Last Disease Page #11
Warbles are extremely common in the cat population. The insect causing warbles belongs to the genus, Cuterebra sp, a fly that normally infests rodents such as squirrels and rabbits. Its larvae cause the problems in cats.
Cuterebra sp usually lays its eggs on long grasses. The eggs hatch and cling to the blades of grass. When a rodent or a cat passes by, the larvae jumps over to the new host and enters an orifice. The ears, nostrils, anus and genital organs are the most common port of entry. The parasite than migrates through the body and usually makes a bee line to the skin. This passage and skin lesions cause the clinical signs associated with warbles.
The parasite is very common up north. I would usually see Cuterebra sp cases beginning around August and lasting up to cool fall weather. Late summer is a very active time period for the insect to reproduce. In wild animals the mature larvae will fall out of the skin hole. It gets its nourishment from cat serum and tissue fluids. Once on the ground, it will pupate.
During the larval passage in the cat, it may traverse the lungs and neurological system resulting in signs such as difficulty breathing as well as ataxia and disorientation. Most cats present with the skin lesion containing a "breathing hole" with the parasite just underneath the skin surface. I have also plucked them from both nostrils and genital tissues.
Any cat presenting with neurological or respiratory signs require a complete workup such as radiographs and blood chemistries. In the more common presentation, most cats do not need any lab work unless the warble area is infected. In that case running a CBC is advisable.
Diagnosis is most commonly made by finding a breathing hole on a cats body in late summer or early fall. Most skin lesions are located over the shoulder blade areas or neck of the cat. Many individuals bring the cat into a hospital thinking that they are dealing with an abscess. If you look at the lesion long enough, you will see the white larvae pop itself up in the hole in the skin.
If the larvae is still present in the hole, it is removed. Some cats require sedation. The goal is to remove the larvae intact. Rupturing the contents into the wound can cause a severe allergic reaction so care must be taken. If needed, I would slightly enlarge the breathing hole so I could remove the parasite with forcepts. The wound is cleaned and debribed. The animal is than put on a broad spectrum antibiotic. Like abscesses, warble damage will heal from the inside out leaving just a small scab.
Cats are accidental hosts of Cuterebra sp. If there are no systemic issues to deal with, the prognosis is excellent. Keeping cats indoors will prevent this problem.
Vaginitis is inflammation of the vagina and the vaginal vestibular area; the cavity from the vaginal opening to the cervix. The most common causes of a vaginal infection are: bacteria, yeast, maggots or other insects, foreign bodies, trauma, urinary tract infection and puppy vaginitis. The latter is seen in immature females that present with pustules around the vulvar area. These usually disappear as estrogen levels increase as the animal sexually matures.
Regardless of the cause, any vaginal irritant will cause an inflammatory response in the vaginal mucosa. This irritation will lead to all clinical signs associated with vaginitis.
Vaginitis bothers the dog. Animals will often have a mucoid or purulent (pus containing) discharge coming out of the vulvar area. It usually has a foul odor. Yeast infections will produce a foul, sweet smell. Dogs will lick at their vulvar and perineal areas. Urine is an irritant and in the female passes right over inflamed vaginal mucosa. This causes a burning sensation and the dog will often urinate inside the home or if outside, more frequently (pollakiuria). The vulvar area may appear enlarged or inflamed.
Vaginal smears and cultures are the hallmark tests of vaginitis. The smear is than stained and looked under high microscopic objective power. Bacteria, yeast cells and white cells can easily be noticed. Cultures will demonstrate bacteria or yeast and sensitivity will provide the most effective treatment option.
In animals with a suspect vaginal mass, ultrasounds are very handy to delineate those growths.
Diagnosis is made by historical, physical exam and laboratory findings. A vaginal exam is performed with a gloved finger and or a special scope that allows the vestibule to be viewed. This is much easier on a large dog!
Treatment of vaginitis usually responds to antibiotic therapy. The drug used depends upon the results of sensitivity tests to the offending pathogen. Douches containing chlorhexidine are also prescribed. The vulvar area should be cleaned several times a day with warm, soapy water. Treatment of the primary cause should also be undertaken. Urinary tract infections, trauma and growths require their own treatment plan.
The prognosis for straight bacterial or yeast vaginitis infections is very good. Prognosis of those caused by urinary tract infections is also good but it may relapse along with the UTI. Prognosis for the removal of tumors or growths depends upon the histopathological diagnosis of the mass.
Vomiting is defined as the active expulsion of stomach contents to the outside. Vomiting can be caused by a myriad of diseases or agents. Some of them are: viral (Parvovirus), bacterial, poisons, spoiled food, parasitic, stomach cancers, food allergies, foreign bodies swallowed, drugs (Clavamox®) and gastric ulcers. Causes of vomiting secondary to other medical problems are: liver disease, pyometra, vestibular disease, pancreatitis, Irritable Bowel Disease/Complex, Cat or Dog Distemper and Canine GDV (bloat).
