At present, there is no uniform conclusion about the characteristics of headache attributed to TIA. The ICHD-3 does not describe it in detail. Few studies have reported the characteristics of headache attributed to TIA, and most studies have analysed headache attributed to TIA together with other neurovascular diseases [1, 3, 4, 11, 6, 12]. In this study, we attempted to provide the clinical features of headache attributed to TIA. Our study found that the incidence of headache attributed to TIA was 8.2% (22/269), while in previous studies, the incidence ranged from 16–44% [1–6]. The reason for our low prevalence is that we emphasized the simultaneous occurrence of headache and TIA when we enrolled patients, and we only enrolled patients who had headaches that were relieved within 24 hours. Our patients were screened strictly according to the diagnostic criteria of ICHD-3 for headache attributed to TIA. In previous studies, TIA patients with related headache were screened.
Headache attributed to TIA was more common in posterior circulation TIAs (59.1%), which was in accordance with previous studies. The reason for our low prevalence is that we emphasized the simultaneous occurrence of headache and TIA when we enrolled patients, and we only enrolled patients who had headaches that were relieved within 24 hours. Our patients were screened strictly according to the diagnostic criteria of ICHD-3 for headache attributed to TIA. In previous studies, TIA patients with related headache were screened.
It was shown that headache attributed to TIA was more common in women in our study. Some studies [13, 14] have shown that the TIA incidence is higher in men than in women , and men have more vascular risk factors than women, such as hypertension and smoking [16, 17]. In a study sample of 5991 TIA patients, headaches were more common in women than men . In our study, we found that there was a higher prevalence of women with a TIA headache. The prevalence of migraine is significantly higher in women than in men. The review by kjersti G vetvik previously showed the complex association between oestrogens and migraine . We hypothesize that the high incidence of migraine in women may result in a higher prevalence in women with headache attributed to TIA. However, the specific mechanism is still unknown, and further research is needed.
Headache attributed to TIA was more common in posterior circulation of TIA (59.1%) which was in accordance with previous studies [1, 2, 4, 21]. It is well known that posterior circulation strokes are rarer than anterior circulation strokes within all of the stroke and TIA types, and we found that posterior circulation ischaemic events accounted for approximately 20–25% of all strokes and TIAs after reviewing the relevant materials [22, 23]. The pathophysiological mechanism is still controversial. Edmeads et al. considered that the pathophysiology may involve the release of vasoactive substances, such as serotonin and prostaglandins, from activated platelets . The pathogenesis of posterior circulation of TIA is unclear and rarely studied.
We found that headache attributed to TIA accounted for 8.2% of all TIA patients. In most of the patients, the headache was bilateral (16/22) and dull (16/22), and the severity of the head was mainly moderate (12/22) in most of the patients, similar to TTH. Consistent with previous studies, we found that headache attributed to TIA was usually bilateral, dull and of moderate intensity [1, 2, 5]. Typical TTH is a mild to moderate, compression or tightness headache that is bilateral and that is not aggravated by daily physical activity . Our study was different from the Russian study. In the Russian study, 16 patients (13.3%) of 120 patients suffered a new type of headache . Among the 16 patients, 12 patients had migraine-like headaches, 3 patients had tension-type-like headaches, and one patient had thunderclap headaches . They found that headache attributed to TIA was similar to migraine-like headache .
TTH and migraines have very different frequencies, severities and durations. The different results of the two studies may have been caused by the following reasons. The authors collected data from TIA patients with headaches, while we registered patients with headache attributed to TIA by strictly following the ICHD-3 . Patients with a history of prior primary headache and who had medication-overuse headaches were excluded. Therefore, there is limited research on headache attributed to TIA, so more research is needed to illustrate the differences between our study and the research from Russia.
The symptoms of migraine with aura (MA) are similar to the symptoms of TIA, so we need to identify the differences between them. The mode of onset is crucial: the focal deficit is typically sudden in TIA and more frequently progressive in migrainous aura
. Furthermore, positive phenomena (e.g., scintillating scotoma) are far more common in migrainous aura than in TIA, whereas negative phenomena are more common in TIA . Although there are some ways to distinguish between the premonitory symptoms of MA and the transient functional loss of TIA, the characteristics of headache associated with TIA have not been fully studied. We hope this study will provide some clinical evidence for the diagnosis of headache attributed to TIA.
There are also some limitations in this study. First, the small sample size we collected is mainly due to the low incidence of TIA headache. Second, it was not a completely prospective study, and we spent much time screening the patients evaluated in this study. Finally, our study only recruited patients from a single centre.