When should imaging be done for a pediatric patient presenting with a headache?

Imaging Guidelines for Pediatric Headache

Neuroimaging is not indicated for pediatric patients with primary headaches and normal neurological examinations, but should be performed when specific red flags are present. 1, 2

When to Image

Red Flags Requiring Neuroimaging:

• Abnormal neurological signs or symptoms (highest positive likelihood ratio of 5.88) 3
• Sudden severe (thunderclap) headache 1, 2
• Headache triggered by Valsalva maneuver or exercise (positive likelihood ratio of 3.06) 3
• Headache with persistent vomiting (positive likelihood ratio of 1.96) 3
• Headache onset before age 6 (positive likelihood ratio of 2.42) 3
• Progressive or worsening pattern of headache 2
• Positional headache (changes with position) 2
• Immunocompromised state 2
• History of cancer 2
• Pregnancy with atypical headache features 2

Imaging Modality Selection

First-Line Imaging:

• MRI without contrast is the preferred initial study when imaging is indicated 1, 2
  • Add contrast only if abnormalities are found on non-contrast scan
  • Include susceptibility-weighted imaging (SWI) or gradient-echo (GRE) sequences when post-traumatic headache is suspected

Special Clinical Scenarios:

1. Thunderclap headache (sudden severe):

   • Non-contrast CT head OR MRI brain
   • Consider adding non-contrast MRA 2

2. Suspected infection-related headache:

   • MRI head with AND without IV contrast 1, 2

3. Suspected vascular abnormality (aneurysm, AVM, dissection):

   • MRA, CTA, or conventional arteriography if hemorrhage or stroke is detected 1

4. Suspected venous sinus thrombosis:

   • MRV (with or without contrast) 1, 2
   • CTV if MRV not possible 1

Clinical Considerations

• The yield of neuroimaging in children with primary headaches is extremely low, with <1% having relevant findings to explain headaches 1
• Despite established guidelines, studies show high rates of unnecessary CT scanning in children with primary headaches and normal neurological examinations 4
• CT should be limited to emergency settings when MRI is unavailable, due to radiation concerns 2
• All children with surgically remediable conditions typically present with clear and objective neurological signs 5

Pitfalls to Avoid

1. Overimaging children with primary headaches - leads to unnecessary radiation exposure and healthcare costs
2. Misdiagnosing "sinus headache" - approximately 62% of pediatric migraineurs have cranial autonomic symptoms that can mimic sinusitis 1
3. Relying on a single red flag - individual red flags have relatively low sensitivity values, but their combined sensitivity for detecting serious secondary headaches is high (86.2%) 3
4. Missing occipital headaches - occipital location has a statistically significant association with serious underlying disease 5

By following these evidence-based guidelines, clinicians can appropriately identify which pediatric patients with headache require neuroimaging while avoiding unnecessary testing in those with benign primary headaches.