Vomiting by itself, is not harmful. It is a mechanism to rid the body of any foreign or dangerous substance. Getting something out of the body before it can cause damage is one of the great functions of the mammalian body. Vomiting entails communicating with the brain. There are vomiting receptor sites in the brain that stimulate nausea and vomiting. This entire procedure requires the contraction of abdominal muscles and the diaphragm to expel food to the outside. It must be differentiated from regurgitation. Regurgitation is the couging up of food that is in the esophagus. It has not entered the stomach. Food that is regurgitated is not digested and looks like it was just swallowed. An example is a cat that regurgitates its meal after eating due to stomach hairballs.
The digestive tract is one long tube that extends from the mouth down to the anus. If one part of it becomes irritated there is a good chance the other part will also. Many dogs that vomit over time will usually start producing a watery diarrhea. This is because the stomach is "hooked" up to the duodenum, the first part of the small intestine.
Vomiting has a safety feature but if it continues unabated, can lead to stomach ruptures, electrolyte imbalances and dehydration. This is what leads to severe medical problems in dogs or cats.
Dogs and cats get into a particular positioning when they are ready to vomit. They often get hunched up and the signs of nausea begin. Excessive drooling is than followed by intense abdominal musculature contractions followed by the expulsion of gastric contents. This expulsion does not occur in dogs with GDV (bloat). The vomit is usually a green, yellow bile color and the ingesta is mixed with stomach mucous.
I was a small animal veterinarian for 33 years and never worked on horses throughout my career. One thing I do remember, is that horses naturally will not vomit. If they do, it means a ruptured stomach!
A CBC and Chemistry profile are always done. Electrolyte imbalances, organ dysfunction and other data can point to the clinical degree of vomiting and a possible systemic cause such as renal failure. Radiographs and ultrasounds are handy to visualize the stomach contents for foreign bodies and masses.
Vomiting must be differentiated from regurgitation when an animal is presented. The history from the client is crucial. Taking a video with a camera phone is very helpful so the veterinarian can actually see what the dog or cat is doing. Once vomiting has been found to be the case, figuring out what is causing it starts the detective case. The history of garbage ingestion or a foreign body or other tidbits is very important. Vomiting in cats can be very difficult to figure out. After years working on cats, my only explanation for that is that well...it is a CAT! Cats always throw curve balls at practitioners!
Diagnosing vomiting is part of the problem. A diagnosis of what is causes it is made by interpreting physical exams, radiographic or ultrasound data and blood chemistries combined with owner history.
Treating vomiting animals is important but the cause of the vomiting must be found and managed. Each systemic disease is different and requires different treatment plans. Foreign bodies need to be removed with an endoscope. Treatment is based on the cause of vomiting.
Sometimes, the cause can not be found. Animals will often just throw up for no reason! Animals should be examined regardless of how many times the animal has vomited. Treatment of vomiting is based around resting the stomach. This allows the stomach muscle to rest and heal. In the hospital, dogs are frequently given injections to stop vomiting. They include: famotidine, Cerenia®, or ondansetron. Famotidine and Cerenia® are also available for oral administration.
Animals that have a systemic disease or are extremely dehydrated will be hospitalized and given fluids via a intravenous route. This hydration is important plus helps to maintain blood flow to the kidneys as well as replenish lost electrolytes. Once animals have been treated with fluids and anti-vomiting drugs the stomach is allowed to rest. Small amounts of fluid are than allowed. If they stay done a bland diet of chicken and rice can be offered in SMALL doses!! Animals are than discharged on the appropriate therapy needed to treat the primary cause as well as anti-vomiting drugs plus an appropriate diet. Owners can feed small amounts of chicken (or beef) and rice in a ratio of 1 part meat to 3 parts boiled rice. If you use hamburger, boil it so as to remove all the grease. If you do not want to cook, purchase Hill's® Prescription Canine i/d or Hill's® Prescription Feline i/d from your veterinarian. If your dog or cat has an off and on problem with vomiting, it may be food induced. Maintaining pets on these prescription diets often stops regular vomiting altogether.
The type of fluids administered to the pet at home is crucial. Do not give pets cow's milk. It will make them vomit and have diarrhea. Dogs can not digest milk sugar since they do not have enough lactase enzyme to do the job. Plain water can be difficult to stay down on an upset stomach. Try offering small amounts of a sport drink such as Gatorade®. If the animal does not drink it straight, try diluting it in a bit of room temperature water. Dogs love ice cubes. Freeze some sports drink and throw just a few ice cubes of it into the dog's water bowl. Sports drinks will help to replenish electrolytes lost during vomiting plus will make the dog or cat feel much better at the gut level.
Prognosis for vomiting runs the gamut from basic to complex. The prognosis for dogs or cats with minor causes of vomiting is excellent whereas the prognosis for a chronic vomiting dog with end stage renal failure is poor. Prognosis depends upon the cause and severity of the primary problem.
