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My dog is lethargic and pupil won't dilate after dog collision.

Updated on September 23rd, 2025

Pet's info: Dog | Greyhound | Male | unneutered | 7 years and 10 months old

My dog collided with another dog yesterday morning and his tooth came out, he's been acting very lethargic since. Even more today. His eye on the side of where his tooth has come out is not dilating (his pupil) his other side is. There's yellow/brown on and in the hole where his tooth was, think there maybe an infection. But I'm most concerned about him being extremely lethargic and his trauma side pupil not dilating? It is slightly but not as much as the other side. I've shone a light onto them

2 Answers

Most Helpful Answer

Jennifer Summerfield, DVM CPDT-KA

Answered By Jennifer Summerfield, DVM CPDT-KA

Veterinarian, Certified Dog Trainer

Published on April 26th, 2017

Poor Beau! The eye not dilating is likely a sign of significant head trauma, which also makes sense if he lost a tooth in the collision - it normally takes quite a bit of force to cause this! It sounds like Beau may have a concussion or other serious head injury, and it also sounds like his tooth socket may be infected - especially if part of the tooth root is still present.

These things will need veterinary care right away, so I would recommend taking him to the vet today to be checked. Your vet can do a complete neurologic exam to help determine how serious his head injury is, and will also evaluate his mouth to see if he needs surgery to remove any remaining part of the tooth that may be infected and causing pain.
Vote Icon1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Answered By Vanessa Yeager DVM MPH

    Veterinarian

    Published on October 30th, 2017

    Hi there and thank you for posting.

    Oh dear! From the picture, I can see one pupil is dilated while the other is not. This is not normal and is concerning.

    If this resulted after he was hit in the head with the ball, this could indicate he has a concussion or trauma to his brain from the impact.

    I would advise you to seek emergency veterinary care immediately!

    Best of luck to you and Maverick!

    Vote Icon

    1Pet Parents found this answer helpful

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My puppy's eye is cloudy and one pupil dilated after injury. What now?
Poor pup! Cloudiness and anisocoria (the medical term for unequal pupils) are signs of a significant eye injury. It would be best to have Massimo examined by an emergency vet tonight if possible. If this isn't an option for you, he should be seen by your regular vet first thing in the morning. Prompt assessment and treatment is important in cases like this because the risk of permanent damage or vision loss increases the longer he goes without treatment.
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