Laurie Anne Walden, DVM
In recent years, monoclonal antibodies have been approved to treat some common medical conditions in animals:
More monoclonal antibodies are likely to become available for dogs and cats. Monoclonal antibodies are used in humans to treat infections, autoimmune disorders, cancer, and other conditions, and they’re being investigated for similar uses in dogs and cats.
How Monoclonal Antibodies Work
Monoclonal antibodies are in a therapy class called biologics, meaning therapies made from living sources like animal cells, plant cells, or microorganisms. Biologics are large molecules that interact with receptors on the outer surfaces of cells; they don’t enter cells. In contrast, most traditional drugs are small molecules that work inside cells.
Monoclonal antibodies are similar to the natural antibodies produced by the immune system. When the immune system detects an antigen, different immune cells release lots of different antibodies that tag different sites on that antigen. (An antigen is anything that triggers an immune response.) Once the antibodies have tagged the antigen, other components of the immune system arrive to destroy it.
Monoclonal antibodies are cloned in a laboratory from just one antibody made by one type of immune cell (mono means “one”). They tag only a single site on an antigen. Monoclonal antibody therapy can be very precise because it directs the immune response to a narrow target.
In addition to tagging invaders like viruses, monoclonal antibodies can be engineered to tag a receptor on an animal’s own cells. The monoclonal antibodies that relieve pain in dogs and cats, for example, block production of a protein that’s partly responsible for the pain sensation.
After monoclonal antibodies have activated the immune system, they’re broken down in the body the same way that natural antibodies are. Unlike small-molecule drugs that enter an animal’s cells, they aren’t cleared through the liver or kidneys.
Monoclonal antibodies are given by injection at a veterinary clinic. They can’t be given by mouth because they’re proteins and would be destroyed by digestion. Their effect lasts a few weeks (4-8 weeks for Cytopoint, 4 weeks for Solensia and Librela). These therapies are species specific: monoclonal antibodies for dogs work only for dogs, not for cats.
The monoclonal antibodies that are available for dogs and cats generally work well for their approved uses. They are less likely than some traditional drugs to cause adverse effects because they have a narrow target of action and don’t enter cells. Because they are not cleared through the liver or kidneys, they can be safer than other drugs for animals with liver or kidney disease. Injections given every few weeks might be more convenient for pet owners than pills given multiple times a day, especially if their pets resist oral medication.
Monoclonal antibodies have fewer adverse effects than many traditional drugs. An antibody injection can cause an allergic reaction, although this is rare. Manufacturers might recommend precautions for individual monoclonal antibody products.
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Laurie Anne Walden, DVM
Vestibular disorders cause problems with balance and coordination. Animals with vestibular disorders typically have a head tilt along with stumbling, walking in circles, and possibly vomiting.
Vestibular problems that start suddenly can look scary to pet owners. The signs can be mistaken for stroke. Some conditions that cause vestibular problems are serious, even life-threatening; others are relatively minor.
One of the most common vestibular disorders in dogs is a benign condition called idiopathic vestibular syndrome (idiopathic means “of unknown cause”). This condition is not serious and gets better on its own with time. Idiopathic vestibular syndrome most often affects senior dogs, so in dogs it’s also known as old dog vestibular disease. Cats can also develop idiopathic vestibular syndrome.
The vestibular system includes the brainstem, cerebellum (part of the brain), inner ear, and nerves that conduct signals between the inner ear and brain. Anything that affects any part of this system can cause vestibular signs.
Vestibular disorders are either central (related to the brainstem and cerebellum) or peripheral (related to the inner ear and surrounding nerves). Central vestibular disorders are usually much more worrisome than peripheral vestibular disorders.
Idiopathic vestibular syndrome is a peripheral vestibular disorder. The exact cause in dogs isn’t known. Similar conditions in humans are caused by inflammation of the inner ear or surrounding nerves, viral infections, and benign positional vertigo (an inner ear problem). These same causes are possible but not proven in dogs.
