Metastatic Lung Disease

One characteristic of most highly malignant tumors, regardless of their point of origin, is that they invariably spread to and end up in the lungs if not detected and treated soon enough. Some cancers spread, or metastasize, more readily to the lungs than others. For instance, malignant melanoma of the skin might be present in the lungs even before the actual skin tumor becomes noticeable.

The clinical signs exhibited by pets afflicted with metastatic lung disease can be similar to those seen with pneumonia. Unfortunately, the prognosis for dogs and cats harboring such tumors in their lungs is grave, even with specific cancer treatment.

Gastrointestinal Response to Disease and Treatment

Considering what they have to go through each day, the stomach and intestines make up a remarkable organ system. In the performance of their daily nutritional functions, they must be on constant guard to protect themselves from autodigestion by digestive acids and enzymes produced and must constantly battle foreign organisms and agents that are inadvertently taken in by mouth. When the stomach and/or intestines become acutely diseased, three major factors come into play that can quickly turn a sometimes seemingly harmless situation into a life-threatening predicament; these include pain, secondary bacterial invasion, and dehydration.

Pain

Any inflammation and/or excessive smooth-muscle contractions occurring within the gastrointestinal system can be quite discomforting and painful. In fact, in severe cases of viral enteritis, intestinal obstructions, and intussusceptions, this pain can be so great that the patient goes into life-threatening shock. As a result, the sooner therapeutic measures are undertaken to correct the problem and stifle the pain associated with it, the less chance of complications occurring.

Secondary Bacterial Invasion

The second factor to contend with is secondary bacterial invasion. Normally, the intestines are inhabited by billions of bacteria that peacefully reside there without causing any problems whatsoever. In fact, the very presence of these non-disease-causing bacteria actually helps prevent the growth of pathogenic, or disease-causing, bacteria within the intestinal setting.

However, if disease strikes the small or large intestine, these “friendly” bacteria can be wiped out, allowing pathogenic ones to proliferate and cause disease themselves. If the inflammation persists, or if an intestinal perforation occurs, these and any other bacteria within the intestines can leak out of the gut and even gain entrance into the bloodstream, causing a life-threatening systemic infectionand shock.

For these reasons, it is obvious that antibiotics become very important in the treatment of moderate to severe cases of gastroenteritis, even if the original cause is nonbacterial in origin.

Dehydration

The final threatening factor that arises when acute gastroenteritis strikes a pet is dehydration. Pets suffering from vomiting and/or diarrhea can quickly become dehydrated as a result of water loss through the bowels. Since inflamed bowels cannot regulate water absorption as they do when they are healthy, any fluid intake that indeed occurs will usually pass right out of the body via vomiting and/or diarrhea without being absorbed. In fact, the disruption of normal motility and distension occurring within the affected bowel can actually attract and draw water right out of the body and into the intestinal lumen. As a result, pets that have become dehydrated or are on the verge of dehydration due to gastroenteritis require intravenous fluids to correct the dehydration occurring within the body’s cells, at least until the gut has healed sufficiently to resume these functions once again.

Treatment

Once the gastrointestinal system is on the mend, and all vomiting has been brought under control, a good level of nutrition is required to counteract any malnutrition induced by the disease. Bland diets that are easily digested are prescribed until complete healing of the stomach and/or intestinal linings has taken place. Offering a convalescent pet some type of electrolyte replacement drinks during these first few days can also promote rapid recovery as well. Feeding plain yogurt is also helpful toward repopulating the gastrointestinal tract with nonpathogenic bacteria.

Tonsillitis

The tonsils are lymphoid tissues located in the back of the oral cavity near the esophagus. Since they are lymphatic tissues, tonsils have an immune function. Tonsillitis refers to the inflammation and/or swelling of these lymphoid structures in response to infections, foreign bodies, and sometimes even noninfectious diseases. For instance, long-term coughing, such as that seen in cases of canine cough, can result in a secondary tonsillar inflammation. Periodontal disease is another common cause of tonsillar swelling. Finally, certain tumors, such as lymphosarcoma and squamous cell carcinoma, can cause the tonsils to swell and should always be kept in mind anytime an older dog or cat develops tonsillitis.

Signs of tonsillitis include gagging, retching, and difficulty swallowing. Affected animals might also go off feed and have a tendency to salivate excessively. Because tonsillitis is usually secondary in nature, other signs of illness related to the primary disease might be present as well.

Diagnosis of tonsillitis is easy when it is based on clinical signs and actual visualization of the swollen tonsils within the oral cavity. Treatment depends on the underlying cause. For example, if the disease is

infectious, appropriate antimicrobial therapy will clear up the tonsillitis. If a tumor is suspected, or if a seemingly simple case of tonsillitis is refractory to standard treatment, then the tonsils should be removed and biopsied.

Feline Stomatitis

Feline stomatitis is a condition of the oral cavity in cats characterized by red, friable gums that often grow over and cover the teeth, as well as inflammation of the teeth and bony tissue of the jaw.

