Heme Flashcards
1
Q
Iron deficiency anemia: review
A
- Results in ineffective erythropoiesis
- Microcytic, hypochromic anemia
- Insufficient iron= insufficient amount of hemoglobin produced
- In infants/small children: most common form of nutritional deficiency
- Adults: reflects depletion of iron stores due to chronic blood loss
- Gastrointestinal bleeds, menstruation, cancer
- Typical Hgb 9-12 g/dL
- Decreased serum ferritin concentration (<30 ng/mL)
- Tx: ferrous iron salts for >1 year
-
In cases of severe anemia or severe coex conditions (i.e CAD) may postpone elective surgery for up to 4 months in order for ferrous iron salts to improve hemoglobin levels
- If unable to delay surgery longer than 3 weeks, IV iron preparations can be considered
2
Q
vitamin B 12 deficiency: review
A
- Essential for normal DNA synthesis results in macrocytic (large RBCs) anemia
- Alcohol abuse, poor diet, intestinal malabsorption syndromes, long N2O exposure at high concentrations
- Pernicious anemia
- Hgb levels 8-10 g/dL with large RBC volume
- Degeneration of the lateral and posterior columns of spinal cord
- Symmetrical paresthesia, loss of proprioception and vibration in lower extremities
- Unsteady gait, diminished deep tendon reflexes
- Memory impairment and depression
- Thick, large smooth tongue (airway!)
3
Q
hemolytic anemia: review
A
- Accelerated destruction (hemolysis) of erythrocytes
- Increased levels of unconjugated bilirubinemia
- Increased lactate dehydrogenase (LDH) level
- Results in tissue hypoxia and hyperproduction of RBCs in the bone marrow
- Immature erythrocytes
- Disorders of red cell structure
- Hereditary spherocytosis
- Paroxysmal nocturnal hemoglobinuria
- Disorders of red cell metabolism
- G6PD deficiency
- Pyruvate kinase deficiency
4
Q
hereditary hemolytic anemia, hereditary spherocytosis: REVIEW
A
- Autosomal dominate, most common hereditary hemolytic anemia in US
- Abnormal RBC membrane protein composition → cell becomes more rounded and fragile
- Ranges from mild/clinically silentà severe with life-threatening hemolysis and anemia
- Splenomegaly and fatigue
- Risk of hemolytic crisis with viral/bacterial infections
- Gallstones and jaundice
5
Q
paroxysmal nocturnal hemoglobinuria: REVIEW
A
- Complement- activated RBC hemolysis
- Stem cell disorder, presents during 2nd- 8th decade of life
- Abnormalities or reduction in a RBC membrane protein
- Life expectancy after diagnosis 10 years
- Thought to be result of CO2 retention and subsequent acidosis
- High risk for DVT due to complement activation
- Hepatic and portal veins
- Aplastic bone marrow
6
Q
hereditary hemolytic anemia, glucose 6 phosphate dehydrogenase (G6PD) deficiency: REVIEW
A
- Phosphogluconate oxidative metabolic pathway
- Normally counteracts environmental oxidants and prevents globin denaturation
- In deficiency of G6PD enzyme, oxidative stress causes denaturation of Hgb which precipitates on the inner surface of the RBC membrane resulting in membrane damage and hemolysis
- Most common enzymatic disorder of RBCs worldwide
- African Americans, Asians and Mediterranean populations
- Ranges from mild/no hemolysis (Class V and IV) → chronic hemolytic anemia (Class I)
- Oxidative drugs, infection, ingestion of fava beans aggravate preexisting hemolysis
7
Q
hereditary hemolytic anemia, pyruvate kinase deficiency: REVIEW
A
- Most common enzyme defect that results in congenital hemolytic anemia
- Worldwide
- Northern European descent and China
- Less prevalent than G6PD deficiency but considerably greater occurrence of chronic hemolysis
- Accumulation of 2,3 DPG
- Shifts oxyhemoglobin curve to the right
- High incidence of hemolysis in the spleen → splenomegaly
- Life-threatening, transfusion-requiring hemolytic anemia at birth
- Chronic jaundice, gallstones
- Splenectomy (early in life) improves degree of hemolysis and may eliminate need for transfusions → at high risk of infections
8
Q
List acquired hemolytic anemias.
