Hemolytic anemia, Hereditary spherocytosis and G6PD deficiency

HEMOLYTIC ANEMIA– Hereditary spherocytosis and

G6PD deficiency

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Dr. Kalpana MallaMD Pediatrics

Manipal Teaching Hospital

Definition:

• Anaemia due to increased red cell destruction (and increased erythropoiesis)

Classification:

• INTRACORPUSCULAR HEMOLYSIS– Membrane Abnormalities– Haemoglobin defects– Enzyme defects

• EXTRACORPUSCULAR HEMOLYSIS– Nonimmune – Immune

Intracorpuscular defects

Membrane Defects • Microskeletal defects

– Hereditary spherocytosis**• Membrane permeability defects

– Hereditary stomatocytosis• Increased sensitivity to complement

– Paroxysmal nocturnal hemoglobinuria

Intracorpuscular defects

• Enzymopathies • Deficiencies in Hexose Monophosphate

Shunt– Glucose 6-Phosphate Dehydrogenase

Deficiency**• Deficiencies in the EM Pathway

– Pyruvate Kinase Deficiency

Intracorpuscular defects

Haemoglobin defects Haemoglobinopathies: Sickle cell anemia

Thalassemias: β-thalassemia major HbH disease

Double heterozygous disorders: Sickle cell β-thalassemia

Extracorpuscular defects -

IMMUNE Autoimmune Hemolysis

– Warm antibody– Cold antibody

Alloimmune Hemolysis– Hemolytic Transfusion Reaction – Hemolytic Disease of the Newborn

Drug-Related Hemolysis

Extracorpuscular defects -

Nonimmune • M echanical• Infectious• Chemical• Thermal

General evidences of haemolysis:• Evidence of increased Hb breakdown: - jaundice and hyperbilirubinemia - reduced plasma haptoglobin / haemopexin - increased plasma LDH e/o intravascular haemolysis

haemoglobinaemia - haemoglobinuria - methaemalbuminaemia - haemosiderinuria

• Evidence of compensatory erythroid hyperplasia:

- Reticulocytosis - Macrocytosis & polychromasia - BM erythroid hyperplasia - Radiological changes in bones• Evidence of damage to red cells: - Spherocytosis & increased fragility - Fragmented RBCs - Heinz bodies• Demonstration of shortened RBC life-span

HEREDITARY SPHEROCYTOSIS

ETIOLOGY

• Usually AD . Rarely AR• 25% have no F/H. New mutations• Northern Europe most common• Also seen in SE Asia incl. India, Nepal

RBC CYTOSKELETON

• “Vertical” and “horizontal” interactions b/w proteins and lipids

• Lipid bilayer skeleton• Spectrin and Ankyrin : major components• Spectrin has α and β chains• Protein 3 also present• Deficiency in either of the 3 causes problem in

the “vertical” interactions

MOLECULAR PATHOPHYSIOLOGYDeficiency in spectrin, ankyrin, protein 3

Lipid bilayer skeleton uncoupling

Membrane loss in the form of microvesicles

Surface area deficiency

Spherocytosis

Impaired passage through splenic cord

Sequestration

VARIOUS PRESENTATIONS

• Hemolytic d/s of newborn• Hemolytic crisis : most common form• Aplastic crisis• Megaloblastic crisis• HS in pregnancy

CLINICAL CLASSIFICATION

• Trait• Mild HS• Moderate HS• Moderately severe HS• Severe HS

HS IN NEONATES

• Hemolytic d/s of newborn• Prolonged neonatal jaundice• May require PT/ exchange transf.• Anemia progressing to CCF• Hydrops fetalis (rare)• Palpable spleen• Investigate parents

HEMOLYTIC CRISIS

• Pptd by viral inf : Infectious mononucleosis

• Exercise induced• Anemia,jaundice• Vomiting, abd pain, tender spleen• May happen also during recovery phase

of aplastic crisis

APLASTIC CRISIS

• Less common, more serious• Parvovirus B19• Fever, chills• Vomiting, diarrhea, myalgias• Slapped cheek apearance• Foll this - sudden pallor, jaundice,

weakness

PATHOGENESIS OF APLASTIC CRISIS

• Parvovirus affects erythropoetic precursors -> arrests cell cycle in G2 phase -> apoptosis.

• Also transient neutropenia, thrombocytopenia (pancytopenia)

• BM: giant pronormoblasts (hallmark)• Unused iron levels increase in serum• Hematocrit and retic count falls• Self limiting process. Self recovery after sometime

MEGALOBLASTIC CRISIS

• Due to a secondary folate deficiency• In patients recovering from aplastic crisis• Hence supplement 1mg/day of F.A. to

children with HS

COMPLICATIONS• Gall stones : young adults/

adolescence . • Gout, Leg ulcers• Chronic erythematous dermatitis of legs• Extramedullary hematopoesis• Hematologic malignancies : multiple

myeloma, leukemia, hepatoma • Heart disease: CCF, cardiomyopathy

INVESTIGATIONS

• Hb: 6-10g/dl• Increased retics• Indirect hyperbilirubinemia• MCV normal. MCHC increased (high

Hb)• PS: polychromatophilia,

spherocytes (usually >15-20% of cells), central pallor absent, hyperchromic,

INVESTIGATIONS

• BM: erythroid hyperplasia• Decreased haptoglobin• Incubated Osmotic fragility test (deprive