Some of the other causes of vestibular disease in animals are deep ear infections (common), cancer, drug adverse effects, toxins, systemic disorders like hypothyroidism, meningitis, and other neurologic disorders.
These are the typical signs of a vestibular disorder:
Idiopathic vestibular syndrome usually affects older dogs and cats. It begins suddenly and then starts to improve within a few days. The signs are most pronounced on the first day and don’t get worse with time. In most animals, the signs disappear after a couple of weeks, although the head tilt can last much longer.
Other diseases that affect the vestibular system cause signs of their own. For example, a central vestibular disorder might cause seizures or changes in consciousness. Vestibular signs that get worse with time are a signal that the animal has something other than idiopathic vestibular syndrome.
Idiopathic vestibular syndrome is a diagnosis of exclusion: it’s diagnosed after other possibilities are ruled out. Diagnosis begins with a neurologic examination, eye and ear examinations, baseline bloodwork, and usually a thyroid function test and urinalysis. Depending on the results, the animal might need referral to a veterinary neurologist and advanced tests like magnetic resonance imaging of the head or cerebrospinal fluid analysis.
For idiopathic vestibular syndrome, the goal of treatment is to make the patient comfortable until the condition resolves on its own. Most animals receive prescription antinausea medication; some also need appetite stimulants or fluid therapy. Home care includes making sure they can eat and drink and protecting them from falling down steps or bumping into things like furniture corners. Physical therapy and postural maneuvers that are used to help people with vertigo aren’t commonly used in animals.
Most animals with idiopathic vestibular syndrome recover completely, although some have a permanent head tilt afterward. Some animals have more vestibular episodes later on. For vestibular signs that aren’t caused by idiopathic vestibular syndrome, the prognosis depends on whether the cause is treatable.
Image source: https://unsplash.com/photos/brown-and-black-german-shepherd-Xy7SLX9zuVM
Laurie Anne Walden, DVM
Inflammatory bowel disease (IBD) causes chronic inflammation and irritation of the digestive tract. This condition is one of the most common chronic intestinal disorders in cats. IBD in cats is similar to Crohn disease in humans.
In IBD, inflammatory cells accumulate within the walls of the digestive tract. The small intestine is the most common location in cats; the large intestine and stomach can also be affected. The intestinal walls become thickened and can’t absorb nutrients normally. Some cats with IBD also have inflammation of the pancreas and liver, a combination called triaditis.
The cause of IBD isn’t known. The disease is probably caused by abnormal immune system function related to intestinal bacteria (which are necessary for normal digestion and immune function), diet, genetics, or other factors. IBD usually affects middle-aged or older cats, although cats of any age can develop the disease.
The signs are similar to those of many other digestive system disorders:
Because so many conditions cause the same signs as IBD, cats with chronic digestive tract problems need a thorough workup. Diagnostic tests are performed to rule out a long list of other possibilities, including intestinal lymphoma (a cancer that is clinically very similar to IBD), parasites, intestinal foreign bodies, bacterial and viral infections, food allergies, other types of cancer, and diseases like hyperthyroidism that cause general illness.
Baseline tests include fecal parasite tests, bloodwork, and urinalysis. Additional blood tests are used to assess the function of the pancreas and check for evidence that the small intestine is not absorbing nutrients properly. Imaging (radiography and ultrasonography) is used to evaluate the digestive tract, liver, pancreas, and other organs.
The only way to definitely diagnose IBD and distinguish it from intestinal lymphoma is to obtain biopsy samples from the intestine and submit them to a diagnostic laboratory for analysis. Biopsy is performed either with endoscopy (tube inserted through the mouth or anus) or abdominal surgery. Both of these procedures require general anesthesia.
