CALCIUM OXALATE UROLITHIASIS IN A CHIHUAHUA

The 6-year-old male Chihuahua was in excellent body condition. Lots of good food had given him a padded body. He stayed in an apartment and seldom went down for exercise.  Around the beginning of December, he stayed with another family member - the brother. At the brother's apartment, he was shut out of the bathroom which he normally used as his toilet. 

As At Jan 20, 2009. Instead, the brother took the dog outdoors to pee. The dog took a long time to pee. Sometimes he took 2 hours to pee. But the dog could not pee normally in Jan 20, 2009. Urinary stones blocked the flow of urine as I could not push the catheter into the bladder easily. "There is a need to analyse the urine under the microscope for urinary stones, cells and infections," I advised the owner. As the dog could pee, the owner did not want any tests as it would add to the costs of veterinary service. 

"If he can't pee, I will have no choice but put him to sleep as it is too costly to treat him," he laughed. I could not persuade him to take urine tests. Clients have freedom of choice but they must be adequately advised and such advices are best put in writing to prevent miscommunication and mistrust in a litigious society.

"Do not worry, my family will not sue you," he laughed when I told him that the problem of difficulty in urination would recur and some family members might be unhappy with no tests being carried out.

Unhappy people see an opportunity to sue the veterinarian to gain money for "incompetent" services and negligence and to prevent other dogs from suffering the same fate of negligence. In such cases, the vet ought to give the owner a written statement that he had had been forewarned about the prognosis. I did not do it but would record this advice in my medical records.

On the 10th day after the first consultation consultation, the dog could not pee at all. "My dog did not really pee normally for the past 10 days," the slim man in his late 30s commented. Urine tests and X-rays were permitted and done.

Surgery on Jan 30, 2009. Two Calcium Oxalate urinary stones removed from a dark red bladder with walls as thick as 0.8 - 1.0 cm. Normal bladder walls are around 0.2 cm. The urinary stones could not be palpated via the bladder as they were too small and the inflamed bladder was too thick. In any case, such a thick bladder wall would prevent palpation to be done properly. The dog was hospitalised till Feb 10, 2009 when he could pee normally. 

What happened after the dog went home? The following record is a follow-up as I met the owner at the Surgery on March 4, 2009.

At home in a high-rise apartment from March 4, 2009

1. "The dog dog urinated all over the kitchen floor for the first 4 days at home," the owner revealed his observations. "He drank a lot and peed a lot. I told him to pee onto the grating (drainage hole cover) in the kitchen.

 "He is an intelligent dog and by the 8th day, he peed at the grating. He is now back to normal in peeing."

2. Going outdoors. The owner said, "I make sure that I bring the dog down to the grass at least once a day, particularly in the morning. I want to see that he pees in a large amount all at once. If the dog is indoors, he will stand on  the kitchen grate to pee."

3. Urine marking. "Nowadays, after the surgery, the dog would pee a lot all at once when brought down. Then he would lift up his leg to mark but sometimes a small amount of urine would come out. Other times, nothing. Prior to surgery, he would pee a little bit at a time. I had to wait 2 hours to ensure that he urinates completely. Other dog owners were puzzled as to why my dog takes such a long time to pee. Now, there is no need."

The owner had time as he was self-employed. I don't really know what he was doing in his profession. He is a happy-go-lucky man in his forties, in my observation and sends out good vibrations.

4. Mum's complaints in the past. "For some weeks, mum had complained that she needed to wash the toilet floor many times" the man said to me in retrospective analysis. The dog used to stay with the mum in another apartment and would use the toilet floor to pee as he had been doing so for the past 6 years.

Mum would then flush the floor with water as family members had to use the toilet. But lately, mum had to do it so many times. Nobody had thought of bringing this dog for a veterinary check up. Other dog owners had also asked the man when he took over the dog to live with him in December 2008, "Why your dog takes such a long time to pee?" 

"As long as two hours outdoors," the owner would wait patiently for him to pee all his urine. This behaviour is not normal but the owner did not think it was abnormal.
 
5. Sorrowful demeanour. "I can't remember why I brought this dog to see you," the owner said when I asked why he consulted me in the first instance.  "It must be because the dog was sorrowful."

10 days before the day of surgery on Jan 10, 2009, the owner consulted me because the dog had difficulty in urinating. The urine was cloudy. The dog seemed to be incontinent, leaking urine drops onto my consultation table. The urethra was blocked. Catherisation of the urethra lead to easier urination. The owner was not keen on X-rays and blood tests then due to the need to save money. Since the dog could urinate, he wanted the dog home. However, I did warn him that there would be the same dysuria again as the urethra was obstructed when I passed the catheter into the urinary bladder with great difficulty.

