Vet TimesThe website for the veterinary professionhttps://www.vettimes.co.uk

INVESTIGATING CAUSES OF CONJUNCTIVALHAEMORRHAGE

Author : EMMA MAPLETOFT

Categories : Vets

Date : July 21, 2014

EMMA MAPLETOFT BVSc, MRCVS Case notes

YOU are asked to examine Teal – a six-year-old, male, neutered cocker spaniel. Aninquisitive dog, he spends most of his time nipping in and out of the undergrowth, and youhave seen him before for minor scrapes and stitch-ups.

Teal’s owner was not at all surprised when Teal returned from his usual stroll around the fieldswith a red left eye. Examination revealed the presence of extensive conjunctival haemorrhage, butno fluorescein uptake (Figure 1). You feel slightly uneasy with the assumption Teal has bumped intosomething.

Question

Could there be more to this than just trauma?

Answer

Any ocular haemorrhages can be caused by potentially life-threatening systemic conditions, so it isimportant to accurately identify the cause.

As well as trauma, the causes of ocular haemorrhages include not only diseases such as chronicuveitis, chronic glaucoma, neoplasia and retinal detachment, but also systemic diseases such as

1 / 8

hypertension, clotting disorders and platelet disturbances.

Intraocular examination of the affected eye is, of course, indicated – particularly because retinalexamination allows a direct assessment of the vascular system (Figure 2). It is important, however, toalso examine the other eye (Figure 3) and perform a complete physical examination (Figure 4).

Thorough investigation of this case would include:

• Obtaining a complete history, including foreign travel, any recent drug administration, possibleaccess to toxins such as rodenticides or whether the dog has had a previous tendency to bleed.

• Ophthalmoscopic examination of the affected eye.

• Examination of the unaffected eye for signs of external (conjunctival or episcleral) and intraocular(iridal or retinal) haemorrhages, as well as for evidence of retinal detachment.

• Complete physical examination – especially to look for petechiae (pinpoint haemorrhages),ecchymosis (bruising), mucosal bleeding or prolonged bleeding after injury, or venepuncture ifapplicable.

• Blood pressure measurement.

• Laboratory investigations: biochemistry, complete blood count, blood smear evaluation andclotting parameters, urinalysis, faecal analysis and possibly in-house SNAP tests for Angiostrongylus vasorum.

Teal’s complete ocular examination revealed retinal haemorrhages in the affected eye and irishaemorrhages in the other eye. Physical examination revealed petechiae and ecchymoses in theinguinal region. Haematology revealed severe thrombocytopaenia with a platelet count of 20×109/L(150 to 450). Urinalysis demonstrated haematuria.

The remainder of his haematology, biochemistry, prothrombin time (PT) and activated partialthromboplastin time (aPPT) were unremarkable, and the A vasorum SNAP test was negative.

Thrombocytopaenia

Thrombocytopaenia is the most common acquired defect of haemostasis in dogs. Spontaneousbleeding can occur when platelet counts are lower than 40×109/L.

The causes of thrombocytopaenia are classified as:

• decreased platelet production;

2 / 8

• increased destruction;

• increased consumption; and

• increased sequestration.

As a rule of thumb, platelet counts of less than 25×109/L are common in dogs with immune-mediated thrombocytopaenia (IMTP), whereas platelet counts of 50×109/L to 75×109/L are seen,for example, with ehrlichiosis, splenic disease or any extensive haemorrhage.

IMTP is a diagnosis of exclusion and so other causes of thrombocytopaenia – such as neoplasia,infectious disease and drug reactions – should be ruled out before starting an immunosuppressivesteroid regimen.

In Teal’s case, no underlying systemic cause was identified and treatment was started for IMTPwith 2mg/kg prednisolone once daily. The need for additional medication might have to beconsidered depending on the response to prednisolone.

Teal remained hospitalised until his platelet count returned to above 50×109/L, to minimise the riskof bleeding being triggered by minor trauma.

Take home message

Investigation of ocular disease should start with a thorough history and complete physicalexamination, as there is a wide variety of ocular manifestations of systemic disease.

Trauma must, of course, be considered as a possible aetiology, but must not be taken forgranted – even in a bouncy spaniel.

3 / 8

Figure 1. Extensive subconjunctival haemorrhage in the left eye. Note the normal corneal health,as evidenced by the clearly defined Purkinje images (representing the camera flashes).

4 / 8

Figure 2. Retinal haemorrhages in another patient with immunemediated thrombocytopaenia.

5 / 8

Figure 3. Iris haemorrhage.

6 / 8

Figure 4. Multiple petechial haemorrhages in the inguinal region.

7 / 8

Powered by TCPDF (www.tcpdf.org)

8 / 8