VonWillebrands Disease is a clotting disorder seen in dogs. It is due to the lack of the VonWillebrand factor necessary for clotting to occur. It is a protein and facilitates the clotting process. It also leads to a defect in the VIII (8th) clotting factor.
In normal dogs, all the clotting factors and platelets come together to form clots after vascular injuries or trauma to the skin or vessel. Without the clotting mechanism, animals can bleed to death even after a small laceration. Clotting will not occur in Von Willebrand deficient dogs. It is akin to human hemophilia.
Von Willebrand's disease is inherited and is the most commonly seen inherited blood disorders in dogs. It is commonly seen in Doberman Pinschers, Golden Retrievers, Miniature Schnauzers amongst others.
The most common signs seen are a prolonged bleeding and clotting time. Even the simplest things that normally clot will take a long, long time to clot. Examples are: nail trim bed bleeding that occurs when a nail is cut too short, a female in estrous will bleed excessively. A small scrape can turn into a huge ecchymotic (subcutaneous hemorrhage) wound area. This is very risky if surgery is being performed, as blood vessels are extremely difficult to ligate to seal off blood flow.
When presented with any blood disorder, a CBC and Chemistry profile must be done to check out platelet levels and red cell counts. Specific tests are the ELISA test that tests for the presence of the Von Willebrand clotting factor. A buccal mucosal test may also be performed. In this test, a small, oral injury is created and the time it takes to clot is measured. Using this value and the platelet level are very helpful.
A lot of animals are diagnosed after an "incident" has occured. That may be due to trauma, difficulty ligating vessels in surgery or any other common day to day procedure. HIstorical findings combined with all the lab work, including specific tests, lead to a diagnosis of the disease. Doberman Pinscher dogs are perhaps numero uno in getting this so just the presence of a Dobey makes you wonder.
Treatment of Von Willebrand's disease is by transfusing the animal with whole blood that contains the essential clotting factor. The disease can not be cured. Some animals may require multiple transfusions. Desmopressin (DDAVP) has been used to stimulate clotting factors prior to surgery in an affected dog. Blood is sometimes treated with this drug. Desmopressin is a synthetic version of the body's own vasopressin (ADH). It is produced in the posterior pituitary and is involved in maintaining sodium levels. For this reason, DDAVP should not be routinely used for periods of time as it will lead to hyponatremia (low blood sodium) and seizures.
Even though the disease can not be cured, animals with Von Willebrand's disease can lead normal lives. Owners have to do their best to keep their pets away from cars and other trauma inducing events. That means using a leash when walking the dog. Care must be taken and advance preparation necessary for any surgical procedure performed on any of these dogs.
Individuals that are breeding the commonly affected dogs might want to see which of their breeding stock is affected by the inherited disorder. One would not want to breed an animal that carries the defect.
Whipworms are small intestinal parasites that cause diarrhea in the dog. The parasite is caused by Trichuris vulpis.
Whipworms are passed from animal to animal by fecal contamination. The egg dissolves leaving a larvae to devolop in the cecum. The cecum is that part of the intestinal tract that separates the small intestine from the colon. Here, they suck blood and cause mucosal injury. This injury leads to typical clinical signs.
Whipworms cause a watery, bloody diarrhea in dogs. In untreated animals, the diarrhea may be off and on depending on the level of intestinal parasites. Lack of condition and weight loss may also be seen in infected dogs.
A fecal flotation will show the characteristic whipworm egg. It looks like a wine barrel with 2 plugs at each end. It looks very similar to Capillaria plica; a parasite that plays havoc in the urinary tract system. The problem is, is that whipworms are not generous egg producers when compared to other intestinal parasites. They do not always produce eggs so a negative fecal may not mean that they are not there.
Diagnosis of whipworms is made by finding the characteristic egg in a fecal flotation test. Many times it is impossible to find the egg so any dog presented with a off and on or chronic diarrhea is always treated for the parasite.
Treatment is effective but the eggs are very difficult to get rid of in the environment so it is important to clean up the animals bowel movements. Multiple treatments may be necessary to eradicate the parasite. The most commonly used preparations are:
1. Drontal Plus® (febantel)
2. Panacur® (fenbendazole)
Monthly heartworm products such as the following are quite useful in treating whipworm infections:
1. Interceptor® (milbemycin oxime)
2. Advantage® Multi (moxidectin)
3. Trifexis® (milbemycin oxime)
Once the animal is treated for whipworms, or any dog that has chronic diarrhea associated with whipworms, a good prognosis is warranted. Once the dog is treated though, does not mean it will not pick up the parasite again. Getting rid of dog feces in the yard and treatment of other pets in the household will aid in eliminating the parasite. Dogs should not be allowed to run free or even sniff other dogs bowel movements while out on a walk. The eggs get on the nose of the dog, the tongue goes in and out, and an infection will commence!