Puppy scratched by cat

24 Puppy scratched by cat

INITIAL PRESENTATION

Pain, discharge

PRESENTING SIGNS

The young puppy presented due to an encounter with the local cat – sometimes the family cat, sometimes belonging to a neighbour – is a familiar problem in general practice and, as such, it deserves some detailed consideration. The presenting signs are usually textbook classic. The puppy suddenly yelps and holds one eye tightly closed. Meanwhile the cat saunters away unconcerned! The owners present the patient with minimal delay.

CASE HISTORY

As with the case presentation the history is normally very straightforward. The puppy is normally very young – less than 5 months and often only 12–16 weeks. Frequently it has only been in the house for a few days. The puppy was playing and suddenly yelped or screamed and came running away from a cat. It might have encountered the neighbour’s cat in the garden, or cornered the family cat in the kitchen, but the outcome is the same. The cat lashed out at the boisterous puppy and caught it in the eye.

CLINICAL EXAMINATION

The most difficult part of the clinical examination is to keep the puppy still for long enough to evaluate it! A general clinical examination should be performed. Occasionally the pup might have other scratch injuries (usually to the face) or it might even become shocked and need immediate attention for this. However, we will assume that it just has an injury to one eye. Full evaluation is required since the trauma could result in simply a very superficial corneal scratch or the far more serious ocular penetration including lens damage.

It is common for the conjunctiva to swell (chemosis) and become markedly hyperaemic, making direct examination of the cornea difficult. The application of topical anaesthesia can help visualization but if the puppy is struggling it is often more sensible to sedate it, or even administer general anaesthesia for a more thorough examination. This is particularly important if a full thickness laceration is suspected – resistance to examination could result in a catastrophic iris prolapse for example. Examination under sedation or anaesthesia obviously has its limitations but it is preferable to exacerbation of the ocular damage. One advantage, however, is that it is possible to fully check the conjunctival sac for remnants of cat claw which could have broken off and if not removed could act as a foreign body later on.

The globe should be evaluated to see if it has been perforated by the cat scratch. The report of a very wet eye, often with a bloodstained discharge, might suggest this (Figure 24.1). Fluorescein can be safely used, even if the eye has been perforated, providing moistened sterile paper strips or single-use vials are used. If the corneal integrity has been broken, a small stream of aqueous might be seen leaking out through the retained dye in the surrounding damaged cornea. Checking the depth of the anterior chamber is useful – it will be shallower than the fellow eye if perforation has occurred. Also the shape of the pupil might alert you to a full thickness injury – normally it would be miotic following the injury but should remain spherical if the cornea is intact. If it is markedly distorted, this suggests corneal rupture with the iris moving forwards to plug the hole (anterior synechia or even iris prolapse) and resultant misshaping of the pupil (see Figure 24.9).

Figure 24.1 Full thickness laceration, resulting in iris prolapse in a 4-month-old Labrador puppy. Note the sticky bloodstained discharge (clotted aqueous) and bulging brown iris with surrounding grey corneal oedema.

Figure 24.9 Iris prolapse in a 4-month-old lurcher which met the neighbouring cat through the fence. Note the dyscoria, bleb of grey–brown tissue on the cornea but lack of haemorrhage or lens damage.

Assuming that the cornea has not been ruptured, the injury can be treated as a superficial or simple deep ulcer. However, cats’ claws often rip through the full thickness of the cornea. If this has occurred, in addition to checking the position of the iris it is essential with any such injury to check the integrity of the lens. Tears in the anterior lens capsule can be catastrophic. If not diagnosed on initial presentation they can result in a serious phacoclastic uveitis, secondary glaucoma and loss of the eye. If the anterior lens capsule cannot be directly visualized, then careful ultrasonography can be considered. However, the ultrasound gel should not be allowed to enter the anterior chamber. If it is not clear whether the lens is involved, then early referral should be considered and offered to the client.

DIFFERENTIAL DIAGNOSES

The list of differential diagnoses is minimal since the history and presentation are classic for a cat scratch injury. Other traumatic incidents such as a thorn or even blunt trauma from a football can be considered but the history will usually rule out such events. Progression of an undiagnosed ulcer is possible, but unlikely. Ocular congenital conditions are rarely likely to cause such a presentation with the exception of congenital keratoconjunctivitis sicca which could present with a suddenly ruptured corneal ulcer.

CASE WORK-UP

The work-up for a puppy scratched by a cat is minimal. Once the degree of ocular damage has been ascertained, further diagnostics can be undertaken. These might include ultrasonography, as outlined briefly above, to evaluate lens integrity and ensure that the posterior segment is not involved. If the anterior lens capsule has been breached, then early referral should be considered.

Phacoemulsification of the damaged lens offers the best long-term prognosis for the puppy. If the lens appears intact, and immediate referral is not being offered, it might be appropriate to take a swab from the edge of the laceration for bacterial culture and isolation – cats’ claws can harbour a wide range of potentially pathogenic organisms and early detection can allow the most appropriate medication to be chosen. Additional work-up is not usually required.

NURSING ASPECTS

Some specific nursing factors need considering when dealing with ocular injuries in young puppies. To start with, they will not be fully trained, and so are unlikely to sit on command and keep still for the application of topical medication. As such, it is usually easier if two people are available at treatment times. Self-trauma is more likely in puppies than in older patients and so the use of Elizabethan collars is common. However, many young animals will react quite violently to the collar, and care must be taken to ensure that they do not exacerbate the ocular damage further by thrashing around due to panic and fear of the collar. They should also be kept quiet while the cornea heals – which again is difficult in young playful animals. Nurses can spend time with the owners explaining ways to keep the pet calm without resorting to sedatives!

General aspects of nursing are similar to previous ulcer cases – gently cleaning away any discharge with sterile saline on soft swabs or moist cotton wool prior to the topical application of various medications. The patient should be stroked and fussed after treatment so that they learn that it is not an unpleasant experience and also to distract them such that they are less likely to rub the eye.

EPIDEMIOLOGY

The epidemiology of cat scratch injuries is easy to understand when remembering that the menace response is a learned response. It is not innate. The response is not present immediately the eyes open (at about 10–14 days in puppies), but develops gradually by about 4 months of age. Thus, when the playful puppy bounds up to the less than enthusiastic cat, it does not realize that the cat’s paw rapidly reaching out to it is a threatening gesture which is likely to hurt. And in the matter of a few seconds the poor puppy has come off worse from the encounter.

Tags: Saunders Solutions in Veterinary Practice Small Animal Ophthalmo

Sep 10, 2016 | Posted by admin in SMALL ANIMAL | Comments Off

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