Anemia Symptoms and Causes

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Nemia

• Characterized by a decrease in hemoglobin or red blood cell concentration, resulting in reduced oxygen carrying capacity of the blood. This decrease can be caused by various factors, including blood loss, bone marrow dysfunction, and increased red blood cell destruction.
• May be suspected in patients with symptoms such as fatigue, pallor of skin, dyspnea, decreased exercise tolerance, chest pain, and impaired cognition. These symptoms can vary in severity and may be subtle, making diagnosis challenging.
• Can be an incidental finding on laboratory testing, particularly the complete blood count (CBC). A CBC measures various components of blood, including hemoglobin, hematocrit, and red blood cell count, making it a valuable diagnostic tool.
• Potential drug causes include chemotherapeutic agents, antiretrovirals, and folate antagonists. Certain medications, such as methotrexate, can interfere with red blood cell production, leading to anemia.
• In addition to these causes, anemia can also be caused by nutritional deficiencies, such as iron or vitamin B12 deficiency, as well as chronic diseases like kidney disease, rheumatoid arthritis, and cancer.

Classification of Anemias

• Classified as macrocytic, microcytic, or normocytic, depending on erythrocyte (RBC) size as reflected by the mean corpuscular volume (MCV)
• Macrocytic anemias: characterized by increased RBC size, caused by deficiencies of vitamin B12 or folate
• Microcytic anemias: characterized by reduced RBC size, commonly caused by iron deficiency

Iron Deficiency Anemia

• Patients typically have decreased serum iron and ferritin levels
• Serum iron may also be decreased in anemia of chronic disease

Coagulation Tests

• International normalized ratio (INR) used to monitor the anticoagulant effect of vitamin K antagonists (warfarin) and to adjust therapy
• INR standardizes the method of reporting prothrombin time to account for variability in testing methods and reagents used to measure clotting time
• Higher than normal (reference) INR range is required to maintain adequate anticoagulation to prevent thrombotic events
• Typically, this INR range is 2.0-3.0, but for some patients, such as those with mechanical heart valves, it is 2.5-3.5

Diabetes

• A1C (glycated hemoglobin) is representative of blood glucose control during the previous 3 months
• Both fasting and postprandial glucose levels correlate with the risk of diabetes complications and contribute to the measured A1C value
• A1C <7% generally reflects fasting glucose levels of 4-6 mmol/L
• False evaluations in A1C may occur in the setting of uremia, chronic alcohol intake, and hypertriglyceridemia
• Recommended targets: A1C ≤7%, Fasting blood glucose 4-7mmol/L, and 2-hour postprandial target of 5.0-10.0 mmol/L

Monitoring Response to Therapy

• Anemia: improvement in Hb levels should occur within 7-14 days; full resolution of anemia may take up to 2 months
• Iron repletion may take 3-6 months, despite an increase in Hb
• Ferritin levels should be checked before stopping therapy
• Macrocytic anemias: monitor via CBC testing in one to two months, along with corresponding vitamin B12 or Folic acid levels, and every 3-6 months thereafter

Drug Adverse Effects

• Electrolytes can be affected by a number of drugs, including antihypertensives, diuretics, and antidepressants
• Sodium, an important indicator of a patient's fluid status
• Increased serum sodium concentrations may signify impaired sodium excretion or volume contraction
• Decreased sodium concentration may reflect hypovolemia or excessive water retention, depending on the underlying cause
• Certain drugs may cause hyponatremia by increasing the action of ADH
• Lithium-induced hypernatremia may occur as a result of decreased ADH activity
• Hypokalemia may occur as a result of inadequate intake or GI tract losses due to severe prolonged diarrhea or vomiting