Anemia Short Notes 📝

 

Anemia

Definition of Anemia:- 

 Deficiency in the oxygen-carrying capacity of the blood due to a diminished erythrocyte mass.

 May be due to:

 Erythrocyte loss (bleeding)

 Decreased Erythrocyte production

 low erythropoietin

 Decreased marrow response to erythropoietin

 Increased Erythrocyte destruction

(hemolysis)

Measurements of Anemia

 Hemoglobin = grams of hemoglobin per 100 mL of

whole blood (g/dL)

 Hematocrit = percent of a sample of whole blood occupied by intact red blood cells

 RBC = millions of red blood cells per microL of whole blood

 MCV = Mean corpuscular volume

 If > 100 → Macrocytic anemia

 If 80 – 100 → Normocytic anemia

 If < 80 → Microcytic anemia

 RDW = Red blood cell distribution width

 = (Standard deviation of red cell volume ÷ mean cell

volume) × 100

 Normal value is 11-15%

 If elevated, suggests large variability in sizes of RBCs

Laboratory Definition of Anemia

 Hgb:

 Women: <12.0

 Men: < 13.5

 Hct:

 Women: < 36

 Men: <41

Symptoms of Anemia

 Decreased oxygenation

 Exertional dyspnea

 Dyspnea at rest

 Fatigue

 Bounding pulses

 Lethargy, confusion

 Decreased volume

 Fatigue

 Muscle cramps

 Postural dizziness

 syncope

Special Considerations in Determining Anemia

 Acute Bleed

 Drop in Hgb or Hct may not be shown until 36 to 48 hours after acute bleed (even though patient may be hypotensive)

 Pregnancy

 In third trimester, RBC and plasma volume are expanded by 25 and 50%, respectively.

 Labs will show reductions in Hgb, Hct, and RBC count, often to anemic levels, but according to RBC mass, they are actually polycythemic

 Volume Depletion

 Patient’s who are severely volume depleted may not show anemia until after rehydrated

RBC Life Cycle

 In the bone marrow, erythropoietin enhances the growth of differentiation of burst forming units-erythroid (BFU-E) and colony forming units-erythroid (CFU-E) into reticulocytes.

 Reticulocyte spends three days maturing in the marrow, and then one day maturing in the peripheral blood.

 A mature Red Blood Cell circulates in the peripheral blood for 100 to 120 days.

 Under steady state conditions, the rate of RBC production equals the rate of RBC loss.

Normal Peripheral Smear

Causes of Anemia --

Erythrocyte Loss

 Bleeding

 Chronic (gastrointestinal, menstrual)

 Acute/Hemodynamically significant:

 Gastrointestinal

 Retroperitoneal

Anemia due to

Low Erythropoietin

 Kidney Disease

 Normochromic, normocytic

 Low reticulocyte count

 Frequently, peripheral smear in uremic patients show “burr cells” or echinocytes

 Target hemoglobin for patients on dialysis is 11 to 12 g/dL

 Administer erythropoietin or darbopoietin

weekly

 Good Iron stores must be maintained

Echinocytes (“burr cells”)

Anemia due to Decreased Response to Erythropoietin

 Iron-Deficiency

 Vitamin B12 Deficiency

 Folate Deficiency

 Anemia of Chronic Disease

Anemia due to Decreased Response to Erythropoietin

 Iron Deficiency

 Can result from:

 Pregnancy/lactation

 Normal growth

 Blood loss

 Intravascular hemolysis

 Gastric bypass

 Malabsorption

 Iron is absorbed in proximal small bowel; decreased abosrption in celiac disease, inflammatory bowel disease

 May manifest as PICA

 Tendency to eat ice, clay, starch, crunchy materials

 May have pallor, koilonychia of the nails, beeturia

 Peripheral smear shows microcytic, hypochromic red cells with marked anisopoikilocytosis.

Iron Deficiency Anemia

Iron Deficiency Anemia - koilonychia

Iron Deficiency Anemia – Lab Findings

 Serum Iron

 LOW (< 60 micrograms/dL)

 Total Iron Binding Capacity (TIBC)

 HIGH ( > 360 micrograms/dL)

 Serum Ferritin

 LOW (< 20 nanograms/mL)

 Can be “falsely”normal in inflammatory

states

Treatment of Iron Deficiency Anemia

 Oral iron salts

 Ferrous sulfate – 325 mg po Q Day

 Side effects: constipation, black stools, positive hemmoccult test

 Vitamin C can facilitate iron absorption.

