Hemolytic Anemias, Hemoglobinopathies, Thalassemia & Secondary Anemias

Hereditary hemolytic anemias ยท Acquired hemolytic anemias ยท Sickle cell disease ยท Thalassemia syndromes ยท Anemia of chronic disease
๐Ÿฉธ Key concepts: Hemolysis markers (LDH, indirect bilirubin, reticulocytosis), spherocytosis, G6PD, sickle cell crisis management, thalassemia transfusion therapy, secondary anemia workup.

๐Ÿ“– Hemolytic anemias & disorders of hemoglobin synthesis

๐Ÿงฌ Hereditary hemolytic anemias
Membrane defects: hereditary spherocytosis, elliptocytosis. Enzyme defects: G6PD (X-linked, oxidative hemolysis), pyruvate kinase. Hemoglobinopathies: sickle cell disease, unstable hemoglobins.
โšก Acquired hemolytic anemias
Immune-mediated: autoimmune hemolytic anemia (warm/cold), alloimmune (transfusion, HDN), drug-induced. Non-immune: microangiopathic (HUS, DIC), macroangiopathic (mechanical valve), infections (malaria, clostridia).
๐Ÿงฌ Hemoglobinopathies & Thalassemia
Sickle cell disease (HbSS): vaso-occlusion, acute chest, stroke. Thalassemia major: transfusion-dependent; thalassemia intermedia: milder. HbE, HbC syndromes.
๐Ÿฉธ Secondary anemias
Anemia of chronic disease (infection, inflammation, malignancy, CKD). Usually normocytic, low iron, normal/high ferritin, low TIBC. Treat underlying cause.
โš ๏ธ Hemolysis clues: Elevated LDH, indirect bilirubin, low haptoglobin, reticulocytosis, hemoglobinuria (dark urine), splenomegaly, gallstones in young children.

๐Ÿฉบ Diagnostic approach to hemolytic anemia & secondary anemias

1
Confirm hemolysis โ€“ Labs: CBC (anemia), reticulocytes (high), LDH (high), indirect bilirubin (high), haptoglobin (low). Peripheral smear (spherocytes, schistocytes, sickle cells, bite cells).
2
Hereditary vs acquired โ€“ Family history, age, Coombs test (direct antiglobulin test). Positive DAT โ†’ immune hemolysis (AIHA, alloimmune). Negative โ†’ hereditary (spherocytosis, G6PD) or non-immune acquired (microangiopathic).
3
Specific tests for hereditary hemolysis โ€“ Osmotic fragility (spherocytosis), G6PD enzyme assay (after recovery), Hb electrophoresis (sickle cell, thalassemia), pyruvate kinase assay.
4
Secondary anemia workup โ€“ Normocytic/normochromic. Check ferritin (normal/elevated), TIBC (low), CRP/ESR. Evaluate for chronic infection, autoimmune disease, malignancy, CKD.
๐Ÿ“Œ Clinical pearl: G6PD deficiency testing during acute hemolysis may be falsely normal (young reticulocytes have higher enzyme). Repeat in 2-3 months. Heinz bodies (oxidized hemoglobin) seen with special stain.

๐Ÿ“‹ Management of hemolytic anemias, hemoglobinopathies & secondary anemias

1
Hereditary spherocytosis โ€“ Folate supplementation. Transfusion if severe anemia. Splenectomy (if significant hemolysis, after age 5-6; post-splenectomy vaccines, penicillin prophylaxis).
2
G6PD deficiency โ€“ Avoid oxidative triggers (fava beans, sulfonamides, nitrofurantoin, naphthalene). Treat acute hemolysis supportively (IV fluids, transfusion if severe).
3
Sickle cell disease (SCD) โ€“ Hydroxyurea to reduce crises. Acute chest: O2, antibiotics, transfusion. Stroke prevention: chronic transfusion or hydroxyurea. Pain crisis: opioids, hydration.
4
Thalassemia major โ€“ Lifelong transfusion (target Hb 9.5-10.5). Iron chelation (deferasirox, deferoxamine). Splenectomy if hypersplenism. HSCT curative.
5
Autoimmune hemolytic anemia (AIHA) โ€“ Warm AIHA: corticosteroids (prednisolone). Rituximab, immunosuppression if refractory. Cold AIHA: avoid cold, treat underlying disorder.
6
Secondary anemia (ACD) โ€“ Treat underlying disease. Erythropoiesis-stimulating agents (ESA) in CKD or chronic inflammation with low Hb.
๐Ÿšจ Emergency in SCD: Acute chest syndrome, stroke, splenic sequestration (rapid enlargement with falling Hb), priapism >4h โ†’ urgent intervention (transfusion/exchange).

๐Ÿง  Reflex prompts: hemolysis, thalassemia, secondary anemia

๐Ÿฉธ Child with jaundice, splenomegaly, spherocytes, negative DAT, and family history of gallstones. Diagnosis?
Hereditary spherocytosis. Osmotic fragility or eosin-5'-maleimide (EMA) binding test. Folate, splenectomy if severe.
๐Ÿงฌ African-American child with acute hemolysis after taking sulfonamide; Heinz bodies on smear. Diagnosis?
G6PD deficiency. Avoid triggers. Test G6PD enzyme after recovery.
๐Ÿฉธ Child with HbSS presents with fever, chest pain, hypoxia, and new infiltrate. Diagnosis and treatment?
Acute chest syndrome. O2, incentive spirometry, broad-spectrum antibiotics, simple/exchange transfusion.
๐Ÿงฌ Infant with severe microcytic anemia, Hb 5, Hb electrophoresis: absent HbA, HbF 95%, HbA2 5%. Diagnosis?
Beta-thalassemia major. Lifelong transfusion + iron chelation. HSCT offers cure.
๐Ÿฉธ Child with pallor, jaundice, dark urine, positive DAT. Most likely diagnosis?
Autoimmune hemolytic anemia (warm type). Treat with steroids, rituximab if refractory.
๐Ÿงช Child with normocytic anemia, low serum iron, low TIBC, normal ferritin. Diagnosis?
Anemia of chronic disease/inflammation. Treat underlying condition. Ferritin helps differentiate from iron deficiency (ferritin low in ID).
๐Ÿฉธ Target cells on smear + microcytosis + normal ferritin + elevated HbA2 (5.5%) โ†’ diagnosis?
Beta-thalassemia trait. No treatment, genetic counseling.
๐Ÿฉบ Schistocytes + thrombocytopenia + renal failure + fever โ†’ likely?
Hemolytic uremic syndrome (HUS). Microangiopathic hemolytic anemia. Supportive care, avoid antibiotics for STEC.
๐Ÿงฌ Which drug is used for stroke prevention in sickle cell disease with elevated TCD velocities?
Chronic transfusion therapy (maintain HbS <30%). Hydroxyurea alternative in some settings.
๐Ÿฉธ What is the most common cause of normocytic anemia in hospitalized children?
Anemia of chronic disease (secondary anemia). Rule out blood loss, hemolysis, nutritional deficiency.