IBD is managed, not cured. Treatment is tailored to the individual cat, depending on what works best for that cat. Most cats receive a dewormer to eliminate parasites as a possible cause. Some cats’ signs improve with a hypoallergenic diet, so treatment can include several weeks of a food trial with a prescription diet. Antibiotics are sometimes used carefully (they can disrupt the normal intestinal bacteria). Probiotics and prebiotics, which contain beneficial bacteria or nutrients for existing intestinal bacteria, might be included in the treatment plan. Drugs that suppress the immune response, such as the corticosteroid prednisolone, are necessary for some cats.
Cats whose disease responds well to treatment can have a good quality of life, although their IBD signs will probably still flare up occasionally. The treatment type and medication doses often need to be adjusted over time.
Image source: https://www.flickr.com/photos/ianlivesey/43270035161/
Laurie Anne Walden, DVM
The prostate gland grows and develops in response to testosterone and related male sex hormones. Almost all prostate disease that we see in companion animal practice is in intact (not neutered) dogs.
In male animals, neutering means surgical removal of the testicles (castration). Some prostate diseases can affect neutered animals, but these are rare. Most pet male cats in the United States are neutered, so prostate disease is much less common in cats than in dogs.
Benign Prostatic Hyperplasia
Because the prostate can keep growing as long as it’s exposed to testosterone, most intact male dogs eventually develop enlargement of the prostate, or benign prostatic hyperplasia (BPH). About half of intact male dogs have microscopic evidence of BPH by the time they’re 4 years old; more than 90% have it by the time they’re 8.
Most dogs with BPH have no signs of the condition and don’t need treatment. Signs can include blood in the urine, straining to urinate or defecate, and constipation. BPH can reduce the fertility of breeding dogs.
In some dogs, an enlarged prostate can be detected with rectal palpation. Ultrasonography is used to measure the prostate and make the diagnosis. Depending on the dog’s signs and test results, samples of prostate fluid or prostate cells might be sent to a laboratory to rule out other prostate disorders.
For dogs whose prostate enlargement is causing a problem, the treatment is to eliminate exposure to testosterone, typically with castration. Medications that block the effects of testosterone on the prostate are available for breeding dogs that need to keep their testicles.
Dogs with BPH are prone to develop prostatitis, which is infection of the prostate. Prostatitis is fairly common in intact male dogs and rare in neutered male dogs. The signs of prostatitis depend on whether the condition is acute (has just begun) or chronic (has been going on for a long time):
Prostatitis is suspected in any intact male dog with compatible signs—especially if rectal palpation is painful—or repeated urinary tract infections. Diagnostic tests include blood tests, urinalysis, ultrasonography of the prostate, and culture of prostate fluid. Some dogs with prostatitis also have abscesses of the prostate, and these can be seen with ultrasonography.
The treatment for prostatitis is several weeks of antibiotics along with treatment of the underlying BPH, which means castration for most dogs. Dogs that are ill with acute prostatitis sometimes need to be hospitalized. Abscesses of the prostate might require surgical drainage.
Prostate cancer is rare but unfortunately very serious in dogs. The types of prostate cancer that dogs get aren’t linked to testosterone level, so castration does not protect dogs against prostate cancer (it’s actually more common in neutered dogs for unknown reasons). The screening tests and treatments for prostate cancer that are used in men don’t work in dogs. Prostate cancer in dogs tends to be aggressive, is metastatic (spreads through the body), and is usually diagnosed at a late stage. Treatment options other than palliative care are limited; a veterinary oncologist is the best source of advice for an individual dog.
Christensen BW. Canine prostate disease. Vet Clin North Am Small Anim Pract. 2018;48(4):701-719. doi:10.1016/j.cvsm.2018.02.012
Palmieri C, Fonseca-Alves CE, Laufer-Amorim R. A review on canine and feline prostate pathology. Front Vet Sci. 2022;9:881232. doi:10.3389/fvets.2022.881232
Image source: https://unsplash.com/photos/black-and-white-short-coated-dog-tKtYHZ13yls
Laurie Anne Walden, DVM
Hepatic lipidosis, or fatty liver syndrome, is a life-threatening condition in cats that stop eating for any reason. It’s most common in overweight or obese cats but can affect cats of any weight. Cats that don’t eat for more than a couple of days need to see a veterinarian without further delay.
