What is the appropriate initial evaluation and management for an 18-year-old female presenting with right lumbar pain and tenderness?

Right Lumbar Pain with Tenderness in 18-Year-Old Female

Initial Evaluation Priority

Begin with a focused assessment for clinical red flags, as their presence fundamentally changes the diagnostic pathway and urgency of imaging. 1

Red Flags to Assess Immediately

• Night pain (pain that wakes patient from sleep or prevents sleep) 1, 2
• Morning stiffness (particularly if lasting >30 minutes, suggesting inflammatory etiology) 1, 2
• Neurologic deficits (motor weakness, sensory changes, abnormal reflexes) 1, 2
• Radiating pain down the leg (suggesting nerve root involvement) 1, 2
• Fever (concern for discitis, osteomyelitis, or epidural abscess) 1, 2
• Unintentional weight loss (malignancy concern) 1, 2
• Duration >4 weeks (increases likelihood of serious pathology) 1, 2
• Gait abnormalities (neurological or mechanical instability) 1, 2
• Tachycardia (systemic infection or inflammatory process) 1, 2
• Abnormal spinal curvature on inspection 1, 2

Physical Examination Essentials

Perform targeted neurological screening including motor strength testing (hip flexion, knee extension, ankle dorsiflexion/plantarflexion), sensory examination in dermatomal distribution, and deep tendon reflexes. 2

• Palpate spinous processes for point tenderness (may indicate fracture, infection, or tumor) 2
• Assess spinal alignment and curvature 2
• Test range of motion in all planes 2
• Evaluate gait including heel and toe walking 2
• Examine skin for abnormalities (café-au-lait spots, hairy patches suggesting spinal dysraphism) 2

Imaging Algorithm

If RED FLAGS Present:

Obtain anteroposterior and lateral radiographs of the lumbar spine as first-line imaging. 1

• Radiographs have 9-22% diagnostic yield when combined with detailed history and physical examination 1
• Critical caveat: Negative radiographs do NOT exclude serious pathology 1, 2
• Skip oblique views—they add minimal diagnostic information 1

If radiographs are negative but red flags persist, proceed immediately to MRI lumbar spine without and with IV contrast. 1, 2

• MRI is the only modality that directly visualizes spinal cord, ligaments, and intervertebral discs 2
• For suspected infection (fever, elevated inflammatory markers): MRI with and without contrast is essential to evaluate for epidural abscess and spinal cord compression 1
• For suspected neoplasm with neurologic deficits: MRI can be obtained as initial study, bypassing radiographs given high sensitivity and specificity 1
• Contrast administration is crucial for suspected discitis/osteomyelitis or neoplasm 1

If NO Red Flags Present:

Do not obtain imaging initially. 1, 2

• Most acute low back pain is self-limiting and responsive to conservative management 1
• Routine imaging provides no clinical benefit in uncomplicated cases and increases healthcare utilization 1
• Imaging is only indicated if pain persists beyond 6 weeks of optimal conservative therapy 1

Initial Management Based on Red Flag Status

With Red Flags:

• Urgent imaging as outlined above 1, 2
• Do NOT initiate physical therapy if progressive neurological deficits are present 2
• Consider inflammatory markers (ESR, CRP) if infection suspected 1

Without Red Flags:

• Avoid bed rest 3
• NSAIDs as first-line pharmacologic treatment (moderate evidence for short-term benefit) 4, 3
• Exercise therapy and remaining active (strong evidence for benefit) 1, 3
• Consider spinal manipulation, massage, or heat therapy 3
• Reassess at 6 weeks; if no improvement, obtain MRI lumbar spine without contrast 1

Critical Pitfalls to Avoid

The most dangerous error is dismissing lumbar pain in a young patient as "mechanical" without systematic red flag screening. 1, 2

• In pediatric/young adult populations, back pain has higher likelihood of serious pathology compared to middle-aged adults 1
• Tenderness to palpation over vertebral body is a specific red flag requiring imaging 1
• Discitis/osteomyelitis has low sensitivity on early radiographs—if clinical suspicion is high, proceed directly to MRI 1
• Intervertebral disk pathology is increasingly recognized as common cause of back pain in young patients with advent of MRI 1