Abstract
Short-lasting unilateral neuralgiform headaches with conjunctival injection and tearing (SUNCT) represent a brief headache form described in 1989 by Sjaastad (1). According to the criteria diagnoses of the Classification of the International Headache Society 2004 (Table 1), they are attacks of orbital, supraorbital or temporal pain with stabbing or pulsating character of 5–240 s duration that happen from three to 200 times per day (2). SUNCT alternates symptomatic periods with spontaneous remissions of unpredictable nature and predominates in men.
The International Headache Society 2004 diagnostic criteria of SUNCT
SUNCT belongs to the trigeminal autonomic cephalalgias, just like cluster headache and paroxysmal hemicrania. It is the most infrequent of this group and has in common with them characteristics such as strictly unilateral pain and the existence of autonomic data; and differs from them in its smaller duration and greater frequency of episodes, although in some cases it can overlap with paroxysmal hemicrania. The remarkably refractoriness to all treatment, including indomethacin, orients to the SUNCT diagnosis.
It happens generally without demonstrable structural anomalies although a significant number of cases secondary to posterior fossa or parasellar lesions has been communicated. We report a patient with diagnostic criteria of SUNCT syndrome, with the existence of a variant of vertebrobasilar vascular development that causes compression in the left ventrolateral region of protuberance. To our knowledge, no other cases of secondary SUNCT to this anomaly have been published.
Case report
The patient is a 55-year-old male, without antecedents of interest, a non-smoker and non-drinker and without a family history of headaches. He had been suffering from recurrent episodes of acute cephalalgia of approximately 30 s duration, of severe intensity, left orbital location and sharp character that were repeated 20–30 times per day for 7 years. The pain attacks were accompanied by tearing and conjunctival injection (we were present at some of these episodes). They were neither preceded nor accompanied by neurological signs; they did not present trigger zones and the episodes had no time predominance. In the beginning, the pain appeared in clusters every 6 months and lasted approximately 1 month, later becoming permanent without periods of intercritical improvement. The general and neurological explorations were normal.
Although there were neither atypical data nor neurological signs, cerebral magnetic resonance (MR) and MR angiography (Figs 1 and 2) demonstrated an anomaly in the morphological development of the vertebrobasilar vascular system with a displacement of the position of both vertebral arteries, causing left vertebral artery compression at the left lateral pons level.
Cerebral magnetic resonance: cerebral parenchyma alterations are not evident; nevertheless, a significant elongation of the right vertebral artery, which crosses totally from one side to the other and joins the left vertebral artery, is observed. Besides this, the left vertebral artery is displaced 7 mm dorsal into the brainstem parenchyma (arrow), near the root of the left trigeminal nerve.
Magnetic resonance cerebral angiography. A great dolicho-ectasia of the vertebrobasilar vascular system can be observed. The inferior portion of the basilar artery is displaced to the left with a horizontal part. The right vertebral artery is considerably displaced to the left. Also, the left vertebral artery is dorsally situated, impressing upon the lateral midpons at the level of the trigeminal root (arrow).
The patient received treatment with ergotamine, sumatriptan (oral and subcutaneous), indomethacin, amitriptiline, prednisone, verapamil, topiramate and oxcarbazepine, in isolated form or in combination, the pain being refractory to these drugs.
Discussion
We present the case of a patient with a strictly unilateral sharp, intense, left orbital location, headache of very short duration, accompanied by evident tearing and eye reddening of the same side, that clearly fulfil the criteria of SUNCT in agreement with the 2nd edition of the recently published International Classification of Headache Disorders. Cases of SUNCT secondary to structural lesions are described in the literature: prolactinomas of hypophysis (3, 4), tumour of cavernous sinus (5), meningioma of olfactory groove (6), intraorbitary mass (7), ocular trauma (8) and mainly lesions of posterior fossa such as venous angioma of the cerebellopontine angle (9), cavernous angioma of pons (10), pilocytic astrocytoma of cerebellum (11), dorsolateral brainstem infarction (12), craneosynostosis (13), neurofibromatosis type 2 (14) and imperfect osteogenesis (15) with important distortion of posterior fossa.
We believe that in our case the SUNCT syndrome can be justified by the anomalies detected in the MR. The left vertebral artery goes 7 mm dorsal in the brainstem parenchyma between the pons and the middle cerebellar peduncle and may compress the root of the trigeminal nerve. As Goadsby et al. have described, we suggest that the trigeminal compression can start the trigemino-autonomic reflex (functional connections between the nucleus of the trigeminus and the parasympathetic neurons of the VIIth cranial nerve located in the superior salivatory nucleus). The irritation of the trigeminus root would explain the pain, whereas the activation of the parasympathetic neurons would be responsible for the autonomic activity (through the greater superficial petrosal nerve, branch of VII cranial nerve responsible for the cholinergic innervation of the lachrymal glands, nasal mucosa and vessels of the nasal cavity) (16).
Although cases of secondary SUNCT to arteriovenous malformations have been published previously (venous angioma of the cerebellopontine angle and cavernous angioma of the protuberance, near the zone of entrance by the trigeminal root), we have found no case described secondary to a variant of the morphological development of the vessels in the vertebrobasilar region, as shown in our patient.
Our patient presented a progressive course, with more infrequent periods of improvement, as well as multiple resistance to tried drugs, which is concordant with the findings of a previous publication (17).
The SUNCT is the most infrequent among the trigeminal automatic cephalalgias. Nevertheless, it is not negligible the number of secondary cases, even displaying typical symptoms. It was for this reason that we carried out an imaging test to rule out underlying structural pathology; MR has greater sensitivity than CT in detecting injuries in the posterior cranial fossa and, if we had thought it necessary, we would have conducted a cerebral angiography study.