Aetiology
Studies of children presenting to the accident and emergency department with headache have demonstrated that the most common aetiologies include primary headache (mostly migraine and rarely tension-type) and sinusitis-related headache.[1][2][5] Primary headache disorders require exclusion of secondary headache aetiologies.
Significant intracranial pathology (including meningitis, ventriculoperitoneal shunt malfunction, neoplasm, intracranial haemorrhage, and idiopathic intracranial hypertension) is rare in children with headache.[6][7][8]
All children presenting with headache require a thorough history and examination, with judicious use of neuroimaging.[1][2][5][7][9]
Traumatic
Head trauma may lead to cerebral contusion, post-traumatic headache, and haemorrhage (e.g., parenchymal, subdural, epidural, and subarachnoid).
Urgent evaluation for secondary causes of headache is generally indicated when there is a history of head trauma preceding the headache. A detailed neurological examination is essential. If one of these secondary aetiologies is suspected, urgent neuroimaging is indicated.
Vascular
Headache may be symptomatic of underlying vascular conditions.
Migraine: unilateral or bilateral; moderate-to-severe intensity; often associated with nausea, vomiting, and visual disturbances.[3][10]
Dissection (carotid, vertebral, or intracranial arteries): may be a history of head or neck injury; onset of symptoms may be delayed.
Intracranial haemorrhage: subarachnoid (can occur due to aneurysm rupture or in the context of traumatic brain injury); parenchymal (may be related to vascular malformations or there may be history of trauma).
Ischaemic stroke: acute onset of headache with focal seizures and symptoms of elevated intracranial pressure (headache, vomiting, depressed consciousness).
Sinovenous thrombosis: gradual onset of headache made worse by bending over or squatting, or while straining with bowel movements (Valsalva).
If secondary vascular aetiology is suspected, urgent neuroimaging with a non-contrast head computed tomography (CT) is indicated (blood appears hyperdense).[9]
Infectious
Intracranial infections include the following:
Encephalitis: can be secondary to common but preventable childhood infections such as measles, mumps, and rubella.
Meningitis: Streptococcus pneumoniae and Neisseria meningitidis are the most common causes of bacterial meningitis in children; viral meningitis is usually milder). Meningitis may be difficult to identify in children, who may present with non-specific symptoms and signs.[11] Patients with headache and fever or neck stiffness should generally undergo a lumbar puncture, unless the procedure is contraindicated.[11] If raised intracranial pressure is suspected, carry out neuroimaging first to rule out any intracranial lesions. If lumbar puncture cannot be performed rapidly, antibiotics and antivirals may be initiated before cerebrospinal fluid (CSF) is evaluated.
Dental caries, abscess, and gingival disease: dental pain requires dental referral.
Sinusitis: tenderness to palpation, inflamed mucosa, and purulent nasal discharge may suggest sinusitis. May be accompanied by dental or ear pain.
Neoplastic
Common brain tumours in children are: astrocytoma, medulloblastoma, and ependymoma.
Brain tumours may lead to intracranial pressure that develops gradually as the tumour enlarges, or abruptly if there is an intra-tumour haemorrhage (with concomitant hydrocephalus). Often these patients present with chronically worsening headache that may be more severe when lying supine and in the morning.
Of children with brain tumours, 62% have headache prior to diagnosis, and 98% have at least one neurological symptom or abnormality on examination.[4]
Head CT may identify large tumours, but magnetic resonance imaging (MRI) without and with contrast is the optimal imaging study.[9]
Medication-associated
Medication overuse headache: overuse of many prescription and non-prescription headache drugs (e.g., ergotamine, triptans, analgesics, opioids, or a combination of these drugs) may cause chronic headache.
With transformation to chronic headache, features of the initial underlying headache condition may be reduced or absent, so the history must include a description of the initial headache that led to drug use.
Identification and withdrawal of culprit drug is an important component of headache treatment.
Indomethacin-responsive headache: some trigeminal autonomic cephalgia forms of primary headache are responsive to indomethacin.
Characterised by headache and autonomic symptoms.
Paroxysmal hemicrania (unilateral, severe, boring headache lasting 20 minutes occurring 10 to 40 times per day with autonomic symptoms such as nasal congestion, lacrimation, and conjunctival injection).
Hemicrania continua (unilateral headache lasting hours or days associated with milder autonomic or migrainous symptoms).
Musculoskeletal
Muscle tension and joint abnormalities (e.g., temporomandibular joint disorders): may result in headache pain.
The headache examination must identify the exact site of the pain. Tenderness and positional exacerbations are important clues for entrapments.
Examination of the oropharynx and teeth and palpation of neck muscles is an important component of the physical examination.
Other
The International Headache Society recognises several other important primary aetiologies to consider.[3]
Cluster headache: patients present with a stabbing excruciating headache often at the orbit that lasts 15 to 180 minutes and occurs 1 to 10 times per day. Autonomic features are present, including lacrimation, conjunctival injection, nasal congestion, ptosis, and eyelid oedema. MRI is indicated because, although rare, it may be symptomatic of a brain lesion in children.
New daily persistent headache: characterised by a headache lasting for more than 3 months that is unremitting and occurs daily from within 3 days of onset. May be secondary to underlying pathology, so MRI with contrast, sometimes also with MR venography, and CSF evaluation including opening pressure is important.
Other important secondary aetiologies include:
Hypertensive encephalopathy: patients may present with blood pressure elevation.
Pituitary apoplexy: may present with abnormalities on eye movement and/or altered mental status.
Ventriculoperitoneal shunt dysfunction: children with ventriculoperitoneal shunts may experience shunt dysfunction (proximal or distal aetiologies). Requires urgent intervention, especially if intracranial hypertension is suspected (optic nerve oedema, cranial nerve VI palsy with horizontal diplopia, headache worse when supine).
Idiopathic intracranial hypertension (pseudotumour cerebri): optic nerve oedema or use of provoking drugs should prompt consideration of idiopathic intracranial hypertension. Lumbar puncture must include an opening pressure.
Intermittent hydrocephalus: may occur when a mass lesion intermittently obstructs CSF flow, especially near the narrow structure of the ventricular system. If pressure remains elevated only briefly, optic nerve oedema may not develop. Diagnosis is important because future obstructions (especially during sleep) might not self-resolve, and can rapidly cause intracranial hypertension due to obstructive hydrocephalus.
A detailed history is important in identifying these rare but important secondary causes of headache.
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