We found that, among 59,000 primary missions for the EMS in the catchment area, 3.5% were reported as suffering from dizziness. Of them, about six per cent fulfilled the criteria for having a time-sensitive condition, among which the majority had had an acute cerebrovascular disease. On the arrival of the EMS, there were eight factors that were associated with the risk of having a time-sensitive condition. Three factors, i.e. having a rotatory type of dizziness, having a sudden onset of symptoms and increasing body temperature, were all associated with a decreased risk.
Five factors, i.e. sudden onset of headache, a history of head trauma, symptoms of nausea or vomiting, on treatment with anticoagulants and increasing blood pressure, were all associated with an increased risk.
Our finding that around three per cent of patients who were seen by the EMS had symptoms of dizziness is in agreement with previous research which states that about three per cent of patients who visit the emergency department have symptoms of dizziness . Furthermore, Hjälte et al. found that three per cent of patients who called for the EMS did so because of dizziness .
The observation that around six per cent of the patients with dizziness had a time-sensitive condition is also within the range that has previously been reported [13–16].
The observation that rotatory dizziness is associated with a reduced risk of a time-sensitive condition is supported to some extent by previous research [14, 17].
Moreover, the observation that the sudden onset of dizziness is associated with a reduced risk of a time-sensitive condition has been reported . However, the proportion of patients with a time-sensitive condition among those with a sudden onset of dizziness has been reported with a frequency varying from 0.7–11% [15, 19–21]. It is possible to speculate that there is difficulty deciding how to describe the type of onset of dizziness in some cases.
The finding that the risk of a time-sensitive condition decreased with increasing body temperature is difficult to explain. It is possible to speculate that, among patients with fever and vertigo, the risk of an underlying infection (not defined as a time-sensitive condition) is more marked.
Sudden onset of headache was strongly associated with an increased risk of a time-sensitive condition. Similar findings were made by Kerber et al. . Others [15, 22–23] did not report results that supported this statement.
Another factor that increased the risk of a time-sensitive condition was a history of head trauma. To the best of our knowledge, this has not been reported before. The mechanism behind the association between head trauma and a time-sensitive condition among patients with dizziness can only be speculated upon.
A third factor was the presence of nausea or vomiting. The fact that these symptoms are associated with an increased risk of a time-sensitive condition has previously been suggested [18, 24]. There is no clear explanation of why nausea or vomiting should be a risk factor for a more alarming aetiology. Among patients with other symptoms such as chest pain, the presence of nausea or vomiting has been associated with an increased risk of an underlying acute coronary syndrome .
A fourth factor that increased the risk of a time-sensitive condition was whether the patient was on chronic treatment with anticoagulants. Although this was not reported by other researchers [15, 23] there is a potential explanation for this finding. This may indicate that the patient has previously suffered from a thromboembolic event or suffers from a disease that is associated with an increased risk of such an event, for example, atrial fibrillation. Somewhat surprisingly, a history of atrial fibrillation did not appear as a risk factor for a time-sensitive condition in our survey.
The last risk factor was increasing systolic blood pressure on the arrival of the EMS. This finding is in agreement with a number of previous studies [15, 16, 18, 23]. The finding that an elevation of blood pressure is a risk factor for the development of a cerebrovascular disease is well documented [13, 25–28].