Pediatric Primary Headache From A to Z

Evaluating Children With Headache: What to Do, and When

Laboratory Studies

A menu of laboratory studies is available, but not all of these should be ordered for every patient. It is important to tailor the evaluation to the headache type. Potentially helpful lab tests included thyroid studies and levels of magnesium, iron, folate, riboflavin, and lead. Clinicians should consider checking vitamin D and coenzyme Q₁₀ levels, as well as ordering a complete blood count, erythrocyte sedimentation rate, and complete metabolic panel to screen for systemic conditions that may have headache as a feature.

A lumbar puncture is typically only needed to rule out pseudotumor cerebri. Genetic testing can be done in selected patients to identify a genetic predisposition to headache.

The Role of Imaging

Dr Kevin Moore gave an overview of imaging techniques and when they might be appropriate in the evaluation of pediatric headache. Headache is among the three most common reasons for head imaging. However, the yield of central nervous system imaging in the setting of pediatric headache tends to be very poor.

A case series by Elliot and colleagues^[4] suggests that only 1.9% of imaging for headache reveals findings of clinical relevance. Yilmaz and colleagues^[5] reviewed imaging in more than 400 patients, 21% of whom had a finding on head imaging. The findings were clinically relevant in only 0.6% of the children (one with a tumor and one with hydrocephalus); however, 11.1 % of the children had extracerebral findings, (such as paranasal sinus disease or adenoid hypertrophy) that probably contributed to headache. Finally, 8.9% of the children had incidental findings, commonly called "unidentified white-matter abnormality."^[5]

Although parents and providers are often concerned that headaches might be resulting from a serious intracranial process, the current rate of increase in central nervous system imaging (CT and MRI) is not sustainable. CT and MRI are the only modalities typically needed for the evaluation of headache in a child. Ultrasonography, plain radiography, and scintigraphy are not usually helpful (or indicated).

The advantages of CT are speed, cost (typically less than MRI), and the fact that it does not cause claustrophobia. CT is not contraindicated in patients with implantable devices, such as a pacemaker. The disadvantages of CT are its lower resolution and associated radiation exposure.

MRI achieves high tissue definition but often requires sedation. The MRI magnet can induce claustrophobia, and the test cannot be conducted on patients with implanted devices. Overall, MRI is probably a better imaging modality than CT to evaluate childhood headaches; however, it also picks up more incidental and clinically unimportant findings.

Angiography is indicated much less frequently. CT and MR venography have the same advantages and disadvantages as regular CT and MRI. That said, venography of either variety is helpful in identifying dural venous sinus thrombosis as a cause of headache.

Besides the striking prevalence of nonspecific white-matter abnormalities (up to 17% in a series by Candee and colleagues in 2013^[6]), other incidental findings, such as Arnold-Chiari malformations, are possible. However, even Chiari malformations are asymptomatic in > 50% of affected children. When symptomatic, they tend to cause occipital headaches. Red flags include a cough or difficulty with swallowing. Therefore, the finding of a Chiari malformation in the setting of headache is probably important only in a patient with neurologic symptoms.

Arachnoid cysts may be identified in 4.4% of patients.^[7] Managing these incidental but potentially clinically insignificant findings is one of the real disadvantages of imaging for headache, especially if it is not clear whether imaging was indicated in the first place.

Dr Moore's take-home points were that imaging is generally overused in the evaluation of headache, and the rate of true abnormalities is low. To limit imaging and focus on the appropriate modalities, the American College of Radiology has developed a set of reference tables to help clinicians decide on the appropriateness of imaging, as well as which imaging modalities to avoid. These tables provide different clinical and headache scenarios, such as "new," "chronic," or "sudden onset."

The tables are organized by chief symptom, and the imaging modalities are ranked by appropriateness (based on evidence) and show the radiation impact of each test. For example, a patient with acute headache ("worst headache ever"), an abnormal neurologic exam, or the suggestion of progressive symptoms should have emergent CT, usually without contrast. (In the acute setting, contrast does not add much benefit but extends radiation exposure). If none of those criteria are present and the headache seems chronic, MRI is generally the recommended modality.

Although having these tables at hand might be a challenge for most clinicians, they can undoubtedly help to ensure that ideal care is delivered to children with headache.

Medscape Pediatrics © 2015  WebMD, LLC

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: William T. Basco. Pediatric Primary Headache From A to Z - Medscape - Jun 24, 2015.