Gastrointestinal Foreign Bodies
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PGF VETERINARY SCIENCE CONFERENCE CENTRE
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‘New and Old’– Alimentary Foreign Bodies in Dogs and Cats
Small animal clinicians often see foreign bodies lodged in the alimentary tract (and adjacent structures) of dogs and cats. Some of these pass without any problems, some cause partial or complete obstruction, while others may cause nasty, life-threatening complications such as perforation or plication (rolling up of the intestines like a sock falling down your ankles) of the gut.
Vets need to be on the lookout for ‘new’ foreign bodies, not well described in older veterinary textbooks, when taking a history and working up cases with vomiting, abdominal pain, regurgitation etc and when instructing/educating owners during routine health checks and vaccinations of potential risks to cats and dogs.
My aim in writing this perspective is to provide a stimulus to experienced and busy clinicians to share their recent and past observations with colleagues through the C&T forum.
Oesophageal foreign bodies
These are typically associated with inability to eat and regurgitation (rather than vomiting). Usually this is a problem in dogs rather than cats, and they tend to reach the veterinarian for investigation a few days after ingestion. The commonest foreign body is an inappropriate bone gobbled up (without chewing) by a greedy dog.
- Chicken bones esecially necks can get stuck in the oesophagus if swallowed whole.
- Vertebrae are big offenders because of their irregular shape.
Most of these require endoscopic intervention to effect a favourable outcome, typically at a centre with facilities for endoscopy and purpose designed bone retrieval forceps.
Nasopharyngeal foreign bodies
Bones, blades of grass, plant awns, berries, pills, plastic toys, bits of fish (especially fish heads) or meat can all cause problems if they become lodged in the nasopharynx (the space right at the back of the throat that joins to the back of the nose).
This usually occurs after vomiting following the initial eating and subsequently gives rise to stertor, inspiratory dyspnoea, snoring and halitosis. If the foreign body is not obvious to the human eye, then, endoscopy or a vigorous flush with saline will aid diagnosis.
Gastrointestinal foreign bodies (GIFB's)
Classic GIFB's in dogs include mango pips, peach and apricot stones, tennis ball remnants (somewhat radio-opaque) and metallic foreign bodies (washers, fish hooks, bottle tops, coins).
Bones very rarely cause problems once they reach the stomach, although excess ingestion may result in constipation if the dog is not accustomed to eating a bone rich diet.
GIFB's may cause irritation of the stomach and thus vomiting, and occasionally they obstruct gastric outflow through the pylorus (the narrow exit region of the stomach). Intestinal foreign bodies give rise to signs of obstruction with or without perforation and peritonitis (initially localised, eventually generalised).
Tampons, for obvious reasons, are especially attractive to dogs and cause an especially nasty syndrome due to severe plication of the gut from the attached, anchored string. This problem is more apparent in these politically correct times, because flushing tampons down the toilet is actively discouraged.
Although this topic may initially appear unseemly, owners need to be made aware of this NEW danger common to many households.
Karon Hoffman has recently published an extremely elegant paper on the sonographic and clinical findings in these cases.
Hoffmann, K. L. Sonographic signs of gastro-duodenal linear foreign body in 3 dogs. [Journal article] Veterinary Radiology & Ultrasound. American College of Veterinary Radiology, Raleigh, USA: 2003. 44: 4,466-469. 10 ref.)
Satay sticks are a novel manifestation of multiculturalism in Australian society. Instead of dogs merely getting pancreatitis from eating the fatty sausages after a BBQ, or getting Heinz body haemolytic anaemia after eating the left-over onions, a new syndrome has emerged due to ingestion of wooden skewers (typically with some tasty shish kebab still attached).
These sharp linear foreign bodies usually make it to the stomach without damaging the pharynx or oesophagus, but exit the gut at points of anatomic tortuosity, such as the duodenal flexure or ileo-caecocolic junction (where the appendix are in humans), giving rise to peritonitis. They often eventually exit the body via the left para-lumbar fossa region (just behind the ribs and under the spine) where they can cause local irritation and infection.
Geoff Robbins and Geraldine Hunt have written detailed papers on the clinical syndrome that is seen with this type of foreign body (Beischer, D.A. Robins, G. M.Vertebral osteomyelitis, ataxia and paraparesis caused by a satay stick.