Cats affected with this disorder often have difficulty chewing their food, have foul-smelling breath, salivate profusely, and might even have inflamed lips. The inflammation associated with the disease can also spread to the back of the throat, making it difficult to swallow.

The exact cause of this disorder in cats is unknown; however, conceivably any type of chronic inflammation that attracts inflammatory cells to the area could cause such a reaction. Diagnosis of feline stomatitis is made by collecting a biopsy sample of the affected tissue and radiographing the oral cavity to determine the extent of involvement.

Treatment consists of surgically removing and/or cauterizing the excess gum tissue, as well as any teeth or bony tissue affected. In especially severe cases, steroid anti-inflammatory medications, antibiotics, and pain relievers may be used as well.

Owners can help slow the recurrence of this disorder by following a strict regimen of dental care for their cats, including the daily treatment of both teeth and gums with a paste, gel, or solution containing chlorhexidine.

Esophagitis

Inflammation occurring anywhere along the esophagus is termed esophagitis. Esophagitis can be instituted by foreign bodies that injure the organ’s lining, by ingestion of caustic substances, and by reflux of stomach contents and acids up into the esophagus. In keeping with the latter cause, chronic, long-term vomiting can also lead to esophagitis.

Regurgitation, loss of appetite, and weight loss are the most frequent signs seen. If left untreated, damage to the lining of the esophagus could occur, causing strictures and secondary megaesophagus.

As with megaesophagus, diagnosis is made using clinical signs, physical exam findings, and endoscopic exam or radiographic X rays of the esophagus using barium as a contrast medium. Treatment of esophagitis consists of treating any primary problems that might be present, and, if stomach acid reflux is to blame, reducing the amount of stomach acid secretions and increasing the rate of stomach emptying.

Gastrointestinal Ulcers

An ulceration within the stomach or intestines occurs when the protective barrier of mucus covering the inner surfaces of the gastrointestinal tract is lost or destroyed, allowing stomach acids and bile acids to erode the gastrointestinal lining. The same type of heartburn humans can sometimes experience with this problem can affect dogs and cats as well, leading to inappetence, vomiting, and lethargy.

Ulcers actually are indicators of disease rather than distinct disease syndromes in themselves. Sharp foreign bodies or harsh chemicals that are swallowed can scrape, injure, and—in the case of the latter—burn the gastrointestinal lining and cause a primary ulceration.

Ulcers occur secondary to stress, infectious diseases, intestinal parasites, bacteria (including Helicobacter), and metabolic diseases such as Cushing’s disease and kidney disease. Certain drugs can also have a deleterious effect on the stomach lining when given orally.

Diagnosis of an ulcer relies heavily on clinical signs seen and the history or evidence of an underlying disorder. Radiographs taken after the oral administration of barium can be used to pinpoint the exact location of an ulcer. In addition, direct visualization of the actual stomach or intestinal lining using an endoscope is another means of diagnosing ulcers in a pet.

Obviously, when formulating any treatment regimen for ulcers, any underlying source for the ulceration must be identified and treated. Specific ulcer treatment is aimed at reducing the amount of stomach acid secretion and providing a protective coating over the existing ulcer until it has time to heal. Medications used to treat ulcers in humans are very effective at treating the same in pets.

Hemorrhagic Gastroenteritis (Dogs)

Hemorrhagic gastroenteritis is a life-threatening condition that can be rapidly fatal if not treated promptly. Characterized by an explosive onset of bloody diarrhea, hemorrhagic gastroenteritis can quickly cause dehydration, depression, shock, and toxemia in affected dogs. It is most often seen with dietary indiscretions and/or bouts of pancreatitis. Toxins produced by bacteria within an irritated gut cause such extensive inflammation that overt bleeding within the digestive system results. Toxins and bacteria may then permeate these blood vessels and gain entrance into the body, with serious consequences.

Diagnosis of hemorrhagic gastroenteritis is based on history and clinical signs seen, as well as ruling out other causes of digestive system disturbances. Treatment consists of intravenous fluids to control dehydration, high levels of antibiotics to combat infection, and high dosages of steroid anti-inflammatories and other medications to control shock and to counteract the effects of toxemia.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease (IBD) is actually a group of chronic digestive disorders characterized by the infiltration of the walls of the bowels with inflammatory cells, leading to abnormal wall thickening and irregularities. IBD has been recognized as a significant cause of chronic vomiting and/or diarrhea in both dogs and cats. As far as the etiology of IBD, research to date has failed to uncover an exact cause.

Many veterinarians believe that bacterial and/or dietary proteins may stimulate an autoimmune type of reaction in these pets. This reaction, in turn, manifests as a buildup of immune cells on and within the surfaces coming in contact with these proteins.

