Diseases

If your older dog acts lost or confused, no longer recognizes familiar people, or seems less social, he may suffer from cognitive dysfunction. Cognitive dysfunction is a newly recognized disease in older dogs that resembles dementia in people. Behavioral changes once attributed to old age may actually stem from complex changes in the brain that affect memory, recognition, and learned behaviors. Some studies show that about 45 percent of dogs over 11 years old will exhibit one or more signs of cognitive dysfunction.

Colitis literally means inflammation of the colon, which is part of the large intestine. Think of the digestive tract as one long tube, starting at the mouth and ending at the rectum. Before reaching the rectum, the byproducts of digestion pass through the colon, where much of the water content is absorbed. When a dog’s colon is inflamed, it may cause diarrhea, possibly with blood or mucus.

Congestive heart failure occurs when the heart fails to pump enough blood, causing a fluid backup (congestion).

The four chambers of the heart contain two pumps. The left side of the heart takes oxygenated blood from the lungs and pumps it to the tissues. The right side of the heart takes blood from the venous system and pumps it to the lungs for oxygenation. If the left pump fails, fluid backs up in the lungs, resulting in pulmonary edema. If the right side fails, fluid backs up in the venous system and leaks into the body cavities. Fluid in the chest cavity is called pleural effusion, and fluid in the abdominal cavity is called ascites.

Your dog didn't get those red, watery eyes from staying up all night. More likely, she's suffering from conjunctivitis. The conjunctiva is the lining of the eyelids and the tissue surrounding the edge of the eye. Inflammation of these tissues is called conjunctivitis—a common disease in both dogs.

Cushing's syndrome, or hyperadrenocorticism, occurs when the adrenal glands release excessive levels of the hormone cortisol. The pituitary gland in the brain directs the adrenal glands to secrete the hormone, so problems with the pituitary gland or the adrenal glands can cause cortisol levels to increase. Cortisol, which is a type of natural steroid, affects many body processes. For example, it influences the body's reaction to stress and infection and has many other functions, making Cushing's syndrome a complex disorder.

If your older dog seems to ignore you when you call or no longer responds to squeaky toys or hand claps, she may be losing her hearing. Hearing loss, which ranges from partial hearing loss to total deafness, affects dogs of any age. Hearing loss can occur gradually or suddenly, but pet owners usually don't notice the problem until it begins to affect their dog's behavior.

Can't bear to face another day of dog breath? Don't despair. Dental disease, one of the most common and potentially harmful health problems for dogs, is also easily avoided. What causes that special smell? Bacterial buildup along the gum line gradually leads to gingivitis, or inflamed gums, and infection. If left unchecked, gingivitis will progress to periodontitis, or inflammation of the deeper tissues surrounding and supporting the teeth. In severe cases, infection in the mouth can spread through the bloodstream to other parts of the body, including the heart and kidneys.

The disease diabetes mellitus, also called sugar diabetes, results from a deficiency of—or decreased response to—insulin. The pancreas produces insulin, which helps body tissues process glucose (sugar). Without insulin or with a decreased response to insulin, blood glucose levels rise, resulting in hyperglycemia, while the body tissues remain starved for glucose. The elevated blood glucose eventually passes into the urine, creating a condition called glycosuria. As the disease progresses, metabolism changes cause ketosis, a condition in which chemicals called ketones accumulate in the blood and body tissues.

Demodectic mange is a noncontagious, nonitchy skin disorder caused by mites that results in hair loss and occasional skin infections in dogs.
As repugnant as it sounds, harmless mites live in our dogs' skin (and our skin too for that matter). Female dogs spread the microscopic Demodex canis mites to their nursing pups.

Healthy dogs’ ears are clean and odor-free. If you notice a strange smell emanating from your pet’s ears, don’t be shy about taking a closer sniff or a closer look. Chances are, your dog is harboring a stinky surprise: thick brown or yellowish green discharge in the outer ear canal.

