Friday, April 2, 2010

2. Hypersensitivity to insecticides?

I was surprised to see this Miniature Schnauzer in the Surgery. He had been vomiting a few hours after the mum applied a spot-on Promeris Duo insecticide. Some weeks ago, the dog had salivated a lot after the groomer had applied "Carington Dog Wash" but he had recovered.

"Many ticks infested his body. So my mum applied the insecticide on the back between the shoulders," the young slim lady said. "How did she do it?" I asked. She shook her head. "Did the dog lick the insecticide accidentally?" I asked. It was not possible in theory. But dogs can surprise human beings. It was possible tinhat he rolled and the insecticide touched his paws. Nobody knows. The other explanation could be that this dog was hypersensitive to insecticides. In that case, no more spot-ones.

"I advise a blood test," I said to this young lady who is a first generation migrant and must be doing well in her career since she works at a central business district office.

"Do you think it is necessary?" she asked. Blood tests cost money.

"Blood test will tell us whether the kidneys or livers are affected as vomiting can be due to disorders in the two organs." I said. "It is up to the owner. I have to advise just in case the dog dies. When the dog dies, some owners begin to question the vet's competence as to why the vet did not propose a blood test."

She phoned her mother and permission was given. Blood test revealed higher than normal blood urea. My assistant, as usual for all assistants, advised the mum that the elevated blood urea was not serious. This advice from assistants sometimes can contradict the vet's advice and cause a lot of unhappiness. Unfortunately, the assistant who may be a veterinary graduate in their own country but whose degree is not recognised in Singapore needs to learn from one bad complaint before he or she shuts her mouth. So far, my assistant had not suffered such complaints and therefore he had to say something now and then. Besides the owner was from his own country. I will talk to him.

Although blood urea results were not excessively high, my assistant could not understand that the results were taken at a "point in time". The kidney disorder may be at the beginning stage. Therefore, the results were not very high. To advise that the results were not serious was to give false hope to the owner.

This is where experience and many years of living and practice comes in. The dog was given an IV drip to dilute the poison. He was active and lively when he went home later in the evening. I advised the owner that the dog cannot be given insecticide anymore in case he dies the next time from hypersensitivity (allergy). "What should I do?" she asked me. "Use the not so potent dog insecticide shampoos but they are not so effective. This may be one alternative." There did not seem to be any point in using impotent anti-tick alternatives. "Well, you could make the dog wear boots," I advised. She went home with a happy dog.

As if the God above was teaching my assistant a lesson, this Schnauzer vomited 5 times after going home. "Why the vomiting?" the owner asked him. They were more comfortable talking to him but I was OK if they wanted to ask me.

It could be that the dog had not fully recovered from his kidney damage. He could have gastritis from licking the insecticide and had not recovered. One interesting medical finding was that his hard palate had 3 ulcers of around 0.5 to 1 cm in diameter. I opened his mouth widely to examine every part of his mouth and tonsils earlier on at the beginning of consultation.

It is important that the vet examines the mouth of a vomiting dog. I was so surprised to see hard palate ulcers as they are rare. Very rare. What was the cause of these ulcers? Were they incidental findings? Were they erosions from licking the insecticide or were they the results of hypersensitivity to the insecticide? Nobody really knows. Only the dog knows whether he had been licking the insecticide and vomited as his stomach got ulcerated by the poison.

It is important that the dog owner be shown the hard palate ulcers. I asked the young lady to hold and shine the torchlight onto the hard palate to see the 3 ulcers, a rare finding. She saw them. The dog resisted as he was wiser the second time I tried to open his mouth again for my assistant to see the ulcers. I pushed his tongue outwards to see the tonsils. They were slightly inflamed. The Schnauzer did not bite and so it was all right. However he was not going to permit his mouth to be opened the 4th time and I did not persevere.

My assistant must also be taught as part of his job to perform a thoroguh oral examination of the dog in cases of vomiting. He is a vet in his own country and should learn as much as he could. One day he might open his practice and he should be well trained in Singapore. I have to teach him the tricks of the trade as his professors could only give theoretical knowledge due to lack of real dogs during lectures.

This case study showed that blood tests are important aids to diagnosis of a vomiting dog. Also that vet assistants ought to keep their mouths shut by not advising on blood test results and other examinations in order not to confuse the dog owner who is already highly stressed out by the vomiting. This tendency of assistants to advise owners is common and not peculiar to my assistant and the only lesson they can learn to keep their mouths shut is when they get into trouble. Human beings learn from mistakes made. I did talk to my assistant about giving advices to dog clients but this time, he had forgotten.

Is this a case of hypersensitivity to insecticide? It is hard to say definitely. There was the hard palate ulcers which might indicate that the dog had had licked the Promerus Duo insecticide. For example, the owner might have applied the spot-on from between the shoulder blades to the tail as is commonly done. The dog might have rolled onto the floor and got the wet insecticide onto its body. The strong smell ensured that he licked it vigorously, causing hard palate ulcerations and possibly stomach ulcerations. So he vomited before and after seeing me. If that is the case, this dog is not hypersensitive to insecticides and there should be salivation (if the owner had seen it). In the first incident, the owner saw the salivation.

What should be done when the owner applies spot-on?
1. Put the spot-on between the shoulder blades and forward to the base of the skull, instead of backwards to the tail. This will be the recommended method to prevent any spillage onto the dog's body.

2. Bring the dog out for a long walk after application so that the insecticide dries up. Most owners in apartments probably applies the spot-on and leave the dog alone at home.

If the application was not done correctly, the vomiting in this case was not due to hypersensitivity to insecticides and adopting the above 2 procedures will ensure no vomiting or salivation in this well beloved and gentle Miniature Schnauzer.

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