Anemia Flashcards
(96 cards)
What is anemia?
Anemia is a decrease in hemoglobin (Hgb) and hematocrit (Hct) concentrations below the normal range for age and gender
What is Hgb and what is its main purpose?
Hgb is an iron-rich protein found in red blood cells (RBCs); its main purpose is to carry oxygen from the lungs to the tissues
Describe the life cycle of RBCs
RBCs are formed in the bone marrow, where they take up Hgb and iron before being released into the circulation as immature RBCs, known as reticulocytes. After 1-2 days, the reticulocytes mature into erythrocytes, which have a lifespan of about 120 days. Erythrocytes are removed from circulation by macrophages, mainly in the spleen
When can anemia occur?
Anemia can occur due to impaired RBC production, increased RBC destruction (hemolysis) or blood loss
What is the danger of anemia?
A decrease in Hgb or RBC volume results in decreased oxygen carrying capacity of the blood
What can anemia result from?
Anemia can result from nutritional deficiencies (e.g. iron, folate, vitamin B12), or it can occur as a complication of another medical disorder, such as chronic kidney disease (CKD) or a malignancy
What are some symptoms that can occur when anemia becomes severe and/or prolonged?
If anemia becomes severe and/or prolonged, the lack of oxygen in the blood can lead to classic symptoms of fatigue, weakness, shortness of breath, exercise intolerance, headache, dizziness, anorexia and/or pallor
What are some symptoms that can occur with sudden blood loss?
If sudden blood loss occurs, the patient can experience acute symptoms, such as chest pain, fainting, palpitations and tachycardia
What are some symptoms that can occur with iron deficiency anemia?
Glossitis (an inflamed, sore tongue), koilonychias (thin, concave, spoon-shaped nails) or pica (craving and eating non-foods such as chalk or clay)
What are some symptoms that occur with vitamin B12 deficiency?
Vitamin B12 deficiency can present with neurologic symptoms, including peripheral neuropathies, visual disturbances and/or psychiatric symptoms
What are some symptoms that can occur with chronic anemia?
In chronic anemia, the heart tries to compensate for low oxygen levels by pumping faster (tachycardia) which can increase the mass of the ventricular (hypertrophy) and lead to heart failure
What is the mean corpuscular volume (MCV)?
The mean corpuscular volume (MCV), which reflects the size or average volume of RBCs, can help determine the type of anemia and the possible underlying cause
What does a low MCV and high MCV mean?
A low MCV means that RBC’s are smaller than normal (microcytic) and a high MCV means that RBCs are larger than normal (macrocytic)
What is the most likely cause of anemia if MCV < 80 fL (microcytic)?
Iron deficiency
What are the most likely causes of anemia if MCV is 80-100 fL (normocytic)?
Acute blood loss, malignancy, CKD, bone marrow failure (aplastic anemia), hemolysis
What are common laboratory tests in anemia?
- Relevant CBC components: hemoglobin (Hgb), hematocrit (Hct), red blood cell (RBC) count, reticulocyte count
- RBC indices: mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW)
- Iron studies: serum iron, serum ferritin, total iron binding capacity (TIBC), transferrin saturation (TSAT)
- Additional tests: serum folate, serum vitamin B12, methylmalonic acid, homocysteine
What do iron studies further evaluate?
Iron studies further evaluate microcytic anemia
What do Vitamin B12 and folate levels further evaluate?
Vitamin B12 and folate levels further evaluate macrocytic anemia
What is the reticulocyte count and what does it indicate?
A reticulocyte count measures production of RBCs. The reticulocyte count is low in untreated anemia due to iron, folate or B12 deficiency and with bone marrow suppression. The reticulocyte count is high in acute blood loss or hemolysis
What is the most common nutritional deficiency in the United States?
Iron deficiency is the most common nutritional deficiency in the United States
What are common causes of iron deficiency?
Inadequate dietary intake (iron-poor diets, malnutrition, disease-related), blood loss (acute, chronic, or drug-induced), decreased iron absorption (high gastric pH, GI diseases), increased iron requirements (pregnancy, lactation, infants, rapid growth)
What are the two available forms of dietary iron and which is more readily absorbed?
Two available forms of dietary iron includes heme iron (found in meat and seafood) and non-heme iron (found in nuts, beans, vegetables and fortified grains). Heme iron is more readily absorbed than non-heme iron, which is affected by gastric pH and other foods being consumed
What increases the absorption of non-heme iron?
Meat, seafood, poultry and ascorbic acid increase the absorption of non-heme iron while foods that contain phytate and polyphenols can decrease non-heme iron absorption
What are some laboratory findings associated with iron deficiency anemia?
Decreased Hgb, MCV < 80 fL, decreased RBC production (low reticulocyte count), decreased serum iron, ferritin and TSAT, increased TIBC