Differential Diagnosis for Fever, Nausea, Elevated Lymph, Low Hemoglobin, Hematocrit, MCH, and MCHC with Vomiting

Single Most Likely Diagnosis

• Gastroenteritis with dehydration and nutritional deficiency: This condition is likely given the symptoms of fever, nausea, vomiting, and the resultant effects on blood parameters such as low hemoglobin, hematocrit, MCH (Mean Corpuscular Hemoglobin), and MCHC (Mean Corpuscular Hemoglobin Concentration) due to possible iron deficiency from chronic blood loss or poor dietary intake.

Other Likely Diagnoses

• Infectious mononucleosis (Mono): Caused by Epstein-Barr virus, it can lead to fever, nausea, vomiting, and elevated lymphocytes. The low hemoglobin and hematocrit could be due to hemolytic anemia associated with the infection.
• HIV infection: Acute HIV infection can present with fever, nausea, vomiting, and lymphadenopathy. The low blood parameters could be indicative of anemia of chronic disease or direct bone marrow suppression.
• Chronic blood loss: Conditions like ulcers, cancer, or inflammatory bowel disease can cause chronic blood loss leading to iron deficiency anemia (low MCH and MCHC), and the body's response to chronic illness can elevate lymphocytes.

Do Not Miss Diagnoses

• Malignancy (e.g., lymphoma, leukemia): Although less common, these conditions can present with systemic symptoms like fever, nausea, and significant alterations in blood cell counts, including anemia and lymphocytosis.
• Sepsis: A severe infection that can cause fever, nausea, vomiting, and alterations in white blood cell count, including lymphocytosis. Sepsis can lead to organ dysfunction, including anemia of chronic disease.
• Autoimmune hemolytic anemia: Conditions like lupus or rheumatoid arthritis can cause anemia due to autoimmune destruction of red blood cells, alongside fever and nausea.

Rare Diagnoses

• Parvovirus B19 infection: Can cause anemia due to transient aplastic crisis, especially in individuals with underlying hemolytic diseases, and may present with fever and nausea.
• Hemophagocytic lymphohistiocytosis (HLH): A rare disorder of the immune system where the body makes too many activated immune cells called macrophages and lymphocytes. It can cause fever, nausea, and significant alterations in blood parameters, including anemia and low platelet count.
• Kala-azar (Visceral leishmaniasis): A rare disease in many parts of the world, caused by Leishmania parasites, which can lead to fever, weight loss, anemia, and an enlarged spleen and liver, alongside elevated lymphocytes.