Overview of Feline Dyspnea (Trouble Breathing)
Respiratory distress, often called dyspnea, is labored, difficult breathing or shortness of breath that can occur at any time during a cat’s breathing process, during inspiration (breathing in) or expiration (breathing out).
When your cat has trouble breathing, he may not be able to get enough oxygen to his tissues. Additionally, if he has heart failure, he may not be able to pump sufficient blood to his muscles and other tissues. Dyspnea is often associated with accumulation of fluid (edema) in the lungs or the chest cavity (pleural effusion). This fluid can lead to shortness of breath and coughing.
Below is an overview of information on Dyspnea in Cats followed by detailed information on the causes, testing and treatment of this condition.
Causes of Dyspnea in Cats
Heart disease or heart failure
Tumors or cancer in the lung or which press on the airway
Infections such as pneumonia)
Obstructions that occlude the airway
Bleeding into the lungs or chest
Abnormal fluid accumulation in/or around the lungs from various causes including heart and lung disease
Intact (non-spayed) female cats are predisposed to breast cancer (metastatic mammary carcinoma). Younger animals are more likely to develop lung infections.
What to Watch For
Shortness of breath
Diagnosis of Dyspnea (Trouble Breathing) in Cats
Diagnostic tests are needed to determine why your cat is having trouble breathing. Tests that may be performed include:
A complete medical history and physical examination with emphasis on stethoscope examination (auscultation) of the heart and lungs
A chest radiograph (X-ray)
Measurement of blood pressure
An electrocardiogram (EKG)
Ultrasound examination of the heart (echocardiogram)
Laboratory (blood) tests
Treatment of Dyspnea in Cats
The treatment for dyspnea in cats depends upon the underlying cause. Often, treatment is initiated to help stabilize your pet and allow him to breath easier while tests are being performed to determine the underlying cause. This treatment may include:
Hospitalization with administration of oxygen
Thoracentesis, which is drainage of fluid that has accumulated around the lungs (pleural effusion) with a needle
Diuretics. A “water-pill” such as the drug furosemide (Lasix®) or spironolactone may be administered or prescribed
Combination drug therapy. If heart failure is suspected, treatment with oxygen, a diuretic such as Lasix, and nitroglycerine ointment is often initiated
The drug digoxin (Lanoxin®, Cardoxin®) may be prescribed in some situations
Dyspnea is usually an emergency. See your veterinarian immediately. When you first note that your cat is having trouble breathing, note his general activity, exercise capacity and interest in the family activities. Keep a record of your cat’s appetite, ability to breathe comfortably (or not), and note the presence of any symptoms such as coughing or severe tiring.
Optimal treatment for dyspnea requires a combination of home and professional veterinary care. Follow-up can be critical and may include the following:
Never withhold water, even if your cat urinates more than normal, unless specifically instructed to do so.
Administer all veterinary prescribed medication as directed and be certain to alert your veterinarian if you are experiencing problems treating your cat.
Schedule regular examinations with your veterinarian. This will include an interview regarding your pet’s clinical symptoms and quality of life. Be prepared to answer questions about your pet’s activity, appetite, ability to sleep comfortably, breathing rate and effort, coughing, exercise tolerance and overall quality of life.
Bring your medications with you to show your veterinarian. Dosing is critical for heart medication. If your pet is on digoxin, your veterinarian may want to measure levels of that drug in the blood to make sure that the appropriate amount is being administered.
In-depth Information on Dyspnea (Trouble Breathing) in Cats
The causes of respiratory difficulty can be classified as follows:
Infections. Pneumonia or infection of the lung can lead to symptoms that are similar to those of dyspnea. Heartworm disease, a parasitic infection of the heart and blood vessels of the lung, must be excluded as a possible diagnosis. This infection can lead to lung injury as well as dyspnea.
Inflammatory diseases of the lungs and airways such as chronic bronchitis. This is similar to a smoker’s cough. The cause of most feline bronchitis is not known but treatment is different than for other causes of dyspnea.
