Fanconi Syndrome in Dogs

Fanconi syndrome in dogs refers to abnormal function of a part of the kidneys called the tubules. The tubules should reabsorb water, electrolytes and nutrients that would otherwise be excreted in the urine, but that are critical to normal metabolic function. In dogs with Fanconi syndrome, the tubules do not properly reabsorb electrolytes and nutrients, instead allowing them to ‘spill’ them back into the urine to be expelled.

This condition represents a major proximal renal tubular defect, which hampers the adequate reabsorption of glucose, amino acids, bicarbonate, sodium, calcium, phosphate, lactate, ketones and carnitine.

Untreated, a dog with Fanconi syndrome will generally die from the disorder. If caught early and put on the treatment protocol, affected individuals can do well. The earlier the disease is detected, the less damage is done to tissues and organs.

Causes of Fanconi Syndrome in Dogs

In canines, Fanconi syndrome is well known as a familial disease in Basenjis. Acquired renal Fanconi syndrome is caused by several drugs such as gentamicin, tetracycline and azathioprine, exposure to toxins such as heavy metals, infections such as leptospirosis and certain diseases such as primary hypoparathyroidism and copper associated hepatopathy.

It has also been reported as an acquired condition in dogs (chicken jerky treat ingestion, gentamicin nephrotoxicosis, and an idiopathic form) sporadically in several different breeds, including border terriers, Norwegian elkhounds, whippets, Yorkshire terriers, Labrador retrievers, Shetland sheepdogs, and mixed-breed dogs.

Symptoms of Fanconi Syndrome in Dogs

Dogs with Fanconi syndrome may demonstrate the following symptoms:

• Lethargy
• Vomiting
• Lack of interest in eating
• Diarrhea
• Excessive thirst
• Excessive urination
• Weight loss
• General weakness
• Seizures (in 15% of cases)

The severity of symptoms will be dependent how much of specific nutrients have been lost. And also whether your dog has experienced kidney failure. As the disease progresses, poor body condition may be seen. Should a dog develop the syndrome when he is very young, which is rare, abnormal bone development may occur.

Diagnosis

Your veterinarian will conduct a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis to test levels of sodium, potassium, glucose, phosphate, bicarbonate, and amino acids. An analysis of blood gases will also probably be used to determine whether the kidneys are functioning normally with regards to absorption. You will need to give a thorough history of your pet’s health, and onset of symptoms.

Treatment of Fanconi Syndrome in Dogs

If your dog suffers from Fanconi Syndrome, your vet will probably prescribe a specific supplement treatment for recovery. In the case of Acquired Fanconi Syndrome, the vet will also want to identify the cause and make sure that the dog has no further exposure to the toxin.

In either case, treatment is lifelong and must be maintained to ensure that the kidneys are working properly. You’ll also need to schedule regular visits with the vet to monitor the success of the treatment plan. Luckily, so long as Owners catch and treat it early, their dogs tend to live out a normal lifespan.