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Treatment of RBC disorders

Terms in this set (21)

Treatment of Iron deficiency
When iron deficiency is treated with iron, the lab will be normal within weeks and may need up to 6 months of supplementation. The preparations are either oral/ parenteral iron. The most common type of iron used is oral iron ( it is also the cheapest form of iron).
Ferrous Sulfate
This is oral iron. This is the most widely used iron and the cheapest form. It is taken orally and is usually 300 mg. The side effects are

1. Nausea
2. Epigastric pain
3. Abdominal cramps
4. Constipation
5. Diarrhea

Patients usually develop black stool.
Parenteral Iron
This form of iron is usually given to patients who cant take oral iron or cant be managed with oral iron alone. This form of iron is usually given to patients who are on dialysis due to chronic kidney disease and those who are taking EPO. There are three forms

1. Iron dextran : IM/IV; this is a stable complex of ferric oxygydroxide and dextran polymers (allows for slow fe3+ release)
2. Iron sucrose complex: IV
3. Sodium ferric gluconate complex: IV

The side effects are headache, lightheadness, fever, nausea, vomiting, back pain, bronchospasm (hypersensitivity), Arthralgia, flushing, iron overload (hemochromatosis), anaphylactic shock (hypersensitvity), and death.

Patients should be monitored by checking iron storage levels (ferritin and transferrin saturation).
Deferoxamine (Desferal)
This is a water soluble compound. It is an iron chelator that is used to treat acute and chronic iron toxicity ( inherited and acquired hemochromatosis). The preferred route of administration is IM/ SC. IV can cause hypotension and neurotoxicity and increased susceptibility to infection with long term use. The Deferoxamine- iron complex is secreted in urine and feces.
Acute Iron toxicity
This usually occurs in children and can be due to accidental ingestion of 10 pills (300 mg each). Symptoms that occur are
1. necrotizing gastroenteritis
2. vomiting
3. bloody diahrea
4. abdominal pain
5. shock
6. lethargy
7. dyspnea

All of the symptoms above can eventually lead to shock, metabolic acidosis, and death.
Treatment of Acute Iron toxicity
1. Whole bowel irrigation ( to rid of unabsorbed iron and monitoring remaining iron via x-ray).
2. Deferoxamine: iron chelator
3. Supportive therapy: to treat symptoms such as GI bleeding, shock (fluids), metabolic acidosis( bicarbonate)
Chronic Iron Toxicity
Can be acquired due to constant blood transfusions or inherited. Hemochromatosis is a condition that leads to iron deposition on organs (heart, lungs, liver, pancreas) and can lead to organ failure.
Treatment of chronic iron toxicity
Identify if the patient is anemic or not.

Not anemic: phelebotomy: with unite of blood removed per week until the excess iron is removed

Anemic: IM deferoxamine or oral deferoxamine
B12 (cobalamin)
Cobalamin is usually ingested as 5-30 micrograms daily in the american diet. Of that amoung only 1-5 micrograms are absorbed. After entering the stomach via R- binders (transcobalamin I), pancreatic proteases degrade the R- binders and B12 is complexed with intrinsic factor which is made by gastric mucosal parietal cells. The intrinsic factor- B12 complex travels to the ileum where it is absorbed and transported to the liver via transcobalamin II. Trace amounts of B12 is lose in the urine.

Remember that B12 is mainly found in meat not vegetables thus veganism can cause B12 deficiency too.

B12 is required for
1. folate production via one carbon transfer
2. conversion of methylmalonyl- coA to succinyl coA as a cofactor of methylmalonyl coA mutase

Deficiency of B12 can lead to anemia because of folate deficiency (folate is needed to make thymidine thus DNA synthesis impairement). This results in megaloblastic anemia.
Causes of B12 deficiency
Causes of B12 deficiency are
1. autoimmune disease; pernicious anemia is a result of antibodies made against the gastric mucosal parietal cells thus no intrinsic factor for B12 transport for absoroption.
2. Partial/ total gastrectomy
3. Malabsorption syndrome
4. small bowel resection
5. Drugs ( nitrous oxide (N2O), alcohol (liver), PAS (paraaminosalicylic acid)
6. veganism

Symptoms
1. Megaloblastic Anemia
2. Neurological syndrome
Treatment of B12 deficiency
Preparations of IM B12 and oral for patients who can't/ wont tolerate injection. There are two preparations,

