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Granulomas

Granulomas are firm, raised masses consisting chiefly of inflammatory cells sent to the particular area by the body in response to skin penetration by a foreign substance or infectious agent. In essence, the body attempts to quickly surround and wall off the foreign invader before it can spread to other parts of the body. Thorns, insect stingers, vaccines, fungal organisms, and certain bacteria are only a few of the things that can trigger granuloma formation.

If a pet develops one of these growths, an attempt should be made to determine the cause of its appearance. If an infectious agent is suspected, appropriate antimicrobial therapy is warranted to prevent further development of the granuloma.

Granulomas might recede with time, depending on the cause. In some cases, surgical removal of the mass gets rid of the unsightly lump and its cause all at the same time.

Tumors

Skin tumors or cancers can appear in a variety of types, sizes, and shapes. Common tumors that might appear as a lump or mass on or beneath the skin include sebaceous adenomas, lipomas, carcinomas, fibrosarcomas, and mast cell tumors. It is imperative that a biopsy is performed in all instances to determine whether the tumor is malignant.

Sebaceous gland tumors are among the most prevalent of all skin tumors in dogs. These wartlike growths are especially common in cocker spaniels and poodles. They can appear anywhere on the body, including the eyelids. The vast majority of these growths are benign and cause no problems whatsoever, unless they become traumatized as a result of sheer size. Excision of these tumors is curative locally, but others often appear elsewhere with time.

Lipomas are benign, soft, fatty tumors that often form beneath the skin of dogs and cause noticeable lumps. They occur with greater frequency in older dogs that have weight problems. Although a diagnosis of lipoma might seem obvious, a fine-needle aspirate should always be performed to rule out the presence of its less common malignant counterpart, liposarcoma.

Lipomas can be surgically removed, yet because they can infiltrate into the muscle bundles and surrounding tissue, this removal might be unknowingly incomplete and the tumor might recur. As a result, many practitioners will choose to remove only those lipomas that are extralarge or those diagnosed as malignant.

Fibrosarcomas in cats have been known to occur infrequently after certain vaccines are administered. As a result, any lump that appears 2 to 6 weeks following vaccination should be brought to the attention of a veterinarian.

Mammary tumors are relatively common in intact dogs. Treatment involves surgical removal of the affected gland(s). For extensive tumors, chemotherapy might also be employed. It is imperative that a biopsy be performed on all firm lumps to determine whether or not a tumor exists.

Corneal Ulcers

The transparent cornea enclosing the front portion of the eye is a remarkable organ in itself. Responsible for gathering light and directing it into the eye, healthy corneas are essential for proper vision. It stands to reason, then, that ulcerations (loss of surface epithelium) or scratches involving one or more corneal surfaces can seriously threaten eyesight if not managed promptly.



Corneal ulcerations in dogs and cats can occur secondary to poor tear production, entropion or ectropion, dust and foreign debris in the eye(s), nail scratches and other direct trauma, and infections.

Some of the most common sources of corneal ulceration seen by veterinarians are soap or shampoo burns caused by inadequate eye protection when bathing. Pet owners should always apply a sterile ophthalmic ointment to their pet’s eyes prior to any procedure that involves potentially caustic substances around the eyes. Since corneas are so sensitive, even shampoos with touted “no tears” formulations should never be used without applying this protection first.

Clinical signs of a corneal ulcer include squinting and aversion to light, ocular discharge, and obvious discomfort, often signified by pawing at or rubbing the affected eye. A change in the normal color or transparency of the corneal surface is also an indicator that something is wrong.

Definitive diagnosis of a corneal ulcer is made by veterinarians using special fluorescein dyes to stain the corneal surfaces. Dead, diseased corneal tissue will readily take up such stains whereas healthy tissue will not.

Fortunately, the cornea is one organ that will heal quite rapidly if treatment is administered quickly and vigorously. For ulcers involving only the superficial layers of the cornea, topical antibiotic ointments or solutions designed for use in the eyes and applied three to six times daily will help speed healing.

Of course, if an underlying cause, such as foreign debris, still exists in the eye, it must be removed before proper healing can take place. Superficial ulcers can heal in 36 to 48 hours with proper treatment applied.

Deep Corneal Ulcerations

Deep corneal ulcerations are treated the same way that superficial ulcerations are, yet these require close observation for progression or worsening of the ulcer. Bacterial cultures of such ulcers are necessary to be certain that the antibiotics being used are effective against any organisms involved.

For deep ulcers that worsen or fail to respond to conventional treatment, additional procedures might be necessary to speed healing or to prevent the cornea from actually rupturing. A favorite procedure among veterinarians consists of surgically freeing and extending a portion of the thin conjunctiva over the ulcer and actually tacking it down against the ulcer using suture material (conjunctival flap). The flap of conjunctiva provides nutrition and speeds healing to the ulcer, and also allows any medications applied directly to the eye(s) to reach the ulcer without hindrance. Once healing has been accomplished, the flap is released, and excess conjunctival tissue is trimmed away from the healed surface.

