Pediatric migraine and episodic syndromes that may be associated with migraine

Abstract

Importance: Migraine is a common disorder and a frequent cause of medical consultation in children. Many childhood episodic syndromes have been described as common precursors of migraine.

Objective: To review current knowledge on migraine and childhood episodic syndromes, and to discuss future directions for research and clinical practice.

Findings: For most children it is difficult to describe a headache and fully verbalize symptoms such as photophobia and phonophobia that must be inferred from behaviour. Classical migraine features are rare before the age of 6 years, but some migraine-related syndromes have been described. Benign paroxysmal torticollis of infancy, benign paroxysmal vertigo of childhood, cyclic vomiting syndrome and abdominal migraine are currently classified as childhood episodic syndromes, and therefore common precursors of migraine. A strong association between infantile colic and migraine has recently been reported. There are similarities between children with episodic syndromes and children with migraine, regarding social and demographic factors, precipitating and relieving factors, and accompanying gastrointestinal, neurologic, and vasomotor features. The real pathophysiological mechanisms of migraine are not fully understood. Current data obtained through molecular and functional studies provide a complex model in which vascular and neurologic events cooperate in the pathogenesis of migraine attacks. Genetic factors causing disturbances in neuronal ion channels, make a migraineur more sensitive to multiple trigger factors that activate the nociception cascade. The expanding knowledge on migraine genetics and pathophysiology may be applicable to childhood episodic syndromes. Migraine preventive strategies are particularly important in children, and could be beneficial in childhood episodic syndromes. Nonspecific analgesics like ibuprofen and acetaminophen are widely used in pediatrics to control pain and have been found to be effective also in the treatment of acute migraine attacks. Triptans are the specific fist-line drugs for acute migraine treatment.

Conclusions and relevance: Migraine phenotype differs somewhat in the developing brain, and childhood episodic syndromes may arise before typical migraine headache. Diagnosing pediatric migraine may be difficult because of children's language and cognitive abilities. The risk of underestimating migraine in pediatric age is high. An adequate diagnosis is important to maintain a good quality of life and to avoid inappropriate therapy.

Figure 1

Migraine pain generation. Migraine triggers initiate the neuronal excitation that leads to clinical manifestations in children with a genetic vulnerability to migraine. Cortical spreading depression (CSD) triggers plasma protein extravasation from cerebral blood vessels, which in turn activates trigeminal (TG) afferents within the trigemino-vascular system (TVS). Gene mutations could reduce the threshold for firing of TG neurons. Signals are transduced to the trigeminal nucleus caudalis (TNC), which receives modulatory inputs from other brainstem nuclei (BN), such as the periaqueductal gray, the locus coeruleus and the raphe. The TNC projects to rostral brain areas, where the perception of pain is generated.

Figure 2

Age-related expression of childhood episodic syndromes common precursors of migraine. * = infantile colic is actually considered as an episodic syndrome that may be associated with migraine.