November 16, 2015
His name was Chipotle. A mismatch for a name if ever I saw one. The timid salt-and-pepper curly coated little Shih Tzu weighed in under 20 pounds and his tail trailed after him over the floor as he puttered around the exam room. Happily I noted that he wasn’t sweeping up any dust balls. There was nothing of a fiery chili pepper about him and I wondered briefly how he got his name. Then he looked up at me. Oh dear. Under long eyelashes I could only see matted hair and mucous covering what should have been his luminous eyes.
I scooped him up and brought him closer to me on the exam table. He stood quietly, the little feather duster tail wagging slowly as he gazed blindly up at me. Both eyes were covered by a sticky, thick layer of mucoid film, which covered a thick coat of brown pigment overlying the corneas. The whites of his eyes were streaked red from inflammation. They looked very painful. Chipotle cocked his head as I bent over him, using an ophthalmoscope (kind of a fancy flashlight) attempting in vain to penetrate deep into the back, or fundus of his eye, where the optic nerve is. But the pigment was so thick over his eyes that I couldn’t see more deeply.
I finished his examination, noting that he also had a chronic ear infection but that over-all he was in good shape, with an excellent weight and coat. I turned to his owner, an earnest man who had recently relocated to our town and was very anxious to find out what was wrong with his dog. To my surprise, he had actually been treating the dog with a prescribed medication. The owner knew it wasn’t working. He had been using it for so long I wasn’t sure if the original problems with the dog’s eye condition might have started out as something else and now changed. Certainly this medication was not effective.
I explained to Chipotle’s owner my thoughts about his eye lesions and discussed the diagnostic tests we needed to perform. First on my list was a Schirmer tear test. Special tiny strips of sterile absorbent paper are gently placed just inside the eyelid for 60 seconds. The paper wicks up the liquid in the pet’s tears. The strips are measured in millimeters, already marked on the strips. Anything over 15 millimeters in 60 seconds is normal. Anything less than 10 mm is suspect for a condition called “Dry Eye” or Keratoconjunctivitis sicca (KCS).
KCS is a horrible condition. For reasons often unknown, frequently ascribed to a problem with the immune system, the dog’s eyes have stopped producing tears from the lacrimal glands. In normal eyes, every time a pet blinks the surface of the eye, the cornea, is covered by a thin film of tears that keeps the cornea moist. Without tears the cornea dries up. Ulcers or holes in the corneal surface may occur. Over time brown pigment covers the dried cornea and that thick ropey mucous appears. The dog will go blind. Every bit of this process is extremely painful.
Chipotle flunked his Schirmer’s tear test. His right eye had a score of 2 mm, his left zero. We also ran a blood panel to rule out immune associated disorders like thyroid disease, diabetes mellitus, lupus and other diseases. Chipotle’s blood tests did not show a clear cause for his KCS.
The recommendations for Chipotle were to clean his eyes of the thick mucous at least twice a day with a sterile saline solution, found in over-the-counter contact lens cleaning products. This would allow his topical eye medications specific for KCS to penetrate better. There are at least two medications used to stimulate tear production in the dog (sadly, they are not terribly effective for the rare cats who develop this disease) : cyclosporine and tacrolimus. Both require twice daily application for the rest of the dog’s life. Eye infections, ulcers or other secondary corneal diseases may require additional topical medications. It’s a daunting prospect to face the requirement to treat your dog twice daily, every day, forever – or he’ll go blind.
Chipotle’s owner was committed to his little dog, but seemed apprehensive about actually using the medication. “He’s mean”, he said. Huh? This little droopy dog? Since I do this for a living I offered to demonstrate how to apply the medication. Which was the precise moment that Chipotle earned his name, as he came to life with a fierce burst of barks. Fiery indeed! Shih Tzu’s are blessed with small, rounded teeth and I’d be pretty embarrassed to be bitten by one (did I put that in writing?). It wasn’t too hard to devise a treatment method and off they went. On recheck 4 weeks later I was startled by the transformation in this little dog! His corneas were still covered by the brown pigment, though that would thin over the coming year, but the mucous was gone. His Tear test was over 15 mm in both eyes. Clearly the pain was gone, as Chipotle bounced all over the room, tail swishing wildly. Most miraculous of all, his bad temper at home about “medicine time” was gone and his owner confirmed that he had his “old dog back”.
Christine B. McFadden, DVM