Punctate retinal hemorrhage and its relation to ocular and systemic disease in dogs: 83 cases.

OBJECTIVE: To describe clinical aspects of dogs with punctate retinal hemorrhage (PRH). ANIMALS STUDIED: 83 dogs (119 eyes) with PRH. PROCEDURES: Medical records of dogs evaluated by the Cornell University ophthalmology service with a clinical diagnosis of PRH between 2006 and 2015 were reviewed. For this study, PRH was defined as retinal hemorrhages ≤ 1 optic disk diameter in size and dogs with other posterior segment ocular diseases were excluded. Signalment and clinical features of the dogs were recorded, including concurrent ocular and systemic diseases. RESULTS: Punctate retinal hemorrhage was identified in 119 eyes of 83 dogs. The mean (±standard deviation) age of dogs was 10.0 (±3.8) years. Mixed-breed dogs, Golden Retrievers, Jack Russell Terriers, and English Springer Spaniels were statistically overrepresented relative to the ophthalmology service canine referral population during the same period. Hemorrhages were found in all retinal locations and varied in number. Concurrent ocular disease was present in 78 eyes (66%) including keratoconjunctivitis sicca, uveitis, and cataracts. Fifty dogs (60%) suffered from concurrent systemic disease and diabetes mellitus, multiple myeloma, and systemic hypertension were statistically overrepresented in the PRH population. Less frequently, other serious systemic diseases were present in dogs with PRH including immune-mediated thrombocytopenia, leptospirosis, metastatic neoplasia, and thromboembolic disease. CONCLUSIONS: The risk of PRH in dogs may be increased by certain ocular and systemic diseases. As the presence of PRH can be associated with underlying systemic disease in dogs, it may prompt further clinical investigation and diagnostics.

Spontaneous intraocular hemorrhage in rats during postnatal ocular development.

To study spontaneous intraocular hemorrhage in rats during postnatal ocular development and to elucidate the underlying mechanism, postnatal ocular development in the albino Wistar Hannover (WH) and Sprague-Dawley (SpD) and pigmented Long-Evans (LE) strains was analyzed. Pups (n = 2 to 5) from each strain were euthanized daily on postnatal days (PND) 0 through 21 and their eyes examined macroscopically and histologically; similar analyses were performed in 26 to 39 additional WH pups daily from PND 7 to 14. At necropsy, ring-shaped red regions and red spots were present in the eyes of WH and SpD rats. These lesions were attributed histologically to hemorrhage of the tunica vasculosa lentis or of the retina, choroid, and hyaloid artery, respectively. Similar intraocular hemorrhages occurred in LE rats, although the macroscopic alterations found in WH and SpD rats were not present in this strain. Among the 3 strains evaluated, the incidence of the intraocular hemorrhage was highest in WH rats. We here showed that intraocular hemorrhage occurs spontaneously during normal ocular development in rats regardless of the strain; however, the region, degree, and incidence of intraocular hemorrhage differ among strains. Hemorrhage in the tunica vasculosa lentis and hyaloid artery may result from the leakage of erythrocytes from the temporary vasculature of these tissues during regression. The mechanisms underlying hemorrhage in the retina and choroid remain unclear. To our knowledge, this report is the first to describe the spontaneous intraocular hemorrhage that occurs during postnatal ocular development in rats.

Natural animal shaking: a model for non-accidental head injury in children?

BACKGROUND: Non-accidental head injury (NAHI) is a form of child abuse where a perpetrator may violently subject an infant to repeated acceleration-deceleration forces with or without head impact, producing injuries including retinal haemorrhages in most cases. Animal models have included laboratory shaking of mice and rats, but only a small fraction develop retinal haemorrhages presumably due to the small eyes, which would require unattainable force levels to mimic that sustained by the infant eye. Animal models are also problematic due to ethical issues raised by subjecting even anaesthetized animals to abusive injury. METHODS: We investigated a naturally occurring event, where three animal victims were shaken by a canine. The eyes were harvested and examined histologically. RESULTS: The victims' eyes showed no haemorrhage or retinoschisis. CONCLUSIONS: Our model may not be a complete NAHI mimic. The discrepancies may ensue from anatomical and mechanical differences in the injury mechanism. Other models must be sought to further study this form of abusive eye injury.

