Blood Diseases Part 2

• Pernicious anemia is a type of megaloblastic anemia
• Due to poor vitamin  B12 absorption from the GI tract

• 1} When the stomach does not make enough intrinsic factor, the small intestine cannot properly absorb vitamin B12 and the intrinsic factor
• {2} Without vitamin B12 and intrinsic factor, immature rbcs membranes rupture easily, thus fewer rbcs and reduced O2-carrying capacity

• Weakened stomach lining (atrophic gastric mucosa)
• {2} Autoimmunity against gastric parietal cells that make intrinsic factor
• {3} Autoimmunity against intrinsic factor itself
• {4} Bacterial infection causing pathological conditions that either
•      {a} Impair vitamin B12 absorption
•    {b} Enhance vitamin B12 elimination

{1} Animal products{2} Vitamin B12 supplements

• {1} Abdominal distress
• {2} Burning of the tongue
• {3} Central nervous system effects

Due to insufficient folic acid (folate, vitamin B9) levels essential for body growth and to synthesize DNA

Low serum folic acid levels conclusive for this disease

• {1} Chronic alcoholism
• {2} Poor nutrition
• {3} Pregnant and lactating females
• {4} Kidney disease
• {5} Inflammatory bowel disease

Insufficient rbcs in blood due to premature destruction

• {1} Inherited abnormalities
•      {a} Hemoglobin defects
•      {b} Enzyme defects
•      {c} rbc membrane defects
• {2} Infections microorganisms
• {3} Medications
• {4} Immune disorders

• {1} Caused by excess yellow-orange bile pigments or bilirubin, a chemical produced when the liver breaks down rbcs
•  

 { a} Sclera   {b} Skin   {c} Urine   {d} Feces

• {1} Splenectomy
• {2} Blood transfusions
• {3} Antibiotics for infections causing hemolytic anemia
• {4} Immunosuppressive therapy for immune disorders causing hemolytic anemia
• {5} Discontinue medications causing hemolytic anemia

Diseases where genetic defects produce abnormal hemoglobins and/or anemia

• Sickle cell anemia
• Thalassemia
• Polycythemia vera

• {1}Autosomal recessive inherited disease
•      {a} Homozygous- full blown disease
•      {b} Heterozygous- Sickle cell trait
• {2} Found in ~10% of African-Americans

• {3} Caused by an abnormal type of hemoglobin called hemoglobin     S that distorts the shape of rbcs under low O2 conditions
• {a} Hemoglobin S molecules form long crystals by cross-linking with each other
• {b} As O2 is released from rbcs, the rbcs become sickle-shaped
• {c} Sickle-shaped rbcs are inflexible and rigid causing mechanical obstruction of small arterioles and capillaries
• {d} Pain and ischemia occurs ultimatelyn leading to organ failure
• {e} Sickle-shaped rbcs more fragile than normal rbcs leading to rbc hemolysis (hemolytic anemia)

• {a} Narcotic analgesics to manage pain from sickle cell crisis
• {b} Blood transfusions and fluid replacement to expand blood volume
• {c} O2 for reperfusion or occluded arteries