Abstract
Cervicogenic headache (CEH) is currently identified with different diagnostic criteria. The latest one is the International classification of headache disorders (ICHD), 3rd edition (2018). At the present time, there are not enough published articles with reliable sensitivity and specificity that may support a classification for clinical and research purposes. Current literature suggests improvement to the classification(s). The ICHD criteria should be modified to reach an optimal sensitive and specific level to identify CEH as a secondary headache. The B, C1, and C2 criteria should be implemented with proposed suggestions. The C3 criterion should be upgraded. Criteria such as mechanical precipitation of pain by digital pressure on neck trigger points and specific movements, strictly unilateral pain without side-shift, diffuse unilateral shoulder and arm pain, pain starting posteriorly and spreading anteriorly should be integral part of the classification.
Introduction
Headache caused by a pathology in the neck was probably described more than 150 years ago, according to Bärtschi-Rochaix (1–3). Cervicogenic headache (CEH) patients were described in 1983 (3), but diagnostic criteria have been described in our time, in 1990, 1998, 2004 and 2018 respectively (4–7).
Later on, possible and probable CEH criteria were proposed (8); in addition, an algorithm for diagnosis and treatment of the headache has been published (9).
In the current literature, two different trends have been put forward. The former was the approach of European headache specialists, proposing diagnostic criteria according to history and neck examinations. The latter trend is the one proposed by headache specialist from Australia and North America especially, focusing on diagnostic blocks as a tool to locate the source of pain (10,11). The latest version of IHS classifications seems to partially include both concepts in the existing knowledge (7).
Epidemiology
CEH prevalence may vary according to which CEH diagnostic criteria are used; it may range between 0.1–4.1% (8,10,12,13). Prevalence according to IHS classification criteria is 1%. (14,15). The prevalence range is 2.2–4.1% in studies that used Cervicogenic Headache International Study Group (CHISG) criteria (12). The figures obtained by the Vaga studies are based on the following criteria: a) Range of motion of neck restricted more than >10° on the painful side; b) pain starting from posterior part of the head; c) headache provoked by mechanical pressure; d) same side shoulder and arm discomfort; e) male predominance, contrary to migraine (12).
CEH affects males and females about the same, with a ratio of 0.97 (F/M ratio). Age at onset is thought to be the early 30s, but patients seek medical attention and diagnosis in their 50s.
Pathophysiology
CEH is a kind of referred pain arising from involved cervical structures that are innervated by the C1, C2, and C3 spinal nerves. An anatomical lesion at such a level could be one of the sources of CEH (10).
CEH is not a disease, it is a syndrome (16). Cervical spine and soft tissue pathologies, and posterior fossa, nasopharynx neoplasias, vertebral and internal carotid artery pathologies may be the cause of CEH (9,10,17). Since different etiologies may cause a clinical picture resembling CEH, the adherence to classification criteria might create difficulties. Anaesthetic blocks may be necessary in some cases.
The trigeminocervical nucleus plays a major role in CEH. In CEH, there is no significant difference between jugular and cubital CGRP level during headache and headache-free days in the symptomatic and the asymptomatic side (18). This may be evidence that CEH does not share migraine pathophysiology.
Diagnostic criteria
The diagnostic criteria for cervicogenic headache according to the IHS classification (7) describe the headache according to two major points:
B) Clinical and/or imaging evidence of a disorder or lesion within the cervical spine or soft tissues of the neck, known to be able to cause headache.
C) Evidence of causation demonstrated by at least two of the following points:
Headache has developed in temporal relation to the onset of the cervical disorder or appearance of the lesion. Headache has significantly improved or resolved in parallel with improvement in or resolution of the cervical disorder or lesion. Cervical range of motion is reduced, and headache is made significantly worse by provocative maneuvers. Headache is abolished following diagnostic blockade of a cervical structure or its nerve supply.
The B criterion provides evidence that the diagnosis can be made on the basis of a solitary criterion; this is the imaging evidence of a neck lesion that may hypothetically provoke headache (tumor, rheumatoid arthritis etc). Such a statement is relatively in conflict with the first Note of the classification, assessing an uncertain role for imaging in the cervical spine.
The C1 criterion is not appropriate for clinical work. It is a limitative statement concerning a headache that started in the past with uncertainty as to the temporal pattern of cervical pathology. Otherwise, one should follow up the patient during the growth and development of the causative pathological process. The C1 point should include headache characteristics (localisation, intensity, and duration) not specified elsewhere, followed by other characteristic traits (trigger mechanisms, limitation in range of motion etc) (12,19).
The C2 criterion has also limitations and excludes the possibility of both a remitting pain and a primary/secondary chronic pain. If we consider the treatment efficacy and amelioration obtained under TENS treatment, manual therapy, exercise treatment, RF neurotomy and surgery, the target of an amelioration of more than 50% is safer than the term “significant”, which implies a greater amelioration. Since there are no placebo controlled, randomised studies, further studies are recommended (9,10,20–23).
