2. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
â˘Hemolytic anemias are characterised by increase red cell
destruction.
â˘Characteristic features are :
1. A shortened red cell life span below the normal 120 days
2. Elevated erythropoietin level and compensatory increase in
erythropoiesis.
3. Accumulation of hemoglobin degradation products that are
produced as a part of process of red cell hemolysis.
3. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
PATHOGENESIS OF RED CELL DESTRUCTION :
Two mechanisms :
â˘Extravascular Hemolysis âThe site of destruction is mainly spleen
and this is the major mechanism of red cell hemolysis. Red cells
are taken up by the cells of RE system where they are destroyed
and digested.
â˘Intravascular HemolysisâThis is the minor pathway of red cell
destruction and red cells are destroyed in circulation releasing
hemoglobin.
7. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
CLINICAL FEATURES :
Clinical signs and symptoms of hemolytic anemia depends upon the severity
as well as duration of hemolysis.
⢠Pallor
⢠Jaundice
⢠Splenomegaly
⢠Gall stones
⢠Skeletal abnormalities in severe hemolysis
⢠Leg ulcers
⢠Dyspnoea
⢠Tachycardia and systolic murmur
8. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
Hereditary hemolytic anemias :
Type Etiology Associations Diagnosis Treatment
Enzymopathies G6PD deficiency Infections, drugs,
ingestion of fava
beans
Low G6PD activity Withdrawal of
offending drug,
treatment of
infection
Membranopathies Hereditary
Spherocytes
Hereditary
Elliptocytosis
family history,
spherocytosis
negative DAT.
Splenectomy
Hemoglobino-
pathies.
Thalassemia
sickle cell disease
Hemoglobin
electrophoresis,
genetic studies
Folate, transfusions
9. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
Acquired hemolytic anemias :
Type Etiology Associations Diagnosis Treatment
Immune-
mediated
Antibodies to RBC
surface antigens.
Idiopathic
Drugs
Autoimmune
Infections,
Transfusions
Spherocytes
Positive DAT
Treatment of
underlying disorder
Steroids
Splenectomy
IV gamma globulins
Microangiopathic Mechanical disruption
of RBC in circulation
TTP ,HUS ,
Pre eclampsia
Eclampsia
Malignant HTN
Prosthetic valves
Schistocytes Treatment of
underlying disorder.
Infection Malaria
Babesiosis
Clostridium infections
Cultures
Thick and thin smears
Serologies
Antibiotics.
10. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
INVESTIGATIONS :
Investigations that establish ACCELERATED HEMOLYSIS :
1. Shortened lifespan of red blood cells by 51Cr labeling
2. Accelerated erythropoiesis:
a. Erythroid hyperplasia in the bone marrow.
b. Reticulocytosis.
11. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
ContinuedâŚ.
3. Increase in catabolic products of hemoglobin in blood :
a. Unconjugated hyperbilirubinemia
b. Hemoglobinemia (intravascular hemolysis)
c. Hemoglobinuria (intravascular hemolysis)
d. Hemosiderinuria (intravascular hemolysis)
e. Increased urinary urobilinogen
f. Increased CO excretion
12. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
ContinuedâŚ.
4. Increased concentration of products released from the breakdown of RBCs
particularly LDH.
5. Effects due to release of hemoglobin
a. Depletion of plasma haptoglobin
b. Depletion of plasma hemopexin.
14. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
SPECIFICTESTSTO ESTABLISHTHE CAUSE OF HEMOLYSIS :
PERIPHERAL BLOOD SMEAR FINDINGS:
The most important investigation in hemolytic anemias.
Morphological findings suggestive of hemolysis : Polychromatophilia,
nucleated red cells, thrombocytosis and neutrophilia with mild shift to left.
Spherocytes, Sickle cell,Target cells, Schistocytes (fragmented red cells,
helmet cells, traingular cells) and acanthocytes
18. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
Tests for RBC membrane abnormality:
i. Osmotic fragility, incubation osmotic fragility.
ii. Identification of specific membrane abnormality
19. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
Identification of abnormal hemoglobin:
a. Electrophoresis, isoelectrofocussing (IEF).
b. Hb A2 by microcolumn chromatography
c. Hb F by alkali denaturation
d. Intracellular Hb F distribution
e. Quantitation of alpha and beta-chains by HPLC or electrophoresis
f. Hb S by sickling test, solubility test .
g. Tests for unstable hemoglobins
h. DNA analysis for detection of mutations.