Anemia due to Decreased Response to Erythropoietin

 Cobalamin (Vitamin B12) Deficiency

 Macrocytic anemia

 Lab Values

 Cobalamin level < 200 pg/mL

 Elevated serum methylmalonic acid

 Elevated serum homocysteine

 Vit. B12 is needed for DNA synthesis

 Binds to intrinsic factor in the small bowel in order to be

absorbed

 Pernicious anemia: antibodies to intrinsic factor

 Diagnosed by checking antibody levels (rather than Schilling test)

 Deficiency can result in neuropsychiatric symptoms

 Spastic ataxia, psychosis, loss of vibratory sense, dementia

 Frequently not reversible with cobalamin replacement

 Smear shows macrocytosis with hypersegmentation of

polymorphonuclear cells, with possible basophilic stippling.

Vitamin B12 Deficiency

Treatment of Vitamin B12 Deficiency

 Vitamin B12 – 1000 micrograms intramuscularly

monthly

-OR-

 Vitamin B12 – 1000-2000 micrograms po QDaily

Anemia due to Decreased Response to Erythropoietin

 Folate Deficiency

 Macrocytic anemia

 Lab Values

 Low folate

 Increased serum homocystine

 NORMAL methylmalonic acid

 Often occurs with decreased oral intake, increased utilization, or impaired absorption of folate

 Folate is normally absorbed in duodenum and proximal jejunum – deficiency found in celiac disease, regional enteritis, amyloidosis

 Deficiency frequently in alcoholics, because enzyme required for deglutamation of folate is inhibited by alcohol.

 Deficiency often found in pregnant women, persons with desquamating skin disorders, patients with sickle cell anemia (and other conditions associated with rapid cell division and turnover)

 Smear shows macrocytosis with hypersegmented neutrophils

Folate Deficiency

Treatment of Folate Deficiency

 Folate – 1 to 5 mg po Qday

 Vit. B12 deficiency must be excluded in folate-deficient patients, because supplemental folate can improve the anemia of Vit. B12 deficiency but not the neurologic sequelae.

Vitamin B12 Deficiency Versus Folate Deficiency

 Vitamin B 12 Deficiency Folate Deficiency

MCV > 100 > 100

Smear Macrocytosis with hypersegmented neutrophils Macrocytosis with hypersegmented neutrophils

Pernicious anemia Yes NO

Homocystine Elevated Elevated

Methylmalonic Acid Elevated NORMAL

Anemia due to Decreased Response to Erythropoietin

 Anemia of Chronic Disease

 Usually normocytic, normochromic (but can become hypochromic, microcytic over time)

 Occurs in people with inflammatory conditions such as collage vascular disease, malignancy or chronic infection.

 Iron replacement is not necessary

 May benefit from erythropoietin

supplementation.

Anemia due to Decreased marrow response

 Thalassemia

 Microcytic anemia

 Defects in either the alpha or beta chains of hemoglobin, leading to ineffective erythropoiesis and hemolysis

 -thalassemia:

 Prevalent in Africa, Mediterranean, Middle East, Asia

 -thalassemia:

 Prevalent in Mediterranean, South East Asia,

India, Pakistan

 Smear shows microcytosis with target cells

Thalassemia

Anemia due to Destruction of Red Blood Cells

 Hemoglobinopathies

 Sickle Cell Anemia

 Aplastic Anemia

 Decrease in all lines of cells – hemoglobin,

hematocrit, WBC, platelets

 Parvovirus B19, EBV, CMV

 Acquired aplastic anemia

 Hemolytic Anemia

Hemolytic Anemias

 Hereditary spherocytosis

 Glucose-6-phosphate dehydrogenase (G6PD) Deficiency

 Most common enzyme defect in erythrocytes

 X-linked

 Brisk hemolysis when patients exposed to oxidative stress from drugs, infections or toxins.

 Thrombotic Thrombocytopenic

Purpura (TTP)

 Thrombocytopenia and microangiopathic hemolytic anemia, fever, renal insufficiency, neurologic symptoms

 Schistocytes on smear

 Hemolytic Uremic Syndrome

 Thrombocytopenia, Microangiopathic hemolytic anemia, renal insufficiency

 Autoimmune Hemolytic Anemia

 Warm-antibody mediated

 IgG antibody binds to erythrocyte surface

 most common

 Diagnosed by POSITIVE Coomb’s Test (detectgs IgG or complement on the cell surgace)

 Can be caused drugs

 Treated with corticosteroids or splenectomy if refractory

 Cold agglutinin Disease

 IgM antibodies bind to erythrocyte surface

 Does not respond to corticosteroids, but usually mild.

 Infections

 Malaria

 Babesiosis

 Sepsis

 Trauma

 Includes some snake, insect bites

Sickle Cell Anemia

Spherocytosis

TTP / HUS – microangiopathic hemolysis with schistocytes

Malaria

Lab Analysis in Hemolytic Anemia

 Increased indirect bilirubin

 Increased LDH

 Increased reticulocyte count

 Normal reticulocyte count is 0.5 to 1.5%

 > 3% is sign of increased reticulocyte production, suggestive of hemolysis

 Reduced or absent haptoglobin

 < 25 mg /dL suggests hemolysis

 Haptoglobin binds to free hemoglobin released after hemolysis