Page 422 - Small Animal Internal Medicine, 6th Edition

394 PART III Digestive System Disorders

VOMITING depends on whether the vomiting is acute or chronic and
whether there is hematemesis (Figs. 26.2 and 26.3). Remem-
VetBooks.ir Vomiting is usually caused by (1) motion sickness, (2) inges- ber that blood in vomitus may be fresh (i.e., red) or digested
to varying degrees (i.e., “coffee grounds” or “dregs”).
tion of emetogenic substances (e.g., drugs), (3) gastro-
In animals with acute vomiting without hematemesis, cli-
intestinal (GI) tract obstruction, (4) abdominal (especially
alimentary tract) inflammation or irritation, and (5) extra- nicians should first search for obvious causes (e.g., ingestion
gastrointestinal tract diseases that may stimulate the medul- of a foreign body, intoxication, organ failure, parvovirus) as
lary vomiting center region or the chemoreceptor trigger well as for secondary fluid, electrolyte, or acid-base abnor-
zone (Box 26.6). Occasionally, central nervous system (CNS) malities or sepsis that require prompt, specific therapy. If the
disease, behavior, and learned reactions to specific stimuli animal appears stable and there is no obvious cause, symp-
may cause vomiting. If the cause of the vomiting is inappar- tomatic treatment is often first tried for 1 to 2 days. If the
ent on history and physical examination, the next step animal is too sick for the clinician to take a chance on

BOX 26.6

Causes of Vomiting

Motion Sickness (Acute) (Important) Gastrointestinal/Abdominal Inflammation (Acute or
Diet (Important) Chronic) (Important)
Dietary indiscretion Gastritis (common)
Dietary intolerance Without ulcers/erosions
Emetogenic Substances (Acute) With ulcers/erosions
Drugs: almost any drug can cause vomiting (especially Non-obstructing foreign body
drugs administered orally [PO]), but the following Parasitic (i.e., Physaloptera, Ollulanus)
drugs seem especially likely to cause vomiting: Enteritis (acute)
Digoxin Parvovirus (common)
Chemotherapeutics (e.g., cyclophosphamide, Acute hemorrhagic diarrheal syndrome (common)
cisplatin, dacarbazine, doxorubicin) Parasites (acute or chronic)
Selected antibiotics (e.g., erythromycin, tetracycline/ Inflammatory bowel disease (IBD) (more common in
doxycycline, amoxicillin plus clavulanic acid) cats)
Penicillamine Pancreatitis (common and very important in dogs)
Nonsteroidal antiinflammatory drugs Peritonitis (acute or chronic; septic or nonseptic)
Apomorphine Colitis (acute or chronic)
Xylazine Splenitis
Toxic chemicals Extraalimentary Tract Diseases (Acute or Chronic)
Strychnine (Important)
Heavy metals Uremia (common)
Gastrointestinal Tract Obstruction (Acute or Chronic) Adrenal insufficiency (uncommon but important)
(Important) Hypercalcemia
Gastric Outflow Obstruction Hepatic insufficiency or disease (Important)
Benign pyloric stenosis (uncommon) Cholecystitis
Foreign object (common) Diabetic ketoacidosis
Gastric antral mucosal hypertrophy Pyometra
Neoplasia Endotoxemia/septicemia
Nonneoplastic infiltrative disease (e.g., pythiosis) Miscellaneous Causes (Acute or Chronic)
Gastric malpositioning Dysautonomia
• Gastric dilation or volvulus (see nonproductive Feline hyperthyroidism (Important)
retching) Postoperative nausea/ileus (uncommon)
• Partial gastric dilation/volvulus (does not always Overeating
cause clinical signs) Idiopathic hypomotility
Intestinal Obstruction Central nervous system disease
Foreign object (very common) Tumor
• Nonlinear objects Meningitis
• Linear objects Increased intracranial pressure
Neoplasia Sialoadenitis/sialoadenosis*
Intussusception Behavior
Cicatrix (rare) Physiologic (epimeletic in female dogs)
Torsion/volvulus (very rare)
*It is important to determine whether this is the cause of vomiting or an effect of vomiting.