1) The Mouth
Causes:
Foreign Bodies (sticks, needles). Bones and sticks often wedge between the upper molars across the hard palate.
Stings and bites, Fractures (RTA's and Falls), Burns ( scalds and chemical damage)
Signs:
Pain, salivation, pawing. Inappettance and dysphagia. Eventually a foul smell may develop (halitosis). The animal may become hysterical when handled around the head. There may be obvious deformity after fractures, particularly RTA's, and there is likely to be bleeding in these cases.
Treatment:
Remove wedged foreign bodies if possible easily, but do not pull out penetrating foreign bodies or fish hooks. In the case of penetrating sticks ( run-on injuries) often a general anaesthetic will be necessary to explore the extent of the damage, and make sure there is no embedded stick.
To remove fish hooks, because of the barb,it is best to either pull on through in the direction of travel, or cut down to the hook. It will only be possible to do this without sedation or anaesthesia if the hook is very superficial.
2) The Pharynx
Causes:
Foreign Bodies- Balls, Hooks, Needles, Bones. Stick injuries can be potentially fatal in this area as a lot of tubes and wires run very close to the pharynx (jugular veins, carotid arteries, oesophagus, trachea, laryngeal nerves, vagus nerves etc..), chemical burns and scalds. Dogs will sometimes suffer laryngeal fractures in fights.
Signs:
- Gagging, dysphagia, pharyngeal retching, particularly if stimulated by applying light pressure to the throat. A gag reflex can be elicited by firm pressure in normal dogs. Cough, halitosis if long standing.
-Salivation, haemorrhage. Unable to swallow food or water so may be dehydrated, and the owners may report the animal "hanging" over the water bowl.
-Noise (usually inspiratory dyspnoea if a pharyngeal foreign body is interfering with the airway. If the larynx is swollen internally, then inspiratory and expiratory dyspnoea can occur). Kennel cough is often mistaken for a pharyngeal foreign body.
Treatment:
Heimlich manoeuvre for a definite foreign body. Apply sharp inward pulling thrust (NOT a thump!) using a fist to the midline ventral abdominal wall just behind the ribs. Works better if the patient can be suspended upside down.
BEWARE of pulling threads, they may be attached to something far away in the intestines, eaten long ago. It is also less than wise to rummage around in the throat of a distressed animal in the hope of extracting a suspected foreign body. Owners will sometimes be convinced that they have felt a foreign body at the back of the throat. This is usually the epiglottis, which is made of cartilage and therefore stiff to the touch, although one of the owner's fingers may rapidly become the lodged foreign body.
Prep for a tracheotomy if the degree of respiratory distress warrants it. Remember that any degree of oxygen supplementation is useful to a dyspnoeic animal - masks, cages, nasal catheters.
3) The Oesophagus
Causes
Foreign bodies- particularly bones in Bull Terriers! Fish hooks (particularly in Swans and other aquatic birds). Corrosive poisons- Acids, Phenols (Jeyes fluid, Dettol, TCP), Caustic soda, Bleach, Antifreeze (Ethylene glycol).
Signs:
Pain if chemical damage, also dysphagia, retching, haematemesis if severely damaged. Foreign bodies stop at one of 3 sites, at which there is a natural anatomical restriction:-
a) Thoracic inlet, b) Heart base, c) Oesophageal hiatus of the diaphragm / cardiac sphincter of the stomach.
Foreign bodies in the oesophagus cause regurgitation, NOT vomiting. Regurgitation is easily distinguished from vomiting by asking the owner a few questions and/or by observation. Vomiting involves distress and abdominal effort. It is a complex series of muscle contractions organised by the vomiting centre in the brain. Regurgitation is effortless and simply involves decanting the accumulated food out of the oesophagus again. Often the regurgitated material is sausage-shaped like the lumen of the oesophagus.
If the oesophagus is penetrated, then infections of the mediastinum may develop.
Treatment
Give 2% bicarbonate of soda for acids, vinegar for alkalis, Activated charcoal can be used if the poison is unknown.
Foreign bodies have to be retrieved under anaesthesia, or pushed on into the stomach so that they can be retrieved from there. It is, of course necessary to identify what the foreign body is.
If the nature of the injury is unknown, withhold all substances by mouth, and start an intravenous fluid drip.
4) The Stomach
Most thing which can affect the oesophagus can also cause stomach problems.
Injuries can arise from INTERNAL and EXTERNAL causes.
a) Internal Causes
i) Poisons and damaging substances.
This category includes both ingested poisonous substances such as bleach, weedkiller etc., also rotten food containing bacterial toxins (scavengers!), and circulating toxins which arise as a result of kidney failure and liver failure. Some vomiting is the result of both local stomach damage and pain, and direct action by circulating chemicals on the vomiting centre in the brain.
Signs: Abdominal pain, inappettance, vomiting (true vomiting not regurgitation, these animals feel sick). Vomiting continues on an empty stomach due to an inflamed stomach wall. Bile may appear in the vomit (green / yellow) due to reflux from the duodenum. Most vomiting on an empty stomach produces sticky white froth which is a mixture of gastric secretion and excess saliva.
Owners may feel compelled to give milk or alcohol. Milk is a food, so not to be advised, and alcohol is a direct gastric irritant.
A small amount of fresh haemorrhage in the vomit is not of concern, and usually arises due to the strain of attempting to vomit. Large amounts, or brownish "coffee grounds" material (digested blood) indicates serious or prolonged bleeding.
Treatment: (see separate handout also). If the dog is not particularly unwell then advise to starve for 24 hours, allowing water little and often. Owners often know if their dog is a scavenger; equally many owners will insist that their dog could not possibly eat anything unpleasant - take these claims with a pinch of salt.
BUT monitor the situation carefully; vomit is water plus acids and ions, so vomiting causes dehydration and acid / base / ionic balance disturbance. This can be corrected for by the kidneys for a while, but remember that dehydration may compromise kidney function.
If the animal deteriorates, then give intravenous fluid sooner rather than later. Ringers is the fluid of choice for vomiters, but Hartmanns is a good second choice. Anti vomiting drugs such as METOCLOPRAMIDE ( emequell ) may be prescribed.
ii) Foreign Bodies
The stomach is a very large organ, so can accommodate fair sized foreign bodies. In general, FB's cause problems due to partial or intermittent occlusion of the exit (pyloric sphincter), or due to perforation of the stomach wall.
Signs: Vomiting intermittently, always brings up food. Poor appetite, particularly seen in fur balls in cats. Rabbits also get fur balls, but rabbits and other domestic rodents are unable to vomit, so these animals just become dull and inappetant.
Treatment: Conservative treatment of starvation and light diet does not usually work in these cases, as although the animal remains bright, vomiting keeps recurring. Diagnosis is usually made on further investigation ( X-rays, endoscopy, etc. ).
b) External Causes
Penetrating or blunt / crushing abdominal trauma. The majority of blunt traumas have bruising of the outer surface of the stomach only, which may cause haematomas to form. There is a risk of stomach rupture if it is very full at the time of injury. Penetrating sharp injury will always require surgery.
Signs: Abdominal pain. If the stomach is ruptured, peritonitis and shock develop very quickly ( less than an hour ). MONITOR CAREFULLY FOR DETERIORATION.
Treatment: Pain relief . Institute fluids and appropriate treatment if shock is developing. Prep for surgery if necessary.
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