Читать книгу Clinical Reasoning in Veterinary Practice - Группа авторов - Страница 60

Reviewing the physiology of vomiting as discussed in the previous section and as shown in Figure 3.1, it is apparent that vomiting may occur due to primary GI disease or from secondary or non‐GI disease.

In contrast, regurgitation is almost always due to primary oesophageal disease (Table 3.1).

Figure 3.1 The relationship between the elements of the emetic reflex.

Primary GI diseases are those where there is specific primary GI pathology such as gut disturbance due to dietary indiscretion, inflammation, infection, parasites, obstruction or neoplasia. There may be metabolic consequences of the GI disease, but the primary pathology is in the GI tract.

Secondary GI disease is where the vomiting or regurgitation has occurred due to pathology elsewhere in the body – the gut is just the ‘messenger’. Abnormalities of other body systems may indirectly cause vomiting either due to the action of toxins on the CRTZ, vomiting centre and vestibular system or by stimulation of peripheral non‐GI‐associated vomiting receptors.

Examples would include renal failure, liver disease, ketoacidososis, pancreatitis, hypercalcaemia, hypoadrenocorticism and other metabolic disorders. In most cases, there is no pathology identifiable in the gut, or where there is, for example, ulceration secondary to liver disease, uraemia or hypoadrenocorticism, the primary cause is the metabolic disorder. While symptomatic management strategies might be directed at the gut pathology in these cases (such as the use of anti‐ulcer drugs), there is no diagnostic benefit to imaging the gut, for example, by endoscopy.