In addition to the general health and management of the animal, the exact circumstances surrounding the incident should be ascertained. Inciting causes should be pinpointed if possible, particularly in animals in which the collapsing episode has occurred on more than one occasion. Important points are summarised in Table 8.6. It is very important to establish whether the episode of collapse occurred during exercise or at rest. Cardiovascular conditions may cause collapse either at rest or during exercise. If an episode of collapse occurs during exercise it is helpful to know whether the horse tired and then collapsed or collapsed without warning. If the animal collapsed at rest, it may be helpful to know whether it was being attended or was alone in its box or field. If the owners were in attendance, it is helpful to establish exactly what were they doing, what had they just done and what were they about to do. Any possible inciting events should be noted. It may be useful to know whether the possible inciting event was part of a regular routine (such as grooming or tacking-up) or was unexpected (such as being scared by a car or another animal).
The details of the episode of collapse itself may also be important. It is helpful to establish how long the animal was on the ground, whether it made any movements when on the ground and whether it was aware of its surroundings. It can be useful to know whether there was any eye movement because these will be absent if the horse was actually unconscious. Owners should be asked what the horse did when it recovered, particularly whether it was apparently normal or remained dazed for some time. Animals which collapse as a result of a cardiac problem are usually normal immediately they stand up, although they may be stunned or scared by the event.
Almost invariably a veterinarian arrives to examine the animal after it has recovered. Under these circumstances a complete clinical examination should be carried out, but points which are particularly worthy of note are summarised in Table 8.7.