Hematology Quiz: Splenomegaly & Hemolytic Anemia

Splenomegaly and Hemolytic Anemia

• Characterized by splenomegaly, mild to moderate hemolytic anemia, and increased bilirubin levels, leading to jaundice and pigment gallstones.
• Chronic hemolysis raises the risk for acute red-cell aplasia, particularly from parvovirus B19.
• Laboratory findings include increased osmotic fragility (Pink test) and elevated mean corpuscular hemoglobin concentration (MCHC).
• Splenectomy is the recommended treatment; vaccinations for encapsulated organisms (e.g., pneumococcus, H. influenzae) are essential.

Morphology in Disorders

• Spherocytosis is a notable morphologic feature, indicative but not exclusive to membrane loss conditions, such as autoimmune hemolytic anemia.

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency

• Affects hexose monophosphate shunt and glutathione metabolism, resulting in red cell vulnerability to oxidative stress.
• G6PD deficiency is a recessive X-linked condition, leading to diminished NADPH and reduced glutathione, causing oxidative injury and intravascular hemolysis.
• Common stressors include fava beans, infections (viral hepatitis, pneumonia, typhoid), and specific drugs (antimalarials, sulphonamides).
• Heinz bodies form due to oxidative stress, leading to hemolysis, as macrophages clear these inclusions in the spleen.

Sickle Cell Anemia

• HbS becomes insoluble under low oxygen conditions, causing red cell sickling and potential vaso-occlusive crises.
• Initially reversible sickling can progress to irreversible changes, leading to extensive hemolysis and complications.
• Clinical manifestations include severe hemolytic anemia, erythroid hyperplasia, increased bilirubin levels, and gallstones.
• Sickle cells cause vessel obstruction, leading to pain crises, autosplenectomy, and increased susceptibility to infections, particularly with encapsulated organisms.
• Risk of complications includes Salmonella osteomyelitis, leg ulcers, and acute chest syndrome.

Thalassemias

• Genetic classification includes α-thalassemia, with silent carriers and various severity levels, including hydrops fetalis, which is lethal without transfusions.

Megaloblastic Anemias

• Caused by impaired DNA synthesis due to vitamin B12 or folate deficiencies, leading to delayed mitosis and macrocytic red blood cells.
• Peripheral blood findings include hypersegmented neutrophils and low reticulocyte counts.
• Elevated serum bilirubin and LDH levels may indicate hemolytic anemia features.

Vitamin B12 Deficiency (Pernicious Anemia)

• An autoimmune condition impairs intrinsic factor production, essential for vitamin B12 absorption.
• Additional causes of deficiency include achlorhydria and gastric surgery.
• Diagnosis confirmed through reticulocyte response post vitamin B12 treatment; associated with increased gastric cancer risk.

Folic Acid Deficiency

• Megaloblastic anemia caused by folate deficiency, without neurological involvement unlike vitamin B12 deficiency.
• Major causes of folic acid deficiency include inadequate intake, increased requirements, and impaired utilization.

Iron Deficiency Anemia

• The most prevalent nutritional deficiency worldwide; primarily caused by inadequate hemoglobin synthesis.
• Iron metabolism involves absorption from the gut, transport via transferrin, and recycling post erythrocyte lifespan.
• Causes include dietary lack, impaired absorption, increased needs, and chronic blood loss.
• Heme iron is more efficiently absorbed than inorganic iron; absorption influenced significantly by dietary components.

Diagnostic Considerations

• In adult men and postmenopausal women, iron deficiency is often attributed to gastrointestinal bleeding until proven otherwise.