10 days later on Jan 10, he consulted me as the dog could not urinate. "The dog had never peed normally since I got him home," he said. Catherisation of the blocked urethra enabled the dog to pass golden yellow. The smell of urine ammonia was strong, as if, the toilet bowl's urine was not flushed for 24 hours.

This time, the owner was agreeable to urinalysis but no blood tests (complete cell count, serum chemistry) and X-rays. Veterinary costs can add up to a large amount and I understood his financial concerns. This recession would be the worst in decades, according to all the experts. 

6. Urinalysis. Calcium oxalate crystals + were the significant finding. See blood test report above.

7. X-Rays. As no big stones were palpable and the bladder wall was considerably thickened, it would be wise to X-ray the bladder to see how many urinary stones were present. The owner consented. Calcium oxalate crystals are radio-dense and 2 were easily seen on the X-ray. If no X-rays were done, the owner would feel that the bladder stones were not all removed should there be a recurrence of difficulty in peeing. Therefore, X-rays are advisable except in certain cases where the urinary stones were so large that they were palpable. This is because the owner may want to reduce veterinary costs. Every test add up to the high costs.

8. Surgery. In this case, 2 stones were seen on the X-ray. It was extremely difficult to pick up the 2nd stone as both stones were around 0.5 mm in diameter and the bladder incision had to be as small as possible. A big bladder incision would not be good for the dog.

Extremely thickened bladder wall indicated that the bladder had been infected by bacteria for several years.

The infection had caused the bladder to thicken and thicken its wall to fight against the bacteria. It was a losing battle and therefore the bladder became severely reddened and swollen.

The mum was not aware of the need to get the dog examined when she had to wash the bathroom floor so many times a day - a change of the dog's behaviour.

 In retrospect, her complaint of having to flush the toilet floor many times recently would be a clue to the urinary tract infection. Mum used to clean the floor once a day previously. Mum's complaints "Must clean the floor many times. The dog did not urinate in a big amount." Therefore frequency increased while urine volume decreased per occasion.

9. Post Surgery. Today is Mar 4, 2009. Surgery was on Jan 30, 2009. The owner was now satisfied and pleased that the dog's first urination in the morning when brought outdoors was a big volume, as in the past. "There is a very small wound which seems not to heal," the owner commented. It was difficult to know what he was saying as he did not bring the dog in for consultation. Overall, he was happy so far as his best friend was living a normal pain-free life now - not having intense pain when passing urine and therefore taking a very long time to pee. Now, the dog just urinate one large volume at one go and get on with enjoying his outdoor exercise and urine-marking (with little or no urine to mark).

As at Mar 4, 2009.
Home-cooked food. Dog drank normally and not a lot as in the lst 4 days home. Urine-marking downstairs where other dogs had been. However little urine production or none at times. I said, "The dog may start to leave more urine inside his bladder in time to come. Then stones might form again."

I asked the owner to monitor the urine intake, colour and consistency over 24 hours. The dog was banned from the bedroom because he would "pee" onto the mattress which had to be thrown away. Doors would be locked. He would pee at the kitchen drainage grate but the owner would always bring him outdoors in the morning so that he could pee all urine at one go within the first time. He continued to urine-mark with little urine as this is the natural behaviour of male dogs that have not been neutered. The dog has to pee on the spots to over-ride the smell of other dogs - to mark his territory.

Conclusion
X-rays are necessary before surgery in this case so as to know how many urinary stones are present in the bladder.  Calcium oxalate crystals are radio-dense and will be easily spotted on X-rays. Due to financial considerations, no X-rays were done after surgery although this is recommended. Two stones were shown to the owner as evidence. It is best to produce evidence to educate the owner.

Urinalysis is also necessary. There is no guarantee that urinary stones will not be formed again. Unlike struvite (triple phosphate) urinary stones which form in the presence of alkaline urine and bacteria, calcium oxalate crystallisation is not related to the alkalinity of urine and therefore acidification of the urine in this case is not advised. If you review the blood test report, the dog's urine was acidic actually.

Will the special Hills' urinary stone prescription diet to prevent calcium oxalate crystallisation work? One veterinary book doubts this will help.

The owner feeds home-cooked food, so the answer in this case will not be known for some time. For other dog owners, it is advised that you get your dog examined by your vet at the first sign of difficulty in peeing as it is much more inexpensive to get early treatment than surgery and hospitalisation.

As at Mar 23, 2009. No complaint from the owner. This case may be one for neutering of the male dog. This male dog needs to urine-mark his territory. He tries to retain some urine to urine-mark. Retention of urine causes crystallisation and bacterial infections of the bladder wall. Urinary stones form. Urine flow gets obstructed in time to come. Can't pee normally again. It is hard for the dog owner to envisage the sequences of physiological events. Therefore advices to neuter this dog fall on deaf ears. I hope for the best for this dog. He would definitely be well cared for and much loved by the brother. If his health is good, he should live to a ripe old age of 15 years.