Gen Med II: Hematologic System and Lab Values

Anemia

reduction in the total number of erythrocytes in the circulating blood or in the quality or quantity of hemoglobin

Anemia can be caused by

-impaired erythrocyte production

-acute or chronic blood loss

-increased erythrocyte destruction

-combination

Myeloproliferative RBC

blood cancer

Polycythemia

increased number of RBCs

-can increase blood viscosity and lead to blood clots

Leukopenia

low leukocyte count

-not normal nor beneficial

-predisposed to infection

Leukemias

malignant disorder

Leukocytosis

high leukocyte count

-can be normal protective physiologic response

Thrombocytopenia

decreased circulating platelets

-decreased platelet production and or increased platelet consumptions

Thrombocythemia

increased circulating platelets

Review of systems - hematologic system signs

-skin color or nail bed changes

-bleeding: nose, gums, easy bruising, melena

-hemarthrorsis, muscle hemorrhage, hematoma

-fatigue, dyspnea, weakness

-rapid pulse, palpitations

-confusion, irritability

-headache

RBC count is

pure number of RBCs in 1ul of blood

Reference ranges of RBCs

4.5-5.3 x10^6 /mm^3 (men) and 4.1-5.1 x10^6 /mm^3 (women)

RBCs are closely linked to

hb and hct

RBC indices used to diagnose and classify ____________

anemia

Hemoglobin

measures the oxygen carrying capacity of RBCs

Hemoglobin therapy implications

-if low, heart has to work harder to meet oxygen demands

-expect low endurance, orthostatic intolerance

-S/sx of hypoxia include dizziness, lightheadedness, syncope, orthostatic hypotension, TIA, seizure, angina, MI, arrhythmias, low urine output, fluid retention

Decreased hemoglobin is common in

anemia, hemorrhage, hemoglobinopathy, sickle cell disease, burns, hyperthyroidism, cirrhosis, pregnancy, leukemia, lymphoma, SLE, some medications, dilution (retaining fluids)

Increased hemoglobin is common in

dehydration, polycythemia, COPD, CHF, dehydration, living at high altitude, some medications

What is required for synthesis of Hb?

iron

Iron status can also be determined by

serum transferrin receptor assay and serum ferritin

Hematocrit is

percentage of whole blood occupied by RBCs

_______________ usually provides the asme information as Hct

hb concentration

Decreased hematocrit is seen in

anemia, nutritional deficiency (iron, folate, B12), leukemia, hyperthyroidism, cirrhosis, severe burns

Increased hematocrit is seen in

polycythemia, severe dehydration, shock caused by severe dehydration or burns, cor pulmonale

Decreased vs elevated levels of WBCs

leukocytopenia: decreased

leukocytosis: increased

Increased WBCs are common in

Infection, inflammation, tissue necrosis, leukemia, tissue trauma or stress, burns, thyroid storm, dehydration

Decreased WBCs are common in

bone marrow suppression/failure (chemotherapy or radiation), AIDS, alcoholism, diabetes, autoimmune diseases

WBC PT implications

If count is <1000/mm3, the patient maybe in protective isolation

Various disease states are characterized by their effects on specific types of _____________

WBCs

Which WBC's are key in bacterial infections?

neutrophils

Neutropenia vs neutrophilia

neutropenia: decreased neutrophils and is clinically significant as a risk factor for infection

neutrophilia: indicates the presence of infection

What is white cell differential?

an analysis of the relative numbers of different types of WBCs

Primary funciton of platelets is

initiate clotting sequence

-also cause vasoconstriction and chemotaxis for fibroblasts, SMCs, and WBCs

Decreased vs increased causes of platelets?

decreased (thrombocytopenia): anemia, use of antibiotics, toxic effects of some drugs, pneumonia, infections, HIV, chemo

increased (thrombocytosis): inflammation, infection, cancer, splenectomy, trauma, RA, heart disease, cirrhosis, recovery from bone marrow suppression

PT implications of decreased platelets

thrombocytopenia is associated with increased risk of bleeding into muscles and joints with activity

What is the basic metabolic panel (BMP)?

a group of 8 specific tests for electrolyte level, acid/base balance, blood sugar, and kidney status