[Journal article] Australian Veterinary Practitioner. 1993. 23: 1, 11-15. 4 ref.; Hunt, G. B.Worth,A. Marchevsky,A. Migration of wooden skewer foreign bodies from the gastrointestinal tract in eight dogs.
[Journal article] Journal of Small Animal Practice. British Veterinary Association, London, UK: 2004. 45: 7, 362-367. 9 ref.)
Remember, however, that prevention is much more effective than a clever surgical cure!
Date palm seeds/pips seem to be an increasingly common cause of partial intestinal obstruction in certain regions of Sydney. They may lodge in the pylorus or small intestine, and being radiolucent, can be hard to detect with radiography and even utilising expert ultrasonography. Sometimes these pips pass spontaneously, having caused a few days of partial intestinal obstruction /irritation, while in other cases surgery is required to effect a cure. The value of lubricants has not been established.
In cats, cotton thread (sometimes with the needle attached), Xmas tinsel, string, fish hooks, other linear foreign bodies (e.g. dental floss) are the best known causes of intestinal obstruction. These ‘linear foreign bodies’ cause a syndrome of intestinal plication if they are lodged at a fixed site, typically the base of the tongue or the pylorus. It is therefore VITAL to always inspect the base of the tongue (by pressure in the inter-mandibular space) in every cat as a routine part of the physical examination. Cutting the string attached to the lingual frenulum can be curative in as many as 50% of cases, although some cats require surgery to unravel the intestines and remove the string.
Recently, the plastic objects used to secure plastic bags have been observed to lodge in the pylorus or intestine of cats. Darren Foster has presented a series of these ‘plastic tie’ cases at a recent feline veterinary meeting.
This is especially a problem in cats that like to play with these plastic bread bag ties, and can be very difficult to diagnose as the objects are not radio-dense (visible on x-rays) and can be visualised only with difficulty using ultrasonography. I understand the same thing happens in young children, and in some countries this has led to them being taken off the market and replaced by other devices. (This is why safety pins are no longer recommended for use with nappies or ‘snugglers’). While visiting Murdoch University last year I heard of a case where one of these plastic ties had snared a portion of colonic mucosa in a dog, causing exsanguination of the patient.
Hairballs remain a potential cause of gastrointestinal obstruction in cats, especially in long haired breeds and cats with skin disease associated with over-grooming. They rarely cause a problem while in the stomach (although occasionally they can get too big to be passed and cause vomiting or inappetence). If passed into the intestine, they can cause a range of symptoms from transient colic to life-threatening intestinal obstruction. They can also complicate linear foreign bodies by becoming ensnared on thread in the oesophagus or stomach.
Classic GI foreign bodies in Queensland
Add macadamia nuts (the Queensland nut), paddle pop sticks, and Kentucky Fried Chicken corn cobs (the Colonel makes them the perfect size to get caught part way along the small intestine).
Where Richard talks about Date palm seeds/pips causing partial obstruction, the Macadamia nut can do this too and its movement along the loops of the small intestine causing see-sawing symptoms of obstruction then relief with some needing surgery and some passing eventually with ‘cure'. A classic ‘zebra’ is when the nut becomes lodged around or just distal to the opening of the common bile duct, giving spectacular haematological and biochemical evidence to support clinical signs of severe cholestatic hepatopathy (vomiting, jaundice, abdominal pain, pancreatitis, etc).
All of these can be difficult to see radio-graphically. We've had two cases of ‘skewer (satay) stickitis’ where the skewers have migrated anteriorly from the stomach through the left side of the liver and diaphragm to lodge in the ventral left thoracic cavity, causing symptoms of malaise, respiratory troubles, pyrexia, weight loss. After the initial GI signs abated; imaging and exploratory surgery have found the intact skewers along with a reactive pleuritis and pericarditis.
Some newer (rarer) foreign bodies that we‘ve seen- pine cone, sausage casing, netting around roasts (this one causes scrunching up of the small intestine as the linear (‘string') foreign bodies do, doll’s head, scrunchies (hair elastic), bobby pin, aquadere (wood glue), wooden sticks (2x sticks and 3x paddle pop sticks that presented with gastrocutaneous fistulas—usually swelling or wound in left caudal thoracic area).
Note: Thanks to Terry King of Veterinary Specialists for generously providing many of the photos and X-rays to accompany this article.