European Headache Federation consensus on technical investigation for primary headache disorders.

The diagnosis of primary headache disorders is clinical and based on the diagnostic criteria of the International Headache Society (ICHD-3-beta). However several brain conditions may mimic primary headache disorders and laboratory investigation may be needed. This necessity occurs when the treating physician doubts for the primary origin of headache. Features that represent a warning for a possible underlying disorder causing the headache are new onset headache, change in previously stable headache pattern, headache that abruptly reaches the peak level, headache that changes with posture, headache awakening the patient, or precipitated by physical activity or Valsalva manoeuvre, first onset of headache ≥50 years of age, neurological symptoms or signs, trauma, fever, seizures, history of malignancy, history of HIV or active infections, and prior history of stroke or intracranial bleeding. All national headache societies and the European Headache Alliance invited to review and comment the consensus before the final draft. The consensus recommends brain MRI for the case of migraine with aura that persists on one side or in brainstem aura. Persistent aura without infarction and migrainous infarction require brain MRI, MRA and MRV. Brain MRI with detailed study of the pituitary area and cavernous sinus, is recommended for all TACs. For primary cough headache, exercise headache, headache associated with sexual activity, thunderclap headache and hypnic headache apart from brain MRI additional tests may be required. Because there is little and no good evidence the committee constructed a consensus based on the opinion of experts, and should be treated as imperfect.

Main text

Headache is a symptom in the main rather a condition. Only when headache attacks fulfill specific diagnostic criteria consistently does a primary headache disorder occur [1]. Accompanying symptoms are important together with the particular headache characteristics including pain severity, duration, quality and location. In most cases headache is primary but secondary headache disorders may be related to life threatening conditions. They may respond to common analgesics and mimic primary ones a lot. Diagnostic tests are necessary therefore when the treating physician doubts for the primary origin of headache. Up-to-date there is no official recommendation for these tests, although headache remains the commonest presenting symptom in people asking medical consultation. To bridge this gap European Headache Federation (EHF) appointed an internal and external committee to prepare a consensus on the diagnostic testing that primary headache disorders may require. The procedure followed was consisted of three phases. In phase one members of the Executive Board of EHF (internal committee: DDM, AS, CL, KP, VO and PM) prepared the first draft that was send to all National European Headache Societies for review. Thirteen National Headache Societies replied (40 %) with comments. European Headache Alliance also participated in this review phase. Based on their comments and suggestions draft 2 was edited (phase 2) that was applied for review in a group of distinguished headache specialists that EHF appointed as the external subcommittee (MA, HCD, MDF, PJG, JP, and JO). After fulfilling all comments into one manuscript the final draft of the consensus was arranged (phase 3), which is presented in the Appendix. Table 1 summarizes the principles.

Table 1

Tests recommended for primary headache disorders

ICHD-IIIb code	Disorder	Tests
1	Migraine
1.1	Migraine without aura	None
	Frequent episodic migraine	Brain MRIa
		Carodit ultrasound or MRAa
		ESRa
1.2	Migraine with aura	Brain MRIa
1.2.2	Migraine with brainstem aura	Brain MRI & MRA
		EEGa
		Carotid and vertebral arteries ultrasound/or CT or MRAa
		Genetic evaluationa
1.3	Chronic migraine	Brain MRI Gd & MRVa
		Fundoscopya
		Lumbar puncturea
		Polysomnographya
1.4	Complications of migraine	Brain MRI
1.4.1/2	Persistence of aura symptoms	Emergency brain CT or MRI
		Carotid and vertebral arteries ultrasound/or CT or MRA
		ESRa
1.4.3	Migrainous infarction	Emergency brain CT or MRI
		Carotid and vertebral arteries ultrasound/or CT or MRAa
		ESRa
1.4.3	Migraine aura-triggered seizures	Repetitive EEGs or video EEG
1.5	Probable migraine	Brain MRIa
1.6	Episodic syndromes that may be associated with migraine	Gastric work-up
2	TTH
2.1	Infrequent TTH	None
2.2 and 3	Frequent TTH and Chronic TTH	Brain MRI MRI Gd & MRVa
		Fundoscopya
		Lumbar puncturea
		Polysomnographya
3	TACs (all)	Brain MRI
		Brain MRA and Carotid and vertebral arteries ultrasound/or CT or MRAa
		Pituitary function testinga
3.1	Cluster headache	+Polysomnographya
3.2	Paraxysmal Hemicrania	Brain MRI and MRA and Carotid and vertebral arteries ultrasound/or CT or MRAa
3.3	Suna & Sunct	+ High resolution MRI of brainstem
3.4	Hemicrania Continua	Brain MRI
		Brain MRA and Carotid and vertebral arteries ultrasound/or CT or MRAa
4	Other primary headache disorders
4.1	Primary cough headache	Brain MRI
		Cranio-cervical and brain MRAa
4.2	Primary exercise headache	Brain MRI and MRA/MRV
		Lumbar puncturea
		Carotid & vertebral ultrasound, or CT or MRA
		Cardiological evaluation a
4.3	Primary headache associated with sexual activity	Brain MRI, MRA/MRV
		Carotid and vertebral arteries ultrasound/or CT or MRA
		Lumbar puncturea
		ESR, CRPa
4.4	Primary thunderclap headache	Brain MRI, MRA/MRV
		Carotid and vertebral arteries ultrasound/or CT or MRA
		Lumbar puncturea
		ESR, CRPa
4.5	Cold-stimulus headache	None
4.6	External-pressure headache	None
4.7	Primary stabbing headache	Brain MRI, MRA/MRV
		Carotid and vertebral arteries ultrasound/or CT or MRA
		Lumbar puncturea
		ESR, CRPa
4.8	Nummular headache	Brain MRI, ESR, ANF and RF
4.9	Hypnic headache	Brain MRI, ESR, CRP
		Polysomnography
		24-hour blood pressure monitoring
4.10	New daily persistent headache	Brain MRI, MRA
		Lumbar puncturea

aIndicates specific conditions