Week 9 - Haematology Flashcards
Lymphoid Organs consist of Primary and Secondary
Primary: Thymus and bone marrow
Secondary: Spleen, lymph nodes, tonsils, peyers patches
Anaemia
Reduction in the total number of erythrocytes in the circulating blood or in the quality or quantity of hemoglobin due to: Impaired erythrocyte production Acute or chronic blood loss Increased erythrocyte destruction Combination of the above
Symptoms of Anaemia
Fatigue, weakness, dyspnea, and pallor
Physiological manifestation of Anaemia
Reduced oxygen carrying capacity
MACROCYTIC-NORMOCHROMIC ANAEMIA
Macrocytic-large cell
Pernicious Anaemia
Caused by a lack of intrinsic factor required for vitamin B12 absorption
Results in vitamin B12 deficiency
Folate deficiency anaemia
Always caused by lack of folate in the diet
Similar symptoms to pernicious anemia
Mechanism of cause unclear
Folate deficiency also causes neural tube defects in the foetus
MICROCYTIC-HYPOCHROMIC ANAEMIA
Microcytic-small cell
Hypochromic-reduced levels of haemoglobin
Related to:
Disorders of iron metabolism
Disorders of porphyrin and heme synthesis
Disorders of globin synthesis
Iron deficiency anemia
Most common type of anaemia worldwide
Nutritional iron deficiency
Metabolic or functional deficiency
Progression of iron deficiency causes:
Brittle, thin, coarsely ridged, and spoon-shaped nails
A red, sore, and painful tongue
Treatment is by iron replacement therapy (usually ferrous sulfate)
Sideroblastic anemia
Altered mitochondrial metabolism causing ineffective iron uptake and resulting in dysfunctional hemoglobin synthesis
Ringed sideroblasts within the bone marrow are diagnostic
Sideroblasts are erythroblasts that contain iron granules that have not been synthesized into hemoglobin
Erythropoietic hemochromatosis or iron overload is usually present
NORMOCYTIC-NORMOCHROMIC ANAEMIA
Characterized by red cells that are relatively normal in size and hemoglobin content but insufficient in number
Five distinct groups
- Aplastic anaemia
- Posthaemorrhagic anaemia
- Haemolytic anaemia
- Sickle cell anaemia
- Anaemia of chronic inflammation
Aplastic anemia usually means
Pancytopenia (reduction or absence of all 3 blood cell types)
Results from failure or suppression of bone marrow
Treatment is with immunotherapy and bone marrow transplant
Posthaemorrhagic anemia
Acute blood loss from the vascular space
Hemolytic anaemia is caused by
Accelerated destruction of red blood cells
Divided into inherited or acquired conditions
Treated by removing cause of problem, or treating under lying cause
Sickle cell anaemia
Includes sickle cell thalassemia and sickle cell-Hb C disease
Inherited autosomal recessive disorder
Anaemia of chronic inflammation
Mild to moderate anemia seen in:
AIDS, rheumatoid arthritis, lupus, hepatitis, renal failure, and malignancies
Pathologic mechanisms
Decreased erythrocyte life span
Ineffective bone marrow response to erythropoietin
Altered iron metabolism
POLYCTTHAEMIA
Overproduction of red blood cells
Relative polycythemia
Result of dehydration
Fluid loss results in relative increases of red cell counts and Hb and Hct values
Absolute polycythemia
Primary absolute
Abnormality of stem cells in the bone marrow
Secondary absolute polycythemia
Increase in erythropoietin as a normal response to chronic hypoxia or by erythropoietin-secreting tumors
Leukocytosis
Normal protective response to physiologic stressors
Leukopenia
A low white count predisposes a patient to infections
Neutrophil
↑Acute infection; ↓ prolonged infection
Eosinophil
↑Allergy and parasite; ↓surgery, shock, trauma
Basophil
↑Inflammation and allergy; ↓ Hyperthyroidism and steroid therapy
Lymphocyte
↑ acute viral infection; ↓ drug destruction, viral destruction
INFECTIOUS MONONUCLEOSIS
Acute, self-limiting infection of B lymphocytes transmitted by saliva through personal contact
- Commonly caused by the Epstein-Barr virus (EBV)—85%