A
- Immune system induced hemolysis
- Sensitization of RBCs (with transfusion)
- Disease- induced
- Drug- induced
- Infection induced hemolysis
- Malaria
- Particles released during hemolysis can result in DIC and hypersplenism
- Malaria
9
Q
Disorders of Hemoglobin Molecule,
Sickle Cell Disease: Review
A
- Inherited homozygous disorder of the hemoglobin molecule
- Substitution of valine for glutamic acid on the beta globulin chain
- Results in mutant hemoglobin (S) → 70-98% Hgb is type S
- Extreme states of deoxygenation → Hgb aggregates forming a polymer distorting the erythrocyte’s membrane → sickled cell shape
- Cells sickle and occlude small vessels → decreasing blood flow and oxygen delivery to tissues
- Increased incidence of hemolysis resulting in average RBC lifespan of 10-20 days (normal 120 day lifespan)
- Oxy-hemoglobin curve shifts to the right as compensation
10
Q
Sickle cell disease: complications
A
- Begins early in life, progression highly variable
- Severe hemolytic anemia → end- organ damage
- Bone marrow, spleen, kidneys, CNS
- Splenic infarction → loss of splenic function within first decade of life → infection!
- Kidney → painless hematuria and loss of concentrating ability → chronic renal failure in third-fourth decade of life
- Pulmonary damage due to chronic persistent inflammation
- Neurologic complications include both ischemic and hemorrhagic strokes
- Vaso-occlusive crises
- Episodic painful bone and joint pain associated with concurrent illness, stress, dehydration
11
Q
What is sickle cell crisis?
A
- Life threatening
- With de-oxygenation, Hgb S forms an insoluble globulin polymer
- Acute episodic vaso-occlusive crisis
- Ischemia / infarction of organs
- Pain, stroke, renal failure, liver failure, splenic sequestration, PE
- Very painful
- Acute chest syndrome
12
Q
Sickle cell crisis: What is acute chest syndrome?
A
- Can be fatal (typically 2-3 days postop)
- Pneumonia-like, presence of new pulmonary infiltrate involving one complete lung segment
- Pulmonary vascular occlusion
- Pleuritic chest pain, dyspnea, fever (>38.5 C), acute pulmonary hypertension
- Transfusion or exchange transfusion to Hct of 30%
- Supplemental 02, inhaled nitric oxide (reduce pulmonary hypertension)
- Antibiotics
- Inhaled bronchodilators
- Aggressive pain management
- Monitor for pain crises, stroke, and infection
13
Q
Disorders of Hemoglobin Molecule:
Thalassemia Major: Review
A
- Inability to form either ⍺ (⍺-thalassemia) or β (β-thalassemia) globin chains of hemoglobin
- Severe- life-threatening anemia, often require repeated transfusions
- Hallmarks: ineffective erythropoiesis, hemolytic anemia and hypochromia with microcytosis
- Chronic deficit in O2 carrying capacity → max erythropoietin release → increased unbalanced globin synthesis → aggregation and precipitate formationà membrane damage
- Some cells destroyed in bone marrow → ineffective erythropoiesis
- Some escape into circulation →hemolytic anemia and hypochromia with microcytosis
14
Q
Thallasemia major: complications
A
- Extramedullary hematopoiesis → bone marrow hyperplasia (maxillary bone and frontal bone), stunted growth and osteoporosis, hepatomegaly
- Hemolytic anemia → splenomegaly, CHF, dyspnea and orthopnea
- Transfusion therapy → iron overload → cirrhosis and jaundice, right sided- heart failure, endocrinopathyà chelation therapy
- Increased risk infection (splenectomy)
- Arrhythmias and very sensitive to digitalis
- Spinal cord compression
15
Q
Clinical sequelae of iron overload (picture)
A
24
Q
Hereditary coagulation disoders (chart)
A