When cats don’t eat, their bodies start to break down stored body fat to use for energy. Eventually the level of metabolized fat in the blood is higher than the body can use, and the excess fat is stored in the liver cells. The liver cells become swollen with fat and can no longer function normally, resulting in liver failure. The swollen liver cells also squash the bile ducts within the liver, obstructing the flow of bile (which is needed for normal digestion).
Overweight and obese cats are at higher risk than average-weight cats because they have more body fat to metabolize. The tendency to store metabolized fat in liver cells is a quirk of feline liver function, so hepatic lipidosis is much more common in cats than in dogs.
Anything that makes a cat stop eating can cause hepatic lipidosis. The cause is usually an underlying disease like a digestive system disorder, diabetes, kidney disease, cancer, or hyperthyroidism. Healthy cats can develop hepatic lipidosis if they don’t eat for some reason, like changing to a new food they don’t like, experiencing a stressor like a new pet or a house move, boarding, getting accidentally locked in a garage, getting lost outdoors, and so forth.
Cats with hepatic lipidosis usually have signs of liver disease like these:
Cats might also have signs related to the underlying disease that caused them to stop eating.
Baseline diagnostic tests (bloodwork and urinalysis) are run to evaluate liver function, assess the cat’s overall condition, and look for an underlying disease. Cats with signs of liver disease usually also have imaging studies like ultrasound of the abdomen. The diagnosis of hepatic lipidosis can be confirmed with liver biopsy, although not all cats need this step.
Cats with hepatic lipidosis are typically hospitalized for at least a few days. Treatment includes intravenous fluids, correction of electrolyte imbalances and anemia (which can happen with liver disease), treatment for nausea and vomiting, nutritional support, and if possible, treatment of the underlying disease.
Nutritional support is crucial for cats with hepatic lipidosis so their bodies will stop metabolizing fat for energy. Because most cats with this condition don’t eat on their own, they are fed through a tube at first. Feeding tubes are placed through the nose (cats tolerate this better than you would think) or surgically placed through the skin. Some cats need to continue tube feeding for weeks. These cats receive surgically placed feeding tubes designed for long-term use, and their owners must continue the tube feedings at home.
Most cats that receive prompt intensive care (including early tube feeding) recover from hepatic lipidosis. The long-term prognosis depends on whether the underlying disease is treatable.
Keeping a cat at a lean body condition reduces the risk of hepatic lipidosis. For cats that stop eating, early intervention to get nutrition into the cat—feeding something the cat will eat, using an appetite stimulant medication, or starting tube feedings—can help prevent hepatic lipidosis. Cats should never be force fed, though. Placing food directly into a cat’s mouth by hand or through a syringe can cause a cat to avoid that food in the future and be even less likely to eat on its own.
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Laurie Anne Walden, DVM
Most dogs and cats cope very well with vision loss. They rely more on the sense of smell than on the sense of sight. Blind animals can have happy, comfortable lives with some help from their owners.
Pets with gradual vision loss often adapt so well that their owners don’t realize their pets are having trouble seeing until they’re completely blind and bumping into things. Animals with sudden blindness can take longer to adjust.
Safety and Navigation
Use gates and other barriers to block a blind animal’s access to stairs, swimming pools, fireplaces, and other dangers. Use foam cushioning (child safety equipment) to pad furniture corners. Keep the floor clear of trip hazards like toys and laundry.
Keep blind animals in a crate or other secure space whenever they’re unsupervised, at least while they’re adjusting to their loss of vision. This space can also become a safe, familiar retreat.