Ear mites are tiny, crab-like parasites that live in the dark recesses of your dog's ear canals. These little critters are barely visible to the human eye, but they can cause a big itch with all their scurrying around. These bugs don't always stay in the ear canal, either. They can live on the skin around the head and neck or down by the tail, causing an itchy problem.

It is important to know how to recognize when your dog is having a seizure. Seizure disorder, or dog epilepsy, is a central nervous system disorder that causes periodic seizures unrelated to progressive brain disease. It is one of the most common neurologic problems in dogs.

All dogs are at risk for a flea infestation, and if your dog spends time outside, she is particularly susceptible to getting flea bites. Why? Many adult fleas live outside and on wildlife hosts until they find a happy home on your pet. Indoor dogs also are at risk because they can pick up fleas when they go outside to exercise or eliminate.

Dog allergies can be caused by pollen, flea bites, and even food. Food allergies in dogs occur when the immune system reacts adversely to one or several ingredients in the dog's diet. Some dogs develop an abnormally intense reaction to certain ingredients, becoming hypersensitive.

I have heard about hiatal hernias in people. What are they and do dogs get them?
A hernia occurs when one part of your body protrudes through a gap or opening into another part of the body. Many types of hernias occur in the abdominal area. Hiatal hernias, also known as diaphragmatic hernias, form at the opening (hiatus) in the diaphragm, where the food tube (esophagus) joins the stomach. When the muscle tissue around the hiatus becomes weak, the upper part of the stomach may bulge through the diaphragm into the chest cavity. Hiatal hernia refers to the protrusion of the abdominal contents into the chest cavity through the esophageal hiatus of the diaphragm.

Gastrointestinal (GI) obstruction is a general term for a blockage anywhere along the GI tract. The causes range from a hairball that's plugging up the intestines to a tumor that's grown large enough to obstruct the rectum.

Gastrointestinal (GI) parasites are worms and protozoa (one-celled organisms) that take up residence in your dog's stomach and intestines. Depending on the dog's age, her level of immunity, and the number of parasites present, the infection can range from unnoticeable to life-threatening. Symptoms include diarrhea, vomiting, weight loss, and a failure to grow and thrive.

Glaucoma is a disease characterized by increased fluid pressure within the eye. Healthy eyes continually produce and drain this fluid, called aqueous humor, to maintain a constant intraocular pressure (IOP). If the drainage network becomes obstructed, IOP increases significantly, causing extreme pain and often blindness.

Heart disease is a general term for many conditions that affect the cardiovascular system. These include congenital defects; heart muscle disease; abnormal heart rhythm; cancer; and infectious, inflammatory, or degenerative diseases. Sometimes heart disease accompanies other conditions, such as hyperthyroidism, high blood pressure, and trauma.

Hypothyroidism is caused by a thyroid hormone deficiency in the body. People suffering from low thyroid levels may feel sluggish or gain weight easily. The same holds true in dogs. But affected dogs may display other symptoms because the thyroid hormone, known as thyroxine, affects just about every organ in the body.

Heartworms are long, spaghetti-like worms that inhabit the pulmonary arteries and the right side of the heart. The worms can interfere with the heart's pumping action, irritate the heart and blood vessels, and lead to death if not treated.

Urinary incontinence is an inability to control urination. Urination is a complex process that coordinates mental awareness, voluntary and involuntary nerve input, urine storage, and muscle relaxation and contractions. Urinary incontinence occurs when some part of this process fails.

Inflammatory bowel disease (IBD) describes a group of diseases affecting the gastrointestinal tract. IBD affects is characterized by inflamed cells infiltrating the stomach, intestines, or both.

Kidney failure, also called renal failure, occurs when the kidneys fail to
remove metabolic waste products from the blood. Toxic levels of these waste products accumulate in the blood, creating a condition called uremia and producing signs of illness throughout the body. Kidney failure can occur suddenly (acute renal failure) or develop gradually over several months (chronic renal failure).

The liver is an important organ with many functions essential for life.
These functions include detoxifying poisons and drugs, metabolizing fats, storing carbohydrates, manufacturing bile, and producing blood proteins and blood clotting factors. The liver is also a key part of the immune system.