Respiratory System Disorders

Canine Bronchitis | Bronchitis in Dogs

Chronic bronchitis in dogs refers to long-term airway inflammation. There is generally a component of irreversible damage. Histologic changes of the airways include fibrosis, epithelial hyperplasia, glandular hypertrophy, and inflammatory infiltrates. Excessive mucus is present within the airways, and small airway obstruction and airway collapse occur. The cause is often not discovered, but long-standing inflammatory processes resulting from infections, allergies, or inhaled irritants can be at fault. Infections can also occur secondary to canine chronic bronchitis, making a cause-and-effect relationship difficult to determine.

Chronic bronchitis in dogs occurs in middle-aged or older, small breeds. These breeds are also predisposed to the development of collapsing trachea and mitral insufficiency with left atrial enlargement causing compression of the mainstream bronchi. These diseases must be differentiated and their contribution to the development of the current clinical features determined for appropriate management to be implemented.

Dogs with bronchitis are evaluated because of cough, which can be productive or non-productive. The cough has usually slowly progressed over months to years, with no systemic signs of illness such as anorexia, weight loss or lethargy. As the disease progresses, exercise intolerance becomes evident; then incessant coughing or overt respiratory distress is seen. Dogs with respiratory distress show marked expiratory efforts because of the narrowing and collapse of the intrathoracic airways.

Increased breath sounds, wheezes, or crackles, are auscultated in dogs with chronic bronchitis. end-expiratory clicks caused by mainstream bronchial or intrathoracic tracheal collapse may be heard in dogs with advanced bronchitis. A prominent or split second heart sound occurs in animals with secondary pulmonary hypertension.

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Symptoms of dog pneumonia

A wide variety of bacteria can infect the lungs. Anaerobes may be present as part of a mixed infection, particularly in dogs with aspiration pneumonia or lung lobe consolidation. Mycoplasma spp. have been isolated from dogs with pneumonia.

The causes and symptoms of pneumonia in dogs are decreased clearance of normally inhaled debris from the lungs, immunosuppression from drugs, malnutrition, stress, dyskinesia, endocrinopathies, viral infections, aspiration of ingestal material or gastric contents and fungal or parasitic infections.

In most cases of dog pneumonia, bacteria enter via the airways, causing bronchopneumonia primarily in the cranial and ventral lobes. Hematogenous spread usually causes pneumonia with a caudal of diffuse pattern and marked interstitial involvement. Dogs with bacterial pneumonia are presented for respiratory signs, systemic signs or both. Respiratory signs can include cough (usually productive and soft), bilateral mucopurulent nasal discharge, execise intolerance, and respiratory distress.

Diagnosis is based on complete blood count, thoracic radiographs and tracheal wash cytology and culture. A finding of neutrophilic leukocytosis with a left shift, neutropenia with a degenerative left shift, or moderate to marked neutrophil toxicity is supportive of bacterial pneumonia in dogs. However, a normal or stress leukogram is ust as likely to be found.

Abnormal radiographic patterns vary. An alveolar pattern is typical, possibly with consolidation that is most severe in the dependent lobes. In most cases tracheal wash is sufficient for diagnosis of pneumonia in dogs. Septic neutrophilic inflammation is seen, and growth on bacterial culture is expected. Further diagnostic tests (e.g., bronchoscopy, conunctival scrapings for distemper virus, serology for fungal infections, hormonal assays for hyperadrenocorticism) are sometimes indicated. We also recommend this natural balanced real-meat dog food and natural dietary supplement for recovery.

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It is easier for the body to prevent edema fluid from forming that it is to mobilize existing fluid. The initial management of treating pulmonary edema in dogs and cats should be aggressive. Once the edema has resolved, the body’s own compensatory mechanisms become more effective and the intensity of therapeutic interventions can often be decreased.

All dogs and cats with pulmonary edema are treated with cage rest and minimal stress. Dogs and cats with significant hypoxemia should receive oxygen therapy. Positive pressure ventilation is required in several cases. Methylxanthine bronchodilators may also be beneficial in dogs and cats edema treatment. They are mild diuretics and also decrease bronchospasms and, possibly, respiratory muscle fatigue.

Diuretics are indicated for the treatment of most forms of edema in dogs and cats but are not used in hypovolemic animals. Dogs and cats with hypovolemia actually require conservative fluid supplementation. If this is necessary to maintain the vascular volume in animals with cardiac impairment or decreased oncotic pressure, then positive inotropic agents or plasma infusions, respectively, are necessary.

Edema caused by hypoalbuminemia in dogs and cats is treated with plasma or colloid infusions. However, the plasma protein concentration do not need to reach normal levels for edema to decrease. Furosemide can be administered to more quickly mobilize the fluid from the lungs, but clinical dehydration and hypovolemie must be prevented. Diagnostic and therapeutic efforts are directed at the underlying disease.

The prognosis for dogs and cats with edema depends on the severity of the edema and the ability to eliminate or control the underlying problem. Aggressive management early in the course of edema formation improves the prognosis for dogs and cats with any given disease.

