Acute conjunctivitis in dogs

10 Acute conjunctivitis in dogs




INITIAL PRESENTATION


Colour change – red



PRESENTING SIGNS


Acute conjunctivitis is very common in dogs and normally presents as a suddenly inflamed, red eye, with some discharge. This is initially serous in nature but can become mucopurulent after 1–2 days. In addition to the colour change, owners will report various degrees of irritation or discomfort. This can range from slight blepharospasm to severe self-trauma and secondary eyelid or periorbital involvement. One or both eyes can be affected. Occasionally more than one dog in the same household will be affected, which obviously suggests an infective aetiology.



CASE HISTORY


Owners will have normally been aware that the dog has had red eye(s) for a day or two before presentation. The conjunctival hyperaemia can be marked and usually it is the change in appearance of the eye(s) rather than the discharge or irritation about which the owner is concerned. The condition could have developed suddenly, after a walk for example, or been slightly more insidious, taking 48 hours to manifest. Sometimes owners might have tried treating the dog themselves with some ocular medication present in the house. It is not uncommon for them to have tried chloramphenicol drops, since these are available over the counter in the UK, prior to bringing the pet to the surgery.



CLINICAL EXAMINATION


Even if the patient seems to be suffering from a straightforward conjunctivitis on initial presentation it is important to perform a full general clinical examination as well as an ophthalmic one, since conjunctivitis can be a manifestation of some systemic diseases (coagulopathies, toxicities and neoplastic processes for example). Failure to appreciate this can be detrimental to the patient. However, assuming that the clinical examination is normal, attention can be focussed on the ocular abnormalities present. Conjunctival hyperaemia is the hallmark of conjunctivitis, with variable degrees of chemosis and some increased lacrimation.



Clinical signs of conjunctivitis



• Hyperaemia

• Chemosis

• Ocular discharge

• Haemorrhage

• Follicle formation

• Pruritus

• Abnormal swellings

• Subconjunctival haemorrhage.

It is very important to establish whether these signs are due to purely conjunctivitis or whether other ocular involvement is present. Intraocular disease will normally be accompanied by conjunctivitis. Thus attention to examining menace responses, pupillary light reflexes, evidence of deeper episcleral congestion and intraocular examination are necessary (Table 10.1). Intraocular pressure should be measured if there is any evidence of intraocular disease.



Table 10.1 Differential diagnosis of ocular inflammation

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If the ophthalmic examination reveals no intraocular disease, the next step is to determine whether the conjunctivitis is primary or secondary. The latter is common, with corneal ulceration, entropion, eyelash abnormalities, foreign bodies and keratoconjunctivitis sicca being most frequently involved. Once these have been ruled out we can, by a process of elimination, surmise a primary conjunctival disease (Figure 10.1).


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Figure 10.1 Steps in the diagnosis of conjunctivitis.




DIFFERENTIAL DIAGNOSES



• Primary conjunctivitis:
– Viral

– Bacterial

– Allergic

– Toxic or chemical (Fungal and parasitic diseases are rare in the UK)

• Secondary conjunctivitis:
– To adnexal disease

– To corneal disease (e.g. keratoconjunctivitis sicca or ulceration)

– To retrobulbar disease

– To systemic disease


CASE WORK-UP


Once a tentative diagnosis of primary conjunctivitis is reached, a decision is made regarding whether to treat empirically initially or to embark on a full investigation. Often the latter is only undertaken should initial treatment be ineffective. Primary viral conjunctivitis is rare in dogs. Swabs for bacterial culture and sensitivity can be taken, while cytology scrapes can be informative regarding cell type (e.g. multiple neutrophils noted in an acute bacterial infection, eosinophils in an allergic reaction). If an allergic aetiology is suspected, careful examination of the patient should be repeated to look for signs of atopy – conjunctivitis frequently accompanies the skin disease. Careful questioning of the owner is also important if an allergic conjunctivitis is suspected – has a smoker moved into the house, have they put some new plants in the garden and so on. Conjunctival biopsy specimens are often less helpful than cytology samples.




NURSING ASPECTS


Other than routine hygiene, preventing self-trauma and topical medication, there are no specific nursing requirements for primary conjunctivitis in the dog.

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Acute conjunctivitis in dogs
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