Anemia

Sample for Anemia

1. EDTA blood is needed.
2. For RBC morphology, a direct smear is preferred.`
3. Bone marrow is also advised.
4. Also, a bone biopsy may be needed.

Definition of Anemia

1. Anemia is defined as a decrease in hemoglobin concentration depending on the patient’s age and sex.
   1. The diagnostic criteria are low hemoglobin, low hematocrit (Hct), or decreased RBC count.

Criteria for the anemia:

1. Hemoglobin:
   1. Male = Hb <13.5 g/dL.
   2. Female = Hb 11.5 g/dL.
   3. 2 years to puberty = 11.0 g/dL.
   4. A Newborn = 14.0 g/dL is taken as a lower limit because of the high Hb.
2. Hematocrit (Hct)
   1. Male = <42%.
   2. Female = <37%.
3. In a broad sense, anemia is the blood’s inability to supply adequate O2 to the tissue for proper metabolism.
4. These are the most common hematological disorders.
5. The diagnosis is essential for the physician to treat the cause of anemia.

Effective erythropoiesis depends upon the following:

1. Level of iron and cobalt.
2. Vitamin B12.
3. Vitamin B6.
4. Riboflavin.
5. Thiamine.
6. Vitamin C.
7. Vitamin E.
8. Hormones like:
   1. Androgens.
   2. Thyroxine.

Types of Hemoglobin:

To understand the anemias, it is better to know the hemoglobin types and structure:

Type of hemoglobin	Structure of hemoglobin	Frequency of the hemoglobin
At birth
Hb F	α2 / γ2	60 to 90%
Hb A	α2 / β2	10 to 40%
At adult age
Hb A1	α2 / β2	>95%
Hb A2	α2 / δ2	<3.5%
Hb F	α2 / γ2	<1 to 2%

Role of hemoglobin in O2 transport (Hb/O2 dissociation curve):

1. The RBCs carry O2 from the lung to the tissue and bring CO2 in the venous blood to the lung.
2. This is dependent upon the 2,3-diphosphoglycerate (2,3-DPG).
3. When the O2 is unloaded, the β-chain of Hb has pulled apart, permitting the entry of the metabolites 2,3-DPG resulting in a lower molecule affinity for O2.

4. O2 saturation is an indicator of the % of Hb saturated with O2.
5. When 92% to 100% of the Hb carries O2, the tissues adequately provide the O2 supply, which means normal O2 dissociation.
6. Normally O2 exchange takes place:
   1. 95% saturated arterial blood with a mean arterial O2 tension of 95 mmHg.
   2. 70% saturated venous blood with a mean venous O2 tension of 40 mmHg.
   3. So the curve’s normal position depends upon the concentration of 2,3-DPG, H+ ions, and CO2 in the RBCs and the Hb molecule structure.

Hemoglobin functions:

1. RBCs in arterial blood carry O2 from the lungs to the tissue and take back CO2 in the venous blood.

1. This main function is with the help of hemoglobin (Hb) molecules, as the Hb molecule load and unload the O2.
2. α1β1 and α2β2 globin stabilize the molecule.

Anemia classification:

Anemia may be classified roughly based on Hb level:

1. Severe anemia when the Hb is <7 g/dL.
2. Moderate when the Hb is  7 to 10 g/dL. This group will not produce evident S/S. in most of the cases.

Anemia classification based on RBC morphology:

1. Normochromic and normocytic anemias are due to:
   1. Anemia of acute hemorrhage.
   2. Hemolytic anemia.
   3. Anemia due to chronic diseases.
2. Hypochromic and microcytic anemias are due to:
   1. Iron deficiency anemia.
   2. Thalassemia.
3. Normochromic and macrocytic anemias are due to:
   1. Vit. B12 deficiency.
   2. Folate deficiency.

Anemia classification based on physiological abnormality:

1. Defective maturation of erythropoiesis.
2. Hemolytic anemia where is the increased breakdown of the RBCs.
3. Defect due to an increase in RBC precursors compared to the degree of anemia.