Blind animals can have a hard time navigating stairs, especially descending. Be patient and use a harness and treats to show blind dogs how to manage stairs. Consider covering short runs of steps with a ramp. Nonslip strips applied to stair treads might make a blind pet feel more secure. Dogs and cats that sleep on furniture might need a ramp or steps so they don’t have to jump up and down.
To help blind pets learn their way around the house, don’t pick them up and carry them; let them walk on their own. Different floor surfaces (mats or rugs) can help them identify specific areas like doorways and the location of food and water bowls. A radio left on at all times in one room and scents applied to furniture at the pet’s head height can also help orient them inside the house.
Face whiskers help animals feel obstacles, so don’t have their whiskers trimmed at grooming appointments. Vests with circular extensions around the head or chest (halo vests) are available for blind dogs who keep bumping into things.
Exercise and Mental Health
Blind animals need exercise just like every other animal, but they shouldn’t go outdoors unsupervised. Even a small fenced yard can have holes and fallen branches that would pose a risk to a blind pet. If you don’t have a fenced yard that’s safe and familiar to your dog, keep your dog on a leash.
When walking your blind dog, attach the leash to a harness instead of a collar in case you need to pull your dog away from a hazard. Teach your dog verbal cues like “left,” “right,” and “stop.” An unexpected touch can frighten a blind dog, so warn people who approach that your dog is blind. Consider using a dog vest with the words “Blind dog” or “Do not pet.” Be very careful if another dog approaches while you’re walking your dog. A blind dog can’t read other dogs’ body language. If you let your dog interact with another dog, be sure that the other dog is friendly and that your dog is comfortable with the interaction.
Provide toys that stimulate senses other than sight. Use toys with bells (with supervision—bells can be a choking hazard), catnip toys for cats, and tracking games for dogs who enjoy following scents. For some animals, playing contact games like tug of war might be easier than chasing toys by sound or scent.
Some animals experience anxiety while they’re adjusting to vision loss. Keep your pet’s routine consistent, stay positive around your pet, and provide a safe retreat like a crate. Behavior changes like hiding, reluctance to walk or play, growling, barking, and snapping can all be signs of anxiety. Contact your veterinarian if your pet has any of these changes or seems to be having trouble adapting. Some pets benefit from short-term or long-term prescription anxiety medications.
For more ideas, see the ACVO Vision for Animals Foundation website: https://www.visionforanimals.org/coping-with-a-blind-dog/
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Laurie Anne Walden, DVM
The retina is a structure made of layers of photoreceptor cells and nerve cells at the back of the eye. The retina converts light into electrical signals that are sent to the brain to be interpreted as visual images.
Disorders of the retina cause vision loss. Whether the animal becomes completely and permanently blind depends on the cause. Inherited disorders, infection, inflammation, eye trauma, eye cancer, and metabolic diseases that affect the whole body can all cause retinal disorders.
Progressive Retinal Atrophy
Progressive retinal atrophy is the name for a group of inherited disorders that cause gradual blindness as the retina degenerates. Progressive retinal atrophy is most common in purebred dogs but also happens in cats and mixed-breed dogs. Some of the dog breeds at more risk than others are poodles, cocker spaniels, Labrador retrievers, golden retrievers, miniature schnauzers, dachshunds, Siberian huskies, mastiffs, and pugs.
Depending on the genetic variation, progressive retinal atrophy can cause vision loss starting very young (in puppies) or later in life. Vision gradually deteriorates over time. Affected animals eventually become blind.
Night blindness—loss of vision in low light—is the first sign in many animals. Because dogs and cats usually adapt well to vision loss, owners might not realize their pet’s vision has been affected unless they move the furniture or take their pet to an unfamiliar place. The condition isn’t painful and doesn’t affect the rest of the body, so animals with progressive retinal atrophy don’t feel unwell.
Progressive retinal atrophy is diagnosed with an eye examination, usually by a veterinary ophthalmologist. Electroretinography, which measures electrical activity in the retina, is also sometimes used. DNA tests can identify genetic variations that put a dog at risk.
