Anaemia

There are several different types of anaemia and each one has a different cause.
Etiologies

1. Production defects:

Nutritional deficiencies-Vitamin B12, folate or iron deficiency.
Inflammation/chronic disease.
Primary marrow disorders-pure red cell aplasia, myelodysplasia.

2. Sequestration (hypersplenism)-usually associated with mild pancytopenia.

3. Dilutional-common in hospitalized patients. Patient's plasma volume increase with laying down and also when they quit smoking. May be responsible for as much as a 3-6% drop in the hematocrit in the first two days of hospitalization.

4. Blood loss.

5. Blood destruction.

Classification
In general, there are three major types of anemia, classified according to the size of the red blood cells:

1. If the red blood cells are smaller than normal, this is called microcytic anemia(MC 80fl). The major causes of this type are iron deficiency anemia and thalassemia (inherited disorders of hemoglobin).
2. If the red blood cells size are normal in size (but low in number), this is called normocytic anemia(MC 80 – 100 fl), such as anemia that accompanies chronic disease or anemia related to kidney disease.
3. If red blood cells are larger than normal, then it is called macrocytic anemia(MC > 100 fl). Major causes of this type are pernicious anemia and anemia related to alcoholism.

Haemolytic anaemias do not fall elegantly into the above classification.
Symptoms
The non-specific symptoms and signs

•

Decreased oxigen transport: Fatigue, syncope, dyspnoea, angina

•

Reduced blood volume: Pallor, postural hypotension

•

Increased cardiac output: Pounding in ears, palpitations

•Congestive cardiac failure: Othopnoea, paroxysmal nocturnal dyspnoea; tachycardia, raised central venous pressure, displaced apex beat, gallop rhythm, basal crackles, bilateral ankle oedema
Specific features of different types of anaemia

Diagnosis
Exams and Tests
Lab tests for anemia may include the following:

• Complete blood count: Determines the severity and type of anemia (microcytic anemia or small sized red blood cells, normocytic anemia or normal sized red blood cells, or macrocytic anemia or large sized red blood cells) and is typically the first test ordered.
• Stool hemoglobin test: Tests for blood in stool which may detect bleeding from the stomach or the intestines.
• Peripheral blood smear: Looks at the red blood cells under a microscope to determine the size, shape, number, and color as well as evaluate other cells in the blood.
• Iron level: An iron level may tell the doctor whether anemia may be related to iron deficiency or not. This test is usually accompanied by other tests that measure the body's iron storage, such as transferrin level and ferritin level.
• Transferrin level: Evaluates a protein that carries iron around the body.
• Ferritin: Evaluates at the total iron available in the body.
• Folate: A vitamin needed to produce red blood cells, which is low in people with poor eating habits.
• Vitamin B12: A vitamin needed to produce red blood cells, low in people with poor eating habits or in pernicious anemia.
• Bilirubin: Useful to determine if the red blood cells are being destroyed within the body which may be a sign of hemolytic anemia.
• Lead level: Lead toxicity used to be one of the more common causes of anemia in children.
• Hemoglobin electrophoresis: Sometimes used when a person has a family history of anemia; this test provides information on sickle cell anemia or thalassemia.
• Reticulocyte count: A measure of new red blood cells produced by the bone marrow
• Liver function tests: A common test to determine how the liver is working, which may give a clue to other underlying diseases causing anemia.
• Bone marrow biopsy: Evaluates production of red blood cells and may be done when a bone marrow problem is suspected.

Iron Deficiency:
1. RBC indices are of little diagnostic value unless the MCV is below 70fl which is only seen in iron deficiency and thalassemia.

2. Serum iron can be decreased in a variety of states including iron deficiency, inflammation and stress. The serum iron level varies tremendously from morning to evening and from day to day. The minuscule amount of iron in a multi-vitamin can falsely elevate the serum iron for up to 24 hours.

3. The total iron binding capacity is very specific for iron deficiency (near 100%) but has poor sensitivity (less than 30%).

4. The iron saturation (Fe/TIBC x 100) can be decreased below sixteen percents
in both anemia of chronic disease and iron deficiency and is of little help in
distinguishing between the two.