Anemia classification based on etiology:

1. Increased RBCs destruction due to intra or extra red blood cell defects.
2. Increased blood loss, which may be acute or chronic.
3. Defective RBCs formation due to Lake of factors necessary for erythropoiesis.

Anemia classification based on the category:

1. increased destruction of the RBCs
   1. Hemolytic anemia (nonimmune).
   2. Immune hemolytic anemia.
2. Anemia due to blood loss in hemorrhage.
3. Nutritional deficiency like folate or vitamin B12 deficiency.
4. Toxicity due to drugs.
5. Infections.
6. Infiltration of the bone marrow by the cancer cells.
7. Hereditary or acquired defect in the RBCs.
8. Hematopoietic stem cell arrest or damage.
9. Idiopathic or unknown cause.

Anemia classification based on RBC indices:

1. Normocytic:
   1. MCV is 80 to 100 fl (femtoliter).
   2. MCHC = 32 to 36%
2. Macrocytic:
   1. MCV = >100 fl.
3. Microcytic and hypochromic.
   1. MCV = <80 fl.
   2. MCHC = <32%.
      

      Type of anemia	MCV fl	MCHC%
      Normocytic and normochromic	80 to 100	32 to 36
      Microcytic and hypochromic	<80	<32
      Macrocytic	>100

Differentiating points of various anemias:

Characteristics findings	Microcytic hypochromic	Normocytic normochromic	Macrocytic
MCV	<80 fl (decreased)	80 to 95 fl (normal)	>95 fl (increased)
MCH	<27 pg (decreased)	≥27 pg (normal)	Increased
MCHC	Decreased	Normal	Normal
Etiological factors	Iron deficiency Thalassemia Sideroblastic anemia Chronic diseases Lead poisoning	Hemolytic anemias After acute blood loss Bone marrow failure by chemotherapy or cancer infiltrates. Renal diseases	Vitamin B12 deficiency Folic acid deficiency Aplastic anemia Non-megaloblastic anemia due to: Alcohol use Liver diseases Myelodysplasia

Laboratory Criteria for the diagnosis of Anemias:

1. Hemoglobin when it is less than 12 to 13 G/dL.
2. Hematocrit when it is less than 36 to 41%.
3. Reticulocyte count was normal at 0.5 to 1.5%.
4. MCV is a better choice to classify the anemias and their differentiation. This is useful for the screening of occult alcoholism.
5. If MCV is high, then advise:
   1. Reticulocytes count.
   2. Vit.B12.
   3. Folate level.
6. If MCV is low, advised:
   1. Serum Iron.
   2. Iron binding capacity (TIBC).
   3. If the above two tests are low, advise Ferritin and Bone marrow examination.
   4. If normal, then advise electrophoresis.
7. If MCV is normal, then advise:
   1. Serum Iron.
   2. Iron Binding Capacity. (TIBC).
   3. Comb’s test.
   4. Peripheral blood for RBC morphology.

Routine workup of the patient with anemia needs:

1. The patient’s detailed clinical history for diagnosis, physical examination, signs, and symptoms with the following lab workup.
2. Hemoglobin and hematocrit.
3. Red blood cell count.
4. Blood indices.
5. MCH has limited value in the differential diagnosis of anemias. This is instrumental calibration.
6. MCHC is also instrumental calibration, and changes occur very late in the iron-deficiency anemia when anemia is very severe.
   1. This is better to evaluate hypochromasia than MCH.
7. Red cell distribution width (RDW) helps to classify the anemia with the help of MCV.
   1. RDW is more sensitive to the differentiation of the microcytic anemia than the macrocytic RBCs cause.
   2. This has no value in patients without anemia.
8. Serum iron (Normal = 50 to 150 µg/dL).
   1. Serum total iron helps in the diagnosis of anemia.
   2. It differentiates between hemochromatosis and hemosiderosis.
   3. It should be measured along with TIBC for evaluation of iron deficiency.
   4. This also helps to evaluate the acute iron toxicity in children.
9. Total iron-binding  capacity (TIBC = Normal = 250 to 450 µg/dL).
   1. It helps in the differential diagnosis of anemias.
   2. It should be done along with serum iron to evaluate the % saturation for the diagnosis of iron deficiency anemia.
10. Transferrin: Serum Transferrin level is needed for the D/D of the anemia.
11. Percent transferrin saturation (normal % transferrin saturation = 20% to 50%).
    1. Calculation of the % transferrin saturation = Serum iron ÷ TIBC x 100 = Transferrin normally 33% is saturated.
    2. This is used for the D/D of the anemias.
    3. This helps in the screening of hereditary spherocytosis.
12. Ferritin: Serum ferritin (normal = 20 to 250 ng/dL).
    1. It correlates with the total body iron stores.
    2. It differentiates iron deficiency or excess.
    3. It correlates with total body iron stores.
    4. It will predict and monitor iron deficiency.
    5. It will give an idea about the iron-deficiency anemia treatment effectiveness.
    6. It differentiates iron deficiency from chronic diseases.
    7. It monitors the iron status in patients with chronic kidney diseases with or without dialysis.
    8. It is used to study the population’s iron level and response to iron supplements.
    9. It can detect iron overload and monitor iron accumulation.
    10. It can help to guide the response to iron depletion therapy.
13. Peripheral blood smear.
    1. This will inform the abnormality of the RBC shape, size, and any kind of inclusions.
    2. There is a dimorphic picture in a mixed deficiency of iron, vitamin B12, or folate; there are microcytes and macrocytes. In this case, blood indices may be normal.
    3. Also, find the abnormal white cells and the assessment of the platelets.
    4. It can find the blast cells like normoblast or granulocytes blast cells.
14. Reticulocyte count.
    
    1. The normal range is 0.5 to 2.5%, and the absolute count is 25 to 125 x 10⁹/L.
    2. Reticulocytes are raised in anemia because of the erythropoietin raised level.
    3. After the acute hemorrhage:
       1. Erythropoietin level rises in 6 hours.
       2. Reticulocyte level increases in 2 to 3 days, and the peak level reaches 6 to 10 days.
       3. Reticulocytes will be raised until the Hb becomes normal.
    4. In the case of anemia, if there is no raised reticulocyte count, it means bone marrow abnormality or lack of erythropoietin stimulus.
15. White blood cells count and platelets count. This will rule out the pancytopenia from the anemia.
    
    1. In hemolysis or hemorrhage, the neutrophils and the platelets are raised.
    2. In leukemias also, the white cells are raised.
16. Bone marrow examination.
    1. Bone marrow may be aspirated or can take the biopsy.
    2. This will give the cellularity myeloid: erythroid ratio, presence of abnormal cells like cancer cells infiltrate.
    3. Can do Special stains like iron.

Signs and symptoms of the anemias:

Clinically S/S seen are:

1. The main symptoms are due to cardiovascular system adaptation.
   1. There are increased stroke volume, tachycardia, and the Hb O2 dissociation curve changes.
      1. Hyperdynamic circulation leads to tachycardia, a bounding pulse, systolic murmurs, especially at the apex, and cardiomegaly.
      2. Older adults may find S/S of congestive heart failure.
2. In some of the patients with anemia, there is no S/S, while mild anemia may have severe S/S.
3. Acute onset effect: There is an effect on the speed of onset; acute onset has more S/S compared to the slow onset.
4. The severity of the anemia: In the case of mild anemia, there is no S/S.
   1. When the Hb is <9 to 10 g/dL, it may show S/S.
   2. Even Hb as low as 6 g/dL may not produce severe S/S.
5. Age: Older people tolerate less as compared to young people.
6. There is pallor on the face, and better judged from the tongue.
7. The patient will feel weakness and fatigue.
8. There are lethargy and malaise.
9. On exertion, there is dyspnoea and palpitation.
   1. The older patients may have cardiac failure, angina, or intermittent claudication or confusion.
   2. There may cause retinal hemorrhage, and this may complicate anemia of rapid onset.
10. The patient may like to eat clay, ice, and starch.
11. The patient may have syncope after the exercise.
12. They may have dizziness and headaches.
13. There is tinnitus or vertigo.
14. Usually, these patients are irritable.
15. These patients may have gastrointestinal symptoms.
16. These patients may have difficulty sleeping or concentrating.