No treatment for progressive retinal atrophy is available. However, because affected animals feel fine, they can continue to live normal lives with environmental management (to prevent falls from heights, for example). Some animals with progressive retinal atrophy also develop cataracts, but they aren’t good candidates for cataract surgery because they would still be blind after the surgery. Animals carrying genetic variations linked to progressive retinal atrophy shouldn’t be used for breeding.
Retinal detachment is separation of layers of the retina from their normal position. The many possible causes include high blood pressure, eye trauma, infection, inflammation inside the eye, immune system problems, eye cancer, and inherited conditions of the retina.
Depending on the cause, retinal detachment can affect one or both eyes and can cause gradual vision loss or sudden total blindness. If the cause is something that affects the whole body, the animal might have other signs of illness.
Retinal detachment is diagnosed with an eye examination and sometimes ultrasonography of the eye. Other tests are needed to find the cause.
Treatment for retinal detachment depends on the cause and whether the retina is only detached or is also torn. Medical treatment is aimed at whatever caused the retinal detachment. In some cases, the retina can be repaired surgically. The best chance for saving vision is by diagnosing and treating the detachment very soon after it occurs.
Sudden Acquired Retinal Degeneration Syndrome
Sudden acquired retinal degeneration syndrome (SARDS) causes sudden total blindness in dogs because of loss of function of the photoreceptor cells of the retina. The cause is not known.
Dogs of any breed, including mixed-breed dogs, can be affected. Miniature schnauzers, dachshunds, pugs, and other small dogs seem to have SARDS more often than others, according to the American College of Veterinary Ophthalmologists. The average age of onset is 7 to 10 years.
Along with vision loss, many patients with SARDS have decreased energy and increased appetite, thirst, and urine volume during the first few months. These signs are similar to those of hyperadrenocorticism (Cushing disease). However, no definite link to endocrine disorders like Cushing disease has been found. Ongoing research has suggested that SARDS might be caused by a neuroendocrine or autoimmune disorder, but these possibilities also haven’t been proven.
SARDS is diagnosed by electroretinography showing no electrical activity in the retina. An eye examination won’t show any abnormalities at first. After some time has passed, a veterinary ophthalmologist might find retinal degeneration on examination.
Because we don’t know how or why SARDS develops, it’s not possible to predict which dogs are at risk. There is also no treatment. Dogs with SARDS become fully blind but still have a good quality of life with some help from their owners to keep them safe.
To read more about eye disorders in animals, see the American College of Veterinary Ophthalmologists website: https://www.acvo.org/common-conditions1.
Image source: https://www.flickr.com/photos/kowal854/49042126841/
Laurie Anne Walden, DVM
The 3 main allergy categories in dogs and cats are allergies to environmental substances, fleas, and food. Food allergies are the least common, diagnosed in about 15% to 20% of dogs and cats with itchy skin and less than 1% of dogs and cats with any disease. Many animals with allergies are allergic to multiple substances in different categories.
An allergy develops after the immune system has become sensitized to the trigger substance. This means that food allergies take time to develop. Any food ingredient that a dog or cat has been eating for a while could potentially cause a food allergy. A new food that an animal just started eating wouldn’t cause allergy symptoms.
The most commonly reported food allergy triggers are ingredients that are most common in dog and cat diets; examples are beef, chicken, dairy products, wheat, and fish. But anything an animal has eaten could theoretically be responsible, and studies have reported individual dogs and cats becoming allergic to foods as diverse as kidney bean, barley, and tomato.
Itching is the most common sign of any type of allergy in dogs and cats. Itching caused by a food allergy is typically nonseasonal, but because animals with a food allergy can also be allergic to environmental substances, their itching might be worse at certain times of the year.