Screening tests or quantitative analysis for enzymopathies
20. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
HEREDITARY SPHEROCYTOSIS
⢠Hereditary spheroytosis is an inherited hemolytic anemia resultimg from
red cell mebrane defect leading to microspherocytosis, splenomegaly and
jaundice
ETIOAPTHOGENESIS :
⢠Spectrin deficiency is the most common abnormality
⢠Mutation of b spectrin gene and point mutations affect the binding of
spectrin to protein 4.1
22. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
HEREDITARY SPHEROCYTOSIS - CLINICAL FEATURES
⢠Seen all over the world
⢠Autosomal dominant with variable penetrance
⢠M=F
⢠present in neonate, childhood or adulthood
⢠Intermittent jaundice is usual presentation
⢠O/E- splenomegaly is a constant feature
⢠Gall stones (pigment type)
⢠Chronic leg ulcers (rare)
23. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
HEREDITARY SPHEROCYTOSIS - LAB FINDINGS :
⢠PBF Findings- Microspherocytes which are small dense rbc without pallor
⢠MCV- Normal
⢠Reticulocytes- Increased
⢠Bone marrow- Erythroid hyperplasia with
normoblastic reaction
⢠S. bilrubin- Increased (unconjugated )
⢠U. bilrubin â Increased
⢠Fecal stercobilinogen- increased
⢠S. haptoglobins- Reduced
24. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
HEREDITARY SPHEROCYTOSIS - OTHER DIAGNOSTICTESTS
⢠Osmotic fragility test- shift of curve to right
⢠Incubated osmotic fragiloty test
⢠Glycerol lysis test â Increased (rate of lysis)
25. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
GLUCOSE 6-PHOSPHATE DEHYDROGENASE DEFICIENCY
⢠Glucose6-phosphate dehydrogenase is the first enzyme in the hexose
monophosphate shunt pathway (HMP) which protects red cells from
oxidant injury
⢠Deficiency of G6PD may result in episodes of hemolysis following certain
drug intake or chemical exposure or infection
⢠G6PD deficiency is a sex linked disease.
⢠Its prevalance is higher in tropical eastern countries.
⢠Prevalance is higher in kurdish jews (60-70%) and lower in japan (.1%)
26. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
CLINICAL AND HEMATOLOGICAL PRESENTATION OF G6PD DEFICIENCY :
⢠Acute hemolytic anemia- Occurs following exposure to drugs like
primaquine, infections like pneumonia, typhoid and oxidative chemicals.
⢠Chronic non-spherocytic anemia-There is moderately severe enyme
deficiency, hemolysis continues throughout life.
⢠Neonatal hyperbilrubinimia- Jaundice in G6PD deficient neonates,
CF- Jaundice, kernicterus
⢠Favism- Common in children, caused by consumption of fava beans.
Glucoside divisine and aglycone isouramil is responsible. Resulting in acute
severe hemolysis within few hours . CF-headache, fever, chills and back pain.
27. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
G6PD DEFICIENCY -DIAGNOSTICTESTS
⢠Peripheral blood film evaluation :Moderate anisopoikliocytosis with
polychromatophilia, Microspherocytes and bite cell.
⢠Reticulocytosis (20-50%)
⢠Hemogobinuria and increase urobilinogen in urine
⢠Quantitative G6-PD assay and DNA analysis by PCR
29. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
THETHALASSEMIAS
⢠Thalassemia syndrome are autosomal recessive disorders
⢠Thalassemia results from defects in the rate of synthesis of a or b chains,
lead to reduced hemoglobin production and accumulation of a or b chains
30. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
SICKLE CELL DISORDERS:
⢠Sickling syndromes are characterized by the presence of HbS which imparts
sickle shape to red cells in a state of reduced oxygen tension
⢠HbS is prevalent in Africa, Mediterranean countries and India.
⢠In India, seen common in tribals and in ethnic groups of MP, Orissa, AP,
Maharashtra (vidharba region),TN (chetti tribes) and Kerala
⢠There is high prevalence of HbS in areas endemic to falciparum malaria.
31. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
SICKLE CELL DISORDERS - GENETICS
⢠Sickle mutation is caused by substitution of valine in place of glutamic acid
in the 6th position of b-chain.
⢠Mutation results in clinical presentation
1. Sickle cell anemia- HbS-HbS, Homozygous state
2. Sickle cell trait - HbA-HbS, heterozygous state
3. Sickle cell disease- Refer to all diseases with HbS in combination with â
normal (HbA), abnormal gene of b-thalassemia, a-thalassemia, HbD, HbE,
HbC,HbQ
32. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
SICKLE CELL DISORDERS -Pathophysiology of vascular occlusion and
hemolysis
⢠Polymerisation of deoxygenated HbS is the primary event in the
pathogenesis of the disease
⢠Red cell containing HbS pass through microcirculation of spleen â various
cycles of sickling and desickling â Irreversible sickeled RBCs â Extravascular
hemolysis in spleen âVascular stasis â vascular occlusion â splenic infarcts â
hyposplenism (lead to infection) and autosplenectomy
33. APPROACHTOTHE DIAGNOSIS OF
HEMOLYTIC ANEMIAS
SICKLE CELL DISORDERS - CLINICAL FEATURES
⢠Delay in puberty, growth and development
⢠Recurrent leg ulcers
⢠Avascular necrosis of femur head
⢠Dactylitis ( Hand âFoot syndrome )
⢠Pneumonia, meningitis, Osteomylitis
⢠Jaundice and liver enlargement
⢠Pigment gall stones
⢠Acute abdominal pain ( infarcts of abdominal viscera)
⢠Priapism
⢠Acute chest syndrome (fever, chest pain, leucocytosis, appearance of pulmonary infilterate with
sickle anemia)
⢠Sickle retinopathy- Salmon patches- intra retinal hemmorhages