Standard laboratory tests on blood and urine are normal, and there is no laboratory test that is diagnostic for migraine. Unless there is a specific indication, tests are unnecessary (Lewis et al 2002). Standard CSF analysis is usually normal, even with hemiplegic migraine. However, the syndrome HaNDL might mimic hemiplegic migraine. HaNDL rarely occurs in children, and can be excluded if CSF is normal (Goncalves et al 2013). In general, if lumbar puncture demonstrates abnormalities, then a process other than migraine should be considered (eg, inflammatory disease, mitochondriopathy, hemorrhage). EEG is not recommended for routine evaluation of migraine (Lewis et al 2002), but may be performed if there is a clinical suspicion for seizures, realizing that abnormalities occur frequently in children with migraine and in most cases do not clearly define an epileptic disorder. Migraine-associated EEG abnormalities are relatively common: 10% to 75% in total (paroxysmal in 20% to 30%). For example, midtemporal or central spikes have been reported in 9% of children with migraine who did not have seizures (Kinast et al 1982). With occipital epilepsy, but not with migraine, spikes occur when the eyes are closed. In children who have typical migraine (ie, migraine with or without aura) and who have normal physical and neurologic examinations, brain MRI is normal or has findings that do not require surgical treatment (Lewis et al 2002). Subsequent studies support this conclusion. Thus, brain MRIs were performed in 375 of 926 pediatric patients with migraine. Among them, 24 (6%) had nonprogressive, predominantly frontal T2/FLAIR white-matter hyperintensities and none had stroke. Other MRI abnormalities were not clearly related to the migraine headaches (Chiari malformations, arachnoid cysts, pineal or other cysts, etc.) (Mar et al 2013). A Head CT scan, eg, in the emergency department, is not useful unless the child has acute abnormalities other than headache.
Lewis and colleagues created a practice parameter for children 3 to 18 years that recommends consideration of neuroimaging in children who have an abnormal neurologic examination, or for children who have other physical findings that suggest disease of the central nervous system (Lewis et al 2002). I often perform neuroimaging in the following situations: