Intermediate cervical plexus block in the management of treatment resistant chronic cluster headache following whiplash trauma in three patients: a case series

Introduction

Cluster headache (CH) is a trigeminal autonomic cephalagia characterized by extremely painful, strictly unilateral, periorbital, short-lasting (15–180 min) headaches accompanied by ipsilateral autonomic symptoms or a sense of restless and agitation, or both [1]. The commonest presentation in 85–90% is episodic CH (ECH) where at least two cluster periods lasting 7 days to 1 year, separated by pain free periods lasting 1 month or more. In 15%, CH can be chronic (CCH) where attacks occur for more than 1 year without remission or with remission lasting less than 1 month [1]. The trigemino-cervical complex has a central role together with synchronous hypothalamic activation and autonomic dysfunction in the pathogenesis of CH [2]. Conventional treatment includes abortive agents to treat an acute attack and preventative medications. In patients who fail to respond to conventional treatment, quality of life can be severely impaired, often presenting with extreme distress [3].

Whiplash can result in a constellation of symptoms referred to as whiplash-associated disorder (WAD). WAD includes neck pain, headache, facial pain, jaw pain, upper back pain, arm pain and tinnitus [4]. There is evidence of activation of trigemino-cervical complex in both whiplash injury and cluster headaches [2, 5, 6]. Intermediate cervical plexus block (iCPB) is a novel treatment in the management of persistent pain following whiplash [7].

The author presents three patients with treatment resistant CCH on a background of whiplash trauma, who reported significant and durable relief following iCPB. Patients provided written informed consent for their de-identified data to be used for analysis and for publication in a peer-reviewed journal.

Case reports

All patients presenting with chronic oro-facial pain including persistent headaches were included in an on-going prospective audit registered with the Clinical Audit Safety and Effectiveness (CASE 8161), University Hospitals of Leicester NHS Trust, United Kingdom [8]. Patients completed brief pain inventory short form (BPI-SF) and Hospital Anxiety and Depression Scale (HADS) questionnaires to record baseline scores. Post-treatment, the patients completed BPI-SF and HADS questionnaire 6 months (Table 1). Specialist pain nurses performed telephone follow-up.

Ultrasound guided intermediate cervical plexus block

The procedure was performed under local anesthesia in the outpatient suite. The patient was positioned in the lateral decubitus position. The skin over the sternocleidomastoid muscle was prepared with 2% chlorhexidine solution. A high frequency (5–10 MHz) ultrasound probe (S-NerveTM; SonoSite Inc., Washington, USA) was placed across the sternocleidomastoid muscle at the third cervical vertebral level. The muscle, the underlying vascular structures and the posterior cervical space (PCS, fascial plane between the posterior sheath of the muscle and the prevertebral fascia) were visualized (Figure 1). Thereafter, a 23-gauge 50 mm hypodermic needle was inserted in the plane of the ultrasound beam towards the posterior cervical space. Once the needle entered the PCS, 9 mL of a mixture of 1% lidocaine and depot methylprednisolone (60 mg) was injected after negative aspiration. The procedure was repeated on the contralateral side, if required.

Figure 1:

The ultrasound image of the neck details the sternocleidomastoid (SCM) muscle, the posterior border of the sternocleidomastoid muscle (coloured line) and the posterior cervical space (PCS). SCM, sternocleidomastoid muscle; PCS, posterior cervical space; IJV, internal jugular vein; CA, carotid artery.

Case 1: A 35-year-old male with a nine-year history of CH (right side) presented to the pain medicine clinic. CH was episodic for the first six years. Patient reported a good response to verapamil and lithium. At presentation, CH had been chronic for three years. The icepick headache was periorbital associated with nasal congestion, tearing and agitation. The patient reported 5–7 episodes/day, each lasting 30–90 min especially at night. Trial of verapamil, lithium topiramate, sumatriptan and pregabalin failed. Home oxygen treatment was effective at night. Magnetic resonance imaging (MRI) of the head and cervical spine was normal. The patient received greater occipital nerve block (GONB) with steroids that provided 30% improvement for six weeks. CCH recurred and the patient reported severe distress, inability to continue employment and suicidal ideation. During a review, the patient reported multiple episodes of neck trauma while playing rugby prior to the onset of CH and treatment for whiplash. He was offered iCPB. At three and six month review, he reported complete absence of headaches. At nine-month review, he reported 40% improvement. CH returned to baseline at 12 months and iCPB was repeated. The patient received iCPB once every 12 months for three years and the treatment effect was reproduced after each intervention (Table 1). The patient was able to maintain gainful employment.

Case 2: A 44-year-old male presented to the clinic with a 10-year history of CH (left side). Patient had seen neurologists in the United Kingdom (UK) and Singapore, where he resided. CH was episodic with clusters in autumn lasting three months for three years followed by remission for seven years. Treatments trialed included verapamil, topiramate, sumatriptan (oral and subcutaneous), steroid infusion, oral prednisolone and home oxygen therapy with variable benefit. GONB provided relief for three days. In the 10th year, on a visit to the UK, CH recurred in autumn and persisted for six months when he presented to the clinic. The patient reported 5–7 attacks/day, each lasting between 30 and 180 min associated with nasal congestion and restlessness. The headaches were unresponsive to sumatriptan, verapamil and topiramate. Home oxygen therapy provided relief at night. Patient reported severe disturbance in sleep pattern causing extreme distress and suicidal ideation that required emergency admission. In the clinic, the patient received GONB that provided 20% relief for five days. On reviewing the clinical history, the patient reported whiplash trauma prior to the onset of CH. The patient underwent iCPB in the clinic. He reported 90% improvement with 1–2 mild attacks at night that resolved completely on home oxygen therapy at three, six and nine months.

