Differential Diagnosis for Elevated WBC and RBC
Single Most Likely Diagnosis
- Dehydration: This is a common cause of elevated red blood cell (RBC) and white blood cell (WBC) counts due to hemoconcentration. Dehydration leads to a decrease in plasma volume, which in turn increases the concentration of blood cells.
Other Likely Diagnoses
- Chronic Infections: Chronic infections such as tuberculosis, endocarditis, or osteomyelitis can cause an increase in WBC count due to the body's ongoing immune response. The RBC count may also be elevated in response to chronic inflammation or as a result of the infection itself.
- Chronic Inflammatory Diseases: Conditions like rheumatoid arthritis, lupus, or Crohn's disease can lead to elevated WBC counts due to chronic inflammation. The RBC count may also be affected, potentially leading to anemia of chronic disease, but in some cases, it might be elevated.
- Smoking: Smoking is known to increase WBC count, possibly due to chronic inflammation and oxidative stress. It can also affect RBC count, potentially leading to an increase due to increased erythropoietin production in response to chronic hypoxia.
Do Not Miss Diagnoses
- Severe Sepsis or Septic Shock: Although the likelihood may vary, it's crucial not to miss severe infections that could lead to sepsis or septic shock. These conditions require immediate medical attention and can present with elevated WBC and potentially altered RBC counts.
- Hematological Malignancies: Leukemia or lymphoma can cause an elevation in WBC count. While the RBC count might not be directly affected, anemia or other cytopenias are common in these conditions, but in some cases, especially in polycythemia vera, RBC count can be elevated.
- Polycythemia Vera: A myeloproliferative disorder that leads to an overproduction of all three blood cell types, resulting in elevated RBC, WBC, and platelet counts.
Rare Diagnoses
- Primary Polycythemia: A rare condition characterized by an increased production of RBCs, which can also lead to an increase in WBC and platelet counts.
- Myeloproliferative Neoplasms: Besides polycythemia vera, other myeloproliferative neoplasms like essential thrombocythemia or primary myelofibrosis can present with elevated blood cell counts, including WBC and RBC.
- Erythrocytosis due to High-Altitude: Living at high altitudes can lead to an increase in RBC count (erythrocytosis) as the body adapts to lower oxygen levels. WBC count might also be affected due to chronic hypoxia.