Haemopoietic and Lymphoid System Pathology: Hemolytic Anemias Flashcards

Vocabulary flashcards covering key terms, clinical definitions, diagnostic tests, and pathogenesis of hemolytic anemias based on HPLS 6124 Lecture #1.

Hemolytic Anemia

A form of anemia caused by the abnormal breakdown of red blood cells.

Intravascular Hemolysis

The breakdown of red blood cells occurring inside blood vessels, manifested by anemia, hemoglobinemia, hemoglobinuria, hemosiderinuria, and jaundice with free hemoglobin detected in blood.

Extravascular Hemolysis

The breakdown of red blood cells occurring usually in the spleen, manifested by anemia, splenomegaly, and jaundice without free hemoglobin detected in blood.

Thalassemia

A heterozygous group of inherited disorders characterized by a lack of or decreased synthesis of either alpha or beta globin chains of hemoglobin.

Beta Thalassemia Major

A severe form of beta thalassemia where reduced beta chains lead to increased free alpha chains forming unstable aggregates, resulting in ineffective erythropoiesis, severe anemia, skeletal deformities, and systemic iron overload.

Sickle Cell Disease

A common hereditary hemoglobinopathy occurring primarily in individuals of African descent, caused by a point mutation in the 6th codon of the beta-globin chain substituting glutamate with valine.

Sickle Cells (Holly Leaf Cells)

Irreversibly sickled red blood cells formed when deoxygenated HbS undergoes polymerization, converting cytosol into a viscous gel.

Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency

An X-linked inherited disorder causing abnormalities in glutathione metabolism that reduce the ability of red blood cells to protect themselves against oxidative injuries.

Heinz Bodies

Precipitates of denatured globin chains within red blood cells seen using supravital staining in G6PD deficiency.

Bite Cells

Red blood cells with membrane defects resulting from splenic macrophages plucking out Heinz bodies.

Hereditary Spherocytosis

An autosomal dominant disorder characterized by a deficiency of ankyrin and spectrin, leading to membrane instability, loss of membrane fragments, spherical RBC shape, and premature destruction in the spleen.

Paroxysmal Nocturnal Hemoglobinuria (PNH)

An acquired hemolytic anemia characterized by chronic intravascular hemolysis caused by a deficiency of Glycosyl-phosphatidyl-inositol (GPI) anchored membrane glycoproteins.

Ham's Acidified Serum Test

The diagnostic test used for the definite diagnosis of Paroxysmal Nocturnal Hemoglobinuria (PNH).

Sucrose Lysis Test

A screening test used to detect Paroxysmal Nocturnal Hemoglobinuria (PNH).

Autoimmune Hemolytic Anemia (AIHA)

A type of hemolytic anemia caused by the formation of anti-red cell autoantibodies against red blood cell surface antigens.

Warm Antibodies

IgG autoantibodies in AIHA that are most active at $37\,^\circ\text{C}$, seen in primary idiopathic cases or secondary to conditions like SLE and drugs.

Cold Antibodies

IgM autoantibodies in AIHA that are most active at $0\,^\circ\text{C} - 4\,^\circ\text{C}$ and dissociate at $30\,^\circ\text{C}$ or above, associated with infections such as Mycoplasma pneumoniae, infectious mononucleosis, HIV, EBV, and CMV.

Microangiopathic Hemolytic Anemia (MAHA)

A non-immune mechanical hemolytic anemia resulting from diffuse narrowing of microvasculature due to thrombus or fibrin deposition, causing mechanical trauma to red blood cells.

Direct Coombs Test

An antiglobulin test used to detect autoantibodies bound directly to the red cell surface.

Indirect Coombs Test

An antiglobulin test used to detect anti-red cell autoantibodies circulating freely in the serum.