Anemias Flashcards
(MCV):
Average size of an RBC
(MCH):
Average amount of hgb in an average RBC
(MCHC):
Average concentration of hgb per unit of volume in an average RBC.
Macrocytic
Too large RBCs
Normocytic
Normal size RBCs
Microcytic
Too small RBCs
Normochromic:
Normal amount of hgb. Aside: Hemoglobin A is the normal hgb.
Hypochromic
Too little hgb, diseased. No such thing as too much hgb!
Reticulocytes
New (young) RBCs, elevated when RBC production increases as the bone marrow compensates for RBC shortage.
Anemia & causes
Abnormally low hgb in blood. Causes: decreased RBCs, decreased hgb, or both. HGB, HCT, and RBC usually move together in a lab assessment.
Anemia s/s
chronic fatigue, SOB, pallor (of skin or oral or conjunctival mucosa), increased HR and RR, syncope, coma
Steps of anemia diagnosis
Step 1. CBC with red cell indices. Step 2. Determine if the anemia is associated with a) failed bone marrow production of RBCs (not enough cells or hgb) versus b) RBC loss either by hemorrhage or destruction. A reticulocyte count should be 0% in failed production and >2.5% in RBC destruction.
IDA
impairs hgb synthesis, so iron deficient RBCs contain less hgb than normal. The RBCs are hypochromic (pale) & low MCHC (small). Pretty unique to IDA
Acute blood loss anemia
main threat is shock or death. The volume of lost RBCs is initially replaced by water and albumin synthesis by the liver, and the patient develops a temporary dilutional anemia until the marrow can replace RBCs.
Dilutional anemia
- healthy RBCs with normal size and hgb content
- increased number of reticulocytes. -The RBCs are normocytic and normochromic (normal MCV and MCHC)
Chronic blood loss anemia
- usually occurs in abnormal menstrual bleeding and intestinal bleeding. Intestinal bleeding is usually slow, and new RBCs from marrow replace lost blood.
- In rapid intestinal blood loss, the lack of RBCs in the vascular space is made up by fluid and the patient initially develops a dilutional anemia until the bleeding stops. And then, oral iron replacement is not absorbed in the intestines and cannot make up for lost RBCs so the patient develops IDA.
Hemolysis
Premature destruction of RBCs
Features of hemolytic anemia
- short RBC life span,
- active, hypercellular bone marrow (as marrow works overtime to replace dying cells),
- increased blood erythropoietin (as kidneys secrete more to stimulate RBC production),
- blood that contains a high count of new RBCs (reticulocytes – on microscopic exam these are blue)
Hemolytic anemia s/s
enlarged spleen (splenomegaly), increased free hgb in plasma (hemoglobinemia), dark urine due to hgb in urine (hemoglobinuria), jaundice
Hereditary spherocytosis
genetic disorder of structural protein (spectrin) in red cell membrane that renders cells stiff and spherical rather than flexible and biconcave, so they are unable to successfully pass through the spleen, leading to splenic destruction.
Hereditary spherocytosis s/s
anemia, jaundice, splenomegaly.
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
X-linked recessive genetic disorder. G6PD is important in the supply of energy to stabilize the red cell membrane, so without it, RBCs are fragile and easily destroyed. Patients are subject to acute hemolytic episodes upon exposure to oxidizing drugs, toxins, or infections. Disproportionately affects black men