Survey of retinal haemorrhages in neonatal thoroughbred foals.

Twenty-seven of 167 neonatal thoroughbred foals (16 per cent) were found to have retinal haemorrhages after a careful examination of the entire fundus. Experience in differentiating haemorrhages from other lesions, and the selection of foals from normal populations, were considered to have an important effect on their apparent incidence. Bilateral haemorrhages were more common and there was a significantly higher incidence in female foals. The numbers of haemorrhages ranged between one and 20; 36 per cent of eyes with retinal haemorrhages had the small punctate type and 56 per cent had the splash-like form. There was no change from one type of haemorrhage to another, and the patterns of resolution were similar. The haemorrhages were in the tapetal fundus, except two that were recorded in the optic disc, and they resolved within 10 days. No short- or long-term ocular or neurological effects of the retinal haemorrhages were detected, and they were not related to the incidence of abnormal foal behaviour.

Subconjunctival haemorrhages in neonatal thoroughbred foals.

A survey of 169 neonatal thoroughbred foals revealed that 8.3 per cent had subconjunctival haemorrhages, but there was no indication of a relationship between retinal and subconjunctival haemorrhages. The haemorrhages were not related to any abnormality of the foals and there was no sex or eye predisposition. In most cases the haemorrhages were fresh and red, occurred mainly dorsally or dorsonasally and extended up to the limbus; they resolved completely within four to 10 days, depending on their initial severity and extent. They had no effect on the foals' vision in the short or long term. The incidence of subconjunctival haemorrhages was associated with foaling category, multiparity and country of birth.

Acute blindness associated with monoclonal gammopathy induced by Ehrlichia canis infection.

Ehrlichia canis infection was diagnosed in a Labrador retriever presented with a primary complaint of acute blindness. Ocular signs on admission included bilateral hyphema, retinal haemorrhage and retinal detachment. Serum protein electrophoresis results revealed monoclonal gammopathy. This report discusses and suggests the pathogenesis of ocular bleeding in canine monocytic ehrlichiosis. Blood hyperviscosity, elevation in oncotic pressure, vasculitis, thrombocytopenia and platelet dysfunction are all proposed to be important factors in the pathogenesis of acute blindness in canine monocytic ehrlichiosis.

Ocular signs in four dogs with hypertension.

Four dogs suddenly developed visual problems associated with retinal detachment and haemorrhage. They all had a high arterial blood pressure measured with a Doppler ultrasonic blood pressure monitor. Two of the dogs showed evidence of cardiac hypertrophy and one had hypercholesterolaemia; in three of them there was no conclusive evidence of underlying systemic disease. The condition was treated and assessed over a period of 12 months. In the absence of any findings suggesting the presence of underlying systemic disease, it is possible that the ocular changes were the result of primary hypertension, although not every possible cause of secondary hypertension could be excluded.

Spontaneous retinal changes in Sprague Dawley rats.

Routine ophthalmological examination of over 6,000 untreated Crl:CD(SD)BR rats up to 2 years old, used in toxicologic studies from 1989 to 1992, has provided information on spontaneous retinal changes and their incidence with age. Focal linear retinopathy and coloboma were the most common findings; retinal hemorrhage, saccular aneurysm of the retinal vessels, retinal fold, absence of optic disk and retinal vascularization, and myelination of optic nerve fibers were also observed. Such accumulated data in untreated animals are of prime necessity in assessing possible drug- and chemical-induced effects on the eye after either systemic or local exposure.

Essential hypertension in a dog.