5. In the normal patient the serum ferritin is directly correlated with iron stores. This relationship holds true even in inflammatory states although the curve is "shifted to the left". That is, for a given level of storage iron in a patient with an inflammatory state the serum ferritin is higher. A ferritin level of greater than 100ng/ml rules out iron deficiency anemia in any patient. The only exception are in acute hepatitis or liver necrosis (but not chronic liver disease) when the serum ferritin will be massively elevated due to release of liver stores of iron. Ferritin may be falsely elevated also in disseminated TB and Hodgkin's disease. Despite these minor exceptions, the measurement of the serum ferritin is the most useful and cost effective test of iron stores.

Differential Diagnosis
Microcytic Anemia:

1. IRON DEFICIENCY. The lack of iron results in decreased hemoglobin available to the developing red cell. Thus the erythrocytes that are produced are underhemoglobinized which result in smaller cells. The earliest sign of iron deficiency is decreased iron stores. This stage has a normal CBC and indices,
although one can see microcytic/hypochromic cells on the smear. The anemia gradually evolves into the classic microcytic- hypochromic anemia. Diagnosis is made by showing decreased iron stores on bone marrow examination. Biochemically the diagnosis is establish by a high TIBC or a low ferritin. The major
diagnostic difficulty is distinguishing iron deficiency from anemia of chronic disease.

2. ANEMIA OF CHRONIC DISEASE. (anemia of defective iron utilization). In patients with inflammatory states iron is sequestered in the RE system and is unavailable for use by the developing red cell (defective iron utilization). Thus at the erythrocyte level the defect is identical to iron deficiency and therefore results in production of underhemoglobinized red cells. This can result in a microcytic/hypochromic anemia. Additional factors including shortened red cell survival and decrease responsiveness to erythropoietin add to the hypoproliferative state. The inflammatory state also leads to a decreased serum iron and decreased TIBC. Recently the spectrum of diseases associated with anemia of chronic disease has expanded. Besides the classic association of temporal arteritis (may be a presenting sign), rheumatoid arthritis, cancer etc., anemia of chronic disease has been found in patients with non-inflammatory medical conditions such as congestive heart failure, COPD and diabetes. Patients with anemia of chronic disease can have hemoglobins decreased into the lower 20% range and many (20-30%)will have red cell indices in the microcytic range. Diagnosis is made by demonstrating ample bone marrow iron stores with decrease sideroblasts (iron containing red cell precursors). Biochemically anemia of chronic disease is a diagnosis of exclusion. The key test is to rule out iron deficiency. The RDW is of ABSOLUTELY no value in differentiating anemia due to iron deficiency from those associated with chronic disease. The serum iron is decreased in both conditions and the TIBC is low in states where iron deficiency and chronic disease co-exists thus rendering these tests useless. The finding of an elevated ferritin over 100ng/ml is an adequate demonstration of good iron stores. In the older patient or one with back pain, one should also rule-out the presence of multiple myeloma by perform a serum protein electrophoresis. In difficult cases one can resort to assessing bone marrow stores of iron.

3. THALASSEMIA. In this disorder it is the defective production of hemoglobin that leads to microcytosis. The main types are the beta-thalassemia, alpha-thalassemia and Hemoglobin E. Patients who are heterozygotes for beta-thalassemia have microcytic indices with mild (30ish) anemias. Homozygotes have very severe anemia. Peripheral smear in heterozygotes reveals microcytes and target cells. Diagnosis is established in by hemoglobin electrophoresis which shows an increased HbA2. One should check iron stores since an elevated HbA2 will not be present in patients with both thalassemia and iron deficiency. Beta-thalassemia occurs in a belt ranging from Mediterranean countries, the Middle East, India, Pakistan to Southeast Asia. Patients with beta-thalassemia trait who are of child bearing age need to have their spouse screened for beta-thalassemia and Hemoglobin E. Alpha-thalassemia also presents with microcytosis. Patients with alpha-thalassemia will have normal hemoglobin electrophoresis. The diagnosis of alpha-thalassemia is made by excluding other causes of microcytosis, a positive family history of microcytic anemia, and a life-long history of a microcytic anemia. Exact diagnosis requires DNA analysis. Alpha-thalassemia is distributed is a similar pattern to beta-thalassemia except for it very high frequency in Africa (up to 40%). Hemoglobin E is actually an unstable beta-hemoglobin chain that presents in a similar fashion to the thalassemia. It is believed to be the most common hemoglobinopathy in the world. Hemoglobin E occurs in Southeast Asia, especially
in Cambodia, Laos and Thailand. Patients who are heterozygotes are not anemic but are microcytic. Patients who are homozygotes are mildly anemic with microcytosis and target cells. The importance of Hemoglobin E lies in the fact that patients with both genes for Hemoglobin E and beta-thalassemia have severe anemia and behave in a similar fashion to patients with homozygote beta-thalassemia.