The classic clinical sign associated with IBD in cats is chronic vomiting. Often misdiagnosed as hairballs, vomiting induced by IBD usually occurs intermittently over months to years, gradually worsening and increasing in frequency with time. In addition to vomiting, bloody diarrhea and abdominal pain are also clinical signs seen in both dogs and cats suffering from IBD. In cats, lymphosarcoma is not an uncommon sequela to severe cases of IBD that cannot be controlled through medical means.

Diagnosis of IBD is made through the use of a thorough history, physical exam findings, radiographs of the abdomen, and more specifically, biopsy samples from affected portions of bowel. Diagnostic techniques such as these will help differentiate this condition from other disorders that may cause similar clinical signs, including foreign bodies, pancreatitis, tumors, and bowel obstruction.

Treatment for inflammatory bowel disease employs the use of drugs designed to reduce the inflammatory response, as well as medications designed to locally suppress the immune system response within the gut. Administration of these medications may be required on a long-term basis to control this disorder. Since food allergies are thought to be an underlying cause in some instances, most treatment regimens for IBD also employ rations that are hypoallergenic in nature.

Unfortunately, a complete cure for IBD is rarely possible. However, with appropriate treatment, most cases can be managed enough to allow the affected pet to live a relatively normal life otherwise.

Colitis

Problems involving the large intestine of dogs and cats are common in veterinary medicine. Colitis refers to the inflammation of the lining of the large intestine, resulting in diarrhea, with the feces often containing an abundance of red blood and mucus. Tenesmus, or straining to defecate, is another prevalent sign that is often mistaken for constipation.

Acute colitis refers to a sudden onset of signs that usually lasts only a short period of time with proper treatment. Chronic colitis is a long-term, recurring condition that might last for the entire life-time of the pet.

Parasites and bacterial infections are common causes of acute colitis in dogs and cats. Dietary indiscretions and stress-induced situations are two other prevalent sources. Less commonly, fungal infections, foreign bodies, intussusceptions, polyps, food allergies, immune system disorders, and tumors can all result in signs related to a chronic colitis. Because of the variety of potential causes, colitis can strike a pet of any age.

Diagnosis of colitis is made from a predisposing history (such as dietary indiscretion), existing clinical signs, and physical examination. Stool examinations and other laboratory tests should be performed in an attempt to identify the underlying cause of the colitis. Radiographs, including barium contrast studies, are indicated in nonresponsive, recurring cases. Biopsies obtained using an endoscope or through exploratory surgery can also prove to be helpful for establishing a definitive diagnosis. In some cases, an exact cause of the inflammation can never be discerned, even with extensive laboratory tests.

Treatment of acute colitis is aimed at eliminating the inciting cause.

Parasites should be treated using proper dewormers and antiparasitic medications. Antibiotics can be used to help remove any disease-causing bacteria within the colon, and steroid anti-inflammatories might prove helpful in diminishing clinical signs. If polyps or tumors are present, surgical removal might be necessary to afford a cure.

However, understand that in many cases of chronic colitis, especially those caused by stress or by immune system disorders, a complete cure cannot be achieved. In these pets, treatment goals are aimed at managing flare-ups as they occur and maintaining a good quality of life for the pet. Antiinflammatories, antibiotics, and local protectants such as kaolin and pectin can help provide relief from these intermittent episodes. Dietary management is an important component of colitis treatment. Acute cases of colitis caused by dietary indiscretion or some infectious process respond well to feeding a bland, easily digestible diet available from a veterinarian.

Chronic, recurring bouts with colitis might be managed by increasing the fiber content in the diet to normalize the gut motility. Finally, for those cases suspected of being caused by food allergies, a hypoallergenic diet can help eliminate the effects of the allergy.

Megacolon (Cats)

Feline megacolon is a disease condition characterized by a large, distended colon that has lost its ability to contract properly. When this occurs, feces build up within the affected segment and prevent normal flow of ingesta through the intestinal tract. Megacolon is caused by a disruption of or lack of nerve activity in the muscular walls of the colon. It might occur secondary to spinal cord trauma, other diseases affecting the nervous system, or, as in the case of some Manx cats, be inherited.

The clinical signs associated with feline megacolon can vary. Straining to defecate is certainly the most obvious sign; diarrhea can also be seen alongside firm, hard stools. If the obstruction is severe, vomiting, dehydration, and loss of appetite can be seen as well.

Diagnosis of feline megacolon can be made on physical examination and, for confirmation, from radiographs. Treatment involves removing the fecal impaction using warm-water enemas and by infusing the colon with mineral oil.

Enemas designed for use in humans should not be used in cats, as the components of a human enema solution can cause severe dehydration in cats, Severe cases might require surgical relief of the impaction.

There is no effective cure for this condition; as a result, preventive maintenance therapy should be used to prevent recurrences. Giving an oral hairball laxative on a daily basis will help keep fecal matter moving along nicely. Increasing the amount of fiber in the diet has also been shown to be helpful in preventing relapses.

Date: 2014-12-21; view: 1103