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Weight Loss and Cachexia in Rabbits

Weight loss in rabbits generally becomes a cause for concern when the rabbit loses ten percent or more of its normal body weight, and the weight is determined to be more than simply the loss of fluid. If the weight loss accompanies a wasting disease, referred to clinically as cachexia and exhibited by loss of body mass, muscle atrophy, and loss of appetite, or is related to a condition where the rabbit is in poor health, is not eating well, and is experiencing general weakness, the rabbit will require prompt attention by a health professional.

Symptoms and Types

The signs and symptoms may depend on the underlying cause for the weight loss and cachexia. General signs will include a thinning of the body, a reduced size and appearance, and weakness. Other signs and symptoms may include:

• Dental diseases or abscesses (infections)
• Drooling, bad breath or problems when eating
• Signs of gastrointestinal diseases, which may include a lack of fecal production
• Distension or abnormal bloating in the intestinal area around the stomach, suggesting gastrointestinal disorders
• Masses or foreign bodies present when touching, or “palpating” the abdomen
• Signs of pain, which may include grinding the teeth, a hunched over posture, or an inability to maintain an upright posture. Pain can reduce the odds of eating or may reduce the rabbit’s ability to process the foods it does eat
• Abnormal breathing sounds, heart murmurs or irregular heart rhythms

Causes

Although weight loss and cachexia share the common symptoms of weight loss, diagnostically they are different in the respect that simple weight loss may be resolved by feeding the rabbit more calories, where cachexia is a loss of weight that often cannot be resolved with nutritional remedies.

There are many different causes for weight loss and cachexia in rabbits. For example, increased metabolism can lead the body to use lean muscle for energy in order to fill the need for increased calories to carry out daily functions. Other causes can include gastrointestinal hypomotility, abnormally slow movement in the gastrointestinal system. Cachexia, with its wasting of muscles and body mass, and chronic loss of appetite, can have more severe underlying diseases that are causing it. These can include metabolic disorders like organ failure, or disorders that are associated with cancer.

Some other common causes may include:

• Dietary causes, including too little food or poor quality food (malnutrition)
• Neuromuscular diseases and pain, including degenerative joint disease
• Spinal problems including spinal fractures or luxations (dislocations)
• Joint or facila infections, which can cause malformations, leading to problems with eating
• Dental diseases, which can make eating difficult
• Central nervous system disorders that can contribute to anorexia (inability to eat, loss of appetite)
• Diseases that promote protein loss in the body

Diagnosis

You will need to give a thorough history of your rabbit's health and onset of symptoms, whether the loss of appetite is sudden (acute), or has been going on for an extended time (chronic). In order to begin to make a diagnosis, your veterinarian will first need to determine how much your rabbit ate prior to the onset of symptoms.

There are several possible causes for this condition, so your veterinarian will most likely use differential diagnosis. This process is guided by deeper inspection of the apparent outward symptoms, ruling out each of the more common causes until the correct disorder is settled upon and can be treated appropriately.

Some of the more obvious reasons will be ruled out, such as the possibility of dental disease, one of the most common causes for weight loss. Your doctor will also look for evidence of obvious infections or metabolic problems, including organ failure that can lead to inflammation. Diagnostic imaging, like ultrasound and X-ray, can be used to help identify masses or cancers in the body, diseases that that are well known for contributing to severe weight loss or inability to digest food. If the cause is linked to loss of protein, the urinalysis may return with evidence of excess protein in the urine, which is referred to as proteinuria.