RBC off glucose overnight): increased fragility to hypotonic saline

• Autohemolysis: spont cell breakdown after incubation for 48 hrs at 37C. Normally <4%, In HS >10-15%

• Molecular and genetic analysis

OSMOTIC FRAGILITY

0

20

40

60

80

100

0.3 0.4 0.5 0.6

NaCl (% of normal saline)

% H

emol

ysis

Normal HS

Other conditions associated with spherocytes on PS:

• Auto-immune hemolytic anemia• Burns• Wilson’s disease• Chemical injury• Infections• HDN due to anti-A

Treatment:

• If Hb > 10 gm/dl and retics < 10%- no Rx• If severe anemia, poor growth, aplastic

crises and age < 2 yrs- transfusion• If Hb < 10 gm/dl and retics > 10 % or

massive spleen- splenectomy• Folic acid- 1 mg/day

TREATMENT

• Splenectomy• Folic acid 1 mg/day• Blood transfusion SOS• Cholecystectomy for gall stones

SPLENECTOMY

• Indications:Hypoplastic/aplastic crisisPoor skeletal growthCardiomegaly

SPLENECTOMY• Recommended >5-6 yrs• Postsplenectomy sepsis with encaps org• Prophlactic vaccinations : Hib, Pneumo,

meningococcus• Prophylactic penicillin V: <5yr: 125mgBD >5yr to adulthood: 250mg BD• Postsplenectomy Thrombocytopenia : self

limiting• Partial spenectomy/embolisation if <5yrs

GLUCOSE-6-PHOSPHATE

DEHYDROGENASE DEFICIENCY

• Two clinical syndromes: - Episodic / induced hemolytic A - Spontaneous chronic non- spherocytic hemolytic A

• Inheritance of abnormal alleles of gene responsible for synthesis of G6PD molecules

ETIOLOGY• X-Linked recessive• Evolutionary advantage of

resistance to falciparum malaria• 90 mutations of G6PD gene• Normal enzyme : G6PD B+• Variant: G6PD A+ (African-

American) G6PD A -

• Synthesis of G6PD determined by X chromosome

• Usually only males affected• Heterozygous females

(intermediate enzyme activity) usually not symptomatic…unless random inactivation of normal X chromosome (rarely) Lyon’s hypothesis

FUNCTION OF G6PD• Regenerates NADPH, allowing

regeneration of glutathione• Protects against oxidative stress• Lack of G6PD leads to hemolysis during

oxidative stress- infection, medication, fava beans

• Oxidative stress leads to Heinz body formation, extravascular hemolysis

HbO2 infections/ drugs Hb O2 H2O2 H2O Gl. Peroxidase meth.Hb 2GSH GSSG Gl. Reductase Heinz bodies NADP NADPH G6PD GG6P 6-PG maintains integrity of RBC membrane when deficient glycolysis haemolysis lactate

PRECIPITATING FACTORS• Antimalarials: primaquine, quinine,

chloroquine• Antibiotics - nitrofuantoin,

furazolidine, cotrimoxazole, Nalidixic acid, Chloramphenicol,• Others : • Vitamin K – large doses• Naphthalene (moth balls)• Benzene, Methylene blue• Probenecid• Acetyl salicylic acid (aspirin)• Fava beans• Septicemia and viral hepatitis in def. pts• Diabetic ketoacidosis

FAVA BEANS

TYPES• Type 1: mild (G6PD A-): Afro- americans• Type 2: moderately severe (G6PD B- and

G6PD Canton): SE Asia, Mediterranean• Type 3: chronic: North America and

Europe

OR

• Episodic hemolytic anemia• Spontaneous chronic nonspherocytic

hemolytic anemia

CLINICAL FEATURESExposure to drug

24-48 hr

• Severe progressive anemia, cardiac failure and jaundice

• Favism: hemolysis after ingestion of fava beans

TYPE 1• Mildest form (enzymes 8-15 % of normal)• Episodic form• Sensitive to strong oxidants• Usual doses of aspirin and Co-trimox well

tolerated• Young RBC have high conc of enzyme ->

hence no neonatal jaundice• Hemolysis doesn’t continue after intial

hemolysis as ageing G6PD cells dead and young ones have enzyme

TYPE 2• Moderately severe• Episodic form• Fava exposure + oxidants• Neonatal Jaundice present• Hemolysis continuous with continuous

administration of drug• Assoc with viral hepatitis – severe

jaundice• Encephalopathy sometimes

TYPE 3• Chronic type• Spontaneous, without any ppt factor• If ppt factor given -> severe hemolysis

with hemoglobinuria• Severe neonatal jaundice -> kernicterus• Hemolysis after febrile episode• Enzyme level very very low

INVESTIGATIONSDuring hemolysis :• Hb decreased • Elevated retics (5-15 %)• PS: Normocytic normochromic

anemia• Polychromasia, fragmented cells• Heinz bodies:- ppted hemoglobin-

supravital staining• Hemoglobinuria• Indirect hyperbilirubinemia

NEVER ASSESS G6PD LEVELS DURING ACUTE HEMOLYSIS

WHY?• During acute hemolysis- all deficient cells

have been hemolysed • Young cells will be in circulation• Young surviving cells may have normal

levels of the enzyme• Hence falsely normal during acute episode• Assess 2-4 months later• Deficient G6PD levels will be evident• Usually affected have <10% of normal level

TREATMENT• Avoid the oxidants• Blood transfusion• Sodium bicarbonate to alkalinise urine

in severe Hburia… or else acid hematin ppt in renal tubules

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