Dog hit by a car: the first minutes and the injuries that declare later

Quick answer

Every dog struck by a vehicle needs to be seen by a vet the same day, including the one that gets up, shakes itself off and walks home. The injuries that kill after a road accident are mostly inside the chest and abdomen, and most of them are invisible from the outside for the first few hours.

Your job at the roadside is narrow: make the scene safe, stop obvious bleeding, keep the dog still and warm, and get it to a vet without making a spinal or pelvic injury worse. Nothing else you do in the first ten minutes changes the outcome as much as arriving quickly.

A first-aid kit buys you a few minutes of bleeding control and a safe transport. It does not replace the trip, and no dog hit by a car is treated at home.

• Phone the practice while someone else is with the dog. Tell them you are coming and roughly when.
• Muzzle a conscious dog before you touch painful areas, unless it is struggling to breathe or vomiting.
• Move the dog as one piece, on a flat surface, rather than lifting it by the body.
• Do not give any human painkiller. Several are directly toxic, and all of them make the vet's job harder.
• Do not offer food or water. Sedation or surgery may be needed within the hour.

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The dog that runs home is the classic fatal case.

A catecholamine surge after impact masks pain and produces a dog that stands, walks and even wags. Meanwhile a torn spleen or liver can be bleeding into the abdomen, and bruised lungs are filling over the next several hours. Owners who wait to see how the dog looks in the morning are the ones who arrive at an emergency clinic in the dark with a dog that is already in decompensated shock.

Any road impact, at any speed, is a same-day veterinary examination.
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Decide in 60 seconds

Why a dog that seems fine after a car strike often is not

Blunt trauma delivers energy that the body absorbs unevenly. Skin and hair are elastic and often unmarked, while the organs behind them, which are fixed by ligaments and full of blood, take the deceleration force directly.

Three things follow from that.

The outside underestimates the inside. A dog can be hit hard enough to tear a liver lobe with nothing visible except a smear of dirt on the coat. Conversely, an alarming skin wound may be the least important thing present.

Some injuries take hours to declare themselves. Bruised lung tissue leaks fluid into the air spaces over the hours after impact, so respiratory effort typically peaks well after the accident rather than at it. A chest that sounds acceptable at the roadside is not a chest that has been cleared.

Adrenaline is a temporary anaesthetic. The sympathetic surge that lets an injured animal escape a threat also suppresses the pain that would otherwise stop it moving. That effect fades over the following hour or two, which is exactly when many owners see the dog become quiet, reluctant and painful and conclude that something new has happened. Nothing new happened. The masking wore off.

This is the whole argument for going in on the day rather than watching. The examination costs an evening. Waiting costs the window in which internal bleeding is still correctable.

The first minutes at the roadside

Make the scene safe first.

You cannot help a dog from under a second vehicle. Get traffic stopped or warned before anyone kneels on a carriageway. In many countries you are also legally required to report a collision involving a dog, and the rules differ, so check what applies where you live before you need it.

Approach from the front, low and slowly, and speak.

A frightened injured dog that is approached from behind and touched without warning will spin and bite.

Muzzle before you handle painful areas.

A tape or fabric muzzle, or a strip of bandage tied in a loop over the nose and behind the ears, prevents an injury to you that would leave the dog with nobody to transport it. There are two absolute exceptions: never muzzle a dog that is struggling to breathe, and never muzzle one that is vomiting or has a mouth or facial injury. A flat-faced dog cannot be safely muzzled at all, because it has almost no muzzle to tie around and relies on an open mouth to move air.

Control obvious bleeding with direct pressure.

Place a clean cloth, sanitary pad, or folded shirt over the wound and press. Add layers on top rather than removing soaked ones, because lifting the pad strips the clot that has started to form. Keep the pressure on during the journey.

Tourniquets are a last resort for a limb that is bleeding uncontrollably despite pressure, and if one is applied, the time it went on must be written down and told to the vet.

Cover wounds, do not clean them.

Nothing caustic goes on a fresh traumatic wound: no antiseptic concentrate, no spirit, no ointment. A clean damp cloth is enough. The wound will be flushed properly under sedation.

Keep the dog warm.

Injured, shocked dogs lose heat fast, and cold blood clots badly. A blanket, coat or foil blanket over the body helps. Do not apply direct heat such as a hot water bottle against the skin, which draws blood to the surface and away from the organs that need it.

Moving a dog that may have a spinal or pelvic injury

What actually gets used: something flat and rigid, a blanket, absorbent padding and a crate. Ordinary household items do the job if they are to hand.

The aim is to move the whole animal as a single unit without flexing the spine or grinding a fractured pelvis.

For a medium or large dog, slide a rigid flat surface underneath: a board, a boot liner, a shelf, a folded rigid blanket. Two people, one at the shoulders and one at the hips, slide rather than lift, keeping the back in a straight line.

For a small dog, a stiff-sided box or an open-top carrier works. Support the chest and the pelvis at the same time.

Never lift a suspected fracture case under the belly with one arm, and never carry a dog by the front legs or under the forelimbs alone. Both twist the spine.

If the dog is in the car, drive smoothly and have a passenger keep a hand steady on it. Do not put a dog with a suspected spinal injury on a car seat where it can slide off.

Reading shock before it becomes obvious

Lift the lip and look at the gum above the canine tooth. Press with a fingertip, release, and count how long the white patch takes to go pink again.

You do not need equipment to detect blood loss. You need the gums.

Colour. Healthy gums are pink and moist. Pale pink, white, grey or muddy gums mean blood is not reaching the surface, either because there is less of it or because the vessels have clamped down to protect the brain and heart.

Refill time. Press a fingertip on the gum, release, and watch. The blanched spot should refill promptly. A spot that stays white for noticeably longer than a second or two is a poor-perfusion sign, and one that refills instantly and looks brick red can mean the opposite problem.

