Case report: Epicranial pain after radiotherapy for skull base meningioma – the first symptomatic epicrania fugax?

Introduction

Epicrania fugax (EF) is a paroxysmal, short-lasting head pain moving along a lineal or zigzag trajectory across one hemicranium. EF pain typically moves between two distant points through the territories of different nerves (1). In most cases, the pain is strictly unilateral, with either forwards or backwards radiation (2,3). Between attacks, many patients have continuous or intermittent pain at the stemming area, and one of the reported cases had a persistent pain extending all through the trajectory of the EF paroxysms (4). EF was classified as a primary headache in the Appendix of the International Classification of Headache Disorders, 3rd edition, beta version (1). To date, no symptomatic forms of EF have been reported. Here we describe the first EF-type pain to be probably caused by an underlying disorder.

Case report

A 77-year-old woman with no relevant medical history started having brief shocks of unilateral facial pain at 72 years of age. The pain spread diffusely over her left forehead, cheek and upper lip (left V1 and V2 dermatomes) and was described as electric and extremely severe (9 out of 10). The paroxysms lasted 10–20 seconds and recurred more than 10 times per day with or without triggers. Between attacks, there was a mild background pain in the affected area. Neurological examination at that time was normal. Magnetic resonance imaging (MRI) of the head showed an extra-axial lesion attached to the left middle sphenoid wing, which was suggestive of meningioma. This space-occupying lesion extended into the lateropontine cistern and Meckel’s cave, compressing the left trigeminal nerve medially (Figure 1). The patient was diagnosed with painful trigeminal neuropathy related to middle sphenoid wing meningioma. During the following years, she tried several neuromodulators with partial response. Four years after clinical onset, linear accelerator stereotactic radiotherapy was administered with a total dose of 50.4 Gy divided over 28 sessions. OPEN IN VIEWER

One month after radiation therapy, the episodes of facial pain were significantly diminished in frequency, but a new type of headache appeared. This new pain was perceived as brief electric paroxysms of moderate intensity (6 out of 10) that moved backwards in a zigzag trajectory from the left frontal area to the left occipital area in 1–2 seconds. There were no autonomic symptoms or other accompaniments. The number of paroxysms was potentially uncountable in the daytime, with no identifiable triggers. Between attacks, the patient felt a continuous, burning pain of moderate-to-severe intensity (5–8 out of 10) confined to the territory in which the motion was perceived. This pain was greatest in the centre of the affected area and gradually decreased with increasing distance. Neurological examination was normal except for hyperalgesia and allodynia in a region of 16.5 × 7 cm in the left hemicranium. Serial MRI examinations demonstrated the persistence of the meningioma without significant changes. Drug treatment with gabapentin 900 mg three times daily only provided a partial reduction in pain intensity. After adding lamotrigine 50 mg twice daily, the patient experienced a substantial decrease in the background pain, as well as in the frequency and intensity of the paroxysms.

Discussion

The patient first presented with painful trigeminal neuropathy secondary to a skull base meningioma. However, 1 month after being treated with radiotherapy, a different pain pattern emerged that was clinically identical to that described in backwards EF (1).

The pathophysiology of EF is unknown. A peripheral generator has been suggested, since the pain always stems from a fixed focal area (3). Such a peripheral source could be internal – at the trigeminal nerve root (5,6) or the higher cervical nerves – or more superficial (i.e. epicranial) – involving the terminal branches of the occipital or trigeminal nerves (7,8). Once it is initiated, peripheral or central mechanisms might be responsible for the irradiation of the pain.

Cranial radiotherapy has been associated with a number of neurotoxic effects, including cranial nerve injury (9). Trigeminal neuropathy can occur as a dose-dependent effect after radiation therapy of skull base tumours (10,11). Recently, a case of shortlasting unilateral neuralgiform headache attacks with conjuntival injection and tearing (SUNCT) occurring as a consequence of radiation therapy has been reported (12). This further supports the role of cranial radiotherapy as a potential cause of some trigeminal-mediated headaches.

Although the pathogenesis of EF remains uncertain, the present case is consistent with a symptomatic origin in the trigeminal root/pathway. The onset of the EF-like pain could have been caused by the compressive effect of the tumour or, most likely, by the radiation. This case highlights the need to rule out underlying disorders in patients with clinical symptoms of EF. Moreover, this first description of symptomatic EF strongly suggests that the trigeminal nerve may act as a generator in some cases of EF.

Clinical implications

A headache with the features of epicrania fugax (EF) occurred after radiotherapy to a skull base meningioma that was compressing the trigeminal nerve.

Patient consent

Informed consent was obtained from the patient included in this case report.