Retinal Hemorrhage
Retinal Hemorrhage is focal or generalized areas of bleeding into part or all layers of the retina. May be acute or chronic.
PATHOPHYSIOLOGY
Depends on cause.
Trauma-induced retinal detachments—may tear retinal blood vessels.
Often involved in congenital malformations, concurrent vascular abnormalities, and neovascularization syndromes.
Intoxications, vasculitis, systemic clotting, neoplastic disorders, systemic infectious disease—may cause focal or more widespread hemorrhage.
Systemic hypertension and immune-mediated diseases (e.g., those causing anemia)—may cause local hemorrhage in conjunction with vascular abnormalities and/or complete or partial retinal detachments.
May note a retinopathy in conjunction with diabetes mellitus—includes the formation of vascular microaneurysms with accompanying hemorrhage or exudation.
SYSTEMS AFFECTED
Ophthalmic
GENETICS
Collie eye anomaly—autosomal recessive trait.
Retinal dysplasia—suspected to be autosomal recessive inheritance.
Retinal detachment—depends on causative factor, hereditary type when observed in conjunction with collie eye anomaly or retinal dysplasia.
INCIDENCE/PREVALENCE
Common in hypertensive retinopathy of elderly cats.
Low incidence in collie eye anomaly.
SIGNALMENT
Species
Dog and cat: any breed, age, or sex.
Breed Predilections
Cause may have a genetic basis and be highly breed- and age-specific—young collies with collie eye anomaly; Labrador retrievers with congenital vitreoretinal dysplasia.
Hereditary breed-specific congenital defects that might cause detachment or severe retinal dysplasia—collies and shelties with collie eye anomaly; Australian shepherds with merle ocular dysgenesis; Labradors, Sealyhams, Bedlington terriers, and springer spaniels with retinal dysplasia; and miniature schnauzers with retinal dysplasia and persistent hyperplastic primary vitreous.
Mean Age and Range
Old cats of both sexes—often affected by systemic hypertension.
Collie eye anomaly and retinal dysplasia are congenital defects and can be observed in 5- to 7-week-old dogs.
Predominant Sex
No sex predilection
SIGNS
General Comments
Signs depend on underlying causes such as inflammatory disease in the posterior segment, systemic disease, or ocular malformations.
Historical Findings
Often none
Vision loss
Bumping into objects
Physical Examination Findings
Depends on underlying cause
Light or dark red appearance of the posterior segment
Blood-filled anterior chamber (hyphema)
Evidence of bleeding elsewhere—petechia, ecchymoses, melena, hematuria
Leukocoria (whitish-appearing pupil) with or without reddish coloration behind the lens
Absence of menace response
Abnormal pupillary responses
CAUSES
Congenital
Retinal detachment secondary to severe congenital malformations in the eye.
Vitreoretinal defects; e.g., in PHTVL/PHPV.
Retinal defects in geographic or complete retinal dysplasia or in partial or complete retinal detachment.
Acquired
Trauma.
Systemic hypertension (especially old cats)—renal disease; cardiac disease; hyperthyroidism; hyperadrenocorticism; idiopathic.
Intoxication—dicumarol; paracetamol; sulfonamide; estradurin.
Rickettsia—Rickettsia rickettsia, Ehrlichia spp. associated.
Systemic mycosis—cryptococcosis.
Neoplasia—lymphosarcoma.
Plasma cell myeloma.
Hematologic disorders—blood-clotting disorder (von Willebrand disease); severe anemia; thrombocytopenia; monoclonal gammopathy and hyperviscosity syndrome.
Diabetic retinopathy.
Retinal detachment.
Immune-mediated vasculitis.
RISK FACTORS
Systemic hypertension or clotting disorders
Hematologic such as anemia and polycythemia
Vascular membranes
DIAGNOSIS
DIFFERENTIAL DIAGNOSIS
Normal choroidal vessel pattern in a subalbinotic fundus. Lightly pigmented eyes. Blood is contained in vascular channels and not outside of the vessel lumen.
Vitreal opacities (blood or inflammation). Vitreal hemorrhage—reddish coloration of the pupil, impossible to rule out concurrent retinal hemorrhage. Vitreal inflammation—generalized or local blurring or lack of fundus detail—usually no reddish coloration. Vitreal opacities can be caused by persistent hyaloid arteries, neoplasia—especially lymphoma or ciliary body tumors; uveitis; glaucoma; lens luxation; blunt or sharp trauma, foreign bodies, and spread from local or systemic diseases (e.g., rickettsial or systemic mycosis).
CBC/BIOCHEMISTRY/URINALYSIS
Usually normal unless secondary to a systemic disease.
Hyperglycemia and/or glucosuria—may note with diabetic retinopathy.
High BUN or serum creatinine and proteinuria—common in cats with retinal detachment and hemorrhage secondary to systemic hypertension.
Thrombocytopenia or other changes consistent with systemic hematologic disorders.
OTHER LABORATORY TESTS
Complete workup—suspected systemic disease; includes thyroid and adrenal endocrine tests, serologic tests for infectious agents, and immune studies.