Pulse and extremities. Pulses that feel thin and fast, cold paws and ear tips, and shivering in a dog that is not cold all point the same way.

Mental state. Quietness in a dog that was just hit by a car is not calm. Deterioration from bright to dull to unresponsive is the most important trend you can report.

Know your dog's normal gum colour. Some breeds have pigmented gums, in which case use the inside of the eyelid or the vulva or prepuce instead. Checking this once on a healthy day is worth more than reading about it.

Dark or brick red gums, or gums with tiny pinpoint bruises, matter too, and should be described to the clinic rather than interpreted at the roadside.

The injuries that declare later

This section is why the follow-up matters as much as the first visit.

Lung contusion.

Bruised lung fills with fluid and blood over the hours after impact. Watch for breathing that becomes faster or takes more effort, an abdominal push on each breath, reluctance to lie on the side, or a soft cough. This commonly worsens across the first day before it improves.

Pneumothorax.

Air leaking into the space around the lungs produces rapid, shallow, restrictive breathing and a dog that stands with its elbows out and its neck extended. It can develop after the initial assessment.

Diaphragmatic rupture.

A tear in the muscular sheet between chest and abdomen lets organs move forward into the chest. Some dogs show it immediately, some show almost nothing for days or even weeks and then present with exercise intolerance or vomiting. Any dog that seems to tire unusually easily in the weeks after a road accident should be re-examined with that in mind.

Ruptured bladder or urethra.

This is the one owners most often miss because the dog looks acceptable at first. Urine leaking into the abdomen is slowly poisonous, and the dog becomes progressively flat, off food and vomiting over a day or two. Record whether the dog has urinated since the accident and what the urine looked like. A dog that strains without producing urine after being hit by a car needs urgent attention.

Cardiac arrhythmia after blunt chest trauma.

Bruising to the heart muscle can produce an abnormal rhythm that often appears a day or two after impact, not at the roadside. Weakness, collapse, or a sudden loss of exercise tolerance in the days after an accident should be reported, and many clinics will recheck an ECG for exactly this reason.

Nerve injuries.

A front leg dragged with the paw knuckled over and no reaction to a firm pinch suggests nerve roots torn where the leg meets the spine. A limp tail with urinary or faecal leaking suggests injury at the base of the spine. Both need a neurological examination, and both change the plan considerably.

Shearing and degloving wounds.

Where skin has been dragged across tarmac, the tissue that looks intact on day one may die over the following days as its blood supply fails. These wounds are managed over weeks, not sutured and forgotten.

Fractures that were not the obvious one.

An animal with a badly broken hind limb hops on the other three, so the cracked rib, the fractured jaw and the chipped carpus can go unnoticed until the painful leg is stabilised. Recheck examinations exist for this reason.

What the emergency team will do

Knowing the sequence makes the visit less frightening and helps you answer usefully.

Triage comes before anything else, and it is not first come first served. A dog struggling to breathe is taken through immediately, and yours may be taken out of your arms without explanation. That is the system working.

Expect some combination of: oxygen; pain relief by injection, usually an opioid rather than an anti-inflammatory in the acute phase because anti-inflammatories are risky in a dehydrated or bleeding patient; an intravenous catheter and fluids; a rapid ultrasound scan of the abdomen and chest looking for free blood or air; blood pressure and blood tests including a lactate measurement as a marker of how well tissues are being perfused; and radiographs once the dog is stable enough.

Definitive repair of fractures is usually delayed. A dog is anaesthetised for orthopaedic surgery when its chest and circulation are safe, which may be a day or more later. That delay is deliberate, not neglect.

Ask the clinic directly what the observation plan is and when the chest will be reassessed, because the answer determines whether the dog stays in.

What to bring and what to record

Speed of impact matters more than it sounds. A dog struck by a car reversing at walking pace and a dog struck at road speed are different clinical problems, and the history steers how aggressively the chest and abdomen are investigated.

What never to do

Do not give human painkillers. Ibuprofen and other human anti-inflammatories cause stomach ulceration and kidney injury in dogs, and paracetamol, also sold as acetaminophen, is toxic. Even veterinary anti-inflammatories are the wrong drug in a shocked or bleeding animal, because they reduce blood flow to the kidneys at the moment that flow is already compromised.

Do not offer food or water, however thirsty the dog seems. A stomach full of water is an aspiration risk under anaesthesia and can delay surgery.

Do not pull out an embedded object, whether that is a stick, a piece of trim or a shard of glass. It may be the only thing preventing serious bleeding.

Do not apply a tourniquet as a first move for any bleeding. Direct pressure controls most haemorrhage and does not risk the limb.

Do not wash a wound with disinfectant concentrate, salt water made by eye, or spirit. Tissue damaged by an antiseptic heals worse than tissue left alone under a clean dressing.

Do not decide from the outside that the dog is fine. The examination is what makes that determination, and it is the cheapest part of the whole event.

When to get help

Go immediately, without phoning first if you cannot do both, for any of these:

• Difficulty breathing, open-mouth breathing at rest, or a blue or grey tongue
• Unconsciousness, or a dog that cannot be roused
• Bleeding that does not slow under firm pressure
• Pale, white or grey gums
• Inability to stand, or a dragged limb or tail
• A visibly deformed limb, or bone through skin

Then, on the same day even if none of the above apply, for every road impact of any kind.

Recovery is confined, boring and monitored. Cage rest with a written recheck plan is the ordinary end point of a good outcome.

And return, rather than waiting for a scheduled recheck, if in the days afterwards your dog develops faster or harder breathing, will not eat, has not urinated, becomes weak or collapses, or stops using a limb it was using yesterday. Those are the delayed injuries arriving, and they are all more treatable early.