Differential Diagnosis for Lymphocytosis, Fevers, and Shoulder Pain in a 10-Month-Old
- Single Most Likely Diagnosis
- Viral infection (e.g., upper respiratory tract infection): This is the most likely diagnosis due to the common occurrence of viral infections in infants, which can cause lymphocytosis, fevers, and musculoskeletal pain, including shoulder pain.
- Other Likely Diagnoses
- Bacterial infection (e.g., pneumonia, osteomyelitis): Bacterial infections can also cause lymphocytosis, fevers, and localized pain, including shoulder pain if the infection involves the bones or joints of the shoulder.
- Juvenile idiopathic arthritis (JIA): Although less common, JIA can present with fever, joint pain (which could be perceived as shoulder pain), and lymphocytosis, especially in the systemic form.
- Do Not Miss Diagnoses
- Meningitis or sepsis: These conditions are medical emergencies that can present with fever and may have associated musculoskeletal pain. Lymphocytosis can be seen in certain types of meningitis. Early recognition is crucial for survival.
- Osteomyelitis or septic arthritis of the shoulder: These are serious infections that require prompt antibiotic treatment and possibly surgical intervention. They can cause significant pain and have systemic symptoms like fever.
- Leukemia or lymphoma: Although rare in infants, these malignancies can cause lymphocytosis, fever, and bone or joint pain due to marrow infiltration.
- Rare Diagnoses
- Langerhans cell histiocytosis: A rare disorder that can cause systemic symptoms including fever, lymphocytosis, and bone lesions that might result in shoulder pain.
- Chronic granulomatous disease: A genetic disorder affecting the immune system, leading to recurrent infections and potentially causing the symptoms described.
- Autoimmune lymphoproliferative syndrome (ALPS): A rare genetic disorder characterized by lymphoproliferation, which can lead to lymphocytosis and may present with systemic symptoms.