Friday, December 9, 2011

763. Pupillary light refex - A paralysed Shih Tzu

Yesterday, Dec 8, 2011, I was consulted about a Shih Tzu that was "paralysed". The sister had phoned me on Dec 7 for a 3rd opinion and I had asked her to send the dog in for examination as it is difficult to know what is going on by phone diagnosis.

The dog was treated by Dr Vanessa on Dec 7 and so I asked her where was the area of pain. I had seen the dog lying sideways in the crate. My assistant Min said Dr Vanessa had treated the dog. She came in around 11.30 am. I was about to talk to Dr Vanessa when the brother came in. This was the best time as it is always good for the owner to be involved in the examination.

AREA OF SPINAL PAIN
The dog had been treated by Vets 1 and 2 with steroids and so the area of spinal pain was not specifically known to Dr Vanessa when she received the dog. "Which area of the spine is painful?" I asked her since she had given a steroid injection and any pain would be masked.

The dog was able to lift his head but was unable to stand on four legs and that was definitely injury to the central nervous system. "Slight pain is further to the back area," Dr Vanessa said. It would be difficult to diagnose pain in the spinal area when the dog had been treated with pain-killers by Vets 1 and 2. Their medical records were brief. Acupuncture was done by Vet 2. But both of them had not done any X-ray. Later in the evening, the sister who had taken the dog to the vet spoke to me and said that she was given the choice of "X-ray" and/or "MRI."

There seemed to be some miscommunication here. Since I did not speak to Vets 1 and 2, I would presume that they had advised X-ray and the owners had opted out but the owner had said she was not a professional and should not be given a choice. It is extremely difficult nowadays. I usually advise X-ray in such traumatic cases and if the owner declines, I will record it down in my medical record. This is to avoid this type of "mis-communication".

For this report, I would focus on the pupillary light reflex done on the Shih Tzu in the presence of the brother. A bright light was shone directly on each eye to check the consensual and direct pupillary light reflex

DIRECT EYE REFLEX
Left eye - pupil does not constrict
Right eye - pupil constricts
So, what is the problem?

See notes from Wikipedia below.



Clinical significance

In addition to controlling the amount of light that enters the eye, the pupillary light reflex provides a useful diagnostic tool. It allows for testing the integrity of the sensory and motor functions of the eye.[1]

Under normal conditions, the pupils of both eyes respond identically to a light stimulus, regardless of which eye is being stimulated. Light entering one eye produces a constriction of the pupil of that eye, the direct response, as well as a constriction of the pupil of the unstimulated eye, the consensual response. Comparing these two responses in both eyes is helpful in locating a lesion.[1][5]

For example, a direct response in the right pupil without a consensual response in the left pupil suggests a problem with the motor connection to the left pupil (perhaps as a result of damage to the oculomotor nerve or Edinger-Westphal nucleus of the brain stem). Lack of response to light stimulation of the right eye if both eyes respond normally to stimulation of the left eye indicates damage to the sensory input from the right eye (perhaps to the right retina or optic nerve).[1]

Emergency room physicians routinely assess the pupillary reflex because it is useful for gauging brain stem function. Normally, pupils react (i.e. constrict) equally. Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates.

Normally, both pupils should constrict with light shone into either eye alone. On testing each reflex for each eye, several patterns are possible.[6]

Optic nerve damage on one side: (Example in parens.: Left optic nerve lesion)
The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, neither pupil constricts, as no signals reach the brain from the left eye due to its damaged optic nerve)
The ipsilateral consensual reflex is INTACT (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)
The contralateral direct reflex is intact (because light shone into the right eye can signal to the brain, causing constriction of both pupils via the normal oculomotor nerves)
The contralateral consensual reflex is lost (because light shone into the eye on the damaged side cannot signal to the brain; therefore, despite the right eye's motor pathway (oculomotor nerve) being intact, no signals from the left eye are able to stimulate it due to the damage to the sensory pathway (optic nerve) of the left eye)