4. SIDEROBLASTIC ANEMIA. Defective production of the heme molecule is the basis of this disorder. The deficit of heme leads to the underhemoglobinazation of the erythroid precursors and microcytosis. Sideroblastic anemia can be congenital, can be due to toxins such as alcohol, lead, INH, or can be an
acquired bone marrow disorder. The peripheral smear may show basophilic stippling in lead poisoned patients, a dimorphic (macrocytic and intensely microcytic red cells) in patient with acquired sideroblastic anemia, or stigmata of a myelodysplastic syndrome. Diagnosis is made by the finding of ringed sideroblasts on the bone marrow iron stain. Iron studies in patients with sideroblastic anemia usually show sign of iron-overload.

Hemolytic Anemias

Hemolytic anemias are either acquired or congenital. The laboratory signs of hemolytic anemias include:
1. Increased LDH (LDH1)-sensitive but
not specific.
2. Increased indirect bilirubin-sensitive
but not specific.
3. Increased reticulocyte count -
specific but not sensitive
4. Decreased haptoglobin-specific but
not sensitive.
5. Urine hemosiderin-specific but not
sensitive.
The indirect bilirubin is proportional to the hematocrit, so with a hematocrit of 45% the upper limit of normal is 1.00 mg/dl and with a hematocrit of 22.5% the upper limit of normal for the indirect bilirubin is 0.5mg/dl. Since tests for hemolysis suffer from a lack of sensitivity and specificity, one needs
a high index of suspicion for this type of anemia. In autoimmune hemolytic anemias (AIHA) one usually see microspherocytes on the peripheral smear and splenomegaly may be present on exam. The diagnosis is
established by the finding of a positive direct antibody test (direct Coombs). AIHA may be idiopathic or associated with malignancies, drugs or other autoimmune disorders. Not all patients with a positive direct antibody test will have AIHA.
Microangiopathic hemolytic anemias are hemolytic anemias in which intravascular destruction of red cells is present. One sees schistocytes in the peripheral smear and an elevated LDH. The most common associated diseases are disseminated intravascular coagulation, thrombotic thrombocytopenic purpura,
hemolytic-uremic syndrome, aortic valvular disease or the presence of an artificial heart valve.
Paroxysmal nocturnal hemoglobinuria is an acquired hemolytic anemia that is due to a clonal proliferation of erythrocytes abnormally sensitive to the action of compliment. Hemolysis may be more conspicuous at night leading to the characteristic hemoglobinuria. The routine lab abnormalities of hemolysis are present. The diagnosis is made by performing a Ham's test (acid-serum lysis) which is based on the abnormal cells unique sensitivity to complement.
The most common congenital cause of hemolysis is hereditary spherocytosis. In this disease the red cell membrane is abnormal leading to increased splenic destruction. Spherocytes are present on the peripheral smear and splenomegaly is present on exam. Patients often have a family history of gallstones. The
laboratory values are consistent with hemolysis and the MCHC is elevated. The diagnosis is established by the finding of increased osmatic fragility. Other rare causes of hereditary hemolysis includes hereditary elliptocytosis.
Enzyme deficiencies such as glucose-6-phosphate dehydrogenase deficiency are also important causes of hereditary hemolytic syndromes. The same population at risk for thalassemia are also at risk for G-6-PD deficiency. It is sex linked and thus only affects males. This defect is in the hexose monophosphate shunt and renders the RBC to be unable to withstand oxidative stress. Most people with this disease have hemolysis only with such stressors as infections and intake of oxidative drugs. There are two main subtypes-African (A-) and Mediterranean which tends to be more severe. Such drugs as dapsone and sulfamethoxazole may provoke severe hemolysis in these patients. Diagnosis is establish by measuring
enzyme activity. Since the reticulocyte has increased G-6-PD activity one may get a false negative normal level during times of hemolysis.
Macrocytosis
Round macrocytosis-due to abnormal lipid composition of the erythrocyte membrane. Common etiologies include:
1. Alcoholism.
2. Liver Disease.
3. Renal Disease.
4. Hypothyroidism ("myxedema of the
red cell").