Food allergies cause the same skin problems as other allergies. Repeated skin and ear infections are common. Food allergies can also cause digestive tract symptoms. These are some of the signs:
The only way to diagnose food allergy in dogs and cats is with an elimination diet trial. An elimination diet is formulated to eliminate all possible allergy triggers from the animal’s food. Food allergy is diagnosed if the allergy signs improve during the diet trial. Single-ingredient challenge trials are then used to pinpoint the trigger ingredients.
An elimination diet trial usually lasts at least 8 weeks. During the trial, the animal can eat nothing except the elimination diet and approved treats: no flavored medications, table food, chew toys made from animal products, and so forth.
Two types of prescription diets are used as elimination diets. Limited-ingredient diets have unusual protein and carbohydrate sources the pet is unlikely to have eaten before. Hydrolyzed protein diets have proteins broken down into molecular units too small to trigger an allergic response. Home-cooked elimination diets are appropriate for some pets and are best planned with the input of a veterinary dermatologist or nutritionist.
Just changing the brand or flavor of dog or cat food doesn’t work to diagnose a food allergy. Commercial grain-free, raw, and boutique diets also don’t work as elimination diets. Nonprescription dog and cat diets usually contain some of the same ingredients (possible allergy triggers), might contain protein or carbohydrate sources not listed on the label, and can be cross-contaminated with other foods during manufacture.
Veterinary dermatologists use skin tests to identify environmental substances that cause an allergic response, but skin tests can’t effectively identify food ingredients that trigger allergies. None of the blood and saliva tests that claim to diagnose food allergy have been found to be reliable.
Animals with allergies are often allergic to multiple substances, so the more allergy triggers you can eliminate, the more comfortable they’ll be. For pets with food allergies, avoiding trigger ingredients reduces the allergic response. Elimination diets that are nutritionally complete can be fed long term as therapeutic diets. Some pet owners prefer to find a less expensive nonprescription diet that lacks their pet’s trigger ingredients. Effective flea prevention is especially important for animals with allergies to eliminate the possibility that a flea allergy is contributing to the itch.
1. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2016;13(1):51. doi:10.1186/s12917-017-0973-z
2. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8
Image source: https://unsplash.com/photos/l1UsjV2WrNM
Laurie Anne Walden, DVM
Glaucoma is caused by increased pressure inside the eye. It can be painful and often causes blindness even with treatment. Acute glaucoma is an emergency, so dogs and cats with any signs of eye discomfort or vision loss need to be examined by a veterinarian right away.
Pressure inside the eye, or intraocular pressure, is controlled by a balance of fluid production and fluid drainage. In dogs and cats, glaucoma results from decreased fluid drainage.
Fluid drains out of the eye mostly at the angle where the clear cornea and the colored iris meet inside the eye. This area, called the iridocorneal angle, contains a sieve-like network of tiny ligaments and tissues that regulate fluid flow. Anything that interferes with the iridocorneal angle can cause glaucoma.
Primary vs secondary glaucoma
Primary glaucoma is caused by an inherited problem with the structure or function of the iridocorneal angle. Some of the dog breeds at increased risk are cocker spaniels, beagles, basset hounds, Siberian huskies, and Samoyeds. Primary glaucoma is a progressive disease. Affected dogs need lifelong treatment, and the chance they will eventually become blind is high. Primary glaucoma is very rare in cats.
Secondary glaucoma is caused by another eye disease (like uveitis, lens luxation, cataract, or cancer of the eye) that results in physical blockage of the iridocorneal angle.
Acute vs chronic glaucoma
Acute glaucoma is an increase in intraocular pressure for less than a day. Chronic glaucoma is an increase in intraocular pressure for longer than a day. The best chance for saving vision is to start treatment during the acute stage. However, the early signs of glaucoma can be subtle or mistaken for another eye problem, so glaucoma often isn’t diagnosed until it’s chronic.
