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Why is my active dog suddenly lethargic, aggressive, and won't stand?

Updated on September 23rd, 2025

Pet's info: Dog | Blue Heeler | Male | unneutered | 2 years and 7 months old | 60 lbs

2yr dog is lathargic, and aggressive if you go near his back legs. Yesterday, he was playing fetch, running around, happy. Today he was sluggish and has progressed to not standing or eating. He is still drinking water and urinating but our typically VERY active dog will only get up to drink/urinate. He wont lift his head unless he hears a loud noise. Normally goes for three walks a day and plays fetch in the park. He had no interest in walks or fetch or eating. At all.

2 Answers

Most Helpful Answer

Answered By Lindsey Edwards MVB, BSc, IVCA

Veterinarian

Published on October 4th, 2018

Please have him assessed by a vet urgently, it sounds like he is extremely painful and this may be due to a severe injury, spinal pain, infection or hip dysplasia and treatment will depend on the underlying cause

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS
Veterinarian
Published on May 18th, 2019
Hi, and thanks for your question.
This is a quite generic but concerning presentation. Differentials are many, from gastrointestinal or respiratory diseases to any disease that can spread systemically (causing lethargy for example) like infection, and anything that can cause pain/discomfort.
A clinical examination at your local veterinarian is essential to confirm these clinical suspicions and treat appropriately. Antibiotics may be needed.
Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!
1Pet Parents found this answer helpful

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