Dogs with congestive heart failure tend to suffer from extreme weight loss called cardiac cachexia. While weight loss is common with many medical conditions, this particular weight loss, known as cardiac cachexia, occurs at a fast rate and causes the loss of both muscle mass and body fat. While loss of appetite or reduced caloric intake is common with traditional weight loss, they're not the only contributing factors to the muscle wasting or loss in dogs with cardiac cachexia.
Cardiac cachexia causes extreme weight loss at a rapid rate. You may notice that your dog is losing weight quickly or that you are able to see his bones. Loss of appetite is a possibility, though your dog may still eat his regular diet and continue to lose weight. As the muscle loss increases, weakness and lethargy may occur. The loss begins to affect the immune system, increasing the risk of infection. Muscle loss typically begins in the gluteal, epaxial, temporal and scapular muscles.
In cardiac cachexia, the cause of weight loss comes from a combination of things: an increased need for nutrients and energy, a lack of nutrient absorption, metabolic changes and anorexia. Dogs with congestive heart failure often suffer from decreased appetite due to either the illness or medications. This loss of appetite affects caloric intake, resulting in anorexia and weight loss. The heart failure also contributes to conditions that affect the dogs' ability to absorb nutrients. Meanwhile, dogs with congestive heart failure often require more calories and nutrients than healthy dogs due to decreased blood flow and cardiac output. While these factors contribute, the main factor contributing to cardiac cachexia is metabolic changes that produce inflammatory cytokines that alter the body’s ability to metabolize carbohydrates, fats and proteins. Instead of using glucose for energy, the body uses amino acids found in the muscles.
If your veterinarian suspects cardiac cachexia, treatment begins with dietary changes. Ensuring your dog is getting all the necessary calories and nutrients is essential. Often, tasty additives, such as yogurt or gravy, may be necessary to increase palatability for your dog. If medications are contributing to weight loss, levels may require adjustment. ACE inhibitors often help promote weight gain in dogs with congestive heart failure. Omega-3 fatty acids, such as those found in fish oils, help to reduce the production of inflammatory cytokines.
In addition to congestive heart failure, other medical conditions can lead to extreme weight loss and cachexia. Some of these conditions include cancer; inflammatory bowel disease; parasites; diseases of the pancreas, liver or gall bladder; diabetes; and various bacterial, viral and fungal infections. Cachexia is termed cardiac cachexia when it accompanies congestive heart failure.
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