Oculomotor nerve damage on one side: (Example in parens: Left oculomotor lesion)
The ipsilateral direct reflex is lost (Example: when the left eye is stimulated, only the right pupil constricts)
The ipsilateral consensual reflex is lost (Example: when the right eye is stimulated, only the right pupil constricts)
The contralateral direct reflex is intact (because light shone into both eyes can still signal to the brain, and the pupil on the undamaged side will still be able to constrict via its normal oculomotor nerve)
The contralateral consensual reflex is intact (because light shone into the left eye can still signal to the brain via the normal optic nerve, causing attempted constriction of both pupils; the contralateral pupil constricts via its normal oculomotor nerve, but the ipsilateral pupil is unable to constrict due to its damaged oculomotor nerve)

I will write more later

Wednesday, December 7, 2011

782. The cat with foul-smelling ears claws the owner ferociously

"My cat cannot walk properly, hunching her back and not walking normally with the hind body upright. What is the problem?"

The cat walked with hind limbs low on the floor as if stalking a prey. Hind limb lameness. Why?

As I did a full body check, the cat's ears were strongly smelling of bad rotten flesh. "Did you get the ears treated?" I asked the lady.

"I consulted the vets (at another practice) twice," the woman said to me. "They give me ear drops. The cat scratches me when I tried applying the ear drops. I gave up."

On the surface, it seems that ear infections and lameness are not related. Yet if you think about being a cat. What would you do if you have such painful smelly ears over the last few months? You would try to relieve your itchy ears with your back paws. Both ears. Both paws. You do it so often and over the months. Would you not strain your hind limbs and joints? Ear drops were not applied. You claw your owners for doing it. So, in time, you feel the back pain in trying to relieve your ear itchiness and hurt your back muscles. So you slink when you walk. Can't walk upright. A hypothesis.

That's my theory. "I will sedate the cat after a day of antibiotics and anti-mite injection," I said to the owner. It was a surprise to her that I had proposed this approach as she expected me to prescribe "ear drops".

Today, 2nd day. The ear stench was much reduced. The cat still clawed but much less. The right ear had lots of wax and debris. Will irrigate the ears under anaesthesia and hope that this will help the cat not to sufer any more pain. The last option would be surgery to open up the vertical ear canal. But not now. Wait and see after ear irrigation and painkiller/antibioitc medication which is a simple way.

781. The father's day present

Yesterday, Tuesday, I worked past 7.30 pm and at 5 pm, I met a senior citizen who brought in a gold and white Shih Tzu of around 8 months old, with a bleeding toe nail. Dr Vanessa had treated it and bandaged the left hind foot.

"I better not do it myself next time," the taxi driver told me.
"Why did you buy this gold and white shih Tzu?" I asked.
"My son bought it for me," he said. "A present on Father's Day. From his friend."
I was surprised that the undergraduate with a scholarship would buy such a big responsibility for his father.
It was a good gift since the father loved the dog. "My wife used to dislike dogs," he told me. "But after getting this one, she loves dogs."
"That is great news," I said. "How is his toilet training?"

"I put his urine on the newspapers and he just go to the papers every time he needs to pee and poop," the father held on tightly to this high-maintenance dog.
"This is an intelligent dog," I said. "However, he is very thin. Feel the sharp spines," I showed the father. The thick luxuriant coat had covered up the thinness of the body.
I advised adding dry dog food to the usual canned food, at 80% dry food and the dog would put on weight. The son is good as now his parents have some company in an empty nest. Aged parents become "children" nowadays and so it is good that the dog keeps them company.

780. The 1.5-year-old cat started spraying his urine is under the scalpel today

Wednesday morning.

A mother and her teenaged daughter rushed in with an older male cat for neuter. An "orange" cat that resembled the other one I wrote about last time. The same colour. That one bit the mother's hand while the mother was preventing him from the stray cat.

As time is precious to Singaporeans, I told the mum to go to Toa Payoh Hub with her daughter (school holidays) for one hour and come back instead of going home and come back again. She lived in Simei which is around a 30-minute drive away. "There are other clinics nearby your condo," I said. For some reason, she preferred Toa Payoh Vets and I was quite surprised.

"319074" was the postal code I had given to her when her daughter phoned the Surgery for the "pin number" as her driver mother could not locate my surgery. Nowadays, it is so easy if you have the GPS to locate places.

