Panting in Dogs

Overview of Panting in Dogs

Panting is rapid, shallow respirations characterized by open-mouthed breathing, often accompanied by a protrusion of the tongue. It is seen commonly in dogs, and less commonly in cats.

A dog’s primary method of cooling is evaporative cooling from the respiratory tract through panting. When a dog pants it provides increased air flow over moist surfaces in the upper respiratory tract through rapid, shallow breathing. The increase in air flow causes an increase in evaporation from the upper respiratory tract. At the onset of panting, respiration rate increases rather suddenly from around 30-40 respirations per minute to around 300-400 respirations per minute. Under a moderate heat load a dog alternates between brief periods of panting at high frequencies and periods of normal slow respiration.

Panting may also be the result of other factors, such as fear, stress or disease. Some cause may include:

• Respiratory disorders
• Cardiovascular disorders
• Hematologic disorders
• Neurologic disorders
• Miscellaneous disordersPanting may have little to no impact on the affected individual, especially in association with transient causes such as fear or stress. On the other hand, panting may represent a more severe, even life-threatening illness, therefore, should not be ignored and should be addressed if it persists or worsens.

What to Watch For

• Associated coughing
• Difficulty breathing
• Cyanosis (blue color to the mucus membranes)
• Fatigue
• Weight loss
• Poor appetite
• Excessive drinking
• Excessive urinating
• Vomiting
• Diarrhea

Diagnosis of Panting in Dogs

Before any testing is performed, consider any factors that may be causative such as heat, stress or over exertion and eliminate them from your pet’s environment. If your pet is still panting despite removing the possible cause, and/or signs are long standing or progressive, it is important to seek veterinary care.

• A complete blood count (CBC), biochemical profile and urinalysis are an important part of any baseline work up. Changes may suggest conditions that cause panting such as anemia, infection and diabetes mellitus.
• Chest and abdominal X-rays should be performed on these patients. It is important to include the area of the neck in some cases so as not to miss a foreign body or tumor in the upper respiratory tract.
• An arterial blood gas may be performed to assess the patient’s acid-base status.
• Echocardiography (an ultrasound of the heart) and chest cavity ultrasound may be of benefit in appropriate cases.
• Abdominal ultrasound may be of benefit, as it evaluates the size of organs, and will detect the presence of fluid or masses.
• Endocrine testing (ACTH stimulation test, thyroid panel) may be of benefit in ruling out hyperadrenocorticism and hypothyroidism, respectively.
• An ARAT (acetylcholine receptor antibody titer) should be considered to evaluate for myasthenia gravis, especially if there is concurrent weakness.
• Heartworm test
• Thoracocentesis (withdrawal of fluid, air, or tissue from the chest) and fluid analysis or cytology may be diagnostic in some cases.
• More advanced diagnostics to include a transtracheal wash, bronchoalveolar lavage, bronchoscopy, computed tomography (CT scan), magnetic resonance imaging (MRI), bronchoscopy and pulmonary scintigraphy, may be indicated in some patients.

Treatment of Panting in Dogs

• Ideally, an underlying cause should be identified and corrected if possible.
• If there is an obvious environmental cause, eliminate it if possible.
• Symptomatic therapy should be instituted while attempting to identify an underlying cause.
• Oxygen therapy and strict rest are of benefit to many of these individuals, especially if they are becoming distressed.
• Antibiotic or anti-inflammatory therapy may be of benefit in animals with infectious or inflammatory disorders.
• Fluid therapy is indicated in animals that are dehydrated or have concurrent systemic diseases.

Home Care

Administer all prescribed medications and return for follow up evaluation as directed by your veterinarian. Keep your pet in a cool, stress free environment, and do not overexert your pet.

