A multidirectional epicrania fugax

Dear Editor,

Epicrania fugax (EF) has been recently classified as a primary headache in the Appendix of the International Classification of Headache Disorders, 3rd edition, beta version (1). EF is characterized by a brief paroxysmal pain following a lineal or zigzag trajectory across the head surface. EF pain typically moves between two distant points through the territories of different nerves. In all the reported cases the pain was strictly unilateral with either forward or backward radiation, although some patients had shifting sides (2,3). Here we report a paroxysmal EF-type pain that changed directions in a striking way.

A 52-year-old woman with migraine history since adolescence started having a new type of headache at age 48. This new pain was perceived as brief electric shocks that crossed her head in less than one second with a zigzag trajectory. The pain always moved between two distant points, but the direction was variable. On some occasions the pain stemmed from the right or left occipital area and then moved forward to reach the ipsilateral frontal area (Figure 1(a)). At times the pain shifted from the right or left occipital area to the opposite frontal area following a diagonal trajectory (Figure 1(b)). Finally, the pain could move from one temple—right or left—to the other in a coronal direction (Figure 1(c)). Regardless of the trajectory, the pain was extremely severe (10 out of 10) and always caught the patient off guard. There were no autonomic symptoms or other accompaniments. The attacks occurred with irregular frequency, from six episodes per month to one episode per day, with no identifiable triggers. Between attacks the patient remained asymptomatic. Magnetic resonance imaging (MRI) of the head and the cervical spine and routine blood tests including erythrocyte sedimentation rate did not show any abnormality. After this workup the patient felt reassured and no treatment was prescribed.

Figure 1.

All possible trajectories of the pain in our patient. (a) Right or left unilateral forward direction. (b) Right-to-left or left-to-right diagonal forward direction. (c) Right-to-left or left-to-right transversal direction.

In this patient all the painful paroxysms had identical features except for their topography. Those with forward radiation on one side of the head were clearly consistent with former descriptions of EF. However, in the remaining episodes the pain moved with a diagonal or transversal direction across both sides of the head. These episodes did not fit any other headache diagnosis and would most probably correspond to atypical variants of EF. In descriptive disorders, an atypical feature may sometimes be accepted if the rest of the features are typical. In fact, other unilateral headaches may switch sides or become bilateral within the same episode. That is the case for migraine, which commonly starts on one side and then spreads to the whole head. Even the trigeminal autonomic cephalalgias may rarely shift from one side to the other within a single attack or appear as a bilateral pain (4–6). It has been postulated that crossed suppressor pathways can operate in unilateral headaches. A failure of suppression can theoretically explain why these headaches may become bilateral (4). Still, the pathogenesis of EF is uncertain. At present we cannot explain the underlying mechanisms that may account for a propagation of the pain over both sides of the head.

Patient consent

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