Canine Tumors and Cancers

Canine Tumors and Cancers

Most people associate the word tumor with a growth occurring on the skin or somewhere in the body. However, any sort of lump, bump, growth or swelling (such as an abcess) is a tumor. Those which are true growths are called neoplasms.

Benign neoplasms are growths which do not invade and destroy, nor do they spread. They are cured by surgical removal.

Malignant neoplasms are the same as cancers (also called carcinomas, sarcomas, or lymphomas depending upon the cell type). Cancers invade and destroy. They tend to spread via the bloodstream and lymphatic system to distant parts of the body. This is called metastasizing.

Cancers are approached in the following manner: Suppose a female dog has a lump in her breast. Since it is solid, it is probably a neoplasm. It could be benign or malignant. The decision is made to biopsy the lump. This is a surgical operation during which the lump, or a part of the lump, is removed and sent to the pathologist who will make a diagnosis by visual inspection of tissue under microscope.

Causes

Although much has been learned, the exact cause of cancer is unknown. Long-standing irritants to tissues are a definite cause of some cancers. The irritant agent appears to speed up tissue repair (and therefore the rate of cell reduplication, or mitosis) and interferes with the immune mechanism which destroys newborn cancer cells.

Examples of agents known to increase the risk of cancer in people are: ultra-violet rays (skin cancer), x-rays (thyroid cancer); nuclear radiation (leukemia); chemicals (analine dyes causing bladder cancer); cigarettes and coal tars (causing lung and skin cancer); viruses (causing experimental cancer in laboratory animals); and parasites (a cause of bladder cancer).

Some benign tumors, such as warts and oral papillomas, are clearly due to a virus infection.

Signs of Cancer

About half the cancers occurring in dogs are visible as growths or sores on the outer surface of the body (on or beneath the skin, in the perianal area, in the mouth, and in breast tissue). Signs that a tumor can be a cancer are visible growth, ulceration of the skin with bleeding, and a sore which does not heal. One other sign is a lump or knot in a place where none should be (the breast). If you observe any of these signs, be sure to discuss them with your veterinarian.

Some tumors occur internally where you would be unlikely to detect them until ther were quite large. When your dog has difficulty eating and digesting his food, or when he has an unexplained bowel disturbance, such as constipation or the passage of blood, you should consider the possibility of gastrointestinal cancer.

Cancer in the reproductive tract of females causes few signs, but you should look for vaginal discharge and bleeding.

Canine conjunctival tumors (hemangiomas and hemangiosarcomas) are also common, but underreported. Risk of conjunctival tumors is seen more often in dogs with increased outdoor activity. Early surgical therapy is recommended and may be curative; however, recurrence is possible and more likely with hemangiosarcomas.

Allergies in Dogs

Like people, dogs suffer from various allergies. In most cases, allergic reactions are annoying but not life-threatening. Your dog doesn't usually sneeze when he has an allergy, however. Sometimes allergies express themselves as urticaria (hives) or angioedema. Urticaria is a condition characterized by small bumps in the skin and is a typical hypersensitive or allergic reaction. Sometimes the bumps are itchy, but not always. A related condition is angioedema, or swelling of the face, especially around the muzzle and eyes. these reactions typically develop within 20 minutes of exposure to the allergen. they aren't usually life-threatening, although severe swelling around the throat can make breathing more difficult for such breeds as Bulldog. The treatment is generally antihistamines, but if breathing is affected, epinephrine is administered.

One of the most severe allergic reactions is anaphylaxis, a life-threatening condition that may include shock, respiratory and cardiac failure, and death. Anything that can cause an allergic reaction can cause anaphylaxis, including stings, antibiotics, vaccines or other medications, and even foods. It is rare but deadly. Common signs include sudden diarrhea, vomiting, pale gums, fast heart rate, shock, seizure, coma, and death. Unlike many other kinds of allergic reactions, there is no facial swelling. This is an extreme emergency—your dog needs epinephrine right away. Immediately drive to the nearest vet clinic. Intavenous fluids, oxygen, and other medications may also be needed. While it is known exactly what may cause animals to react so badly, dogs who have previously ahd an allergic reaction (like hives) are most at risk. If your suffers severe allergic reactions that affect his breathing, you may be able to secure an "epi-pen" from your vet, a syringe and needle containing a single dose of epinephrine for future emergencies.

Allergy

Latest research news on allergies and allergy treatments. Learn the symptoms of a food allergy, how to treat dog allergies, cat allergies, mold allergies and other allergy problems.

Treatment of Allergies There is no real cure for allergies, but several treatment options are available, ranging from avoiding the allergen (not easy), to administering special shampoos and oils, to dispensing medications. Check with your vet to determine the best option for you and your dog.

Some reasearch suggest that about one third of all allergies are caused by foods. If you suspect your animal has a food allergy, try the following diet, which omits the common allergens implicated in both animal and human conditions: beef, wheat, milk, egges, nuts, fruits, tomatoes, carrots, yeast and various spices and additives. If the problem clears up during the diet, then slowly reintroduce foods one at a time to find out which one or ones are causing the problem.

To give the diet an adequate chance, keep your animal on it for at least two months. If your pet's condition has not improved by then, the cause of its problem may not be in allergy. Or there is still an offending substance in the food. In most cases it is the meat. Therefore, try the vegetarian diet

Vitamin C when given in high doses acts like a natural antihistamine, and the B complex is also very useful. Be sure to include these as regular dietary supplements.

BRUCELLOSIS

This is a worldwide infection, first identified in the 1960s and caused by Brucells canis. Geographically, there is considerable variation i its incidence. In some parts of North America up to 5% of stray dogs are infected, while in Great Britain and Australia the incidence is much less than 1%. Brucellosis is usually most prevalent among dogs that are kept in kennels.

In acute cases, individuals show enlarged lymph nodes in the groin area, sometimes beneath the jaw. Many infected dogs, however, show no clinical signs of illness. The bacteria may remain in an infected animal for as long as 2 years, duting which time the dogs develops immunity.

The optimum time for the spread of Brucella bacteria is during breeding. The bacteria are transmitted through infected urine, or through the semen of male dogs and the vaginal discharges of females. Infected male dogs may become infertile, or they may have and inflammatory condition affecting the testicles (orchitis) or the prostate gland (prostatitis). Pregnant females who are infected often abort their fetuses at 6 to 8 weeks of gestation. If the pups are born live, they usually fade and die within a few days.

Diagnosis & Treatment of Brucellosis

A positive blood culture, in which bacteria are found, is the most definitive method of diagnosis. A test for antibodies is more practical when larger number of dogs need to be screened. A negative test is a true negative, but false positives are not uncommon. If a dog tests positive, more specific tests are available.

In breeding kennels, a test-and-remove policy is the most practical option. Affected dogs can remain Brucella carriers for years. Antibiotics clear bacteria as long as they are used, but are not always effective in eliminating the disease.

Prevention of Brucellosis

All dogs for breeding should be blood-tested. A negative test essentially confirms that a dog is free from the disease.

Brucella canis can cause a zoonotic disease in humans, although cases of human infection are very rare. The risks of catching it can be reduced by wearing rubber gloves and taking sensible precautions handling aborted puppies, tissue, or fluids from infected animals.