In-depth Information on Panting in Dogs

Panting is seen in both dogs and cats, but is more common in dogs. Panting is often seen associated with environmental changes such as anxiety, fear, excitement, exercise and heat. However, panting may reflect disease, and should not be ignored or assumed “normal” unless there are circumstances around the panting that suggest it is acceptable for the situation at hand. If your pet is panting excessively, or more often than normal, it is important to be evaluated by a veterinarian.

There are many causes of panting. Because panting may be a normal response to environmental and psychological events, it is quite feasible that no underlying illness exists and a full diagnostic workup is not in order. If, however, panting is excessive or your pet is in distress, it is important to identify an underlying cause.

Respiratory Disorders That Cause Panting

• Upper respiratory tract disorders may limit the ability to breathe normally. These include nasal blockages, laryngeal dysfunction (disorders of the voice box), nasopharyngeal polyps (benign growths of the nose and pharynx) and collapsing trachea.
• Lower respiratory tract disorders may not allow for ample gas exchange at the level of the lung, causing panting. Some examples include pulmonary edema (fluid in the lungs), hemorrhage or cancer, lung lobe torsion (twisting), emphysema and asthma.
• Diseases of the chest cavity may not allow the lungs to expand. Examples include pneumothorax, (air in the chest), pleural effusion (fluid in the chest cavity), mediastinal masses (growths in the chest), and diaphragmatic hernias (the displacement of abdominal contents into the chest cavity).

Cardiovascular Disorders That Cause Panting

• Pulmonary (lung) disorders include vascular disease such as heartworm disease and pulmonary thromboembolism, which is blockage of a vessel by material carried through the blood stream.
• Cardiac disorders include heart failure, cardiomyopathy (heart muscle disease) and congenital heart abnormalities.

Hematologic Disorders That Cause Panting

Diseases that cause reduced oxygen-carrying capacity such as anemia or carbon monoxide poisoning often cause panting.

• Hypercapnia (excess carbon dioxide in the blood) can be secondary to kidney disease, diabetes mellitus, diarrhea or shock.

Neurologic Disorders That Cause Panting

• Head trauma or brain tumors may affect the respiratory center.
• Dysfunction of the muscles of respiration may contribute to panting. Some examples include myasthenia gravis, nerve disorders with diabetes mellitus, and laryngeal paralysis associated with hypothyroidism.
• Seizures and high body temperature can stimulate the respiratory center.

Miscellaneous Causes of Panting in Dogs

• Certain drugs, such as diazepam, may cause panting.
• High altitude is associated with decreased oxygen availability.
• Abdominal pressure on the diaphragm caused by ascites(fluid in the abdomen), pregnancy or enlarged abdominal organs may cause difficulty breathing and panting.
• Hyperadrenocorticism (Cushing’s disease) may be associated with panting for several reasons. An enlarged liver puts pressure on the diaphragm, limiting the ability of the lungs to fully expand. Additionally, excessive cortisol stimulates panting, and pulmonary thromboembolism, a complication not infrequently seen with Cushing’s disease, can cause difficulty breathing as well.
• High body temperature secondary to any cause will contribute to panting.
• Anxiety or excitement are more common “benign” causes of panting.
• Hyperactivity secondary to hyperthyroidism or a pheochromocytoma, a tumor of the adrenal gland that makes too much adrenaline, can cause panting.
• Pain associated with any disorder is often associated with panting.

Diagnosis In-depth

Obtaining a complete medical history and performing a thorough physical examination are necessary in order to create an appropriate diagnostic plan for the panting patient.