Specific Signs of anemia are:

1. K0ilonychia, which is spoon-shaped nails. This is usually seen in:
   1. Iron-deficiency anemia.
   2. Jaundice with hemolytic or megaloblastic anemia.
   3. Leg ulcers in Sickle cell anemia.
   4. Other hemolytic anemias.
   5. Bone deformities are seen in thalassemia and other severe congenital anemia.
   6. There may be infections and bruising with anemia due to bone marrow failure related to thrombocytopenia and neutropenia.

Normal adult blood indices values:

RBCs values	Male	Female
Hemoglobin (Hb g/dL)	13.5 to 17.5 g/dL	11.5 to 15.5 g/dL
Hematocrit (Hct % or Packed cell volume = PCV)	40 to 52 %	36 to 48%
RBC count	4.5 to 6.5 x1012 /L	3.6 to 5.6 x 1012/L
Mean cell volume (MCV)	80 to 95 fL
Mean cell hemoglobin (MCH)	27 to 34 pg
Mean cell hemoglobin concentration (MCHC)	30 to 35 g/dL
Reticulocytes count	25 to 125 x 109/L

Types of Anemias

Anemia is divided based on RBCs indices (MCV) into the following broad categories:

1. Microcytic, MCV <80 fl.
2. Normocytic, MCV 80 to 100 fl.
3. Macrocytic, MCV >100 fl.

Normochromic, Normocytic Anemia:

Lab findings:

1. Low hemoglobin.
2. Normal MCV 80 to 95 fL.
3. Normal MCH ≥27 pg.
4. Normal MCHC.
   1. Mostly these are due to acute blood loss.

The peripheral blood smear shows normal-looking RBCs and normal RBCs indices.

1. 1. The RBCs produced by the bone marrow are normal, but the number of RBCs in circulation is reduced for many reasons.

The causes of normochromic and normocytic anemia are:

1. Iron deficiency in the early stages.
2. Acute blood loss.
3. Chronic diseases of the kidneys and the liver.
4. Infiltration by leukemia and multiple myeloma.
5. Drugs like chloramphenicol cause aplastic anemia.
6. Acquired hemolytic anemia may be from the prosthetic surgery of the heart.
7. Pregnancy due to increased plasma volume.
8. Overhydration.

Microcytic, hypochromic anemia:

1. These are the most common type of anemia, and iron deficiency is the most common cause.

Causes of microcytic hypochromic anemia:

1. This is due to iron deficiency caused by decreased iron intake in the diet or impaired absorption.
2. Iron deficiency anemia.
3. Lead poisoning.
4. Thalassemia.
5. There may be an increased iron loss by chronic bleeding.
6. There may be an abnormality in iron metabolism.
7. Increased demand by the body in:
   1. Infancy.
   2. Pregnancy.
   3. Lactation.
8. Due to cancer.
9. Hemorrhoids.
10. Hookworms.
11. Drugs like salicylates (aspirin).

Lab findings of microcytic hypochromic anemia:

1. Low hemoglobin, males <12 g/dL and females <10 g/dL.
2. Low MCV <80 fL.
3. MCH < 27 pg.
4. Findings in the iron-deficiency anemia:
   1. Serum iron is deficient.
   2. TIBC is very high.
   3. Serum ferritin = <10 ng/dL
   4. Free RBCs protoporphyrin is high.
   5. RDW is high.
   6. RBC survival time is slightly less.
5. Peripheral blood smears show microcytes and pale, hypochromic RBCs.
   1. There may be leucopenia.
   2. Platelets are high in case of bleeding.
   3. Reticulocytes are low than expected in the degree of anemia.
6. Bone marrow shows erythroid hyperplasia.
   1. Iron stain shows deficient iron.