Case 3: A 34-year-old female nurse presented to the clinic with CH (right side) since childhood that transformed into bilateral CH following a major motor vehicle accident (MVA) requiring hospitalization. Patient recalled onset of headache at the age of six that remained misdiagnosed as migraine (primary care setting) till adulthood. Episodic CH would occur in spring for three months every three years. The patient’s father had a history of ECH with a similar pattern for 51 years. Icepick headaches were periorbital, associated with nasal congestion, conjunctival injection and agitation. Three years prior to the clinic presentation, the patient suffered a major MVA with whiplash injury. Soon after the MVA, the patient developed bilateral CH within each cluster cycle. Pain would start in the right eye at night and the patient would wake up with pain in the left eye. Both eyes were equally affected. The patient reported 4–5/day headaches lasting 90–180 min for six months before complete remission. Bilateral CH recurred two months prior to the clinic presentation. The patient was in severe distress, unable to maintain employment, reporting suicidal ideation with multiple emergency admissions. Trial of verapamil, sumatriptan and topiramate had failed. Oxygen therapy provided significant relief. MRI of the head and cervical spine were normal. The patient received iCPB. Post-intervention, the patient reported complete absence of headaches for two weeks. Four weeks thereafter, she reported one CH per day. At three, six, nine and 12-month follow up, she reported complete absence of symptoms with improvement in mood and was able to maintain employment (Table 1).

Discussion

Ultrasound-guided iCPB with depot methylprednisolone provided significant and durable relief in three patients with treatment-resistant CH. A history of whiplash trauma preceded the onset of CH in all three cases. Whiplash injury can result in an array of symptoms including neck pain, headaches, oro-facial pain, tinnitus and upper back pain. This has been termed as whiplash associated disorder (WAD) [4]. Headaches are the second commonest presentation after neck pain. In 40% patients, headaches can persist [9]. The common phenotype is either cervicogenic or migraine-like headache although cluster-like headaches have been reported following trauma to the head and neck [10].

CCH can be treatment-resistant in 20% of patients [3]. A recent European Headache Federation consensus statement has defined refractory CCH as CCH that satisfies ICHD-3 beta criteria with at least three severe CH attacks per week, that impacts quality of life, with negative brain MRI and that failed consecutive prophylactic treatment trials with at least three agents with established clinical efficacy used at maximum tolerated dose for sufficient period of time [3]. Patient 1 developed ECH following recurrent neck trauma playing rugby that was responsive to verapamil and lithium. Following transformation to CCH, trial of verapamil, lithium, topiramate, triptans, pregabalin and GONB proved ineffective. Intermediate CPB provided significant benefit lasting nine months and the benefit was reproducible.

It has been reported that one in three patients with ECH can transform to CCH in 10 years [3]. Patient 2 reported ECH for nine years with variable response to standard treatment. In the 10th year, CH attacks became persistent for six months, were refractory to treatment necessitating emergency admission. Intermediate CPB provided significant relief for nine months and probably prevented or delayed progression into CCH.

Bilateral CH that switches sides within a cluster is rare [11]. Patient three presented with history of right-sided ECH from childhood with a positive family history. CH was episodic for 20 years. Post-whiplash injury, the patient developed bilateral CH that switched sides within a cluster cycle. Intermediate CPB resulted in significant relief and may have aborted the attack and prevented progression into CCH.

It is proposed that several structures within the peripheral and central nervous system are involved in the initiation of CH [2]. Current evidence from functional imaging studies suggests synchronized abnormal activity in the hypothalamus, the trigeminocervical system and the trigeminal autonomic system (parasympathetic) [2, 12]. The key component appears to be trigemino-cervical complex activation that in turn stimulates the parasympathetic nervous system (trigeminal autonomic reflex) [2]. The trigemino-cervical complex includes the trigeminal nucleus caudalis and the dorsal horns of the upper cervical nerves [13]. The trigeminocervical system acts as a rely station connecting the peripheral neurons to the higher centers in the brain [2]. Head and neck trauma is known to result in persistent headache including CH phenotype [10, 12]. The mechanism could be a direct or indirect result of the trauma [12]. There is emerging evidence that whiplash trauma can cause forceful stretch loading to the cervicothoracic musculature that are in close proximity to the upper cervical nerves (cervical plexus) [14, 15]. Whiplash induced mechanical trauma to the cervical plexus could activate the trigemino-cervical complex leading to headache phenotypes (cervicogenic, migraneous, tension-type or CH) according to individual susceptibility. Intermediate CPB targets the upper cervical nerves thereby possibly dampening the activation of trigemino-cervical complex. This may explain the effectiveness of iCPB in patients with CH in this series. We have previously reported on the benefit of iCPB in refractory neck pain from whiplash [7].

The authors are aware of the limitations of this report including small number, single centre open labeled case series. However, CH is not only associated with substantial psychological and physical burden, and loss of quality of life, but also with enormous healthcare costs [16]. Any intervention that provides symptomatic relief in refractory CH mandates evaluation. Intermediate CPB is a safe technique when performed under real time ultrasound guidance [7, 17, 18]. The intervention was performed as an outpatient procedure in this series.

In conclusion, iCPB with depot methylprednisolone appears to have some benefit in the management of refractory cluster headache following whiplash trauma. The report includes abortive as well as preventative effects of iCPB in CCH. Further definitive studies are recommended to confirm these findings.