Glaucoma causes the same signs of eye discomfort as other eye disorders. Animals with glaucoma can also have subtle behavior changes caused by eye pain. The signs usually start in only 1 eye but might not be noticed until chronic glaucoma has affected both eyes. These are some of the signs of glaucoma:
A high intraocular pressure measurement confirms the diagnosis of glaucoma. Devices used to measure intraocular pressure in animals are similar to those used in humans. Animals with glaucoma benefit from referral to a veterinary ophthalmologist to evaluate the iridocorneal angle and assess the risk of glaucoma in the other eye. Animals with secondary glaucoma usually need additional tests.
Glaucoma is managed, not cured. The goals of treatment are to prevent pain, preserve vision as long as possible, and delay glaucoma onset in the other eye. Animals with acute glaucoma need emergency treatment to quickly reduce intraocular pressure, and they are typically hospitalized for intraocular pressure monitoring and pain management. Some patients need surgical treatment. Dogs with primary glaucoma need ongoing treatment with eye drops, oral medication, or both.
Once an eye with glaucoma is irreversibly blind and painful, the kindest option is surgery to remove the eye. Animals tend to do well with this surgery and feel much better after the eye is removed.
For dogs with primary glaucoma, the long-term prognosis for vision is typically poor. However, early diagnosis and treatment can help these dogs stay comfortable and able to see for some time. Blind animals can have a very good quality of life with care and environmental management.
If secondary glaucoma is identified and treated quickly and the cause can be eliminated, the prognosis for retaining vision is better than with primary glaucoma.
Image source: https://www.publicdomainpictures.net/en/view-image.php?image=460143
Laurie Anne Walden, DVM
Warm weather brings some extra risks for pets. Some animals need protection from sunlight, and all animals need protection from hot temperatures.
Sun-Related Skin Conditions
Ultraviolet (UV) radiation in sunlight causes skin damage in animals just like it does in humans. Fur and melanin (dark pigment) protect the skin from UV rays, so animals with short white hair or no hair are at higher risk than those with thick dark fur. Most animals with sun-related skin disease spend a lot of time outdoors, but even indoor cats can develop skin disease caused by UV rays coming through windows.
Sun-related skin damage typically affects areas of the body that don’t have thick fur and are exposed to the sun. Any part of the body with thin or light-colored hair can be involved, but these are the most common areas:
Solar dermatitis, also called actinic dermatitis, is skin disease caused by exposure to UV radiation. It can be mistaken for allergic skin disease because the lesions are similar and it is often seasonal. Affected skin is red, painful to the touch, and scaly or flaky. Bumps and oozy lesions might develop. Over time, the skin becomes thickened and scarred. Because solar dermatitis usually causes a secondary skin infection, the lesions might improve with antibiotics, at least at first.
UV radiation causes mutations within skin cells, so solar dermatitis can transform into skin cancer (squamous cell carcinoma or hemangiosarcoma, for example). These cancers are malignant: they can spread throughout the body. Solar dermatitis and skin cancer are diagnosed with skin biopsy.
Heat stroke is a life-threatening risk to animals during warm weather. Unlike solar dermatitis and skin cancer, it doesn’t require direct exposure to UV rays. The outdoor temperature doesn’t even have to be very hot for an animal to develop heat stroke. The temperature inside a parked car quickly rises higher than the outside temperature, so animals inside parked cars are at risk even in moderately warm weather. Brachycephalic (short-nosed) animals like pugs and bulldogs are at especially high risk.
Signs of heat stroke include panting, dark red or purple gums, vomiting, collapse, and seizures. Heat stroke requires immediate first aid (cooling with water, not ice) and emergency veterinary care. For more information, see the blog post on heat stroke.
How to Protect Your Pet
The best way to protect animals is to minimize their exposure to UV rays and heat:
Image source: Elisa Kennemer on Unsplash
Laurie Anne Walden, DVM
The contents of this blog are for information only and should not substitute for advice from a veterinarian who has examined the animal. All blog content is copyrighted by Mallard Creek Animal Hospital and may not be copied, reproduced, transmitted, or distributed without permission.