Fusiform aneurysms of the vertebral artery: A hidden cause of exertional headache?

Abstract

Background: There is only one reported case of recurrent coital headache related to an unruptured saccular aneurysm of the carotid artery.

Case reports: We report on two cases of isolated recurrent coital/exertional headaches ipsilateral to unruptured fusiform aneurysms of the vertebral artery diagnosed by CT angiography. While one case is being managed conservatively, a vertebral stent has been set in the other.

Conclusions: CT angiography with full visualisation of intracranial and upper cervical arteries could be used as a screening diagnostic procedure in these cases. Together with saccular aneurysms, fusiform aneurysms should be added to the IHS classification as aetiology for exertional recurrent headaches.

Introduction

Headaches provoked by exertion – including cough, exertional and sexual headaches –are an infrequent chief complaint in routine neurological practice, accounting for 1–2% of appointments due to headache in a general neurological service (1). Diagnosis of these provoked headaches is challenging. About half of those patients presenting with cough headache have a posterior fossa structural lesion, usually a Chiari type I malformation. Headaches due to prolonged physical exercise and sexual headache share many features; in fact, they frequently coexist in the same subject. In contrast to cough headache, fewer than 20% of the cases with exertional and/or sexual headaches are secondary, with subarachnoid haemorrhage and space-occupying lesions being the most frequent and feared aetiologies (1). There is no consensus regarding what would be the workup for those patients attending due to recurring exertional headaches that were clinically thought to be primary. Recommendations range from performing just conventional neuroimaging (CT and/or MRI) due to the low incidence of secondary cases to performing full neuroimaging, lumbar puncture and cranial angiography. Here we describe two patients with exertional headaches on whom a fusiform aneurysm of the vertebral artery was found.

Patients

Case 1

This 44-year-old man, with a history of arterial hypertension (treated with enalapril) and obstructive sleep apnoea (managed with nocturnal continuous positive airway pressure), presented to our clinic due to headache that had begun 2 months earlier. He experienced at least six episodes – always related to sexual intercourse – of severe, pulsating, right posterior hemicranial pain lasting from 45 to 180 minutes. The pain appeared during orgasm and always reached its maximum in less than 2 minutes. Neurological examination was unremarkable. Routine laboratory determinations and ECG were normal. CT brain scan was normal, but a CT angiography (Figure 1A) disclosed a fusiform aneurysm of the right vertebral artery (9 mm wide and 14 mm long). Nadolol, 80 mg daily, was initiated and we recommended avoiding sexual intercourse and heavy physical exercise. One month later, a flow diverter stent was set along the right vertebral artery without incidence. The patient has resumed his normal life, including sexual intercourse, and has had no further exertional headaches after a follow-up of 9 months. A control angiogram after 6 months confirmed an adequate parent vessel reconstruction (Figure 2).

Figure 1.

(A) CT angiography of Case 1 showing a fusiform aneurysm of the right vertebral artery. (B) CT angiography of Case 2 with a fusiform aneurysm of the left vertebral artery.

Figure 2.

Control angiogram after 6 months in Case 1 after flow diverter deployment with adequate parent vessel reconstruction.

Case 2

This 56-year-old man, with no past medical history, attended our hospital due to two recent headache episodes, which had triggered firstly while climbing stairs immediately after running and secondly when passing urine right after walking quickly. Both headache episodes were described as sudden (reaching a maximum in less than 1 minute), severe and pulsating, localised over the left occipital area and lasting around 1 hour. Routine laboratory determinations, ECG and CT brain scan were unremarkable. A CT angiography disclosed a small fusiform aneurysm (5.6 mm wide and 9.1 mm long) of the left vertebral artery (Figure 1B). Arterial pressure was repeatedly within normal limits and aspirin, 100 mg daily, was initiated. He has not experienced further headache episodes after 9 months of clinical follow-up, although he has avoided jogging during this period. The aneurysm remains unchanged in a control CT angiography carried out 6 months later.

Discussion

Even though a causal link between these two aneurysms and recurrent exertional headaches cannot be established with certainty, several clinical arguments suggest there is a chance that these two are the first formally described patients with repetitive exertional/sexual headache episodes which could be related to unruptured fusiform aneurysms of the vertebral artery. In both cases, exertional headache history was of recent onset, aneurysms were exactly localised in the side of the occipital pain and – at least for Case 1 – there seemed to be a relationship between treatment and pain resolution. Considering the limited availability of quick access to MRI/angioMRI in some clinical settings, this experience shows that CT angiography with full visualisation of intracranial and upper cervical arteries could be used as a screening diagnostic procedure in these cases. Patients with unruptured aneurysms often suffer from headaches, which can improve after treatment (2,3), even though headache has also been described as a complication of treated unruptured aneurysm (4). Despite thunderclap headache caused by subarachnoid haemorrhage of an intracranial aneurysm having been associated with sexual intercourse or other forms of physical exercise (5), there has only been one reported patient with recurrent coital headache clearly related to an unruptured aneurysm (6). That aneurysm was located in the internal carotid artery and of the saccular type, the only form accepted by the IHS classification as pain-producing aneurysm (7).

Aneurysms are classified according to their shape into saccular and non-saccular types. Fusiform aneurysms are non-saccular dilatations involving the entire vessel wall for a short distance (8,9). Although the number of cases has increased during recent years, fusiform aneurysms of the cerebral arteries are rare, accounting for 3–13% of all aneurysms. At least one-quarter are located in the vertebrobasilar system. As compared to saccular aneurysms, fusiform aneurysms exhibit a male predominance and become symptomatic in younger patients, usually in the 40s. Aetiologies for fusiform aneurysms include atherosclerosis, hypertension, vessel dissection and association with other diseases, such as fibromuscular dysplasia, neurofibromatosis, systemic lupus erythematosus and various collagen-associated vascular diseases. Fusiform aneurysms can be incidental or asymptomatic and may appear as headache, subarachnoid haemorrhage, ischemia, transient ischemic attack, complete stroke or as a mass effect. Various mechanisms have been proposed to explain their association with headache. These include local thrombosis, localised meningeal inflammation, bleeding within the vascular wall and aneurysm expansion or dissection (2,3,10,11). The last two mechanisms in particular could be a plausible explanation for the repetitive exertional headaches seen in our two patients. The extracranial cerebral arteries are known to be pain-sensitive. While most cerebral arteries, including the rostral basilar artery, are innervated by the trigeminal nerve, vertebral arteries are mainly innervated by the upper cervical (C1–C3) cervical dorsal root ganglia. This explains its electrical stimulation in humans causes, concurring with our observations in these two cases, pain on occiput and neck (12).

Management of unruptured fusiform aneurysms of the vertebral artery is a challenge and remains controversial, considering that their natural history remains uncertain. Nevertheless, a conservative approach is sparingly recommended due to the possibility of rupture, which has been prospectively assessed for these aneurysms at an annual rate of 0.9% (9,10). Endovascular treatment is currently favoured as the first-line option, being recommended if the aneurysm diameter is more than 10 mm or if it doubles the normal artery diameter, as well as in those cases showing irregular wall or irregular stenosis proximal to the lesion (13). Flow diverters belong to a new generation of self-expanding stent-like devices with high metal surface area coverage. They have been designed to achieve a more physiological and durable occlusion of complex aneurysms through the endoluminal reconstruction of the diseased segment of the artery (14).