What are the recommended evaluation and treatment steps for a 10-year-old with a small lump on their right lower back after a fall?

Evaluation and Management of a Small Lump on the Right Lower Back After a Fall in a 10-Year-Old

For a 10-year-old with a small lump on the right lower back following a fall, obtain a detailed history focusing on trauma mechanism, pain characteristics, and neurological symptoms, followed by a thorough physical examination to assess for spinal injury risk factors before determining if imaging is warranted. 1

Initial Clinical Assessment

History Taking

• Document the fall mechanism precisely: height of fall, landing surface type, body position at impact, and time elapsed since injury 1, 2
• Assess for clinical "red flags" that would necessitate imaging: constant pain, night pain, radicular symptoms, pain lasting ≥4 weeks, or any neurological deficits 1
• Evaluate spinal injury risk factors: the patient's age (10 years falls within the high-risk 10-30 year range for spinal injuries), fall from greater than standing height, and presence of back pain or tenderness 1
• Screen for concerning symptoms: tingling in extremities, sensory deficits, muscle weakness in torso or limbs, or bowel/bladder dysfunction 1

Physical Examination

• Inspect the lump carefully: assess size, consistency, mobility, tenderness, and associated skin changes (discoloration, warmth, fluctuance) 1
• Perform complete neurological examination: test sensation, motor strength (particularly proximal muscles), reflexes, and gait 1
• Palpate the spine systematically: identify point tenderness over vertebrae or paraspinal muscles, assess for step-offs or deformities 1
• Evaluate for paraspinal muscle spasm which may present as a palpable lump 3, 4

Imaging Decision Algorithm

If No Red Flags Present

• Conservative management without imaging is appropriate for isolated back pain with normal examination, short duration (<4 weeks), and minor trauma history 1
• Observation period of 4-6 weeks with serial examinations is reasonable before pursuing imaging 1

If Red Flags Present or Lump Characteristics Concerning

• Obtain plain radiographs (AP and lateral views) of the lumbar spine as initial imaging - this is the appropriate first-line study 1, 5
  • Oblique views add unnecessary radiation without diagnostic benefit and should be avoided 5
  • Radiographs can identify spondylolysis (most common diagnosed pathology in this age group), fractures, and primary bone tumors 1, 3, 5

If Radiographs Are Negative But Clinical Suspicion Remains High

• MRI of the spine (area of interest) without and with IV contrast is the next appropriate study 1
  • MRI has superior soft tissue resolution for evaluating paraspinal masses, spinal cord pathology, and soft tissue injuries 1, 4
  • Contrast is particularly important if infection (paraspinal abscess, diskitis) or neoplasm is suspected 1, 3
• Consider MRI as initial imaging (bypassing radiographs) if the lump suggests soft tissue pathology, skin abnormalities are present (discoloration, draining sinus), or neurological deficits exist 1

Differential Diagnosis for Post-Traumatic Lump

Traumatic Etiologies

• Paraspinal muscle hematoma or contusion - most common benign cause after blunt trauma 3, 4
• Soft tissue swelling from muscle spasm or inflammation 3

Serious Pathologies to Exclude

• Spondylolysis/spondylolisthesis - most common diagnosed pathology causing back pain in adolescents (though typically not presenting as a lump) 1, 3, 5
• Paraspinal soft tissue sarcomas - can present as a mass with or without pain 6
• Primary bone tumors (osteoid osteoma, osteoblastoma, aneurysmal bone cyst, Ewing sarcoma) - more common ages 5-20 years 3, 6
• Spinal cord tumors (schwannoma, ependymoma) - rare but can cause progressive neurological symptoms 7, 6
• Infection (paraspinal abscess, osteomyelitis, diskitis) - more common in children <10 years but must be considered 3, 4

Critical Pitfalls to Avoid

• Do not dismiss persistent back pain in children as "growing pains" - unlike adults, pediatric back pain often has identifiable pathology requiring investigation 1, 3, 4
• Do not order CT as first-line imaging - it delivers significantly more radiation than plain films and has lower sensitivity than MRI for soft tissue pathology 1, 5
• Do not obtain oblique lumbar spine views - they double radiation exposure without improving diagnostic yield for spondylolysis 5
• Do not delay imaging if neurological deficits are present - spinal cord compression requires urgent evaluation and intervention to prevent permanent sequelae 7, 6

When to Pursue Urgent/Emergent Evaluation

• Immediate MRI with contrast is indicated for: progressive neurological deficits, bowel/bladder dysfunction, fever with back pain (suggesting infection), or rapidly enlarging mass 1, 7, 6
• Consider admission if neurological examination is abnormal, reliable follow-up cannot be ensured, or pain is severe and uncontrolled 1

Follow-Up Strategy

• Re-examine in 1-2 weeks if initial evaluation is reassuring but symptoms persist 1
• Escalate to imaging if pain persists beyond 4 weeks, neurological symptoms develop, or the lump enlarges 1
• Laboratory evaluation (CBC, ESR, CRP) may be helpful if infection or systemic disease is suspected 1, 4