Differential Diagnosis for a 27-year-old Female with WBC 11.8 and Absolute Lymph 3.5

• Single most likely diagnosis:
  • Viral infection (e.g., upper respiratory tract infection): This is the most likely diagnosis due to the mild elevation in WBC count and the presence of a slightly elevated absolute lymphocyte count, which is a common response to viral infections.
• Other Likely diagnoses:
  • Bacterial infection (e.g., urinary tract infection, pneumonia): Although the absolute lymphocyte count is slightly elevated, bacterial infections can also cause a mild increase in WBC count.
  • Stress or exercise-induced leukocytosis: Physical or emotional stress, as well as strenuous exercise, can cause a transient increase in WBC count.
  • Medication-induced leukocytosis: Certain medications, such as corticosteroids, can cause an increase in WBC count.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Leukemia or lymphoma: Although unlikely, these conditions can present with an elevated WBC count and abnormal lymphocyte count, making them crucial to rule out.
  • HIV infection: Acute HIV infection can cause an increase in WBC count and absolute lymphocyte count, and it is essential to consider this diagnosis to provide timely treatment.
  • Tuberculosis: TB can cause an elevated WBC count and abnormal lymphocyte count, especially in immunocompromised individuals.
• Rare diagnoses:
  • Lymphoproliferative disorders (e.g., lymphocytosis with eosinophilia): These rare conditions can cause an elevated absolute lymphocyte count and may require further evaluation.
  • Autoimmune disorders (e.g., systemic lupus erythematosus): Certain autoimmune disorders can cause an elevated WBC count and abnormal lymphocyte count, although this is less common.