Lesions causing airway obstruction or compression
Diseases of the lung tissue. These include edema, hemorrhage, pneumonia, cancer and fibrosis.
Tumors of the mediastinum, which is the area between the left and right lungs. These tumors can cause symptoms that resemble those of dyspnea.
Fluid surrounding the lungs (pleural effusion). When fluid accumulates within the chest cavity, it can cause shortness of breath. Pleural effusion is a common problem in cats.
Diseases of the heart and blood vessels of the lungs.
Other causes of altered respiration include: metabolic diseases, neurologic disease, steroid or drug (for example, phenobarbital) administration, ingested toxins and drug reactions.
A detailed list of potential causes of dyspnea include:
Mechanical Disorders Causing Airway Obstruction
Obstructed nostrils or nasal cavity
Pharyngeal (throat) disorder, such as post-nasal drip, overlong soft palate, pharyngeal polyps (cysts)
Hair, hairballs or foreign bodies
Laryngeal (voice box) diseases, including paralysis; granuloma, polyp or tumor; trauma; edema (abnormal accumulation of fluid in tissues)
Aspiration of liquid or solid into the lungs
Tracheal (windpipe) diseases. Collapse or hypoplasia (incomplete development of trachea), foreign body, trauma/hematoma (blood clot), compression from thyroid mass lesion
Primary bronchial collapse (collapse of airways)
Bronchial compression from hilar lymphadenopathy
Bronchial foreign body
Trauma to the bronchopulmonary tree
Non-infectious Inflammatory Causes
Bronchitis. Idiopathic (occurring without known cause), allergic
Bronchiectasis, which is chronic dilatation of the bronchi and bronchioles with secondary infection
Pulmonary granulomatosis, which is a collection of tumor-like masses in the lungs
Pulmonary infiltrates (foreign bodies in the lungs) with eosinophilia (collection of specific white blood cells in the blood)
Inhalation of noxious gases or smoke
Alveolitis (inflammation of the walls of the alveoli in the lungs) leading to pulmonary fibrosis
Infectious Causes of Respiratory or Thoracic Disease
Viral, including infectious tracheobronchitis, viral pneumonia
Rickettsial infections, which is a type of parasite
Bacterial infections, including pharyngitis (infection of the voice box), tonsillitis (infection of the tonsils), bronchitis (infection of the breathing tubes/airways), pneumonia, lung abscess (growth, cysts and tumors)
Toxoplasmosis, which is a contagious disease caused by a parasite
Systemic mycosis, which is any disease caused by fungi, including histoplasmosis, blastomycosis and coccidioidomycosis
Osleri osleri, including nematodes and traveling parasites
Larval migrans, which is migration of parasites through the lung
Dirofilariasis, which is infection with heartworms
Bronchopulmonary dysplasia, which is abnormal development of adult cells
Anemia, hypoxemia or hemoglobin abnormality
Neurologic (brain, spinal cord) lesions that alter ventilation
Neuromuscular weakness or disease
Rupture or paralysis of the diaphragm, including diaphragmatic hernia
Flail chest or rib fractures
Severe ascites or abdominal space occupying lesion
Drugs, such as steroids that may cause panting, phenobarbital, preservatives in injectables
Pulmonary edema from electrocution, airway obstruction, seizures, smoke inhalation, aspiration of gastric contents into the lungs, pulmonary embolism (the sudden blocking of an artery by a clot or foreign material), heartworm thrombus, drug reaction, uremia (an excess of waste products in the blood when the kidneys are not working properly) and DIC (disseminated intravascular coagulation)
Pulmonary hemorrhage (heavy bleeding into the lung) from trauma; rodenticide coagulopathy, which is a disorder of blood coagulation due to ingestion of rodent poison; DIC; disseminated pulmonary neoplasia (tumor)
Pulmonary fibrosis (scarring of lung tissue)
Tumors and Mass Lesions
Pharyngeal/tonsillar tumor or polyps
Laryngeal tumor or polyp
Chondromatous hematoma of the trachea
Tracheal adenocarcinoma (cancer)
Lymphoma (cancer of lymphoid tissue) in the respiratory tree, lung, mediastinum or lymphatics
Thymoma (disease or cancer of the thymus)
Primary lung tumors (carcinomas)
Cardiac or heartbase tumors
Metastatic (pertaining to the transfer of disease from one organ or part to another not directly related to it) lung tumors
Cardiac and Vascular Diseases
Left bronchial compression from left atrial dilatation
Left-sided congestive heart failure (pulmonary edema and/or pleural effusion)
Heartworm disease (canine)
Pericardial disease (disease of the sac enclosing the heart and the roots of the great vessels)
Pulmonary thromboembolism (blood clot in the lungs)
Air embolism (e.g. with IV lines or urinary negative contrast studies)
Diseases of the Mediastinum and of the Pleural Space
Mediastinal mass, which is a mass in the tissues and organs separating the two lungs, including lymphoma, thymoma and teratoma
Hilar lymphadenopathy (disease of the lymph nodes) with bronchial compression. These include mycosis (any disease caused by fungi), granulomatous lung diseases, lymphoma and other neoplasms.
