Differential Diagnosis for a 14-year-old Girl with Leg Pain
The patient's symptoms of morning achiness, improvement over the day, and spread to multiple joints, along with fatigue and mild swelling, suggest an inflammatory or rheumatological condition. Here's a categorized differential diagnosis:
- Single most likely diagnosis
- Juvenile Idiopathic Arthritis (JIA): The patient's symptoms of morning stiffness, joint pain, and swelling in multiple joints are classic for JIA. The improvement in symptoms over the day and the presence of fatigue also support this diagnosis. JIA is a common cause of chronic arthritis in children and adolescents.
- Other Likely diagnoses
- Rheumatic fever: Although less likely, rheumatic fever can cause joint pain and swelling, particularly after a streptococcal infection. However, the patient's symptoms have been present for 3 months, and there's no mention of a recent infection.
- Vitamin D deficiency: The patient's recent transition to a plant-based diet may increase the risk of vitamin D deficiency, which can cause musculoskeletal pain and fatigue. However, the patient's symptoms are more suggestive of an inflammatory condition.
- Overuse injury: The patient's new daily walking routine could contribute to overuse injuries, such as stress fractures or tendonitis, but the involvement of multiple joints and the presence of morning stiffness make this less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lyme disease: Although the patient's symptoms are not typical for Lyme disease, it's essential to consider this diagnosis, especially if the patient has been exposed to ticks during her outdoor walks. Lyme disease can cause arthritis, fatigue, and other systemic symptoms.
- Leukemia: Bone pain, joint pain, and fatigue can be symptoms of leukemia, particularly in children and adolescents. Although this diagnosis is less likely, it's crucial to rule out leukemia due to its potential severity.
- Osteomyelitis or septic arthritis: These conditions can cause joint pain, swelling, and systemic symptoms, such as fever and fatigue. Although the patient's temperature is normal, it's essential to consider these diagnoses, especially if the patient has a history of recent trauma or infection.
- Rare diagnoses
- Sarcoidosis: This condition can cause joint pain, swelling, and fatigue, but it's rare in children and adolescents.
- Mixed connective tissue disease: This autoimmune disorder can cause joint pain, swelling, and other systemic symptoms, but it's rare in children and adolescents.
- Hemochromatosis: This genetic disorder can cause joint pain, fatigue, and other systemic symptoms, but it's rare in children and adolescents.
The most appropriate medication for this patient's condition would likely be D. Naproxen, a nonsteroidal anti-inflammatory drug (NSAID) that can help manage the patient's joint pain and inflammation. However, a definitive diagnosis and further evaluation by a pediatric rheumatologist or other specialist may be necessary to determine the best course of treatment.