Severe hypertension was diagnosed in a dog that initially was referred for evaluation of visual deficits and retinal hemorrhage and eventually was donated for medical treatment of hypertension. Initial blood pressure measured by direct methods was markedly high (systolic, 275 mm of Hg; diastolic, 170 mm of Hg). Measures of renal function were within normal limits, with the exception of hypotonic urine. A test protocol was designed to exclude possible secondary causes of hypertension; negative results of such tests allowed the diagnosis of essential hypertension. The consistency of the hypertension and its response to medical control were studied for 5 years. Blood pressure while the dog was untreated during those years was 240 +/- 24 mm of Hg (systolic) and 146 +/- 14 mm of Hg (diastolic). Plasma renin activity was within normal limits, and the response of the renin-angiotensin system to varied salt intake was normal. The most effective medications used to lower blood pressure were propranolol and captopril, both of which were more effective than salt restriction alone. Five years after the diagnosis of hypertension, the dog was euthanatized because of chronic renal failure secondary to pyelonephritis. Hypertension was less severe as the condition progressed into chronic renal failure. Complete necropsy did not reveal an obvious cause of the hypertension, and histopathologic changes were limited to the cardiovascular system, eyes, and kidneys.

Neonatal ophthalmology.

This discussion of normal and abnormal findings on routine ophthalmic examination of the foal should prove useful to the equine practitioner who must provide counsel to the concerned owner and/or breeder. Early diagnosis and treatment of ocular abnormalities improve the prognosis for continued function and aid determination of the significance of lesions observed in later life.

Metastatic ocular squamous cell carcinoma in a cat.

Bilateral ocular metastatic squamous cell carcinoma was diagnosed in a cat. Ophthalmic signs included bilaterally swollen optic discs, choroidal pallor, and retinal vascular engorgement. A retinal detachment was apparent in the left eye and retinal edema and hemorrhage in the right eye. Systemic signs of progressive visual impairment, ataxia, and weakness were noted. The patient's condition continued to deteriorate despite therapy with systemic antibiotics and corticosteroids, and euthanasia was performed. The diagnosis was made upon histologic examination that revealed metastasis of malignant squamous cells to both globes, the brain, and lungs.

Collie eye anomaly in the United Kingdom.

Approximately 2500 rough collies, smooth collies and Shetland sheepdogs were examined during a three year period in an attempt to establish the incidence of collie eye anomaly in the United Kingdom and to produce data on the hereditability of the disease. The overall incidence in the two collie breeds was approximately 64 per cent, but the disease was seen with slightly more frequency in the Shetland sheepdog, 72 per cent of the dogs examined being affected. Pedigree analysis and test mating has confirmed the opinion held in the USA that the disease is inherited as an autosomal recessive trait. In this report the pleomorphism of the disease in these three breeds is discussed together with the inherent problems in diagnosis.

Fluorescein angiography of the normal and diseased ocular fundi of the laboratory dog.

A method was determined for fluorescein angiography of the ocular fundus of the laboratory Beagle, using a portable fluorescein fundus camera. A 10% solution of sodium fluorescein was injected by a syringe pump in the right cephalic vein of each dog. Acepromazine maleate (0.5 mg/kg, IV) with ketamine hydrochloride (10 mg/kg, IM) provided chemical restraint. Of the 10-, 25-, and 50-mg/kg dosages of fluorescein, 25 mg/kg permitted satisfactory fluorescence of the choroidal and retinal vasculature and the recirculation phase. High-speed color film permitted good quality photography of the tapetal and nontapetal retinal vessels. Reduced retinal blood vessel and pigment epithelium permeability was demonstrated by fluorescein angiography in dogs with chorioretinitis associated with systemic blastomycosis, retinitis associated with distemper, serous retinal detachment, and preretinal hemorrhage.

The clinical picture of diabetic retinopathy in the dog.

After an extensive review of the literature showing how the existence of diabetic retinopathy in the dog had been confirmed by various research workers and in particular by histological studies, a clinical picture of this retinopathy is given, together with a description of tis individual features based on opthalmoscopic examinations carried out on 13 dogs with diabetes and illustrated with the photographs taken with the KOWA retinograph.