Diseases Causing Pleural Effusion
Congestive heart failure (CHF)
Hydrothorax (fluid in the pleural cavity that encases the lungs and thoracic cavity)
Chylothorax (milky fluid in the chest)
Hemothorax (collection of blood in the chest)
Pyothorax (accumulation of pus in the chest)
Pneumothorax (entry of air into the chest)
Metastatic neoplasia (tumor)
Pleuropneumonia (pneumonia accompanied by inflammation of the pleura)
Diffuse lymphatic dysplasia
Protein losing enteropathy (disease of the intestine)
Idiopathic pleural effusion
A complete medical history and physical examination should be performed by your veterinarian. These diagnostic tests depend on the duration of signs, presence of other abnormalities, and what is found on your cats physical examination. They may include:
Complete medical history and physical examination with emphasis on stethoscope examination (auscultation) of the heart and lungs. Identification of abnormal heart sounds such as heart murmurs or irregular heart rhythms (arrhythmia) is extremely important. During physical examination, your veterinarian will pay particular attention to your pet’s breathing, the character of his/her heart and lung sounds, and mucous membrane color. Care must be taken not to stress your cat during the examination. Your cat should also be evaluated for weight loss and any concurrent disease.
Your veterinarian will want to know the following:
What medications your cat has been taking?
Is there a history of illness and if so, did your pet respond to therapy?
Has your cat has been anesthetized recently?
Is your cat intact or spayed?
Does your cat cough?
What circumstances make the breathing worse?
Has your cat ever had heartworms and are you giving preventative medication?
What is your cat’s home environment and travel history?
Has there been any exposure to toxins (such as rat poison)?
Has your cat had any trauma?
Does your cat vomit or gag?
Diagnostic tests may include:
A chest radiograph (X-ray) to identify heart enlargement and fluid accumulation in the lung and to exclude some of the previously mentioned conditions that can mimic dyspnea.
Measurement of blood pressure with the special device that measures blood flow noninvasively. High and low blood pressure values may be identified because either can occur in patients with dyspnea.
An electrocardiogram (EKG) to identify heart enlargement and determine the electrical activity of the heart. The electrocardiogram is a noninvasive test done by attaching small contact electrodes to the limbs and body.
Ultrasound examination of the heart (echocardiogram) for a definitive diagnosis. This noninvasive test requires sophisticated equipment that creates high frequency sound waves much like the sonar of a submarine. An image of the heart is created. The echocardiogram is usually the test of choice to establish the final diagnosis of the cause of dyspnea, but this examination may require referral to a specialist.
Laboratory (blood) tests to evaluate other organ function, such as the kidney, and exclude anemia as a complicating factor. This can be critical to evaluating the effect of dyspnea on other organs and to monitor the effects of treatment.
A blood test to detect heartworm infection
A complete blood count (CBC) and serum biochemistry in sick or older animals.
