Clinical aspects of anemia Flashcards
What is anemia?
It is the reduction in the RBC mass or blood hemoglobin concentration
Anemia is most commonly defined as a reduction in hematocrit (HCT) or Hemoglobin (Hb), Normal Hb in women <12, and <13.5 in men, while normal HCT in women is <36, and <41 in men
What is meant by red blood cell distribution width (RDW)?
It is the (standard deviation of RBC volume divided by the mean cell volume) * 100
- The normal value is 11-15%
- If the RDW is elevated it suggests a large variability in the sizes of RBCs
What are the different etiologies behind anemias?
1) Impaired cell formation
A: Deficiencies due to
- Decreased dietary intake
- Increased demand
- Decreased absorption
- Increased loss
B: Bone marrow failure
- Failure of a single or all cell lines
- Infiltration of the bone marrow
2) Blood loss
3) Hemolytic anemia
A: Corpuscular/membrane
- Sphorocytocis
- Enzymatic G6PD Deficiency
- Hemoglobin defects (sickle cell, thalassemia)
B: Extracorpuscular
- Immune
- Idiopathic
What are the different anemias that cause a low MCV <80?
- They are the hypochromic/microcytic anemia
1) Iron deficiency anemia
2) Thalassemia
3) Sideroblastic anemia
4) Chronic infection
5) Lead poisoning
6) Inborn errors of metabolism
7) Severe malnutrition
8) Copper deficiency
What are the different anemias that cause an increase in the MCV >100?
Macrocytic anemia:
1) Normal newborn
2) Increased erythropoiesis
3) Post splenectomy
4) Liver disease
5) Aplastic anemia
6) Megaloblastic anemia
7) Down S.
8) Obstructive jaundice
What are the different anemias that are associated with a normal MCV 80-100?
1) Acute blood loss
2) Infection
3) Renal failure
4) Connective tissue disorders
5) Liver disease
6) Disseminated malignancy
7) Early iron deficiency
8) Aplastic anemia
9) Bone marrow infiltration
10) Dyserythropoietic anemia
How to treat iron deficiency anemia?
- Oral iron supplementation: 4-6mg/kg/day
- You must stay within the treatment plan for 1-2 months to replenish all of the iron stores
- In cases of severe bowel disease, acute diarrhea disorder, gastrectomy, etc we give iron as a parenteral administration
What is the recommended dosage of vitamin B to avoid megaloblastic anemias?
> 2mg/day
What happens to neutrophils in folic acid deficiency?
The number of lobules will increase from the usual 3-5 to 8 lobules
How to detect the cause of vitamin B12 deficiency (chilling test)?
1) First, radioactive cyanocobalamin is given orally and its urinary secretion is measured to estimate cobalamin uptake. Low urinary secretion suggests pernicious anemia, a failure in intestinal transport, defective uptake of cobalamin in the terminal ileum, or a blind loop syndrome.
2) The second part is performed in the same manner, except that IF is given orally along with radioactive cyanocobalamin. If IF restores cobalamin uptake, the patient most likely has pernicious anemia. If not, an abnormality in cobalamin intestinal transport, defective absorption in the terminal ileum, or a blind loop syndrome might be responsible for the deficiency.
3) In the third phase, the patient is treated with antibiotics before the administration of radioactive cyanocobalamin. If antibiotics restore cobalamin uptake, the patient most likely has blind loop syndrome (bacterial overgrowth).
What is meant by hemolytic anemia, and what are its signs?
- It is a reduction in the life span of RBC, causing jaundice, splenomegaly, and reticulocytes in blood
What are the different classifications of hemolytic anemias?
1) RBC abnormality (intracorpuscular factors)
A.Hereditary:
- Membrane defects (spherocytosis, elliptocytosis)
- Metabolic defects (G6PD, and PK deficiency)
- Hemoglobinopathies (unstable hemoglobin, thalassemia, and sickle cell anemia
b. Acquired:
- Membrane abnormality-paroxysmal nocturnal hemoglobinuria (PNH)
What is meant by spherocytosis?
It is an Autosomal dominant condition, that is most often diagnosed in childhood, a disorder of the red blood cell membrane leading to chronic hemolytic anemia, where the patients have an abnormality in spectrin and actin of the membrane of RBC, it will result in an RBC with a low S.A to volume ratio, that forms spherical shape RBC (as it is less deformable) and they won’t be able to pass through the splenic fenestrations, and thus hemolyzed there which might cause gallstones, and cholecystitis attacks
How to diagnose spherocytosis?
1) Positive family History
2) Splenomegaly
3) Spherocytes and increased reticulocytes on blood smear
4) Microcytic, hyperchromic indices
5) Osmotic fragility test (swelling and hemolysis by hypotonic media)
What is the treatment for spherocytosis?
1) Folic acid 1mg/day
2) Splenectomy
What are the laboratory diagnosis of hemolytic anemias?
