What causes bone pain in the arms?

Bone Pain in Arms: Causes and Diagnostic Approach

Bone pain in the arms can arise from multiple etiologies including metastatic cancer, primary bone disorders, inflammatory arthritis, trauma-related complications, and rare histiocytic neoplasms, with the diagnostic workup beginning with plain radiographs followed by advanced imaging based on initial findings. 1

Cancer-Related Causes

Metastatic bone disease is a leading cause of arm bone pain, particularly from breast, lung, prostate, and kidney cancers, as well as multiple myeloma. 1 The pain is characteristically worse with movement and can be debilitating. 1 Osteolytic lesions stimulated by tumor-derived cytokines cause the majority of cancer-related bone pain. 1

Inflammatory and Degenerative Conditions

• Osteoarthritis causes bone pain through multiple mechanisms including subchondral microfractures, periosteal stretching from osteophyte growth, bone marrow lesions, and increased intraosseous pressure (bone angina). 2
• Inflammatory arthritis (rheumatoid arthritis, crystalline arthropathies) can cause bone pain through periarticular inflammation and bone erosions. 3, 4
• Osteoporosis and treatment-induced bone loss are additional causes of bone pain. 1

Rare but Important Causes

Erdheim-Chester disease presents with bone pain in 50% of patients, though it characteristically affects lower extremities more than upper extremities (axial skeleton involvement occurs in 47% of cases). 5 Langerhans cell histiocytosis causes cortex-based osteolytic lesions in 15% of cases. 5

Diagnostic Algorithm

Step 1: Initial Imaging

Always begin with plain radiographs of the affected arm. 5, 4 Standard views (posteroanterior, lateral, oblique) assess for fractures, joint space narrowing, erosions, osteolytic or osteosclerotic lesions, soft tissue mineralization, and alignment abnormalities. 5, 3

Step 2: If Radiographs Are Normal or Show Only Nonspecific Findings

• MRI without IV contrast is the primary next step for evaluating soft tissue pathology, bone marrow lesions, occult fractures, and inflammatory changes. 4 MRI changed clinical management in 69.5% of cases in one series. 5, 4
• Ultrasound is equivalent to MRI for tendon pathology, tenosynovitis, and superficial soft tissue evaluation, with the advantages of lower cost, dynamic assessment capability, and greater availability. 5, 4
• Bone scan or PET-CT should be considered when metastatic disease is suspected, as these modalities are sensitive for detecting skeletal pathology throughout the body. 1

Step 3: Laboratory Evaluation

When bone pain is present, check calcium, phosphate, 25-hydroxyvitamin D, parathyroid hormone, alkaline phosphatase, creatinine clearance, and biochemical markers of bone metabolism. 1

Pathophysiologic Mechanisms

Bone pain arises from nociceptors in the periosteum, bone marrow, and surrounding soft tissues (articular cartilage lacks pain receptors). 2 Injury triggers peripheral sensitization of primary afferent neurons and central nervous system hyperexcitability. 2, 6 Ectopic sprouting of sensory and sympathetic nerve fibers creates neuroma-like structures that amplify pain signals. 7, 6

Critical Pitfalls to Avoid

• Never order MRI as the initial study—radiographs must come first to exclude obvious bony pathology. 5, 4
• Do not dismiss normal radiographs in patients with significant pain, as early inflammatory arthritis, bone marrow lesions, and occult fractures require MRI for detection. 4
• Consider systemic disease when bilateral arm bone pain is present, particularly metastatic cancer or histiocytic disorders. 5, 1
• Evaluate for impending pathologic fractures in patients with known bone metastases, as prophylactic stabilization before fracture provides better outcomes than post-fracture intervention. 1

Special Considerations

In transplant recipients on cyclosporine, consider a vascular etiology causing episodic bone pain that characteristically occurs at night or with recumbency and responds to calcium channel blockers. 8 This syndrome affects primarily the lower extremities but can involve upper extremities. 8