Differential Diagnosis

The patient presents with a recent sore throat, shortness of breath, upper abdominal pain, and laboratory results showing a slightly elevated white blood cell (WBC) count of 12.0 with an absolute lymphocyte count of 4.3. Other CBC parameters are normal, and the patient has normal amylase, lipase, and most of the comprehensive metabolic panel (CMP) except for a mildly elevated ALT of 31.

• Single Most Likely Diagnosis

  • Viral Infection (e.g., Mononucleosis): The recent sore throat, shortness of breath, and mild elevation in liver enzymes (ALT) along with lymphocytosis (absolute lymphocytes 4.3) could suggest a viral infection such as infectious mononucleosis (caused by Epstein-Barr virus). The symptoms and lab findings are consistent with this diagnosis, especially in a young adult.

• Other Likely Diagnoses

  • Strep Throat with Reactive Lymphocytosis: The patient's recent sore throat could be due to streptococcal pharyngitis, which can cause an increase in WBC count and sometimes a reactive lymphocytosis.
  • Acute Viral Gastroenteritis: Although amylase and lipase are normal, the upper abdominal pain could be part of a viral gastroenteritis presentation, which might also explain the shortness of breath if there's associated dehydration or anxiety.
  • Pneumonia: Shortness of breath could indicate a lower respiratory tract infection like pneumonia, which could also explain the elevated WBC count.

• Do Not Miss Diagnoses

  • Pulmonary Embolism: Although less likely given the patient's age and presentation, pulmonary embolism can cause shortness of breath and abdominal pain (if the embolism affects the lung's pleura) and must be considered due to its high mortality rate if missed.
  • Diabetic Ketoacidosis (DKA): Despite normal amylase and lipase, the abdominal pain and shortness of breath could also be seen in DKA, especially if the patient has undiagnosed diabetes. The non-fasting state of the labs could mask hyperglycemia.
  • Sepsis: Any infection can potentially lead to sepsis, a life-threatening condition that requires immediate recognition and treatment.

• Rare Diagnoses

  • Lymphoma: Although very rare in this age group and with these symptoms, lymphoma could cause lymphocytosis and systemic symptoms like abdominal pain and shortness of breath.
  • Autoimmune Hemolytic Anemia: This condition could cause an elevated ALT and might explain some of the patient's symptoms if anemia is present, although other CBC parameters are currently normal.
  • Wilson's Disease: A rare genetic disorder that can cause liver dysfunction (elevated ALT) and might explain some of the patient's symptoms, though it's less likely given the acute presentation.