Differential Diagnosis for 14-year-old Male with Progressive Bilateral Lower Extremity Pain
Single Most Likely Diagnosis
- Growing Pains: This condition is common in adolescents and can cause bilateral lower extremity pain, especially in the legs, calves, or thighs. The pain typically occurs at night and can be severe enough to interfere with daily activities. Given the patient's age and the progressive nature of the pain, growing pains are a plausible explanation.
Other Likely Diagnoses
- Overuse Injury or Stress Fracture: Despite normal X-rays, overuse injuries or stress fractures could be considered, especially if the patient has recently increased physical activity. These conditions might not always show up on initial X-rays.
- Juvenile Idiopathic Arthritis (JIA): Although the patient has negative ANA and RF, and normal ESR and CRP, oligoarticular JIA could still be a consideration. Some forms of JIA can have a more subtle presentation and may not always have elevated inflammatory markers.
- Legg-Calve-Perthes Disease: This condition affects the hip joint and can cause pain in the lower extremities. It typically presents in children between the ages of 4 and 10 but could be considered in an adolescent with progressive lower extremity pain.
Do Not Miss Diagnoses
- Bone Cancer (e.g., Osteosarcoma, Ewing's Sarcoma): Although rare, bone cancers can present with progressive pain and must be ruled out, even with normal initial X-rays. Further imaging, such as an MRI, might be necessary.
- Infection (e.g., Osteomyelitis): Normal ESR, CRP, and negative cultures do not entirely rule out an infectious process, especially if the patient has been partially treated or has a chronic infection.
- Neurological Conditions (e.g., Peripheral Neuropathy, Spinal Cord Tumors): Conditions affecting the nerves or spinal cord can cause pain and should be considered, especially if there are any neurological symptoms.
Rare Diagnoses
- Chronic Recurrent Multifocal Osteomyelitis (CRMO): A rare condition characterized by recurring episodes of bone pain and inflammation, often without an identifiable infectious cause.
- Sickle Cell Disease: Although less likely given the lack of other symptoms and a normal CBC, sickle cell disease can cause vaso-occlusive crises leading to pain episodes.
- Fabry Disease: A genetic disorder that can cause pain in the extremities due to peripheral neuropathy, among other symptoms. It is rare and typically presents with additional systemic symptoms.