Introduction
Vomiting is one of the most common problems for which dogs and cats are presented to their veterinarian. Vomiting is a complex physiological mechanism mediated by the emetic center located in the medulla.
It is there that triggered input from abdominal viscera (e. g., secondary to inflammation, distension, chemical irritation, or osmolality shifts), CRTZ (e. g., secondary to toxins carried by the blood), semicircular canals of the vestibular apparatus, and cerebral cortex and limbic system (e.g., secondary to excitement, stress, fear, or increased intracranial pressure) are processed and ultimately result in a coordination of abdominal and visceral muscle contractions leading to the expulsion of material from the stomach and /or proximal small intestine.1,2 Chronic vomiting is defined as persistent vomiting, either intermittent or continuous, of greater than ten days duration. The chronicity need not be the result of some insidious problem, but may be due to an acute problem unresponsive to initial therapy or for which therapy was never instituted. Chronic vomiting as a clinical sign can result from a multitude of different disease states and the clinical approach can be daunting as well as frustrating to both the veterinarian and the client alike (Table 2.3). Furthermore, the workup of this common problem can vary significantly based on the severity of the illness, availability of certain diagnostic modalities, and regional differences in disease prevalence. If vomiting has been occurring for months with no concurrent clinical signs, the diagnostic approach may be staged. If the patient has been vomiting frequently over a period of a few| Table 2.3: Causes of chronic vomiting | |
| Drugs | Endocrine Disorders |
| ■ NSAIDs | ■ Hypoadrenocortism |
| ■ Antimicrobials (e. g., metronidazole) | ■ Hyperthyroidism |
| ■ Many others (usually acute) | ■ Diabetes mellitus |
| Gastrointestinal tract obstruction | Metabolic Disorders |
| ■ Gastric outflow obstruction | ■ Renalfailure |
| - Benign pyloric stenosis | ■ Hepatobiliary disease |
| - Foreign body | ■ Hypercalcemia |
| - Gastric antral mucosal hypertrophy | |
| - Neoplasia | Toxins |
| - Chronic gastric malpositioning (GDV) | ■ Lead |
| ■ Intestinalobstruction | ■ Zinc |
| - Foreign body | ■ Planttoxins |
| - Neoplasia | ■ Grapes and raisins |
| - Cicatrix | |
| - Non-neoplastic infiltrative disease (e. g., pythiosis) | Neurological |
| - Intussusception | ■ Limbic epilepsy |
| - Adenomatous polyps (in cats) | ■ Neoplasia ■ Meningitis/ encephalitis |
| Gastrointestinal Inflammation | ■ Increased intracranial pressure |
| ■ Inflammatory bowel disease | ■ Hydrocephalus |
| ■ Small intestinal bacterial overgrowth | ■ Psychogenic |
| ■ Helicobacter spp. infection | ■ Vestibular disease |
| ■ Food hypersensitivity | |
| ■ Food intolerance | Miscellaneous |
| ■ Chronic gastritis ± ulceration | ■ Abdominal steatitis |
| ■ Bilious vomiting syndrome | ■ Dysautonomia |
| ■ Parasitic - Physaloptera spp., Ollulanus tricuspis, Ascarids, Giardia spp., | ■ Feline heartworm disease |
| and Aonchotheca putorii | ■ Hiatal hernia |
| ■ Viral - FIV FeLV, FIP virus | ■ Idiopathic delayed gastric emptying |
| ■ Chroniccolitis | ■ Idiopathic hypomotility ■ Mast cell tumors |
| Abdominal Inflammation | ■ Obstipation |
| ■ Chronic peritonitis | ■ Overeating |
| ■ Chronic pancreatitis | ■ Sialoadenitis/ sialoadenosis |
| ■ Cholecystitis | ■ Others |
weeks with concurrent weight loss, anorexia, and /or dehydration, a more aggressive approach is warranted so that a targeted treatment plan can be instituted as soon as possible. In the end, the workup of a patient with chronic vomiting requires the assimilation of data from the history, physical examination, and diagnostic testing to establish a diagnosis that permits a focused and specific management strategy. This chapter represents the view of the author on a rational systematic approach to the evaluation of a patient with chronic vomiting.
2.2.2