Migraine in children

Migraine is a recurrent headache that may occur with or without aura. It is a highly prevalent condition, affecting around 12% of the population. It may occur at all ages from infancy up until adulthood.

The distribution between boys and girls is the same in prepubertal years, but during puberty it begins to affect girls more than boys.

Pathophysiology

The pathophysiology behind migraine is not well understood at this point. It seems to be an interplay of genetic factors and environmental factors alike.

Let’s look at some of the factors involved:

1. Genetics

Seeing as individuals with a family history are more likely to experience migraines, there seems to be a clear genetic component to the disease aetiology.

2. Neuronal hyperexcitability

When migraines occur, there seems to be abnormalities in the activity of the brain especially in migraines with aura. There is a wave of sustained depolarisation followed by a period of neuronal inhibition. This is known as cortical spreading depression (CSD) and is responsible for the aura symptoms perceived.

3. Vascular changes

There was previously the theory that migraines were the result of vasodilation within the brain. This was known as the vascular theory of migraine and has subsequently been discredited. It now seems as though the vascular changes seen in migraine are due to neuronal mechanisms. The changes in blood flow and vasodilation do seem to have a role in the headache phase of migraines.

4. Neurotransmitters

Neurtotransmitters suc has serotonin, dopamine, calcitonin gene-related peptide (CGRP) are all involved in migraine pathophysiology. Serotonin levels drop during an attack and this may contribute to the vascular changes seen within the cranial blood vessels. It may also be involved with sensitisation of the afferent fibres in the meninges which leads to pain sensitisation.

5. Trigeminovascular system activation

The trigeminovascular system is a neural pathway primarily involving the trigeminal nerve (CNV)and associated blood vessels that plays a pivotal role in pain perception, particularly related to migraines and headaches. Activation of this system can lead to the release of inflammatory mediators, sensitizing nerve fibres and contributing to the sensation of pain.

6. Neuroinflammation

Evidence shows that inflammation of the brain and the perivascular regions are involved in migraines.

7. Sensory processing abnormalities - individuals suffering from migraines experience altered perception and sensitivity to light, sound and smells during an attack.

Migraine with aura is associated with right → left cardiac shunts (such as a foramen ovale or an atrial septal defect). However, this is more likely an association and not causative relation.

🔢 😷 Classification and presentation

In this section we will discuss:

• Migraine without aura
• Migraine with aura
• Episodic syndromes associated with migraines

Migraine without aura:

Migraine without aura is the second most common primary cause of headache in children after tension headache.

😷 Presentation

• Headache - the headache is commonly bilateral and in the frontotemporal region in children. As the child grows older and nears adolescence, migraines tend to become unilateral. The headache is pulsatile in nature and can range in severity.
• Nausea and vomiting
• Photophobia
• Phonophobia

There may also be prodromal and postdromal symptoms:

• Prodromal symptoms - these include fatigue, poor concentration, neck stiffness, yawning, thirst. These may occur 1-2 days before the onset of the migraine.
• Postdromal symptoms - these include fatigue, depressed mood, elated mood. This may last up to 48 hours after resolution of the migraine.

Migraine with aura:

Migraine with aura is characterised by transient focal neurological symptoms that precede/accompany the headache.

Aura symptoms are usually:

1. Unilateral
2. Reversible
3. Most commonly visual or sensory

• Visual auras - symptoms include:
• Blurred vision
• Fortification spectra - flashes of light in a zigzag pattern that resembles a fort.
• Scotoma (can also be seen as a scintillating scotoma).
• Micropsia - objects are perceived to be smaller than they are.
• Macropsia - objects are perceived to be bigger than they are.
• Dysmorphopsia - visual distortion.

• Sensory auras - symptoms include:
• Tingling or numbness - often starting in the hand, face, or one side of the body and then spreading.
• Altered sensations - such as the feeling of the skin being touched or skin crawling.

These symptoms develop gradually over ≥5 minutes and the headache follows within 60 minutes usually.

There may also be prodromal and postdromal symptoms:

• Prodromal symptoms - these include fatigue, poor concentration, neck stiffness, yawning, thirst. These may occur 1-2 days before the onset of the migraine.
• Postdromal symptoms - these include fatigue, depressed mood, elated mood. This may last up to 48 hours after resolution of the migraine.

Migrain with aura now has some subtypes based on the clinical phenotype:

1. Hemiplegic migraine - hemipleIgia or hemiparesis precedes or accompanies the headache and there is often a positive family history.
2. Basilar migraine - there may be aura followed by dizziness, syncope and a minimal headache. Often seen in adolescent girls.
3. Ophthalmic migraine - there may be eye movement disorders or abnormal pupillary responses followed by the headache.
4. Acute confusional migraine - these are transient episodes of amnesia, confusion, Broca’s aphasia (expressive aphasia) or dysphasia after minor head trauma. This may be preceded or followed by a headache.

Episodic syndromes associated with migraines:

In childhood, there sometimes are a group of syndromes associated with migraines that are predominantly seen in children. These syndromes often precede or occur in the absence of an actual migraine headache. Some of the episodic syndromes associated with migraines include:

• Cyclical vomiting with migraine - this is characterised by recurrent episodes of intense nausea and vomiting occurring often at night and with complete recovery in between attacks. Girls are more affected. Stress and dietary triggers may be identified.
• Abdominal migraine - this is characterised by recurrent bouts of abdominal pain in an otherwise healthy child. The pain is associated with nausea and vomiting but there is no headache. It is followed by sleep which is then followed by complete recovery The typical migraine may occur separately.
• Benign paroxysmal vertigo - usually seen from 2-6 years of age. It is characterised by brief episodes of vertigo and nausea with no hearing loss or loss of consciousness. The headache ensues later on. It is important to rule out a posterior fossa tumour in these children.
• Benign paroxysmal torticollis - this is characterised by an abnormal, sustained posture of the head and neck in which the head is tilted to one side with/without rotation. It can last minutes - days. Associated symptoms include pallor, irritability, malaise, vomiting and ataxia.

🔍 Investigations

The diagnosis of migraine in children is a clinical diagnosis based on history from the child or parent/guardian.

To diagnose migraine with/without aura we need to meet the following criteria:

• Episodic migraines - must occur on <15 days a month.
• Chronic migraines - must occur on ≥15 days a month.
• Menstrual migraines - migraine occurs in menstruating women from 2 days before menses until the 3rd day of menses. It must have happened for ≥2 of 3 consecutive cycles.

Further investigations are indicated when:

1. Aura not followed by migraine - this is known as a silent migraine and it makes it difficult to rule out an alternative diagnosis such as a TIA.
2. Atypical aura - this is an aura with the following features:
1. Motor weakness
2. Double vision
3. Unilateral visual symptoms
4. Poor balance
5. Decreased consciousness

🧰 Management

The aim of management in children is to reduce headache frequency, duration, severity and associated disability.

We can provide migraine attack relief as well as anti-emetics.

🚨 Complications

• Status migrainosus - a debilitating migraine lasting 72 hours or more.
• Medication overuse headache
• Migrainous infarction - 1 or more symptoms of aura lasting >60 minutes with evidence of an ischaemic brain lesion on neuroimaging.
• Migraine aura-triggered seizure
• Persisten aura without infarction - aura symptoms lasting >1 week with no evidence of infarction on neuroimaging.
• Increased risk of stroke