Oval macrocytosis (macroovalocytes) is a sign of problem with cell DNA replication. The developing red cell has difficulty in undergoing cell division but RNA continues to be translated and transcribed leading to growth of the cytoplasm while the nucleus lags behind. Often one or more cell division are skipped leading to a larger than normal cell. Common causes are:
1. Drug effect including cytotoxic
chemotherapy.
2. Folate Deficiency
3. Myelodysplasia
4. Vitamin B12 deficiency
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Folate/Vitamin B12 deficiency
Although the classic sign of these two nutritional deficiencies is a megaloblastic anemia, many patient who are folate or vitamin B12 deficient will have a normal MCV. This is due to co-existing microcytic anemia or can be seen in early stages of the anemia. All patients who are folate and vitamin B12
deficient will have macroovalocytes and hypersegmented neutrophils (six or greater lobes in one neutrophil or greater than 5% with five lobes) present on careful review of the smear.
It is now being realized that a presenting sign of vitamin B12 depletion is neuropsychological problems. This can occur in patients with low-normal vitamin B12 levels. These include paresthesia, ataxia, weakness, reflex changes and orthostatic hypotension. In fact non-anemic patients may have the worst
neurologic defects. Although some of these patients are not anemic, macroovalocytes and hypersegmented neutrophils are present on the smear. Low normal vitamin B12 levels in patients with neuropsychological problems or in the elderly may represent a true deficient state and should not be ignored. The role
of the Schilling test remains controversial in the management of vitamin B12 deficiency. One use is in the young patients to better define the "lesion" in vitamin B12 metabolism. For best results patients should be replaced with vitamin B12 2 months before the test to allow for the intestinal mucosa to heal
and prevent misdiagnosis of a malabsorption syndrome.
Since vitamin B12 absorption is complex, many patient are at risk for deficiencies. These would include the elderly (achlorhydria); patients with pancreatic insufficiency, small bowel disease, and autoimmune disorders (pernicious anemia).
Folate deficiency is due to malabsorption or nutritional deficiency. Patients at risk include alcoholics, patients with hemolysis, pregnant patients, goat's milk imbibers, and patients on dilantin. Prophylactic administration of folate may be indicated in these at risk patients. Red cell folate is the most accurate diagnostic test. One must be sure of adequate vitamin B12 store before initiating folate replacement to prevent exacerbation of any neuropathy induced by vitamin B12 deficiency.
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Myelodysplasia
The myelodysplastic syndromes are a group of bone marrow diseases marked by various cytopenias, morphologically abnormal blood cells, dysplastic bone marrow changes and a propensity to evolve into acute leukemia. The changes on the peripheral smear can range from very abnormal looking blood smears to subtle changes. Hallmarks on the peripheral smear are pseudo-Pelger Huet cells (two-lobed neutrophils), macroovalocytes and hyposegmented neutrophils. This is commonly a disease of older patients and manifests itself as an anemia with normal iron, vitamin B12, and folate studies. Often these patients are misdiagnosed and treated ineffectually with iron or vitamin shots. Another group of patients in whom the myelodysplastic syndromes are common is patients who have undergone therapy for malignancy. Diagnosis is by bone marrow examination. Often cytogenetic abnormalities will be present and aid in diagnosis and assessing prognosis.
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Aplastic Anemia/Pure Red Cell Aplasia
Destruction of the hemopoietic cells of the marrow by whatever means leads to the clinical condition of aplastic anemia. The patient with this condition presents with pancytopenia. A thorough history should be taken from the patient to try to identify any possible drug or toxin exposure, although in most patients the cause is unknown. Splenomegaly is absent. The peripheral smear shows a decreased number of normal red cells. Diagnosis is established by bone marrow biopsy which reveals a hypocellular marrow. Since paroxysmal nocturnal hemoglobinuria can initially present as aplastic anemia, when marrow functions recovers, a Ham's test should be preformed. In young patients with aplastic anemia, bone marrow transplantation is the treatment of choice. Since prognosis significantly worsen in these patients if they had receive transfusion, one should not transfused these patients unless absolutely necessary.
Pure red cell aplasia is the condition where the red cell precursor are selective destroyed. Since this condition can be associated with thymomas (and responsive to its removal), this should be sought with radiographic studies. Parvovirus B19, which is selectively toxic to the developing red cell, can cause
a chronic infection which leads to clinical picture resembling pure red cell aplasia in susceptible patients. Parvovirus infection is also hazardous in patients dependent on increased RBC production such as those with congenital hemolytic anemia or sickle cell anemia. In those patients parvovirus infection
may lead to a dramatic "aplastic crisis".
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Anemia and Alcoholism
Anemia of complex etiologies is often present in the alcoholic patient. Alcohol has a direct toxic effect on the bone marrow which leads to decreased red cell production. Folate metabolism is also interfered with leading to functional folate deficiency. This is aggravated by the poor dietary intake of folate by alcoholics and impaired absorption of folate in these patients. The alcohol abusing patient may also have increased blood losses due to gastrointestinal bleeding and trauma. Hypersplenism due to liver disease can be a contributing factor to the anemia. This group of patients will often have co-existent inflammatory states which will lead to defective iron utilization. Heavy alcohol use
can even lead to a sideroblastic anemia.
Diagnosis of specific defects in the alcoholic can be difficult due to the myriad of problems. The serum ferritin is a dependable gauge of marrow iron stores. Although the MCV may be normal, most alcoholics with folate deficiency will have either macroovalocytes or hypersegmented neutrophils present on the
peripheral smears. Sources for blood lost should be aggressively sought. Often a bone marrow examination is required to fully elucidate the etiology(s) of the anemia.
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Anemia and HIV Disease
Patients infected with HIV can also be anemic for multiple reasons. HIV infection itself leads to decreased hematopoiesis through multiple direct effects on the bone marrow. Opportunistic infections such a MAI, histoplasmosis and other pathogens can infect the marrow. Chronic infection with parvovirus B19 can lead to a profound anemia. Marrow invasion by malignancies such as non-Hodgkin's lymphoma and Kaposi's sarcoma may be a cause of anemia. AZT is toxic to hematopoietic cells, especially red cell precursors and its use leads to a megaloblastic anemia. Other drugs such as DHPG and trimethoprim-sulfa can have marrow suppressive effects. Since the gastrointestinal tract is often a target of many infections, this can be a major portal of blood loss. Malabsorptive syndromes have been reported in HIV disease and when combined a with poor nutritional status can lead to deficiency of folate and vitamin B12.
The anemic patient with HIV disease should receive aggressive evaluation to rule out reversible causes of anemia. Nutritional deficiency should be sought out by appropriate testing. The direct antibody test (direct Coombs) is often positive in this group of patients without signs of clinically apparent hemolysis and should be disregarded unless there is evidence of on going hemolysis such as microspherocytes. In patients with profound anemia and a very low reticulocyte count a bone marrow should be done to look for parvovirus B19 infection. Pure red cell aplasia secondary to AZT has been reported. Bone marrow biopsy can also show marrow invasion by tumor or pathogens. Erythropoietin levels should be measured because patient with levels of less than 500u/ml are responsive to this hormone. Since blood transfusion are immune-supressive, it may be preferable to treat anemic AIDS patients with erythropoietin.

General Treatment

Medical treatment of anemia varies widely and depends on the cause and the severity of anemia.

• if anemia is mild and is found to be related to low iron levels, then iron supplements may be given during further investigation to determine the cause of the iron deficiency is carried out. Iron may be taken during pregnancy and when iron levels are low. It is important to determine the cause of iron deficiency and treat it properly.

·On the other hand, if anemia is related to sudden blood loss from an injury or a rapidly bleeding stomach ulcer, then hospitalization and transfusion of red blood cells may be required to relieve the symptoms and replace the lost blood. Further measures to control the bleeding may occur at the same time to stop further blood loss.

·Blood transfusion may be required in other less critical circumstances as well.

• Vitamin supplements may replace folate and vitamin B12 in people with poor eating habits. In people with pernicious anemia who are unable to absorb sufficient amounts of vitamin B12, monthly injections of vitamin B12 are commonly used to replete the vitamin B 12 levels and correct the anemia.
• epoetin alfa (Procrit or Epogen) injection can be used to increase red blood cell production in people with kidney problems. The production of erythropoietin is reduced in people with advanced kidney disease, as described earlier.
• Stopping a medication that may be the cause of anemia may also reverse anemia after consultation with a physician.
• If alcohol is the cause of anemia, then in addition to taking vitamins and maintaining adequate nutrition, alcohol consumption needs to be stopped.