Differential Diagnosis for a 2-year-old Girl with Limping and Knee Pain
- Single most likely diagnosis
- Toxic synovitis (E): This is a common cause of hip pain and limping in children, especially after a recent viral infection. The patient's symptoms, such as pain with rotation of the left hip, erythema, swelling, and tenderness to palpation of the left knee, are consistent with toxic synovitis.
- Other Likely diagnoses
- Juvenile idiopathic arthritis (A): Although less likely given the acute presentation, juvenile idiopathic arthritis is a possible diagnosis, especially if the patient has a history of joint pain or swelling.
- Lyme-induced arthritis (C): Given the patient's recent travel to Connecticut, a region with a high incidence of Lyme disease, Lyme-induced arthritis is a possible diagnosis. However, the lack of other symptoms such as a rash or fever makes it less likely.
- Do Not Miss diagnoses
- Leukemia (B): Although rare, leukemia can present with joint pain or limping, and it is essential to consider this diagnosis to avoid missing a potentially life-threatening condition.
- Septic arthritis: Although not listed as an option, septic arthritis is a medical emergency that requires prompt diagnosis and treatment. The patient's symptoms, such as pain, erythema, and swelling, could be consistent with septic arthritis, especially if the patient had a recent infection.
- Rare diagnoses
- Rickets (D): Rickets is a rare condition caused by vitamin D deficiency, and it is unlikely given the patient's age and diet. However, it could be considered if the patient had a history of inadequate nutrition or limited sun exposure.
- Other rare conditions: Other rare conditions, such as osteomyelitis or a bone tumor, could also be considered, but they are less likely given the patient's presentation and age.