Some definitions:

Dysphagia: Difficulty eating or swallowing food, unrelated to the degree of hunger. Caused by jaw pain / mechanical / neurological problems.

Anorexia: Complete loss of appetite. Partial anorexia can be described as inappetance. Usually involves the appetite centres in the brain, and so associated with metabolic disease (Liver, kidney), poisonings, nausea.

Pica: Depraved appetite- soil eating, eating faeces etc. Can be a sign of malabsorption or vitamin deficiency, but is usually behavioural.

Used when the patient is unable or unwilling to eat, but enteral nutrition is necessary. ( Total parenteral or intravenous nutrition is possible but very difficult, and research has shown that feeding via the alimentary tract has considerable advantages.)

All post operative or traumatised patients have an increased metabolic demand.

Methods:

1) Forced oral feeding- can use a cut off syringe and force food plugs into the animal’s mouth, but this is stressful.

2) Nasooesophageal tube - introduced via the nose after a squirt of local anaesthetic. Extremely well tolerated by cats. The distal end of the tube lies in the oesophagus, so this is a "mouth by-pass" tube. The tube bore is small so only fine liquids pass through these.

3) Oesophagostomy tubes- Have superseded pharyngostomy tubes. As the name suggests, they are introduced via the oesophagus, and then threaded into the stomach. Large bore tubes can be used and well tolerated but installation is a surgical procedure:

Prep lateral cervical region then introduce curved forceps into the mouth and press the tips laterally so they can be palpated through the skin. Incise down into the oesophagus, then use the forceps to pull the distal end of the feeding tube out into the mouth. Loop this end around and redirect it down the oesophagus past the stoma. The tube can then be pushed on down from the lateral stoma. The tube is then sutured to skin, or to the periosteum of the atlas wing, capped and bandaged in place. The wound can be allowed to granulate after tube removal.

Amount: 1-4ml/ kg body weight every 2-4 hours up to caloric needs. Give slowly and flush the tube with water after use.

Warmed food gives off volatile oils which are attractive. Some animals will take hand offered food. High fat or high protein foods are inherently attractive, where it is possible to use them. Liquid foods may be preferred in free feeding tests over other consistencies, particularly by cats. Also in cats, low dose intravenous valium can cause feeding behaviour, but this is last resort.

Regurgitation is the passive return of food via the mouth. It is not associated with distress or effort on the part of the animal, and is an oesophageal disease. It usually occurs in association with either a foreign body, or megaoesophagus. In the latter, there is failure of peristalsis in the oesophagus, and the wall ballons out as it courses through the thorax, forming a sac, easily diagnosed on contrast X-rays.

Causes: Congenital, Persistent aortic arch (vascular ring), damage, hypothyroidism, myasthenia gravis. 

Vomiting is an active process co-ordinated by the vomiting centre in the medulla. This controls the complex series of abdominal muscle contractions, closure of the epiglottis etc. which culminates in the active expulsion of material from the stomach and upper intestines. ( Owners report bile as a yellow/ yellow green liquid). Vomiting is a common problem, particularly in dogs which scavenge. It is less common in cats, and small mammals such as guinea pigs and rabbits cannot vomit as they lack a vomiting centre.

Causes of vomiting:

1) Gastrointestinal- inflammation, infection, ulceration, damage, neoplasia of the wall of the GI tract, foreign body, dilatation and twists/ intussusception.

2) Abdominal- Any intra abdominal pain can cause vomiting, such as neoplasia, pancreatitis, peritonitis, hepatitis, nephritis, ruptures, prostatitis.

3) CNS stimulation- renal failure (azotaemia), liver failure, drugs, inflammatory or neoplastic brain disease, motion sickness.

Inhalation pneumonia

Dehydration- assess skin turgor. Sluggish skin return starts at 5-10% dehydrated. Check mucous membrane dryness, conjunctival dryness and sunken eyes suggest serious dehydration. Measure blood protein / PCV levels - rise in dehydrated animals.

Alkalosis ( loss of stomach acids) and electrolyte loss.