ANAESTHESIA
Weight: 5 kg
Xylazine 0.15ml + Ketamine 0.6 ml = 0.7 ml IM in one syringe.
Waited 10 minutes. Needed isoflurane gas 5% top up for less than 30 seconds. This shows that the dosage is a bit low for 5-kg cat. Should be xylazine 0.2 ml + Ketamine 0.8 ml without the need of topping up with isoflurane gas.

I ensured that whole scrotal and surrounding area has been plucked clean by Min and showed him how it could be done. Cleaned up scrotal area. Horizontal cut exposed two testicles. Removed them. Washed away the blood. When the owner came 2 hours later, the horizontal would appears to close together, so no bleeding or wound is seen. I asked Nicole to take a video and to record oral instructions of post-neuter care for video production. Hope this will turn out very interesting.

I asked my assistant Nicole to take some pictures to prepare a video on how to care for the cat after neutering. I had a rare case of a male cat's scrotal wound not healing some 14 days after neuter by Vet 1. So, these two cases would be able to illustrate the educational video on "post op care after neutering."

"You need to be a good story teller to connect with the audience viewing your video," I said to Nicole. "A good story is usually one where the viewer wants to know what's happen to the protagonist. For example, the video of FIV in a stray cat done by the two Temasek Polytechnic Vet Tech students. Do you find it engaging?"

"Yes," she said.
"Now, if you produce a video of 100 FIV cats with all their diseases, would that make it an interesting education video on FIV in cats?"
"No," she agreed.
"Similarly for the video on Caesarean sections produced by you for the 'Responsible Pet Ownership' video. There is no connection showing many picures of the dog and puppies after Caesarean section in the video. I would have shown the Maltese about to go under the Caesarean section. What happened to her. Did she give birth or not? Were all puppies alive? What happened next? Instead, several images of other dams and puppies after Caesarean sections were in the video."

I give free rein to the young ones to be hands on in producing the videos and that is how they learn. If I spoon-feed, they learn nothing.

759. Health screening for an 8-year-old Silkie

"You have got your money's worth today," I said to the strict-looking wife as my assistant expressed more than 5 ml of road-tarry grey granular oil from the 8-year-old solid body male neutered Silkie Terrier. "For the past 8 years, no groomer or vet had expressed his anal glands and the normally light yellow oil had turned grey. I am surprised that the dog had not bitten his tail or his backside."

Showing what is wrong is important in vet practice. The woman in her late 30s and her taciturn husband smiled a bit. Humour is sometimes important in connecting with new clients. They were from Woodlands. The wife wanted a health check up from me and had made the appointment the day before. Vet 1 had told her that her dog suffers from Grade 1/2 heart murmurs and so she would want me to give a complete check. "The heart murmurs are confirmed," I said. "But it is not serious since your dog has no coughing or loss of energy." That was good news. "If you want X-ray to see whether the heart is enlarged and the lungs are normal, let me know." The left femoral pulse was of poor quality but I have to check again this Sunday.

"Is it necessary?" she asked.
"No," I said. "It is advised as there are no signs of heart disease.

"There are so many new practices with beautiful furnishings and furniture," I compared my older premises to such new practices and asked where she would come quite far to consult me. Many Singapoean pet owners are impressed by new clinics with their shine. "New furnishings are not important," the wife said to me. "It is the vet's experience."

PHYSICAL EXAM - normal despite complaint of the dog turning his neck to the side sometimes. A painful throat but the dog disallowed mouth opening. He would twist and turn whenever I tried to pry open his mouth. "I will check for infection or tumours of the tonsils and the back of the throat during dental next week," I recorded this finding.

BLOOD TEST - ALT increase double the higher range. Liver or muscle damage but this will need another test.

URINE TEST - "Not a chance that my dog had peed this morning," the wife said to me. "We watched him closely and brought him straight to you from Woodlands." Yet when I passed a urinary cathether into the small bladder, I could get around 10 ml of urine. Why?

Results - Bacteria 3+, protein trace, bilirubin +, SG high, pH 6.5, casts but no urinary crystals. Only the bacteria count was considered significant.

