Pneumonia is a condition which refers to an inflammation of the lungs. Bacterial pneumonia, meanwhile, refers to an inflammation of the lungs in response to a disease-causing bacteria. This inflammation is characterized by an accumulation of inflammatory cells and fluid in the lungs, airways, and alveoli (the portion of the airways in which oxygen and carbon dioxide are exchanged).
Prognosis for bacterial pneumonia is generally good if properly treated. However, there are two secondary conditions that may result from bacterial pneumonia, and which are associated with increased fatalities: hypoxemia and sepsis. Hypoxemia refers to severely low levels of oxygen in the blood, while sepsis refers to a systemic infection with the presence of toxic, pus-forming bacteria in the dog's blood stream.
Bacterial pneumonia is relatively common in dogs. Sporting dogs, hounds, and larger mixed-breed dogs seem to be at greater risk for bacterial pneumonia than other breeds.
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Symptoms and Types
Symptoms of bacterial pneumonia include cough, fever, difficulty breathing, lack of appetite and consequent weight loss, sluggishness, nasal discharge, dehydration, and rapid breathing. Intolerance to exercise due to breathing difficulties may also be apparent. Listening to the lungs with a stethoscope may reveal abnormal breathing sounds, a diagnostic process known as auscultation. Symptoms may include short rough snapping sounds known as crackles, and whistling sounds known as wheezes.
Causes
Causes of bacterial infection in the lungs may vary -- with no single bacterium being thought of as responsible for this condition. In dogs, the bacterial organisms Bordetella bronchiseptica and Streptococcus zooepidemicus are the primary bacterial causes of pneumonia. Additional types of bacteria, as well as anaerobic bacteria - which are capable of living and growing in the absence of oxygen, may also be to blame.
Some risk factors that may increase the risk of bacterial pneumonia include a pre-existing viral infection, difficulty swallowing, metabolic disorders, and regurgitation.
Diagnosis
Bacterial pneumonia is just one cause of pulmonary dysfunction. Additional causes may include aspiration pneumonia, in which the lungs become inflamed due to inhalation of material, such as a foreign body, or vomit. The symptoms of bacterial and aspiration pneumonia may be similar, and diagnosis must properly determine between them in cases of pulmonary dysfunction.
If bacterial pneumonia is suspected, there are a number of diagnostic procedures that may be used for your dog. A tracheal wash may be performed to gather some of the material (fluids and cells) that lines the trachea for analysis. Because the bacteria cannot always be seen via microscope, any specimens taken should be cultured for further examination. Other tests may include visual imaging, specifically X-rays of the chest and lungs. Blood analysis, and urine analysis tests will also be conducted.
Treatment
Medication is necessary in cases of bacterial pneumonia; the proper antimicrobial can be selected based on results of bacterial cultures taken from a tracheal wash, for example. Additional treatment depends on the severity of signs. If multiple symptoms occur, such as anorexia, high fever, and weight loss, your dog will be actively treated in hospital to start.
If respiratory distress is apparent, oxygen therapy may be necessary. To avoid dehydration, your veterinarian may recommend administering electrolytes by intravenous (IV) fluid therapy.
Restrict your dog's activities throughout treatment, except as part of physiotherapy, or to help improve clearing of the lungs and airways. Be attentive to your pet's needs. Although you will need to allow for plenty of recuperative rest, you will also need to prevent your dog from lying in one position for long periods of time to avoid the risk of fluid accumulation in one spot. Encourage your dog to change positions semi-frequently.
Living and Management
After the initial treatment, your dog should be fed a diet high in protein and energy density. Your veterinarian will monitor your dog's progress with blood tests, and if needed, X-rays of the chest and lung cavity. Any prescribed antimicrobial medications should be administered regularly, as prescribed by your veterinarian.
Prevention
One way in which bacterial pneumonia can be prevented is by ensuring that pets receive regular vaccinations for prevention of infections.
Additional vaccinations may be necessary in special situations; for example, dogs housed in kennels, and thereby exposed to a large number of animals, should be vaccinated against the B. bronchiseptica virus.