Nasolacrimal flushing in rabbits

How many times have you seen a rabbit with tear overflow and prescribed antibiotic drops and hoped for the best? A few drops of fucidic acid may help, but it’s likely that the problem will persist or recur if the original cause isn’t identified and addressed. It’s at times like that that you need to consider nasolacrimal flushing.

Posted: 14 January 2020

Nasolacrimal flushing in rabbits

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Why flush?

A consequence of dacrocystitis is that the tear ducts become inflamed, clogged and blocked by purulent debris. As a result of this, tear overflow is inevitable as drainage is compromised. By flushing the nasolacrimal duct, you’ll be able to push this debris through and out, thereby restoring normal drainage.

Flushing is frequently used with some success to treat and cure primary bacterial infections, and in the case of secondary infections, it will almost certainly improve the patient’s quality of life.

Unless you’re familiar with flushing, it’s likely that sedation or anaesthesia will be required as it can be fiddly and uncomfortable.

Key anatomical features in the rabbit

  • Lacrimal punctum – also known as the punctum lacrimale, this is the opening of the nasolacrimal duct in the conjunctiva. It’s in the lower conjunctiva, close to the medial canthus. Occasionally it’s slightly pigmented and can be larger than you think, making it a little easier to identify.
  • Lacrimal sac – this is a dilation of the duct and is just a few millimetres from the punctum.
  • Lacrimal canal – past the lacrimal sac, the duct travels via the lacrimal foramen in the lacrimal bone into the maxilla. At this point the duct is surrounded by bone. It narrows from around 2mm to 1mm and becomes squeezed between the nasal cartilage and the alveolar bone. This is the most likely place for an obstruction, especially if there are some tooth root abnormalities.
  • Lacrimal canal opening – this is at the ventromedial aspect of the alar fold in the nasal cavity.

Step by step guide to flushing the nasolacrimal duct

The nasal mucosa is extremely sensitive, so without analgesia the patient will almost certainly resist. In most cases it’s wise to anaesthetise or sedate the animal first. In some situations, if the rabbit is very calm, you can place a few drops of topical anaesthetic to the eye, but this needs to be reserved for those cases where the obstruction is minimal.

What equipment do you need?

  • Sterile syringe – have 2ml and 5ml sizes available.
  • Irrigating cannula – it’s best to use a cannula specially designed for flushing tear ducts. A 22-25G is ideal.
  • Saline – always use warmed sterile fluids.

Method

  1. Fill the syringe with sterile saline.
  2. Gently evert the lower eyelid to show the lacrimal punctum.
  3. Insert the cannula into the nasolacrimal duct and guide it in a ventromedial direction. You’ll know when it’s in the right place as there shouldn’t be any resistance.
  4. Carefully advance the cannula into the lacrimal sac.
  5. GENTLY (and be very gentle!), flush the duct with the saline. Be aware that if you force the fluid you can easily rupture the sac if the duct is fully blocked. Trauma can lead to the formation of scar tissue and stenosis.
  6. If the duct is patent, fluid and contents of the duct should come through the nostril. However, if the duct is very blocked, the flushing can result in purulent material emerging between the eye and lids from the punctum.
  7. Apply gentle pressure to the lacrimal punctum with your thumb during flushing, as this will help force saline down the duct and hopefully help clear the blockage.
  8. Collect any flushed purulent material on a sterile swab and send to your external laboratory for culture and sensitivity. The most commonly isolated organisms are Pasteurella, Moraxella, Streptococcus and Neisseria species.
  9. Inject antibiotics via the cannula into the duct at this stage if you intend to treat an infection. Common antibiotics used include enrofloxacin and gentamycin. We would always recommend you follow the cascade when choosing an antibiotic, and ideally culture any pathogens and confirm the choice of antibiotic.

Here is a YouTube video of a tear duct being flushed >

Good nutrition, the key to dental and ocular health

An awareness of the nutritional and husbandry needs of rabbits is essential to prevent many of their health problems. Unfortunately, many owners don’t fully appreciate their specific requirements and can inadvertently cause a multitude of problems, including dental disease and dacrocystitis.

Avoid dental disease and prevent blocked tear ducts

It makes sense to always keep nutritional advice high on our list of things to discuss with rabbit owners. By promoting good nutrition, the long term complications of dental disease can be avoided.

  • Plenty of hay - rabbits should eat between 3% and 5% of their own body weight of hay per day. This can be a large volume, almost the same size of the rabbit itself.
  • Put fibre first – only offer good quality feeding-hay and grass. At Burgess Pet Care we’ve got the several perfect products – see our range of feeding hay.
  • Monitor appetite – encourage all owners to monitor their pet’s body weight, body condition and food intake.  Any major changes should be brought to your attention early.
  • Never feed muesli – stress the consequences of feeding muesli style, high carbohydrate diets. There is plenty of evidence to show that this is harmful. Download the pdf from The University of Edinburgh.

At Burgess Pet Care we are passionate about good nutrition and the importance of high fibre diets. We’ve developed a full range of products that completely satisfy the needs of rabbits and other fibrevores.

Check our range of rabbit hay and pelleted foods here 

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