The C3 criterion does not indicate the way one should evaluate the range of motion and at which degree (e.g. 10 degrees), so it should be considered limited. The same criticism concerns the extent to which the pain should be worsened. Under this criterion, it should also have been mentioned that local provocation or worsening of the original pain attacks can be evoked in two different ways: Digital pressure or positioning the neck awkwardly for a sufficient time. A careful specification of the aforementioned points is important because myofascial triggering points may be found in different types of primary headaches (24). The range of motion (ROM) may be decreased as well. The cervical ROM is reduced in the flexion-rotation test by 10° or more on the symptomatic side. This criterion should probably be added (25–30).
The C4 criterion concerns the diagnostic capacity of an anaesthetic blockade, and this is recommended in the present form. According to some authors, a sensitivity of 95% can be reached by blocking a cervical structure or its supplying nerve using randomly short- or long-acting local anaesthetic and placebo (11). In our view, the diagnostic accuracy and specificity of the criterion would greatly benefit from the addition of the last point of the Note of the IHS classification.
At the present time, we may suggest that a definite diagnosis of CEH can be reached using the diagnostic criteria suggested by the Vaga study (12,19,31). The criteria are the following: i) Unilateral head pain without side shift; ii) provocation via unphysiological neck positions; iii) external provocation of the neck/occipital area; iv) deficit of range of motion, neck; v) diffuse shoulder pain; vi) diffuse arm pain; viii) pain, starting posteriorly and ending anteriorly; ix) diagnostic, anaesthetic blockades.
New diagnostic criteria proposals for cervicogenic headache are shown in Table 1.
Suggested diagnostic criteria for cervicogenic headache.
1–5Notes 1–5 are the same as ICHD-3 (7).
Clinical picture
The clinical picture of CEH is characterised by a prevalence of unilateral headache, pain spreading to the other side may occur if attacks are long lasting and/or severe but the usual side dominates. Neck pain commonly spreads along the shoulder and arm. Pain starts in the nape of the neck then spreads to the forward area. Neck mobility is reduced (25–30). Typical CEH attacks can be precipitated by uncomfortable positioning of the neck or by digital compression of sensitive areas.
Work-up
Diagnostic imaging of the cervical spine is not sufficiently helpful to diagnose a cervicogenic headache. Cervical CT, plain x-ray, cervical, cranial and craniocervical MR, cerebral angiography, and cervical myelography did not show any significant pathology in patients selected according to CHISG criteria. No specific radiologic abnormalities were found by recent studies (32–35).
A careful clinical examination of the neck should be carried out evaluating neck muscles, tendon insertion and trigger points (i.e. great occipital nerve, minor occipital nerve, etc). Decrease in ROM of the neck, especially in the flexion-rotation test, has been proposed as significantly meaningful. This test differentiated CEH from migraine (25–30).
Occipital pain and pain starting from the neck may indicate possible CEH. If pain radiates to the shoulder and has a non-throbbing quality, has a varying duration or is continuous, and if patients have a history of neck trauma, a probable CEH diagnosis may be considered. When we consider all these findings for clinical purposes, the “probable” and “possible” CEH diagnosis by Antonaci et al. can be used to diagnose CEH (8).
Differential diagnosis
A cervicogenic headache is a frequent cause of chronic headache, which is commonly misdiagnosed. The first step in patients suffering from CEH is a differential diagnosis with migraine. CEH has different characteristics at variance with migraine. Two studies may provide evidence in this context. First, the absence of CGRP increase in plasma concentration during pain in the CEH period (16) and second, the lack of a protective effect of pregnancy in CEH as there is in migraine (36). Moreover, treatments for migraine (triptans etc) and CEH (TENS, exercise, nerve blocks, radiofrequency neurotomy and surgery) support the hypothesis that we are facing two different entities.
Treatment
Early diagnosis and treatment are important to decrease the sensitisation and alleviate pain in these patients. Management of this condition requires a multidisciplinary approach.
The treatment of choice at this level may be physical therapy modalities such as TENS, exercise and manual therapy. When these treatment modalities do not work, diagnostic blocks according to the Bogduk algorithm can be applied (9). The use of diagnostic blocks may corroborate the diagnostic criteria. Unfortunately, blockade of the zygopophysial joint (ZAJ) and nerves is not familiar to the general neurologist; therefore, a collaborative approach with pain therapy physicians is suggested (11,37).
Another option for treatment of a cervicogenic headache is invasive interventional treatment, which will differ depending on the cause of the headache.
In conclusion, we are aware that setting up randomised, placebo-controlled studies for headache stemming from the neck may present several difficulties. We foresee the time when planning therapeutic guideline and observational studies will be carried out and the results used in the daily routine (38).
Key findings
Current diagnostic criteria should be upgraded. Side-locked pain, mechanical precipitation and reproduction of pain attack, and radiation of pain from back to front should be included in the current IHS criteria. Proposal for upgraded diagnostic criteria is suggested.
Footnotes
Acknowledgements
The authors thank TA Fredriksen and O Sjaastad for their useful comments.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.