Special contact lenses and/or corneal tissue adhesives can also be applied over the damaged surface of the cornea. These serve to protect it from further degradation and help promote rapid healing. For difficult ulcers, actual grafts using fresh or frozen corneal tissue may be required.

Conjunctivitis

Inflammation of the thin, transparent mucous membrane lining the inner portion of the eyelids and front part of the sclera is termed conjunctivitis. Conjunctivitis is the most common cause of “red eyes” in dogs and cats. Other signs seen with conjunctivitis include discharge, swelling, and pain.

The type of discharge present can sometimes give a clue as to the underlying cause of the conjunctivitis. For instance, a watery discharge can indicate irritation from an allergy, virus (canine distemper or feline rhinotracheitis), or contact with dirt or dust; a mucuslike discharge often links the problem to abnormal tear formation (“dry eye”) or to a bacterial infection, either primary or secondary to any of the causes previously mentioned.

Because conjunctivitis can be secondary to other problems, diagnostic tests performed by veterinarians should be directed at identifying any underlying causes. Corneal staining using a fluorescent stain is usually performed to determine whether the cornea is affected. In dogs, if a mucuslike discharge is present, a tear flow test should be performed to rule out “dry eye” as the cause of the conjunctivitis.

In cases of conjunctivitis that don’t respond to conventional therapy, a bacterial culture or sensitivity test should be performed to be sure treatment measures being used are correct.

Treatment of conjunctivitis is aimed at treating or eliminating any inciting causes, and at controlling the localized inflammation. If dust or pollens are the source of the conjunctivitis, daily flushing of the eyes with a sterile saline solution designed for use in the eyes or daily application of a sterile ophthalmic lubricant can help reduce the irritation caused by these offenders.

Ophthalmic drops or ointments containing antibiotics are necessary if a bacterial infection is present. In addition, ophthalmic preparations containing steroids can be used to reduce the inflammation present, provided the surface of the cornea is intact. Preparations containing both antibiotics and steroid compounds for use in the eyes are readily available for pets through a prescription from a veterinarian.

Glaucoma

Glaucoma is a condition characterized by an increase in fluid pressure from the aqueous humor within the eye(s). In the normal eye, pressure and aqueous levels are maintained at a constant plateau by the continual drainage of excess aqueous humor out of the eye through tiny ports (drainage angles) located where the edge of the iris meets the cornea. If this drainage is obstructed or altered in any way, a rise in pressure within the eye can result. Unfortunately, even short-term rises in this pressure can lead to irreversible damage if not detected and treated in a timely fashion.

Conditions such as a buildup of inflammatory material within the eye, luxation of the lens due to trauma or cataracts, and synechia, where the iris “sticks” to the lens or cornea, can all effectively prevent the normal drainage of the aqueous humor from the eye.

Heredity is also thought to play a role in some cases of glaucoma in dogs, with basset hounds, beagles, and cocker spaniels having a higher incidence of the disease due to improper development of the drainage angles. In addition, a predisposition for lens luxation has been identified along family lines for many of the terrier breeds, predisposing them to glaucoma. Finally, allergies and overactive immune system responses are also thought to be important precursors to glaucoma in dogs and cats.

Clinical signs of a glaucomatous eye include a marked redness affecting both the conjunctival tissue and the sclera; a blue, hazy cornea; a dilated, unresponsive pupil; and apparent blindness due to the pressure the fluid is placing on the optic nerve. In instances where the glaucoma has been present for quite some time, enlargement of the affected eyeball might become noticeable, and actual rupture of the cornea could occur.

Diagnosis of glaucoma can be easily confirmed by a veterinarian through the use of an instrument called a tonometer. This instrument, when placed directly on the surface of the cornea, measures the exact pressure within the eye. If the pressure reading is indeed elevated, then treatment should be instituted immediately to prevent lasting damage to the eye.

Treatment for glaucoma is aimed at decreasing the pressure within the eye to an acceptable level as quickly as possible, and then stabilizing this pressure to prevent future increases.

Drugs designed to quickly draw fluid out of the eye and into the bloodstream will initially be used to reduce the pressure within a pet’s eye(s). Other drugs that act by decreasing the production of aqueous humor and by increasing the size of the drainage angles are then prescribed for the long-term management and prevention of recurrence.

At the same time, anti-inflammatory medications can be used topically on the eye to clear up any primary or secondary inflammation that might be aggravating the glaucoma.

In instances where a luxated lens is causing the increase in pressure, surgical removal of the offending lens should always be performed.

Cryotherapy (freezing) can be used as well. This involves surgically inserting a special needle within the eye and freezing the cells within the eye responsible for the production of aqueous humor. With this technique, aqueous production can be reduced by up to 30 percent in some patients.


Date: 2014-12-28; view: 1141


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