As with humans, dogs can sometimes have a medical emergency that cannot wait until their next check-up. Getting your dog to an emergency vet as needed can literally save your pet's life, alleviate any pain it may be experiencing and also ensure its overall health. Note when it's good to get your dog to an emergency vet and why this can be so important for its well-being.
Losing the use of hind legs
A pet losing the use of the hind legs doesn't refer to when they drag themselves on the carpet to scratch their underside. If they've really lost control of their hind legs, it means that they cannot walk or stand with their back legs at all. Don't assume your dog is just playing, especially if it seems to be in obvious distress; this can mean that they've suffered some type of paralysis, back injury or injury to the back legs that is not letting them stand up or walk properly. Your dog is usually in severe pain when this happens. Depending on the reason for losing the use of their back legs, they could be treated and completely cured if you get them medical intervention as soon as possible.
Exposure to poisons or dangerous substances
If your dog has been eating or licking something off the garage floor or has gotten into certain vegetation and is now showing signs of abdominal distress, don't assume that it's just indigestion. Your dog could have ingested a poison or something toxic to them and may need to have their stomach pumped or may need medication to counteract something they've eaten. Without the right treatment, their digestive system could shut down and this condition could become fatal.
Not eating or drinking
A dog may pass up a meal on occasion, especially if they're older and not very active. Some animals may also be too tired to eat their regular dinner, such as when it's very hot outside and they simply want to nap. However, going more than a day without eating usually signals a digestive disorder or illness. Also, if your pets don't drink regularly, this can also by a symptom of a serious digestive illness and can lead to dehydration, which is very dangerous for any animal. If your pet skips meals for a full day, especially if it seems overly tired and lethargic for a day or more, if it's panting severely, if it's consistently whimpering or otherwise seems distressed, get it to an emergency vet for treatment.