- Laboratory features
- normocytic/macrocytic, hyperchromic anemia
- reticulocytosis
- antiglobulin Coombs’ test is positive (tests for antibodies that act against your red blood cells)
- Indirect hyperbilirubinemia
- Blood smear
- anisopoikilocytosis, spherocytes
- schistocytes
- Bone marrow smear
- erythroid hyperplasia
What are the different treatments for different types of hemolytic anemias?
1) Treat underlying cause
2) Remove the cause (Fava beans)
3) Blood transfusion for Anemias
4) Steroids if Coombs +
5) Splenectomy
Describe the anemia that occurs due to a deficiency in G6PG
- The most common disease that produces enzyme abnormalities in humans, this enzyme is involved in the pentose phosphate pathway, which is important for the synthesis of RBC
- G6PD protects the RBC from the effects of potentially harmful oxidative molecules
- It is caused by 400 different mutations in the gene coding for G6PD
- Only a few of them will cause clinical symptoms
- All patients with favism show G6PD dehydrogenase deficiency
- In G6PD deficiency RBC destruction can be triggered by infections, severe stress, certain food (fava beans), drugs, etc
What is a characteristic feature of RBC in G6PD deficiency?
They appear as Heinz bodies (due to the fact that their Hb is phagocytosis by macrophages)
What is the treatment of G6PD?
1) Treat infection if present
2) Avoid and remove drugs or food if taken
3) Blood transfusion in some cases
4) Educate the patient about offending agents
5) Folic Acid Should be used in any disorder featuring high red cell turnover
What is the hallmark of sickle cell anemia?
Pain especially around the joint
What are the signs and symptoms of sickle cell anemia?
1) Acute and chronic pain
2) Bone pain often due to bone marrow infarction
3) Chronic hemolytic anemia
4) Splenic sequestration: onset of life-threatening anemia with the rapid enlargement of the spleen and high reticulocyte count
5) Hand-foot syndrome: This is a dactylitis presenting as bilateral painful and swollen hands and/or feet in children
6) Growth retardation, delayed sexual maturation, being underweight
7) Stroke in case of cerebral BV occlusion
What is the treatment of Sickle cell anemia?
1) Oxygen
2) Hydration
3) Pain management
4) Anemia management (blood transfusion)
5) Treatment of infection
6) Hydroxyurea/glutamate (a drug that decreases the vasso-occlusive crisis)
7) It is cured by a bone marrow transplant
What is thalassemia?
- A genetic disorder that impairs the production of either the a-globin chain or the b-globin chain
- B-thalassemia is mostly due to point mutations in one or both b-globin genes located at chromosome 11 (one on each chromosome)
- A-thalassemia is due to deletion of one or more a-globulin genes on chromosome 16 (which has two genes on each chromosome)
- Silent carrier, Hemoglobin H disease, and Hydrops fetalis (a-thalassemia major) are the different types of a-thalassemia, they cause severe microcytic anemia, splenomegaly, jaundice, hepatomegaly, and thalassemia facies
What are the clinical features of thalassemia?
1) Failure to thrive in early childhood
2) Anemia
3) Jaundice, usually slight, gallstones
4) Hepatosplenomegaly, hypersplenism
5) Abnormal facies: prominence of malar eminence, frontal bossing, depression of bridge of the nose, exposure of upper central teeth
6) Skull radiographs showing hair-on-end appearance due to the widening of diploid spaces
7) Fractures due to marrow expansion and abnormal bone structure
8) Growth retardation, primary amenorrhea, delayed puberty in males
9) Leg ulcers
10) Skin bronzing
- If untreated, 80% of patients die in the first decade of life
What is the microscopic photo of thalassemia?
1) Severe hypochromic anemia
2) Microcytic RBC
3) Prominent target cells
4) Spherocytic cells
5) Thalassemia minor is usually discovered by mistake
6) Reticulocytosis
7) Increased Hb-F & Hb-A2
How to manage thalassemia?
1- Transfusion therapy (when Hb falls <7g/dl)
2- Chelation therapy to maintain serum ferritin close to 1000 ng/ml
3- Splenectomy to reduce the transfusion requirements
4- Bone marrow transplantation
What are the complications of thalassemia?
1) Endocrine disturbance
2) Liver failure
3) Cardiac failure due to myocardial iron overload
4) Bony deformities
5) Osteoporosis
Different some other types of anemia that are caused by genetic disorders
1) Fanconi anemia:
- Short stature
- Spots on the tongue
- Thumb anomalies
2) Dyskeratosis Congenita:
- Mucocutaneous triad of dysplastic nails
- Lacy reticular pigmentation of the skin
- Oral leukoplakia
3) Shwachman-Diamond syndrome
- Pancreatic insufficiency
- Bone marrow dysfunction
- Skeletal abnormalities