Your veterinarian may recommend additional diagnostic tests to ensure optimal medical care. These are selected on a case-by-case basis if indicated from the examination, prior test results or lack of response. Tests may include:
Serologic tests for toxoplasmosis and systemic fungi
Respiratory cytology and culture if clinical signs and prior laboratory test results do not explain dyspnea with abnormal densities in the lungs. Samples for culture and respiratory cytology (characterizing the cells by looking at a sample under a microscope) may be obtained by using one of the five methods listed below; the method of choice depends on your veterinarians experience, availability of supplies and equipment, and nature of the lung disease.
Tracheal aspiration (removing a fluid sample using suction)
Bronchoscopy to obtain samples for culture and cytology and to provide a visual examination of the trachea and bronchopulmonary tree
Bronchoalveolar lavage (BAL), performed through a wedged bronchoscope, if no exudate (fluid high in protein) is observed in the trachea and main bronchi
A fine needle aspirate (FNA) of the lung is an alternative for assessment of the dyspneic patient with some types of lung disease.
Endoscopy. This direct visualization of the upper airways, trachea and bronchi is indicted when intraluminal masses, foreign body, Osleri osleri (a type of traveling parasite) nodules or other causes of unexplained airway obstruction or inflammation are suspected.
Biopsy of the lung (by thoracoscopy or mini-thoracotomy). This test is sometimes the only method for attaining a diagnosis in disseminated pulmonary disease, especially interstitial disorders, unexplained by previous less-invasive test results. When a singular localized lung lesion is evident and either a foreign body or tumor is suspected consider surgical removal of the affected lobe.
Direct fecal smears and special sedimentation methods (Baerman), along with fecal flotation to screen for lungworms, in pets that have radiographs that are compatible with lungworm infection
Fluoroscopy or endoscopy to demonstrate dynamic collapse of a major airway when it cannot be shown by routine X-ray films
Cytologic evaluation of conjunctival membranes (for distemper inclusions), skin ulcers (for systemic fungi) and enlarged lymph nodes (for infection or tumors)
Esophagoscopy to diagnose esophageal-tracheal fistula or causes of aspiration pneumonia
Specialized blood tests, such as blood taurine, in cases of dilated cardiomyopathy
Thyroid tests to exclude abnormal function of the thyroid gland
Blood cultures in suspected infection of the heart valves
Consultation with appropriate specialists as needed
Definitive therapy is always dependent on establishment of a diagnosis. Since there are numerous potential causes of dyspnea, it is necessary to identify a specific cause to provide optimal therapy. Goals in therapy may include improving heart function, preventing fluid accumulation, preventing further deterioration of the heart muscle and antagonizing chemicals and hormones produced in excessive quantities in dyspnea. Rarely is it possible to cure heart disease.
The most important causes of dyspnea in cats are valve degeneration and cardiomyopathy (heart muscle disease). Definitive treatment likely would require valve replacement (which is rarely done in cats) or heart transplantation (not done currently).
Dyspnea caused by fluid accumulation in the sac around the heart (pericardial effusion) is not treated by drugs but instead requires drainage of the fluid or removal of a portion of the pericardial membrane. Congenital (present at birth) heart defects should be referred to a specialist for management.
Animals with respiratory distress must be handled with care because struggling can result in respiratory arrest.
Initial treatments may include:
Minimize stress and handling
Provide oxygen and cage rest
Remove fluid or air from the chest cavity (thoracentesis) if present in large quantities
Perform tracheal intubation and ventilation if life-threatening dyspnea is evident and respiratory arrest is imminent
Administer furosemide (Lasix®), oxygen and possible vasodilator therapy (Nitroglycerine®) for pulmonary edema
Treat acute dyspnea of infectious origin with rest, inhalation of humidified air and antibiotics if bacterial infection is suspected . Maintenance of hydration is essential and administration of certain drugs, such as expectorants and bronchodilators, might be useful in bronchitis and pneumonia.