Hyphema in Cats
Hyphema is the presence of blood within the front (anterior) chamber of the eye and is a symptom of either a serious ophthalmic disease or systemic disease. The amount of blood within the front chamber can vary. Mild hyphema may appear only as a pinkish-red discoloration to the fluid in the front of the eye, or as red blood settled out on the bottom of the chamber. Severe hyphema is when the entire chamber is filled with blood and the animal is rendered blind.
Hyphema usually originates from bleeding of the iris blood vessels, but the blood may also originate from the ciliary body (tissue behind the iris), choroidal blood vessels (tissue layer beneath the retina), or retinal blood vessels.
Below is an overview of Hyphema in Cats followed by detailed information about the diagnosis and treatment options for this disease.
Hyphema in Cats
Many cats have some level of decreased vision the affected eye(s); however, if only one eye is involved, their behavior is usually normal. Eyes with hyphema may be painful, with symptoms of squinting, increased blinking and tearing. Trauma-induced hyphema is often accompanied by hemorrhages or bruising of the conjunctiva and tissues around the eye.
Bleeding that is extensive or recurrent may completely fill the anterior chamber, resulting in total hyphema and blindness. Eyes with severe hyphema are at increased risk for developing glaucoma (elevated pressure within the eye) and must be monitored closely for this potential complication.
Initially, the color of the blood within the eye appears bright red. The blood may remain unclotted and settle on the floor of the eye. The blood may also clot and turn dark brown or bluish-black with time.
The presence of hyphema can either be a symptom of a serious eye disease or a manifestation of some internal problem elsewhere in the body. While hyphema is often caused by trauma to the eye, spontaneous hyphema may occur with numerous different ocular and systemic disorders. Therefore, it is imperative that the cause of the hyphema be identified immediately.
Prognosis for vision depends on whether the hyphema is mild or severe, whether the pupil can be effectively dilated during treatment, and whether there is bleeding or damage in the back of the eye as well. The presence of severe hyphema, failure to dilate the pupil, hemorrhages in the back of the eye or retinal detachment often results in blindness.
Causes of Hyphema in Cats
In general, the causes of hyphema fall into one of several categories:
- Induced by blunt or penetrating trauma
- Chronic or severe uveitis, which is an inflammation of the iris, ciliary body, and choroid tissues of the eye
- Blood clotting disorders from abnormalities in the number or function of platelets and other clotting factors
- Systemic hypertension, which is an elevation in arterial blood pressure
- Systemic diseases that effect blood clotting or the vessels of the eye, such as certain viral infections (feline infectious peritonitis), some leukemias, and severe elevations in serum proteins.
- Retinal detachment or tearing of retinal vessels
- Tumors or cancer within the eye or somewhere else in the body
- Blunt trauma or injury through the closed eyelids, such as with automobile accidents, blows to the head, and horse-kick injuries
More Potential Causes of Hyphema in Cats
- Sharp trauma or injuries that penetrate or perforate the eye
- Proptosis of the eye, which is the forward displacement of the eyeball out of the orbit that usually arises from blunt trauma to the head
- Uveitis, with bleeding from blood vessels of the iris, ciliary body and choroidal tissues
- Systemic hypertension (high blood pressure) associated with diseases such as chronic kidney disease and hyperthyroidism (hyperactivity of the thyroid gland)
- Accidental ingestion of rodenticide toxins, such as warfarin or brodifacoum, or the ingestion of rodents that have died from these toxins
- Chronic liver disease with decreased production of coagulation factors and vitamin K
- Coumadin toxicity from an overdose of this medication (prescribed for the treatment of certain cardiovascular diseases)
- Decreased number (thrombocytopenia) or function of platelets
- Hyperviscosity syndrome, which develops with extremely high levels of large protein molecules in the bloodstream
- Primary tumors of the iris and ciliary body, or other tumors that originate within the eye
- Metastatic tumors that have spread to the eye from other parts of the body
- Systemic hypertension (high blood pressure) resulting in choroidal, retinal and vitreal body hemorrhage and retinal detachment.
- Retinal detachment with bleeding from the choroid and/or torn retinal vessels, resulting from eye trauma, systemic hypertension, uveitis, post-surgical uveitis (e.g. after cataract surgery), and chronic glaucoma resulting in enlargement of the globe with movement of the lens.
Diagnosing Hyphema in Cats
A complete medical history is obtained and a thorough physical examination performed. Be sure to tell your veterinarian if you are aware of any potential exposure to toxins or poisons, of any head or eye trauma, the time and rate of onset of the bleeding (sudden or slowly progressive), medications currently being given, ongoing medical conditions or recently observed physical abnormalities of your pet.
A complete ophthalmic examination usually includes examination of the interior of the eye under magnification, staining of the cornea with fluorescein, and tonometry to detect glaucoma. It is important to determine the extent of the hyphema, whether it is confined to the anterior chamber, whether the posterior part of the eye is also involved, and if the condition exists in one or both eyes. Your veterinarian may refer your cat to a veterinary ophthalmologist for further evaluation of the hyphema using specialized instrumentation.
Complete blood count (CBC) including a platelet count are performed to look for evidence of infection/inflammation, and to ensure there are adequate numbers of platelets present. Then, a serum biochemistry panel is run to evaluate organ functions and measure protein levels in the serum.
Your veterinarian or veterinary ophthalmologist may recommend further diagnostic tests to search for other conditions in the body or to evaluate how much damage is present in the eye. Some commonly performed additional tests include:
- Ocular ultrasonography, which is an imaging technique that shows the structures in the back part of the eye and behind the eye. This test is particularly helpful when the hyphema is so severe that the back of the eye cannot be examined with the usual instruments.
- Ultrasonography helps to identify the presence of abnormal masses within the eye, lens displacement (luxation), retinal detachment or vitreal hemorrhage. A veterinary ophthalmologist or radiologist may perform or interpret this test for your veterinarian.
- Radiographs of the head and orbit (bony socket for the eye) may be necessary to identify fractures in cats that have sustained head injuries. Plain X-rays are also useful to identify any metal foreign objects like gunshot pellets or BBs lodged in the area.
- Abdominal ultrasonography may be recommended if there is evidence on the laboratory tests that certain organs in the abdomen are not functioning well, or that there may be cancer in the abdomen.
- A bone marrow aspirate (cell collection from the bone marrow) may be done to evaluate the bone marrow’s ability to produce platelets or to search for cancer of the bone marrow.
More Information on Treatment of Hyphema in Cats
The goals of therapy of hyphema are two-fold. It is intended to both treat the inflammation that arises in the eye from the bleeding and to treat any underlying causes of the bleeding.
Treatment of the hyphema itself involves the following:
- Topical corticosteroids, in the form of eye drops or ointment, are used to reduce inflammation within the anterior chamber.
- Topical atropine, in the form of eye drops or ointment, is used to dilate the pupil. Dilation of the pupil helps to relieve pain and to minimize adhesions between the iris and the lens.
- Treatment for glaucoma, whether it initiated the hyphema or developed as a result of the hyphema, is indicated if pressures within the eye are elevated. See the Client Education article on Glaucoma.