High Altitude Disease in Dogs and Horses: Pulmonary Edema
Signs, Prevention, Treatment
Sid Gustafson DVM
Practicing in Big Sky, at 6000-10000 feet and higher, our practice sees and treats many cases of pulmonary edema, altitude sickness, and heart disease in horses and dogs are exacerbated by the altitude.
Difficult Breathing is the first and most obvious sign.
Pulmonary edema/altitude sickness can include swelling of the lungs or accumulation of fluid that interferes with effective breathing. Struggling for air is uncomfortable, and afflicted dogs and horses cannot catch their breath, even at rest.
Causes: Unacclimated to high altitudes accompanied by high altitude activity. Distressed, rapid, relentless, or difficult breathing may be associated with underlying med¬ical conditions such as heart disease, respiratory infection, asthma, collapsing trachea, etc. That said, the healthiest dogs and humans can succumb to the vagaries of altitude sickness from time to time. The body likes oxygen, and when oxygenation becomes impaired, breathing troubles can be intense. High temperatures contribute to the breathing distress. Make sure your dog and horse stay cool.
Heart weaknesses and lung conditions contribute to the severity of the condition, as can allergies and infection. Gradual, measured acclimation to altitude is recommended. Subtle conditions not apparent at lower altitudes may present themselves clinically under the duress of altitude and exercise. Aging dogs become susceptible as time wears on. Just because Fido had an uneventful climb last year doesn't mean the trip will be a merry one this year. Don't forget your dog's annual physical before tackling the mountain peaks this year. Make sure your dog stays hydrated during mountain adventures.
Signs: Difficult and labored breathing caused by airway inflammation or fluid in the airways and/or lungs. Your horse or dog tires easily and requires frequent rests, refuses to continue (can’t continue); relentless panting fails to diminish with rest.The dog may refuse to sit or lie down, as those postures makes breathing more difficult. As the condition worsens, coughing and blood-tainted spittle accompany shortness of breath. Milder cases of altitude sickness manifest as coughing at night, often beginning a few hours after activity has subsided. The dog may prefer a sitting position with the elbows held wide and head stretched out, refusing to lie down. Other signs include a worried expression, distressed eyes and unremitting panting. When horses pant, the condition is sever. In young dogs and horses, the cause can be congenital heart disease or anemia from internal parasites. Older or heavy dogs and horses may suffer from congestive heart failure. that is severely worsened with exercise at altitude. Backup of fluid into the lungs from a weak or aging heart is aggravated by strenuous or even mild activity at high elevations. Intake of untoward amounts of salt can aggravate heart disease and pulmonary edema. Many aging dogs should be on a low sodium, or sodium-free diet. Adequate hydration and maintenance of normal electrolyte levels becomes compensated at high elevations, and medical problems ensue on several levels.
Prevention: Careful conditioning and gradual acclimation to high altitudes are recommended before all high altitude trips. Proper medical treatment of underlying health conditions can prevent exercise-associated breathing complications at any altitude. Avoid strenuous exercise—especially at high altitudes—to which your dog is not accustomed, difficult snow (deep, wind-pressed, crusted) and extremes of hot or cold weather. See your veterinarian for a physical exam and consultation prior to departure. He or she will discuss proper conditioning and consider the need for administration of preventive and ameliorative medications, which can be critical as pulmonary edema and altitude sickness can be life-threatening. Retreating to a lower altitude is always recommended and often required for the breathing to return to normal. Avoid salt, and salty treats, bacon, ham, and cheap dog treats, as these cause additional fluid retention and contribute to pulmonary edema. Many dogs coming to altitude manifest symptoms of underlying heart disease that was asympotamtic at sea level. Weak hearts and lungs become even weaker at altitude. It is possible to prevent lung and heart issues with medication prescribed by your veterinarian.
Treatment: Discontinue activity. Transport the dog to a lower altitude in a manner that allows easy breathing. If the gums become pale or purple, mouth-to-nose breathing may be necessary until the gums regain their normal color and refill time. Administer oxygen if available, which it often is at high altitudes. I recommend that you bring oxygen for yourself and your dog if you plan to travel at unaccustomed elevations where there could be problems. Simply allow the oxygen to flow near your dog's nostrils, rather than into the mouth, in a wind- free environment.
Seek veterinary care if breathing difficulty doesn't improve with rest or the return to a lower elevation. Subsequent or underlying lung disorders or infections and aggravation of pre-existing medical conditions can complicate altitude sickness. See your veterinarian if your dog experiences difficulty breathing or tires easily on high altitude hikes. Furosemide is a commonly employed pharmaceutical treatment. It is a diuretic which lowers the arterial blood pressure in the lungs. Side effects include electrolyte imbalances and dehydration. Other preventive medications include triamcinolone. Cortisones that have a fluid retention effect should be avoided (prednisone and the like).