Table 4.
Summary of studies on patients with sudden headache
| Current study | Perry[5] | Landtblom[4] | Linn[3] | Harling[26] | |
|---|---|---|---|---|---|
| SAH |
3.3% |
6.2% |
11.3% |
25% |
71.4% |
| No diagnosis |
19.4% |
57.7% |
73.0% |
62.8% |
2.0% |
| (3.3%)* | |||||
| Onset |
sudden |
< 1 hour |
sudden |
< 1 minute |
sudden |
| Intensity |
NS |
NS |
NS |
Severe |
NS |
| Duration |
> 1 minute |
NS |
NS |
> 1 hour |
NS |
| Onset to visit |
< 30 days |
< 14 days |
NS |
NS |
NS |
| Settings |
Clinic |
Emergency department |
Emergency department |
Clinic and emergency |
In-hospital |
| Follow up |
6-42 months |
6 months |
12 months |
12 months |
18-30 months |
| Further SAH | 0 | 0 | 0 | 0 | 0 |
SAH: subarachnoid hemorrhage; NS: not specified.
*When we conducted the study, patients with multiple triggers could not be classified by the criteria of International Classification of Headache Disorders, 2nd edition (ICHD-2) (Table 1). However, five of these six patients may be categorized as probable reversible cerebral vasoconstriction syndrome by the criteria of ICHD-3, beta version (Table 1) (Figure 2).