Macrocytic Anemia:

1. These are basically megaloblastic anemias resulting from the deficiency of vitamin B12, folic acid, or a combination of both two.

Lab findings of macrocytic anemia:

1. Low hemoglobin.
2. MCV > 99 fL.
3. The peripheral blood smear shows macrocytosis and many hypersegmented neutrophils.
4. Occasionally may see leucopenia and thrombocytopenia.

Causes of macrocytic anemia:

1. Vitamin B12 deficiency.
2. Folic acid deficiency.
   1. Or a combination of both
3. Chemotherapy side effects.
4. In the case of hydantoin therapy.

 Hemolytic Anemia:

Definition of hemolytic anemia:

1. Hemolytic anemia is a disorder associated with the decreased life span of RBCs.
2. The shortened life span of RBCs may be an intracorpuscular or extracorpuscular abnormality.
3. The severity depends on the rate of destruction and the removal of RBCs.
4. The normal bone marrow can increase its work by 6 to 8 folds, so the anemia may not be apparent until the RBC’s life span reaches only 20 days.

Causes of hemolytic anemia:

1. Intrinsic defects like:
   1. Hereditary defects like:
      1. An abnormal RBC membrane detects hereditary spherocytosis.
      2. Inherited RBC enzyme disorders like G-6-phosphate dehydrogenase deficiency.
   2. Disorders of abnormal hemoglobin production like sickle cell disease.
   3. Thalassemia syndrome.
   4. Paroxysmal nocturnal hemoglobinuria.
2. Extrinsic defects like:
   1. Chemical and toxic agents.
   2. Infection causing hemolysis.
   3. Hypersplenism.
   4. Immune hemolytic anemia.

Lab findings of hemolytic anemia:

1. There is a raised bilirubin level.
2. There are increased reticulocytes.
3. There is polychromasia.

Table showing findings in various anemias:

Type of anemia	Hb	MCV	MCH	MCHC
Iron deficiency	low	low	low	low
Megaloblastic	low	high	high	normal
Thalassemia	low	low	low	low
Chronic illness	low	low	low	low

Characteristic findings in various Anemias:

Anemia type	HB	MCV	MCH	MCHC	Ferritin	Iron binding capacity	serum iron	RDW
Iron deficiency	low	low <76 fl	low	low/normal	decreased	increased	decreased	increased
Megaloblastic	low	high >100 fl/cell	increased >32 pg	low 32 to 36 g/dL			raised/normal	increased
Chronic illness	low	low/normal	low	low	normal/ increased	normal / decreased	decreased	normal
Alpha Thalassemia	low or normal	low	low	low	normal /increased	normal	normal or increased	increased
Beta Thalassemia	low	low	low	low	increased/normal	normal	increased/normal	increased
Aplastic anemia	low	increased	normal	normal				normal

Classification of anemia based on RDW:

Cell size	Normal RDW	High RDW
Microcytosis	Thalassemia minor Chronic diseases, Some hemoglobinopathy trait	Iron deficiency Hb H Anemia of chronic diseases some cases of thalassemia.
Normocytic	Hereditary spherocytosis Acute bleeding some chronic diseases Some Hb traits	Some early or partially treated iron deficiency anemia Sickle cell anemia
Macrocytosis	Aplastic Anemia	Autoimmune hemolytic anemia vit. B or folate deficiency Liver disease thyroid disease Myelodysplasia Alcohol use

Mean corpuscular volume (MCV) and Red cell distribution (RDW) in relation to various diseases:

Red cell distribution (RDW)	Mean corpuscular volume (MCV)	Etiology (causes )
Normal	Decreased (Low)	Thalassemia chronic diseases
Normal	Normal	Hemoglobinopathies Hereditary spherocytosis Hemolysis Hemorrhage (acute bleeding) Transfusion Chronic diseases (90%) Liver diseases (cirrhosis) Chronic lymphocytic leukemia Uremia
Normal	Raised (High)	Aplastic anemia Preleukemia Alcoholism Myelodysplastic syndrome
Raised (High)	Decreased (Low)	Thalassemia S-thalassemia Iron deficiency anemia (RBCs fragmentation) Artificial valves Hb H RBC fragmentation
Raised (High)	Normal	Abnormal hemoglobin Myelofibrosis Early iron or folate deficiency Sideroblastic anemia SS disease (HbS is present in both genes) SC disease (one gene Hb S is combined with Hb C)
Raised (High)	Raised (High)	Folate or B12 deficiency Cold agglutinin disease (Mycoplasma infection) Autoimmune hemolytic anemia Newborn