• A complete blood count (CBC) evaluates for the presence of infection, inflammation, anemia or polycythemia (high red blood cell count) associated with some diseases that cause panting.
• A biochemical profile helps rule out metabolic causes of panting. It can assess the kidney, liver, electrolytes, total protein and blood sugar status. All of these parameters are important to establish in the patient with panting.
• A urinalysis helps evaluate the kidneys and hydration status of the patient.
• Thoracic radiographs evaluate for the presence of fluid, air or masses in the chest cavity. It also assesses for the presence of metastasis (spread of tumor), pneumonia, edema (fluid in the lungs) and helps evaluate the heart, esophagus and trachea.
• Abdominal X-rays evaluate the abdominal organs, presence of a foreign body or tumor, and may help evaluate for other disorders that may relate to pain.
• An arterial blood gas should be obtained as it may help formulate an appropriate treatment plan, and help identify an underlying cause.
• An echocardiogram (ultrasound of the heart) should be considered in those cases where heart disease is suspected. It is a safe test that usually necessitates the involvement of a specialist.
• An abdominal ultrasound evaluates the size, shape and texture of abdominal organs and helps assess for the presence of tumors, fluid or potential inflammatory disorders that may cause pain and in turn, panting. This procedure is relatively safe, but may necessitate a mild sedative. It is often recommended that a specialist perform the procedure.
• Endocrine testing to include an ACTH stimulation test and a thyroid profile may be recommended to rule out hyperadrenocorticism (Cushing’s disease) and hypothyroidism, respectively. They are blood tests that can usually be performed at your local veterinary hospital. Both Cushing’s disease and hypothyroidism are endocrine disorders that are commonly seen in veterinary medicine, and can be associated with panting.
• Heartworm testing is recommended in endemic areas.
• A thyroid level (T4) should be performed in all cats six years of age or older.

Your veterinarian may recommend additional tests to insure optimal medical care. These are selected on a case-by-case basis.

• A coagulation (clotting) profile should be considered when blood in the lungs or chest cavity is thought to be the cause of panting.
• Thoracocentesis (withdrawing fluid or air from the chest cavity) should be considered as both a diagnostic and therapeutic tool in the panting patient.
• Transtracheal wash/bronchoalveolar lavage should be considered when certain respiratory disorders are suspected in the patient. Both procedures assess cells/fluid/tissue from the lower respiratory tract for the presence of tumor, inflammation or infection. These are relatively benign procedures that may be performed at your local hospital, although in some cases it may be performed at a specialty facility.
• Bronchoscopy, or evaluation of the inside of the trachea and bronchi with a scope, is recommended in selected cases. The procedure necessitates general anesthesia, and usually requires a specialist. It helps visualize the inside of the bronchi directly, and may be a tremendous benefit in certain cases. It is usually best to have the procedure performed by a specialist.
• Pulmonary scintigraphy (injection of a radioactive substance) may be helpful in trying to identify pulmonary thromboembolic disease.
• Computed tomography (CT scan) or magnetic resonance imaging (MRI) may be indicated if central nervous system disease is suspected. These procedures necessitate transport to a specialty facility and general anesthesia and are generally quite costly.
• An acetylcholine receptor antibody titer (ARAT) may be recommended if myasthenia gravis is suspected. Generally, concurrent signs of illness, such as weakness, regurgitation and possibly pneumonia are usually seen.

Therapy In-depth

One or more of the diagnostic tests described above may be recommended by your veterinarian. In the meantime, treatment of the symptoms might be needed, especially if the problem is severe. The following nonspecific (symptomatic) treatments may be applicable to some, but not all pets with panting. These treatments may reduce severity of symptoms or provide relief for your pet. However, nonspecific therapy is not a substitute for definitive treatment of the underlying disease responsible for your pet’s condition.

• Treating the underlying cause is recommended if possible.
• If the patient’s panting is thought to be a normal response to something environmental, no specific treatment other than removing the problem is warranted.
• Symptomatic therapy should be instituted while attempting to identify the underlying cause.
• Oxygen therapy and strict rest is of benefit to many of these individuals, especially if they are becoming distressed.
• Fluid therapy is indicated in those who are dehydrated or have concurrent systemic diseases.
• Blood transfusions may be indicated if the patient is panting secondary to anemia.
• Antibiotic or anti-inflammatory therapy may be of benefit in those with infectious or inflammatory disorders.