-sodium

-potassium

-chloride

-calcium

-blood urea nitrogen (BUN)

-creatinine

-glucose

-carbon dioxide

PT implications of low sodium

Watch for signs of dehydration/edema, monitor cognition & for neurological s/sx

PT implications of low or high potassium

Closely monitor cardiac status

Watch for muscle weakness

PT implications of low or high chloride

Similar to sodium; Watch for signs of dehydration/edema, monitor cognition & for neurological s/sx

PT implications of low or high calcium

Watch for muscle changes including weakness & tetany, arrhythmia, CNS changes

PT implications of low or high BUN or creatinine

Elevated levels don't usually contraindicate therapy

Watch for fatigue, lethargy and confusion

PT implications of low or high glucose

Exercise contraindicated with critical values, Use caution if >250, Watch for symptoms of ketoacidosis

If <100 recommended to encourage CHO intake prior to exercise

Sodium roles

critical determinant of fluid volume

_________________ neurons particularly susceptible to fluid changes - leads to neurological dysfunction, mental status changes, coma

sodium

Hyponatremia

•decreased sodium

•Excessive infusion/ingestion of water

•Increased ADH

•Diseases causing fluid retention (CHF, cirrhosis, nephrotic syndrome)

Hypernatremia

•increased sodium

•Excessive water loss (sweating)

Decreased ADH

Potassium roles

•Particularly important for function of excitable cells - nerves, muscles, and heart

•Maintains resting membrane potential

•Small alterations can have critical effects on muscle causing weakness, muscle irritability, and arrhythmias

•May see mental status changes, dizziness, myalgia, muscle twitches, N/V/D, numbness/tingling, paralysis

Hypokalemia

•Use of loop diuretics (loss of K+ in urine)

•Intestinal losses (vomiting or diarrhea)

Hyperkalemia

•Excessive potassium replacement

•Medications

Typically chloride levels tend to change along with changes in

sodium and water

Chloride shifts in response to _________ changes

pH (can be affected by hyperventilation/hypoventilation)

Altered chloride levels can lead to

lethargy, decreased levels of consciousness, weakness, edema, tachypnea, tachycardia, agitation, irritability, hyperreflexia, cramping, twitching

Calcium role

•Regulates neuromuscular activity, excitation of cardiac cells, bone development

Hypercalcemia

may decrease firing of neurons and cause muscle weakness, fatigability, decreased muscle tone and reflexes, numbness, muscle spasms

•Hyperparathyroidism

•Kidney stones

•Cancer (multiple myeloma, bone tumors)

•Excessive intake (antacids)

Hypocalcemia

•Impaired absorption

•Inadequate intake

BUN and creatinine

used to evaluate kidney function

Creatinine is

a waste product from muscle metabolism, released into blood from muscle at constant rate

Rise in creatinine indicates

decreased kidney excretion (loss of nephron function)

•May also indicate muscle injury

BUN reflects

balance of nitrogen added to blood from protein metabolism and that excreted by the kidney

Rise in BUN indicates

•decreased renal function

•May also rise with increased protein catabolism or dietary protein intake

•May decrease with malnutrition or liver disease

What is a better measure of glucose control over time?

A1C

Bicarbonate is

•produced in a reaction between CO2 and water

•90% of CO2 in the body exists as bicarbonate

Bicarbonate acts as a buffer, preventing changes in

plasma protein

Altered bicarbonate can indicate

respiratory or metabolic acidosis or alkalosis

•May be compensated or uncompensated

•See slide on ABGs for interpretation

What is the comprehensive metabolic panel (CMP)?

composed of the BMP with the addition of tests for liver function

Albumin is

•Product of the liver - synthesized by the liver

•Major protein of the blood

•Albumin can be used to assess nutritional status and wound healing

•Looks at protein synthesis over time

•Decreased with liver damage, burns, Crohn disease, SLE, malnutrition

Decreased albumin can indicate

malnutrition or risk for impaired wound healing

Tests of coagulation

•Prothrombin Time (PT)

•Activated Partial Thromboplastin Time (aPTT)

•International Normalized Ratio (INR)

•Anti-Xa

•D-dimer