What is the best course of action for an 8-year-old boy with nighttime vomiting (emesis) for 5 nights, lower back pain for 4 weeks, mucous in vomit, poor appetite, and no fever, after a normal spine X-ray?

Urgent MRI of the Spine is Required

This 8-year-old boy requires immediate MRI of the complete spine with and without IV contrast to exclude serious pathology including spinal neoplasm, discitis/osteomyelitis, or inflammatory disease, given the constellation of multiple red flags: persistent nighttime vomiting for 5 nights, lower back pain lasting >4 weeks, and poor appetite. 1, 2, 3

Critical Red Flags Present

This child has several concerning features that mandate urgent advanced imaging:

• Pain duration >4 weeks is a major red flag requiring immediate investigation 2, 3
• Nighttime symptoms (both vomiting and back pain) are highly concerning for spinal neoplasm, which presents with persistent nighttime back pain in 25-30% of pediatric cases 1, 2
• Poor appetite and systemic symptoms combined with back pain suggest serious underlying pathology rather than benign mechanical causes 2, 3
• Normal spine X-ray does NOT exclude serious pathology - radiographs have low sensitivity for early discitis/osteomyelitis, intraspinal neoplasms, and inflammatory processes 1, 2, 3

Why MRI Should Be Obtained Immediately

The American College of Radiology recommends proceeding directly to MRI without waiting, bypassing the typical stepwise approach, when intraspinal neoplasm or inflammatory process is suspected with concerning clinical features. 1

• MRI has high sensitivity and specificity for detecting primary neoplasms of the neural axis, syringomyelia, transverse myelitis, and discitis/osteomyelitis 1
• Gadolinium contrast administration is essential in this scenario for suspected neoplasm or infection 1
• Complete spine MRI (not just targeted) should be obtained given the possibility of multifocal disease 1
• Prompt diagnosis is paramount - delays in identifying spinal cord compression, epidural abscess, or malignancy can result in permanent neurologic disability 1, 2

Differential Diagnosis to Exclude

Spinal Neoplasm (Most Concerning)

• Persistent nighttime back pain is the hallmark symptom, present in 25-30% of children with spinal neoplasm 1, 2
• Nighttime vomiting may represent increased intracranial pressure if tumor involves the posterior fossa or causes hydrocephalus
• Poor appetite and systemic symptoms are consistent with malignancy 2, 3

Discitis/Osteomyelitis

• Can present with back pain >4 weeks, poor appetite, and systemic symptoms 1, 2
• Radiographs have low sensitivity in early stages of disease 1
• MRI can detect paraspinal soft tissue extension and epidural abscess 1
• Note: Absence of fever does NOT exclude infection 2

Inflammatory Spondyloarthropathy

• Juvenile idiopathic arthritis can present with nighttime pain and systemic symptoms 1, 2
• Most commonly affects cervical spine but can involve other regions 1

Immediate Workup Before MRI

While arranging urgent MRI, obtain:

• Inflammatory markers: ESR, CRP, complete blood count to evaluate for infection or inflammatory disease 2
• Complete neurologic examination: assess gait, strength, reflexes, sensation - any abnormal findings increase urgency 2, 3
• Vital signs: check for fever, tachycardia (may indicate systemic infection or inflammatory process) 3
• Physical examination: palpate spinous processes, assess spinal curvature/alignment, check for lymphadenopathy 3

Management of Vomiting Pending Workup

• The mucousy vomiting for 5 nights requires symptomatic management if it impedes oral intake 4
• Ondansetron can be used to prevent vomiting and improve tolerance of oral fluids 5
• Assess hydration status carefully - significant dehydration is unlikely if urine output is maintained 5
• Do NOT attribute vomiting to gastroenteritis without excluding serious causes - the combination of nighttime vomiting with prolonged back pain and poor appetite is NOT consistent with viral gastroenteritis 4, 6

Common Pitfalls to Avoid

• Do not be falsely reassured by normal spine X-rays - radiographs miss early infection, intraspinal tumors, and inflammatory processes 1, 2, 3
• Do not delay MRI for conservative management or physical therapy - progressive neurological deficits or serious pathology require immediate imaging 3
• Do not assume vomiting is gastrointestinal in origin - nighttime vomiting with back pain may indicate neurologic pathology including posterior fossa lesions or increased intracranial pressure 1, 4
• Do not wait for fever to develop - serious spinal infections and neoplasms can present without fever 2

Next Steps Based on MRI Findings

• If infection confirmed: immediate IV antibiotics targeting Staphylococcus aureus with orthopedic/neurosurgical consultation for possible surgical drainage 2
• If neoplasm identified: urgent oncology referral and staging workup 2
• If inflammatory arthritis diagnosed: rheumatology referral and consideration of disease-modifying therapy 2
• If MRI negative: consider cyclic vomiting syndrome, abdominal migraine, or other causes, but serious pathology must be excluded first 7