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Pepsi is a beautiful eight year old flat coat retriever. Pepsi was first seen by Veterinary Surgeon Louise Simpson as she had become slightly lame on her hind limbs, and she was behaving strangely. No spinal pain was found and on a neurological exam, nothing abnormal was observed. Pepsi was prescribed anti inflammatory pain relief, rest and was due to have a recheck later on that week.

However, a few days later Pepsi’s owner brought Pepsi back in to see us as she had gone downhill. She was now inappetant, her gait still seemed abnormal although she was no longer lame, and she had developed a high temperature. A high temperature could be due to bacterial or viral infections, or an immune mediated condition. The decision was made to admit Pepsi to our hospital for further investigations.

That day, Pepsi had an abdominal ultrasound and abdominal and chest xrays in house. We also ran extensive blood tests in our laboratory. Nothing particularly abnormal was found, except slight anaemia on her blood results. Pepsi was started on intravenous fluid therapy to replenish the fluid she would have lost from not eating for a couple of days and to bring her temperature down, and was also started on intravenous antibiotics. Her cough was becoming more productive so, using our bronchoscope, we examined Pepsi’s airways, which looked normal except an overproduction of saliva and mucous. While many of her symptoms improved over two days, her mobility worsened, and she become very reluctant to get out of her bed. 

Our Veterinary Surgeons had a meeting regarding Pepsi’s case and came up with a number of potential diagnoses, including tick bourne diseases, Immune-Mediated PolyArthritis ( a disorder of the immune system leading to inflammation in multiple joints) and Myasthenia Gravis (an autoimmune condition that causes muscle weakness and muscle fatigue).

The decision was made to perform a joint tap, whereby a sample of the synovial fluid (fluid within joints) is collected. Synovial fluid analysis is most useful for differentiating normal or degenerative (i.e. osteoarthritis) joints from joints with inflammatory joint disease (septic and immune-mediated). The results of Pepsi’s joint tap confirmed the diagnosis of Immune-Mediated PolyArthritis.

Pepsi was started on steroids to suppress her over active immune system, and she was sent home to continue with these and her antibiotics and anti inflammatories. Later that week Pepsi began to scratch and rub her face, and soon her skin started to bleed and become ulcerated. Soon her whole face had lost all the hair and the skin was very sore and peeling. It is still unknown whether this was a very rare reaction to one of the medications or if it was something to do with her immune mediated condition.

One month on, Pepsi is doing great and is back to her beautiful self. She will continue on her steroids and then we will gradually reduce the dose in the hope that eventually Pepsi will no longer need them. Most dogs with immune-mediated polyarthritis are treated for several months with immune-suppressive medications; some may be able to be weaned off completely, however some dogs may need to be on them for life.