We also recommend this natural balanced real-meat dog food and natural dietary supplement for recovery.

The same general mechanisms that cause edema elsewhere in the body cause edema in the pulmonary parenchyma. Major mechanisms are decreased plasma oncotic pressure, vascular overload, lymphatic obstruction, and increased vascular permeability.

Edema in dogs and cats is initially a fluid accumulation in the interstitium. However, because the interstitium is a small compartment, the alveoli are soon involved. When profound fluid accumulation occurs, even the airways become filled. Respiratory function is further affected as a result of the atelectasis and decreased compliance caused by compression of the alveoli and decreased concentrations of surfactant. Airway resistance increases as a result of the luminal narrowing of small bronchioles. Hypoxemia results from ventilation-perfusion abnormalities.

Clinical features of pulmonary edema in dogs and cats

Dogs and cats with pulmonary edema are seen because of cough, tachypnea, respiratory distress, or signs of the inciting disease. Crackles are heard on auscultation, except in animals with mild or early disease. Immediately preceding death from pulmonary edema, blood-thinged froth may appear in the trachea, pharynx or nares. Respiratory signs can be peracute, as in acute respiratory distress syndrome (ARDS), or subacute, as in hypoalbuminemia. However, a prolonged history of respiratory signs (e.g., months) is not consistent with a diagnosis of edema in dogs and cats.

Pulmonary edema in most dogs and cats is diagnosed on the basis of the finding of the typical radiographic changes in the lungs in conjunction with clinical evidence (from the history, physical examination, radiography, echocardiography, and serum biochemical analysis (particularly albumin concentration) of a disease associated with pulmonary edema.

Early pulmonary edema in dogs and cats assumes an interstitial pattern on radiographs that progresses to become an alveolar pattern. In dogs, edema caused by heart failure is generally more severe in the hilar region. In cats, the increased opacities are more often patchy. Edema resulting from increased vascular permeability tends to be most severe in the dorsocaudal lung regions.

Canine pulmonary edema diagnostic plan:

History
Physical examination
Chest auscultation
Chest X-rays
Electrocardiography
Blood work
Urinalysis

Canine pulmonary edema treatment:

Active restriction
Oxygen therapy
Morphine
Diuretics
Corticosteroids
Nebulization
Bronchodilators
Vasodilators
Drugs to strengthen the heart

Canine pulmonary edema dietary plan:

A diet based on individual patient evaluation including body condition and other organ system involvement or disease. Also, consider sodium restriction. We recommend this natural balanced real-meat dog food and natural dietary supplement for recovery.

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Pneumothorax in dogs and cats is the accumulation of air in the pleural space. The diagnosis is confirmed by means of thoracic radiography. The pleural cavity is normally under negative pressure, which helps to keep the lungs expanded in health. However, if an opening forms between the pleural cavity and the atmosphere or the airways of the lungs, air is transferred into the pleural space because of this negative pressure. A tension pneumothorax occurs if a one-way valve is created by tissue at the site of leakage, such that air can escape into the pleural space during inspiration but cannot reenter the airways or atmosphere during expiration. Increased intrapleural pressure and resultant respiratory distress occur quickly.

Leaks through the thoracic wall can occur after a traumatic injury or as a result of a faulty pleural drainage system. Air can also enter the thorax during abdominal surgery through a previously undetected diaphragmatic hernia. Pneumothorax from pulmonary air can occur after blunt trauma to the chest (traumatic pneumothorax) or as a result of existing pulmonary lesions (spontaneous pneumothorax). Traumatic pneumothorax in dogs and cats occurs frequently, and the history and physical examination findings allow this to be diagnosed. Pulmonary contusions are often present in these dogs and cats.

Spontaneous pneumothorax in dogs and cats occurs when preexisting pulmonary lesions rupture. Cavitary lung diseases include blebs, bullae, and cysts, which can be congenital or idiopathic or result from prior trauma, chronic airway disease, or Paragonimus infection. Necrotic centers can develop in neoplasms, thromboembolized regions, abscesses, and ganulomas involving the airways, and these can rupture, allowing air to escape into the pleural space. Thoracic radiography should be performed to identify cavitary lesions in dogs and cats with spontaneous pneumothorax, although lesions are not always apparent.

Dogs and cats with pneumothorax and a recent history of trauma are managed conservatively. Cage rest, the removal of accumulating air by periodic thoracocentesis or by chest tube, and radiographic monitoring are indicated. If abnormal radiographic opacities persist without improvement for more than several days in trauma patients, further diagnostic tests should be performed.

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Pulmonary contusion in dogs and cats is caused by blunt trauma and is a common finding in animals that have been hit by cars. Hemorrhage into the interstitium and alveoli occurs, usually in localized regions of the lungs. Pneumothorax, hemothorax, and rib fractures can also occur. Thoracic involvement should be considered in any animal with evidence of severe trauma, even if there are no external signs of trauma in that region of the body.