"Your dog may have cystitis - a bladder infection," I said to the wife by phone. The dog was neutered very young at 8 months and his belly and neck were pigmented due to scratching. As to the cause of this black skin pigmentation, it is hard to say but it resulted from skin scratching over a long time of years.

"Does he need antibiotics?" she asked.
"I did give you some baytril tablets 2 days ago for dental scaling, to kill off bacteria in the mouth 7 days before dental scaling," I said.

"Is my dog fit for anaesthesia since he has liver disorder?" she asked.
"The ALT enzymes are not very high and the dog has good appetite. He should be OK for anaesthesia this Sunday."

Today is Wednesday. I will do the dental scaling this Sunday. Overall, the dog has passed his health screening.

758. A dog owner asked about post-op spay care from Dr Sing

Pre-Operation Guidelines for Spaying your Dog.

. The best time to spay your female dog is 2 months after her heat and at an age over 6 months

• Schedule an appointment with your vet. A blood test to screen your dog's health is advised one day before surgery.
• Make sure your dog is healthy, eating & drinking well for the past 3 days before surgery
• Give your dog a good bath, and wash the surgery area well the day before surgery

• Your dog should not eat or drink after 10pm the day before surgery, or 12 hours before surgery to prevent vomiting and choking during anaesthesia
• Bring your dog to the vet in the morning so that you can collect it in the evening after the day surgery.

Operation Procedure

• Your dog will be weighed and examined before surgery.
Isoflurane gas anaesthesia and/or an injectable anaesthesia will be given according to your dog’s health and temperament.
• The spay operation take about 30 minutes if there are no complications like bleeding


Post-Operation Guidelines for Spaying you Dog.

Frequently Asked Questions

1. What kind of food do I give, and when can I start feeding her?
If you take your dog home on the evening of the operation, it’s best to feed your dog the next day as there will be a possibility of vomiting due to the anaesthesia.

2. When can I bathe her?
Wait at least three days before bathing your dog. Cover up the wound with a water-proof plaster before bathing.

3. When do we remove the stitches?
Some vets use dissolvable stitches which will dissolve on its own, however, the vet may instruct you to return after 14 days to remove any remaining stitches.

4. What do I do in an emergency, or if the stitches break down?
If there is minor bleeding after a stitch tears apart, bandage the wound and bring your dog back to the vet as soon as you can. In case of emergency when the intestines can be seen or there is heavy bleeding, call your vet immediately.

5. When can I take off the Elizabeth Collar?
The E-Collar must be worn for 24 hours for 10-14 days, or until the stitches are completely removed.

6. Change the plaster protecting the wound on Day 2 if the vet has used a plaster.

7. Give pain relief and other medication as advised.

Tuesday, December 6, 2011

4-month-old red poodle scratches his ears vigorously

Today, Tue Dec 6, 2011, I was surprised to see a trim couple in their late 20s all the way from Sengkang wanting to vaccinate their puppy (3rd vaccination). The puppy was bought from a groomer in Pasir Ris with scales like dandruff in the legs and ears and ear edges.

"My puppy keeps scratching her ears vigorously," the wife said. The edges of both ears had fine scales. The ear pinnae, the four legs also had lots of scales. What's the cause?

SKIN SCRAPINGS 3 AREAS
I suspect scabies. I used a new scalpel blade and scrape the skin of ear edges and the paw. No ringworm. No mites seen under the microscope.
"No mites can be seen as it is possible that the experienced groomer-breeder has had treated this puppy," I said. "The mites are deep under the skin and that is why they are so irritating as they tunnel under the skin and breed."

No proof of mites but I could demonstrate the ear scratch reflex. I rubbed the edge of the right ear and the right hind limb starts to wriggle and ready to scratch the flank and chest.

GRATE + PEN TRAINING.
The puppy was paper-trained in a confined area for the first 5 days but started accidents as the wife decided to widen the space for the puppy. "It should take 14 days of close confinement to succeed in paper training," I said. "The puppy can go inside the crate (grate+pee pan) as a toilet or living den. However, the couple bought a grate + pee pan. It worked. So good.