IMAGING
Ocular ultrasound to evaluate position of lens and retina in cases with blood-filled posterior segment.
If neoplasia is possible consider chest radiographs.
Abdominal ultrasound may be considered if systemic disease is suspected.
DIAGNOSTIC PROCEDURES
Ophthalmic examination with a penlight—usually permits diagnosis of complete retinal detachment with partial retinal hemorrhage; detached neuroretina may often be visualized through the pupil as a whitish veil of tissue.
Indirect ophthalmoscopy—diagnosis of funduscopic and vitreal changes.
Vitreous paracentesis and cytologic examination—aid in the diagnosis for suspected neoplasia or mycotic disease.
Blood pressure measurement—indicated in all patients with severe retinal and vitreal hemorrhage.
PATHOLOGIC FINDINGS
Depends on the cause.
Findings include preretinal, intraretinal, or subretinal hemorrhage that may be focal or involve large areas.
Secondary morphologic changes include fibrotic areas with proliferation of cellular extensions into the subretinal space, intraretinal, and thickening of the external limiting membrane.
TREATMENT
APPROPRIATE HEALTH CARE
Infections and intoxications—often require specific treatment. Systemic hypertension should be treated in a timely fashion to improve chances of retinal reattachment.
Consider referral for a more detailed ophthalmic examination, including ultrasound, before attempting empirical therapy.
NURSING CARE
Depends on the cause.
Supportive care often needed with well-trained veterinary technicians to monitor progress several times daily.
ACTIVITY
Retinal detachment—cage rest until the retina is reattached in trauma cases.
DIET
Depends on underlying cause; there may be dietary restrictions if the primary disorder is due to hepatic or renal disease.
CLIENT EDUCATION
Discuss living with a blind dog or euthanasia of young puppies with severe bilateral hemorrhage due to congenital abnormalities (of the breeds listed under “Signalment”).
Advise client that unilaterally affected dogs can function as pets but should not be used for breeding, a fact not always obvious to the owner.
SURGICAL CONSIDERATIONS
Surgery—refer patient to an ophthalmologist for vitrectomy and/or reattachment surgery.
MEDICATIONS
DRUG(S) OF CHOICE
Depends on underlying cause.
CONTRAINDICATIONS
Systemic corticosteroids and other immunosuppressive drugs—use with extreme caution in patients with systemic infection.
Systemic NSAIDs—contraindicated with bleeding disorders, impaired renal function, or preexisting hypersensitivities; predispose patient (especially cats) to gastrointestinal ulceration.
PRECAUTIONS
NSAIDS—carprofen and meloxicam commonly used but may exacerbate bleeding; either may be administered to control intraocular inflammation in dogs. Use with caution in cats.
ALTERNATIVE DRUG(S)
Oral azathioprine—may be used in immune-mediated fundus disease; see “Drug(s) of Choice.”
FOLLOW-UP
PATIENT MONITORING
Repeated monitoring—required to ensure that condition subsides and retinal morphology normalizes.
Preretinal hemorrhages—usually absorbed within a few weeks to several months if localized.
Larger or repeated hemorrhages—may be followed by fibroplastic processes; may lead to the formation of fibrous preretinal membranes and vitreoretinal adhesions, which may cause vitreoretinal traction and retinal detachment.
Intraretinal hemorrhage—reabsorbed within several weeks to months; may produce retinal scarring.
POSSIBLE COMPLICATIONS
Retinal detachment
Blindness
Impaired vision
Chronic uveitis
Glaucoma
EXPECTED COURSE AND PROGNOSIS
Depends on underlying cause.
Most retinal hemorrhagic lesions are small, observed during routine ophthalmoscopic examination, usually heal rapidly, and cause no visual problems.
Retinal hemorrhage due to systemic diseases or retinal malformations is usually more serious, and most have an uncertain prognosis.
MISCELLANEOUS
ASSOCIATED CONDITIONS
Trauma—may often note concurrent lesions in other parts of the eye or body.
Hypertension—cardiac, renal disease, hyperthyroidism, or hyperadrenocorticism—common; may cause systemic medical problems that must be monitored.
Intoxication—often a generalized bleeding disorder affecting other organs.
Cryptococcus infection—often causes concurrent leptomeningitis and pneumonitis.
Lymphoma—may affect several parts of the body; fatal disease.
Hematologic disorders—cause systemic disease; symptoms depend on pathophysiology; anemia and recurrent bleeding common.
Secondary cataracts—may develop within weeks after the onset of diabetes mellitus in dogs.
AGE-RELATED FACTORS
May occur at any age.
Often due to congenital diseases (usually have a hereditary background) or to developmental disease processes.
PREGNANCY/FERTILITY/BREEDING
Dogs affected with hereditary retinal disease causing retinal hemorrhage should not be used in the breeding program.
Corticosteroids and immunosuppressive drugs may cause complications in regards to pregnancy.
ABBREVIATIONS
NSAID = nonsteroidal anti-inflammatory drug
PHPV = persistent hyperplastic primary vitreous
PHTVL = persistent hyperplastic tunica vasculosa lentis
Visit your veterinarian as early recognition, diagnosis, and treatment are essential.