Vomiting in cats: aetiology and diagnosis of chronic vomiting
Introduction
Vomiting in cats may be the body’s defence mechanism following the ingestion of harmful substances, but it can also be caused by various diseases, both gastrointestinal and otherwise.3
Management mainly depends on the severity of the patient’s clinical picture, the characteristics of the vomit and whether it is an acute or chronic problem.
- Most cases of acute vomiting are self-limiting and respond well to fluid replacement, fasting for 12–24 hours, and if the clinician deems it appropriate, antiemetic treatment. These patients do not usually require a complex diagnostic approach to identify the aetiology of the vomiting and administer specific treatment.
- On the contrary, once vomiting has become chronic, symptomatic treatment will most likely fail and the patient will require specific treatment of the cause.1,3 So, it is important to be familiar with the diseases that most commonly cause chronic vomiting in cats.
Vomiting in cats: causes of chronic vomiting
The causes of chronic vomiting in cats include bothprimary gastrointestinal diseases (inflammatory bowel disease [IBD], food allergy/intolerance, infectious or parasitic diseases, neoplasms, motility disorders, foreign bodies, gastric ulcers) and extra-gastrointestinal diseases (pancreatitis, hepatobiliary disease, chronic kidney disease, neurological diseases, infectious diseases, intoxications, drugs and endocrinopathies).
The most common causes are summarised below.
INFLAMMATORY BOWEL DISEASE (IBD)
IBD is one of the main causes of chronic vomiting in cats.
Cats with IBD suffer from persistent or recurrent vomiting, along with hyporexia, weight loss and diarrhoea. It mainly affects middle-aged animals, and it has been suggested that Asian breeds may be more predisposed, although all breeds can be affected.
As the definitive diagnosis of IBD requires a digestive tract biopsy, when IBD is suspected, all other causes of vomiting that can be tested through noninvasive methods must be ruled out and a diet-based therapeutic trial carried to exclude the existence of food-responsive chronic enteropathy.2,4
ADVERSE FOOD REACTIONS
This is another frequent cause of vomiting in cats. They include food intolerance, an abnormal physiological response with no immunological basis, and food allergy, which does have an immune-mediated basis. Patients with an actual food allergy may also show cutaneous signs, but not always. The food ingredients typically involved in these reactions include beef, dairy and fish,2 and are usually treated by changing to a hydrolysed diet.
DELAYED GASTRIC EMPTYING
Animals with delayed gastric emptying usually vomit undigested or partially digested food over 12 hours after its ingestion. This may be accompanied by gastric distension, abdominal pain and weight loss.
MOTILITY DISORDERS
As for delayed gastric emptying, patients vomit undigested or partially digested food.
The problem may be due to a mechanical obstruction (polyps/neoplasms, granuloma, foreign bodies, stenosis, extramural masses) or functional impairment.
Delayed gastric emptying may also be secondary to electrolytes imbalances (hypokalaemia or hypocalcaemia), metabolic disorders (diabetes, uraemia), drugs (anticholinergics, ß-adrenergic agonists and opioids), constipation, peritonitis and pancreatitis.2
NEOPLASMS
Lymphomas are the primary type of neoplasm reported in cats, with the gastrointestinal tract being the most common location. It is not surprising, therefore, that lymphomas are a frequent cause of vomiting in cats.
Other, less common digestive neoplasms that may also cause vomiting include adenocarcinomas, mast cell tumours and leiomyosarcomas.2,5
Diagnostic approach to cats with chronic vomiting
The initial diagnostic evaluation of a cat with chronic vomiting should include a blood count, full blood chemistry profile, T4 (in middle-aged and elderly cats), urinalysis and a stool analysis.
Based on the results and clinical suspicion, X-rays and/or abdominal ultrasound and fPLI and fTLI concentration tests may be indicated, as could tests for cobalamin and folate levels (to assess pancreatic and intestinal function), dynamic bile acid (if there is an unconfirmed suspicion of liver disease), analysis of any effusions, serology of infectious diseases (if suggested by the patient’s history), and finally digestive endoscopy to collect a histopathological sample.
Conclusions
Vomiting in cats is a leading cause for consultation in veterinary practice. When approaching each case, it is important to differentiate clearly between an acute and chronic condition. For the former, vomiting is often self-limiting, even without antiemetics, whereas in chronic cases, it will persist despite pharmacological management. The vet must explain to owners of a cat with chronic vomiting the need to establish adequate aetiological treatment, and that this requires a multistep diagnostic approach, possibly including invasive procedures to reach a definitive diagnosis and/or treatment.