1. Cyanocobalamin
2. Hydroxycobalamin: highly protein bound and remains in circulation longer
Folate
Dietary folate is primarily in the polyglutamate form and has to be hydrolyzed to remove all nut one glutamate for absorption at the brush border of the intestinal mucosa. It is cleared by alpha- 1- glutamyltransferase and either stored in the liver, excreted in the urine/ stool, or destroyed by catabalism. 5-20 mg of folate is stored in the liver with some are unaltered and absorbed in the jejunum. Because the body's stores of folate are relatively low and daily requirements are high, folic acid deficiency and megaloblastic anemia can develop 1-6 months after the intake of folic acid stops depending on the patient's nutritional status and rate of folate utilization.
Folate deficiency
Causes/ clinical use of folate
1. Treatment of megaloblastic anemia due to folate deficiency
2. anemia due to drugs that inhibit dihydrofolate reductase (methotrexate, trimethoprim, pyrimehtamine).
3. Alcoholism
4. Phenytoin(Dilantin)
5. Dialysis: removes folate from the blood and causes a deficiency
6. chemotherapy
7. pregnancy: increased requirement

Measure serum/ rbc folate to determine if there is a deficiency
Preparations and Drug Interactions
1 mg daily. The goal is to
1. reverse megaloblastic anemia
2. restore serum folate levels
3. replenish folate stores

Drug Interactions
1. Tetracycline: folate reduces absorption
2. Phenytoin (Dilantin): Folate reduces the action
3. Pyrimethamine (antimalarial drug): folate increases its levels
EPO
EPO is a glycoprotein that is produced in peritubular cells in the proximal tubule of the kidney. A small amount is synthesized in the liver. It has a serum half life of 4-13 hours in patients with chronic kidney failure. EPO induces erythrocyte proliferation and differentiation and induces the release of reticulocytes from bone marrow. It activates the EPO receptor and regulates gene expression via JAK/STAT pathway. EPO is used for
1. Patients with chronic kidney failure with secondary anemia
2. Anemia due to HIV therapy
3. Anemia due to myelosuppressive cancer chemotherapy to reduce need for transfusion.
4. Patients undergoing elective non- cardiac, non- vascular surgery ( to reduce need for transfusion).

It can also be given to patients with low risk of myelodysplastic syndromes and anemias requiring blood transfusion.
EPO preparations
1. Epoetin alfa (Procrit)- IV/SC twice/ week
2. Darbepoetin (Aransespo)- IV/ SC weekly; it has a longer half life.

Patients with chronic kidney disease on EPO requires iron supplementation.

Side effects are
1. Hypertension
2. Thrombotic complications
3. Allergic reactions (infrequent)

The black box warning (clinical trials) show that it may increase the risk of tumor progression and recurrence in cancer patients. In patients with renal failure, it increases the risk of mortality, stroke, and cardiovascular and thromboembolic events.
Treatment of Aplastic Anemia
1. No treatment if it is mild to moderate aplastic anemia.
2. Severe Aplastic Anemia can be treated by blood transfusions, blood and marrow stem cell transplants, and immunosuppressive therapy.

Immunosuppressive therapy: Is usually given to patients who cannot undergo a bone or blood marrow transplant. Immunosuppression is a good option because it reduces T cell response/ driven immune response.
Anemias due to loss of rbc
Usually due to
1. Bleeding that is caused by GI ulcers, blood loss during menstrual cycle, and use of drugs that can irritate the GI tract like aspirin.
2. Hemolysis caused by

1. Sickle cell anemia
2. Thalassemias
3. G6PD
Treatment for Sickle Cell Anemia
Hydroxyurea aka hydroxycarbamide. It is used to prevent veno- occlusive event that are associated with sickle cell anemia. Hydroxyurea increases HbF concentration blood thus decreasing or interfering with HbS polymerization.

Adverse effects are hematopoietic depression, GI effects, teratogenicity in pregnant women. Hydroxyurea should be coupled with supportive treatment such as
1. Analgesia
2. Antibiotics
3. pneumococcal vaccinations
4. blood transfusions
Treatment for Thalassemias
Mild Thalassmia: No treatment
HbH disease: supplement folate and avoid oxidative drugs (sulfonamides).
Sever Thalassemia: Folate supplementation and regular blood transfusions. Splenectomy, deforoxamine due to transfusions and free iron that is not used to due to the disease (secondary hemochromatosis), and low iron diet.
G6PD Treatment
Give no treatment except for avoidance of oxidant drug.
1. Antimalarials
2. Sulfonamides
3. Nitrofurans (nitrofurantoin)
4. Phenylhydrozine
5. High doses of Aspirin
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