smear
- high LDH
- no hemoglobinuria/hemosiderinuria
- increased UCB (–> jaundice)
- urobilinogen in urine
intravascular hemolytic anemia - findings
- low haptoglobin
- high LDH
- schistocytes
- high reticulocytes
- hemoglobinuria
- hemosiderinuria
- urobilinogen in urine
- increased UCB
Fanconi anemia - mechanism of action
DNA repair defect causing bone marrow failure
Fanconi anemia - presentation
- Aplastic anemia
- Increased incidence of tumor/leukemia
- Cafe au lait spots
- Thumb/radial defects