Abnormalities of RBCs and their etiology:

Type of RBCs abnormality	Etiology for the abnormality
Microcytic RBCs Sickle cell Hb structure	Iron-deficiency anemia Thalassemia Sideroblastic anemia Lead poisoning
Macrocytic	Megaloblastic anemia Liver diseases Myelodysplastic syndrome Increased reticulocyte count
Spherocytes	Hereditary spherocytosis Hemolytic anemia Post transfusion
Target cells	Thalassemia Liver diseases Sideroblastic anemia Hemoglobinopathies
Teardrop cells	Severe anemia Pernicious anemia Myeloproliferative anemia
Elliptocytes	Hereditary elliptocytosis Thalassemia Iron-deficiency anemia
Sickle cells	Sickle cell anemia Sickle-thalassemia
Stomatocytes	Malignant tumors Acute alcoholism
Burr cells	Renal diseases Liver diseases Bleeding gastric ulcer Severe burns
Acanthocytes	Alcohol intoxication Post splenectomy Vitamin E deficiency Congenital abetalipoproteinemia
Helmet cells	G-6-PD deficiency Pulmonary emboli
Schistocytes	Hemolytic uremic syndrome Thrombotic idiopathic thrombocytopenia (ITP) Disseminated intravascular coagulopathy (DIC)

Summary of lab findings in various anemias:

Lab test	Iron-deficiency anemia	Pernicious anemia	Folic acid deficiency	Aplastic anemia	Thalassemia	Sideroblastic anemia	Hemolytic anemia	Post hemorrhagic anemia	Anemia of chronic diseases
Hemoglobin	Low	Low	Low	Low or normal	Low	Low	Low	Normal or low	Low
Hematocrit	Low	Low	Low	Low or normal	Low	Low	Low	Normal or low	Low
MCV	Low	High	High	A normal or mild increase	Low	Low	Normal or high	Slightly low	Low or normal
Reticulocytes count	A normal or mild increase	Low	Low	Low	Increased	A normal or mild increase	High	Increased	Normal
Plasma Iron	Low	Increased	Increased	Increased	Increased or normal	Increased	Normal or high	Normal	Low
TIBC	Increased	Normal	Normal	Normal	Normal	Normal	Normal	Normal	Low
Ferritin level	Low	Increased	Increased	Normal	Increased or normal	Increased	Normal	Normal	Normal
Folate level	Normal	Normal	Low	Normal	Normal	Normal	Normal	Normal	Normal
Serum B12 level	Normal	Low	Normal	Normal	Normal	Normal	Normal	Normal	Normal
Transferrin	Low	Mild increase	Mild increase	Normal		Increased	Normal	Normal	Mildly low
Bilirubin level	Normal	Mild increase	Mild increase	Normal	Increased	Increased	Increased	Normal	Normal

 

Panic values are:

1. Hb = <5 g/dL or >20 g/dL
2. Hct = <20 % ( leads to heart failure)  or > 60% (leads to spontaneous clotting).

Questions and answers:

Q 1: Does red cell distribution (RDW) differentiate between Thalassemia, anemia of chronic diseases, and iron deficiency anemia?

Q2: What will happen to the following laboratory parameters in hemolytic anemia:

1. Reticulocytes      2.  RDW     3. Indirect bilirubin    4. Haptoglobin

Answers:  Q1 = RDW is usually normal in Thalassemia and anemia of chronic diseases while raised in iron deficiency anemia.

Q2 = Indirect bilirubin, reticulocytes, and RDW are increased, while haptoglobin is decreased.

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