Historical or physical examination evidence of trauma is generally present in dogs and cats with pulmonary contusions. Although increased respiratory efforts may be noted, pneumothorax, pain from rib fractures, cardiovascular shock, or neurologic damage may also affect breathing patterns. Crackles may be auscultated over the contused areas.

Pulmonary contusions are diagnosed on the basis of evidence of trauma and the finding of typical radiographic signs, although the latter may not be evident until almost a day after trauma. Large localized ares of alveolar and interstitial opacities are seen in dogs and cats with pulmonary contusions.

Dogs and cats with pulmonary contusions receive treatment for trauma-related problems as indicated by clinical signs. The contusions themselves are not treated directly. Although antibiotics have been recommended to prevent infection in damaged tissue, they are more effectively used to treat animals that have developed actual signs of infection. It is recommended that radiographs be obtained periodically to monitor the resolution of abnormalities. The frequency of this depends on the severity of the initial abnormalities and the clinical signs. Complications that may arise in animals with pulmonary contusions include a secondary bacterial infection, abscesses, lung lobe consolidation, and cavity lesions.

The prognosis for recovery from pulmonary contusions is excellent, provided that the animal’s condition can be stabilized after the trauma. The possible complications of contusions noted earlier are rare.

Several parasites can cause lung disease. Certain intestinal parasites, especially Toxocara canis, can cause transient pneumonia in young animals, usually those less than a few months of age, as the larvae migrate through the lungs. Infections with Dirofilaria immitis can result in severe pulmonary disease through inflammation and thrombosis. Oslerus osleri resides at the carina and mainstem bronchi of dogs. The other primary lung larvae that are most commonly diagnosed are Capillaria aerophila and Paragonimus kellicotti in dogs and cats and Aelurostrongylus abstrusus in cats.

Infection occurs as a result of the ingestion of infective forms, often within intermediate or paratenic hosts, that subsequently migrate to the lungs. An eosinophilic inflammatory response often occurs within the lungs, causing clinical signs in some, but not all, infected animals. The definitive diagnosis is made on the basis of the identification of the characteristic eggs or larvae in respiratory or fecal specimens.

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Bronchitis can develop in cats of any age, although it most commonly develops in young adult and middle-aged animals. The major clinical feature is cough or episodic respiratory distress or both. The owners may report audible wheezing during an episode of cat bronchitis. The signs are often slowly progressive. Weight loss, anorexia, depression or other systemic signs are not present when cats have bronchitis.

Owners should be carefully questioned regarding an association with exposure to potential allergens or irritants – such as new litter (usually perfumed), cigarette or fireplace smoke, carpet cleaners, or household items containing perfumes such as deodorant or hair spray. They should also be questioned about whether there has been any recent remodeling or any other change in the cat’s environment, which could also be a source of allergens. Seasonal exacerbations are another sign of potential allergen exposure.

The physical examination findings result from small airway obstruction. Cats that are in distress show tachypnea, with increased respiratory efforts during expiration. Auscultation reveals respiratory wheezes, particularly during such episodes. Crackles are occasionally present. Physical examination findings may be unremarkable between episodes.

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Bronchoscopy is indicated for the evaluation of the major airways in animals with suspected structural abnormalities; for visual assessment of airway inflammation or pulmonary hemorrhage; and as a means of collecting specimens in animals with undiagnosed lower respiratory tract disease.

Bronchoscopy in dogs and cats can be used to identify structural abnormalities of the major airways, such as tracheal collapse, mass lesions, tears, strictures, lung lobe torsions, bronchiectasis, bronchial collapse, and external airway compression. Foreign bodies or parasites may be identified. Hemmorrhage or inflammation involving the large airways may also be seen and localized.

Specimen collection techniques performed in conjunction with bronchoscopy in dogs and cats are valuable diagnostic tools because they can obtain specimens from deeper regions of the lung than is possible with the tracheal wash technique, and visually directed sampling of specific lesions or lung lobes is also possible. Dogs and cats undergoing bronchoscopy must receive general anesthesia, and the presence of the scope within the airways compromises ventilation. Therefore bronchoscopy is contraindicated in animals with severe respiratory tract compromise unless the procedure is likely to be therapeutic (i.e, foreign body removal).

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Ultrasonography is used to evaluate pulmonary mass lesions adjacent to the body wall, diaphragm, or heart, and also consolidated lung lobes. Because air interferes with the sound waves, aerated lungs and structures surrounded by aerated lungs cannot be examined. The consistency of lesions often can be determined to be solid, cystic, or fluid filled. Some solid masses are hypolucent and appear to be cystic on ultrasonograms. Vascular structures may be visible, particularly with Doppler ultrasound, and this can be helpful in identifying lung lobe torsion. Ultrasonography can also be used to guide biopsy instruments into solid masses for specimen collection. It is also used for evaluating the heart in animals with clinical signs that cannot be readily localized to either the cardiac or respiratory systems.

Nuclear imaging can be used for the relatively noninvasive measurement of pulmonary perfusion and ventilation. Restrictions for handling radioisotopes and the need for specialized recording equipment limit the availability of these tools to specialty centers though.

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