What is the next best step to make a diagnosis in a 10-year-old boy presenting with intermittent bilateral lower leg pain for a month, with no signs of trauma, swelling, ecchymosis, or tenderness, and normal vitals, including no signs of abuse?

From the Guidelines

The next best step to make a diagnosis in a 10-year-old boy presenting with intermittent bilateral lower leg pain for a month, with no signs of trauma, swelling, ecchymosis, or tenderness, and normal vitals, including no signs of abuse, is to obtain conventional radiographs in two planes, as recommended by the most recent guidelines 1. This approach is based on the principle that persistent non-mechanical pain in any bone lasting more than a few weeks should cause concern and lead to further immediate investigation, as stated in the guidelines 1. The guidelines also emphasize the importance of a full physical examination, focusing on symptoms such as duration, intensity, and timing of complaints, as well as specific events for bone tumors, including prior benign/malignant lesions, family history, and previous radiotherapy 1. Given the age of the patient and the presentation of intermittent bilateral lower leg pain, it is essential to consider the possibility of a bone tumor, although the lack of concerning features such as point tenderness, swelling, limited mobility, systemic symptoms, or signs of trauma or abuse makes this less likely. The use of conventional radiographs in two planes as the first investigation is supported by the guidelines, which state that this modality is the best initial imaging step for evaluating bone pain 1. If the diagnosis of malignancy cannot be excluded with certainty on radiographs, the next imaging step would be magnetic resonance imaging (MRI) of the whole compartment with adjacent joints, as recommended by the guidelines 1. It is also important to note that the patient's symptoms could be consistent with growing pains, a benign condition common in children, as described in the example answer. However, given the potential for serious underlying conditions, such as bone tumors, it is essential to prioritize a thorough diagnostic evaluation, starting with conventional radiographs in two planes, to ensure the best possible outcome for the patient in terms of morbidity, mortality, and quality of life. Some of the other evidence provided, such as the guidelines for suspected osteomyelitis, septic arthritis, or soft tissue infection 1, and the guidelines for back pain in children 1, may not be directly relevant to this specific case, but they do emphasize the importance of a thorough diagnostic evaluation and the use of imaging modalities such as radiographs and MRI in evaluating bone and soft tissue pain in children. The most recent and highest quality study, 1, provides the best guidance for this case, and its recommendations should be prioritized in determining the next best step for diagnosis.

From the Research

Diagnosis of Growing Pains

To diagnose growing pains in a 10-year-old boy presenting with intermittent bilateral lower leg pain, the following steps can be taken:

• A thorough patient history and physical examination are essential to establish the diagnosis 2, 3, 4
• The diagnosis of growing pains is one of exclusion, and other serious conditions that may present with limb pain should be ruled out 2, 5, 3, 4
• Clinical cautionary signs such as unilateral pain, morning stiffness, joint swelling, and systemic symptoms (e.g., fever, weight loss, and malaise) should be identified, and if present, an extended evaluation should be triggered to exclude other more serious conditions 2

Laboratory Investigations and Imaging

• Laboratory investigations and imaging are not necessary for the diagnosis of growing pains unless clinical cautionary signs are present 2, 4
• However, some studies suggest that elevated serum levels of alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) may be associated with growing pains 6

Key Characteristics of Growing Pains

• Growing pains are characterized by recurrent, self-limited, bilateral lower extremity pain, mostly in the afternoon and evening, and even at night, in an otherwise healthy child 5
• The pain is typically intermittent and may awaken the child from sleep 3
• The prognosis is excellent, and the condition is self-resolving 5, 4