Mistaken for vomiting/ regurgitation:

Pharyngeal retching, associated with tonsillitis, pharyngitis, or a foreign body (e.g. grass in cats).

TREATMENT-

NO FOOD

Check for an underlying more serious cause

Fluid and electrolyte replacement

Antacids, demulcents in gastric vomiting

Anti emetic (Emequell = metoclopramide)

Antibiotics if infection

Another common presenting sign at surgeries, and consists of passage of faeces of increased frequency / bulk / water content.

Diarrhoeas which are emergencies are those accompanied by significant (to the vet ! ) haemorrhage, or very profuse and causing the animal to deteriorate rapidly in itself, particularly if accompanied by vomiting. Animals which are well in themselves but exhibit short- term diarrhoea can be treated conservatively, as for vomiting.

Black or tarry faeces also indicate upper tract bleeds as the blood has been digested, and these can be serious. Pale faeces tend to indicate lack of bile, and fatty faeces indicate absorption / digestion problems.

Dietary problems ( intolerance, scavenging)

Infections- parvo, coronavirus, campylobacter, salmonella, distemper.

Parasites- worms, giardia, coccidia

Maldigestion / malabsorption

Neoplasia

Lymphangiectasia

Inflammatory bowel diseases

Foreign bodies and intussusception

Psychological disorders

Management- Starve then bland diet, particularly low fat diets. Treat any primary cause. Kaolin or adsorbents, motility regulating drugs. Hospitalise repeated cases to differentiate psychological causes.

Are usually characterised by long term inability to gain weight, ravenous appetite, and diarrhoea without vomiting. The motions are often fatty (steatorrhea) and contain starch granules on microscopy if pancreatic insufficiency is present (failure of the exocrine pancreas). Blood samples are usually used to diagnose this, for:

TLI - trypsin like immunoreactivity, levels in the blood correspond to the secretory ability of the pancreas.

Vitamin B12- Also low in pancreatic insufficiency

Folate- Low in intestinal malabsorption, high in cases of bacterial overgrowth

Must be differentiated from small intestinal problems as the causes tend to be very different ( see table). The key characteristics are frequency, straining (tenesmus) and mucus/ fresh blood. Colitis often accompanies a prolonged small bowel diarrhoea.

The commonest cause is inflammatory infiltration of the bowel wall (allergic) but hookworm and "irritable bowel syndrome" also occur.

Some large diarrhoeas are fibre responsive, others are not. An allergen controlled diet is often useful. The drug sulphasalazine is often used in dogs, and prednisolone may be used in cats in long term problem cases.

Inability to pass faecal material accumulated in colon due to problems associated with the faeces or due to problems restricting passage along the colon. Faeces will impact if retained in the colon for longer than 3 or 4 days. N.B... obstipation will also cause tenesmus- this is when something obstructs the exit from the bowels, e.g. matted hair.

Causes:

Problem foods- bones etc. Occasionally foreign body

Pain

Obstructive disorder- hernia, pelvic fracture, prostate

Neurological malfunction (megacolon).

Treatment:

Short term relief provided by enema administration. The impacted faeces are softened by introducing a liquid via a soft rubber tube, Lubrication is paramount in these cases and it is always preferable to use dilute lubricant as an enema solution. Water is only useful if the faeces are of relatively normal consistency ( e. g. in some megacolon cases ), or if plenty of time and a co-operative patient are available to allow repeated administrations.

A Phosphate enema is also useful in some patients- the solution is instilled via a tube, and then draws water into the colon via osmosis. Be careful in ill animals, particularly in renal failure, as phosphate enters the animal’s body, using this technique. This is a very nice, non-traumatic enema to use, however.

Long term constipation may be treated with drugs to stimulate the colon; faecal consistency modifiers ( Peridale, sterculia) ; surgery to shorten the affected colon. Liquid paraffin over the long term will cause vitamin malabsorptions, so should be used sparingly.

NEVER FEED BONES TO DOGS.

They lodge at all levels of the digestive tract,cause constipation, are unnecessary or even detrimental as part of a balanced diet, and the marrow is often a cause of diarrhoea as it contains unsterilised material.