Acute Respiratory Distress Syndrome (ARDS) in Dogs

Shock Lung in Dogs

Acute Respiratory Distress Syndrome (ARDS) refers to a condition of sudden respiratory failure due to fluid accumulation and severe inflammation in the lungs. ARDS is a life-threatening problem, with current mortality rates in dogs at almost 100 percent. This condition is also medically referred to as shock lung, as it occurs following an episode which leads to a state of shock, such as traumatic injury. As typified by a syndrome, ARDS is indicative of an underlying medical condition, usually an injurious event that has allowed blood, fluid and tissue to cross over the barrier and into the alveoli, the air cells in the lungs, causing them to collapse. Once the alveoli have been compromised in this way, breathing becomes labored, and eventually impossible if not treated with haste.

In humans there appears to be a genetic factor for the development of ARDS, but this factor has not yet been investigated in dogs.

Symptoms and Types

Acute respiratory distress syndrome can occur in a number of conditions and with varying symptoms, depending upon the underlying cause. Following are some general symptoms seen with ARDS:

• Extreme efforts to breath
• Cough
• Discharge from nostrils
• Fever
• Cyanosis (blue discoloration of skin)
• Other signs related to underlying disease

Causes

Following are a few of the major causes of ARDS in dogs:

• Pneumonia
• Inhalation of smoke and noxious gases
• Near drowning
• Thermal burns
• Aspiration of gastric contents
• Serious infections of the lungs or bloodstream
• Lung injury due to trauma
• Other serious illness

Diagnosis

Acute respiratory distress syndrome is a medical emergency requiring immediate attention. Your veterinarian will evaluate your dog's condition and start emergency treatment at once. You will need to provide your veterinarian with a thorough history of your dog's health, onset of symptoms, and possible incidents that might have preceded this condition, such as trauma to any part of the body, or inhalation of gases, fumes, or solid matter. Along with the emergency treatment your veterinarian will work to find the underlying cause for the sudden lung failure. Various laboratory test panels will be ordered, including blood tests, serum biochemical tests, urine tests and blood gas analysis. Blood gas analysis is one of the most important diagnostic methods used in veterinary practice for the diagnosis of ARDS. Your veterinarian will also order chest X-rays and echocardiography in order to visually examine and evaluate the functioning capability of the lungs and heart.

Treatment

Dogs suffering from this syndrome will need emergency treatment in an intensive care unit. Along with emergency treatment, the underlying cause must be established and treated in order to prevent further complications or death. Despite recent advances, ARDS remains one of the most difficult and challenging problems to treat in veterinary practice.

Supplemental oxygen therapy will be started immediately to minimize the respiratory distress. If your dog does not respond well to the oxygen therapy and continues to have severe breathing problems, there may be more success with ventilator supported breathing. Medications for treating ARDS include antibiotics, pain killers, fluid therapy, and corticosteroids for reducing inflammation and swelling. Frequent readings of temperature, pulse, respiration rate, and blood pressure will be necessary for following your dog's progress in the initial stage of the treatment. If your dog has been placed on ventilator support it may also require regular physiotherapy sessions and frequent changes in body position to prevent complications related to ventilator support. Dogs affected with ARDS are kept in strict cage confinement until they have fully recovered.

Living and Management

ARDS is a very serious health problem needing constant support from your side for the successful treatment, management and care of the condition. Be sure to follow your veterinarian’s guidelines closely, and if you are in doubt, consult with the doctor. If an underlying disease has not been conclusively diagnosed and resolved, another episode of respiratory distress may follow. Dogs that have been affected, and have survived this condition usually need time, rest, and good nutrition to fully recover. Do not confine your dog to stuffy or hot places, and allow your dog to signal when it has had enough walking or exercise. Some dogs will have scarring of the lungs even after the condition has been resolved, a condition referred to as fibrosis, and the tissue of the lungs will be stiffer and less capable of holding oxygen. Following the diet and management recommendations made by your veterinarian, and keeping activity minimal will be the best course for preventing a recurrence.

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