Gastric motility is the movement of food through the body. This process starts when food enters the mouth and is chewed and swallowed, passing through the esophagus, stomach, small and large intestines and waste products leave the body via the anus. Wavelike contractions of the smooth muscle in the gastrointestinal (GI) tract are responsible for the passage of food to different locations for processing and absorption. These contractions (known as peristalsis) are regulated by neural impulses by the autonomic nervous system (the part of the nervous system responsible for control of the bodily functions not consciously directed) and a number of endocrine (hormonal) mechanisms.
In the cat with normal digestion, food is consumed and passes through the esophagus to the stomach where mixes with gastric juices and is churned into a liquid called chyme. From there it moves to the small intestine where nutrients are absorbed through the intestinal walls and into the bloodstream. Waste material and indigestible parts pass into the large intestine where water is removed and the remaining products are excreted from the body via the feces.
Gastric motility disorders are a number of conditions which affect the normal passage of food through the GI tract. They can be accelerated, retrograde (backward moving) or delayed. Most feline cases are due to delayed or impaired motility. This, in turn, causes food to accumulate in the GI tract.
Any dysfunction along the gastrointestinal tract can cause gastric motility disorders.
Gastric motility disorders can be primary or secondary, most cases are secondary, and usually due to underlying gastrointestinal disease.
Mouth and esophagus:
- Dysphagia – Difficulty swallowing
- Esophagitis – Inflammation of the esophagus
- Reflux (GERD) – A condition in which gastric juices flow back from the stomach and into the esophagus
- Megaesophagus – Enlargement of the esophagus
- Delayed gastric emptying – A slower than normal emptying of the stomach contents which can be due to gastric dilatation, gastritis (inflammation of the stomach lining), gastric ulcers, electrolyte imbalances, diabetes, tumours, hypothyroidism, certain drugs (cholinergic antagonists, adrenergic agonists and opioid agonists), foreign object and defective propulsion)
- Obstruction – Tumour, heavy roundworm burden
- Intestinal sclerosis
- Post-surgical pseudo-obstruction
- Enteritis – Inflammation of the intestine
- Megacolon – Abnormally dilated and enlarged colon
- Ilius – Inability of the large intestine to contract normally to push feces out of the body, there are a number of causes including drug-induced, obstruction, complicaitons of surgery, peritonitis, pancreatitis, hypokalemia, uremia
- Key-Gaskell syndrome – A rare condition of the sympathetic and parasympathetic nervous systems which work in harmony to prepare the body for fight or flight (sympathetic) or relax the body (parasympathetic). This system is responsible for functions in the body which the cat does not consciously control such as respiration, digestion, heartbeat, hormone secretion and pupil dilation/constriction, collectively called the autonomic nervous system (ANS)
- Psychogenic – Pain, fear or stress
- Immune-mediated diseases
- Idiopathic (no known cause)
Common symptoms of gastric motility disorders include:
- Vomiting of mostly undigested food
- Abdominal swelling and bloating
- Abdominal pain
- Loss of appetite
- Nausea (drooling, reduced appetite, lip licking)
- Allotriophagia (eating unnatural foods or non-food items)
- Weight loss
In addition, other symptoms can present depending on the underlying cause.
The veterinarian will perform a complete physical examination of the cat and obtain a medical history which will include symptoms, how long they have been present, any underlying medical conditions, and medications your cat is currently taking.
Diagnostic tests will be necessary to determine the underlying cause of the gastric motility disorder as well as evaluate the gastrointestinal tract.
- Baseline tests – Complete blood count, biochemical profile and urinalysis to evaluate the overall health of the cat and liver and kidney function.
- Gastroscopy – An examination of the esophagus, stomach and duodenum (upper part of the small bowel) using a flexible telescope called a gastroscope
- Abdominal xrays and ultrasound – To evaluate the gastrointestinal tract for tumours and blockages
- Gastric emptying scintigraphy (gamma scan) – Radioisotopes (which emit gamma radiation) are ingested to measure the speed in which food empties from the stomach
- Upper gastrointestinal series (upper gastrointestinal study, barium study or contrast radiography) – Barium sulphate, a white radio-opaque metallic powder, is administered to the cat via syringe into the cheek pouch. Once swallowed, the barium coats the inside walls of the gastrointestinal tract which shows up the structures as bright white on xrays. The veterinarian can also monitor transit time of the barium during this procedure.
- Barium-Impregnated Polyethylene Spheres (BIPS) – Plastic spheres that are impregnanted with barium (a radio-opaque contrast medium), which the cat ingests, and then a series of xrays are taken to evaluate the GI tract for motility disorders or blockages
The goal of treatment is to address the underlying cause, as well as increase gastric motility and provide supportive care including fluid and nutritional therapy and surgery or gastroscopy to remove blockages.
Prokinetic agents – These medications increase peristalsis and/or promote gastric emptying. There are a number of medications available which include:
- Cisapride (only available through compounding veterinary pharmacies)
- Erythromycin (an antibiotic)
- Clarithromycin (an antibiotic)
Liquids pass through the stomach faster than solids, and high calorie foods remain in the stomach longer than protein, which remains in the stomach longer than carbohydrates. Based on this, dietary modifications will be implemented which may include:
- Low fat, low protein diets which promote gastric emptying
- Feed small but frequent meals
- Canned and liquefied diets can also help to increase gastric emptying