Hit by Car: Stabilisation and Hidden Injuries

A dog or cat hit by a car can appear stable at the roadside while harbouring internal bleeding, a ruptured bladder or a diaphragmatic hernia that will not become obvious for hours. Trauma cases require systematic veterinary assessment even when the animal is walking and alert immediately afterward.

Why 'Walking Fine' Doesn't Rule Out Serious Injury

Blunt force trauma can rupture the spleen, liver or bladder, or shear the diaphragm, without any external sign of injury, and the resulting internal haemorrhage or organ displacement often takes hours to produce measurable clinical effects. Adrenaline released in the immediate aftermath of trauma can mask pain and mobility deficits for a short period.

Diaphragmatic hernia occurs when the sudden pressure change from impact tears the muscular diaphragm, allowing abdominal organs to migrate into the chest cavity; this can be immediately apparent as respiratory distress or remain subtle for days before compromising lung expansion.

Internal Bleeding and Delayed Shock

• Pale or white gums indicating internal blood loss
• Rapid, shallow breathing or increased effort to breathe
• A distended, painful or fluid-filled abdomen
• Reluctance to move or vocalising when the abdomen is touched
• Bruising visible on the belly skin or inside the ears and gums

Shock can be compensated for the first hour or two after trauma, with a deceptively normal heart rate and blood pressure maintained by the body's compensatory mechanisms before a sudden, rapid decline, which is why observation alone at home is not sufficient after any significant impact.

Chest and Diaphragm Trauma

Trauma assessment follows a systematic primary survey checking airway, breathing, circulation and level of consciousness, followed by chest and abdominal X-rays to check for free air, fluid, fractures or organ displacement into the thorax. Abdominal ultrasound (a FAST scan) can detect free fluid within minutes even before X-rays are taken.

Serial blood pressure, packed cell volume and lactate measurements over the following hours help detect developing internal bleeding or shock that was not apparent on initial presentation, which is why hospitalisation for observation is often recommended even for animals that look well.

The Trauma Workup at the Clinic

Initial management focuses on stabilising shock and identifying life-threatening internal injuries before addressing visible fractures or wounds.

• Intravenous fluids or blood products to address shock and blood loss
• Oxygen supplementation for respiratory distress or suspected chest trauma
• Emergency surgery for diaphragmatic hernia, bladder rupture or splenic bleeding
• Pain management and stabilisation before non-urgent fracture repair

Fracture Repair Timing and Staged Surgery

Dogs and cats with isolated fractures and no internal organ involvement generally do well with surgical repair and recover full function over 8 to 12 weeks. Those with internal organ trauma face a more variable recovery depending on which organs were affected and how quickly bleeding was controlled.

Fracture repair is often deliberately delayed by a day or two while the animal is stabilised from shock, since orthopaedic surgery under anaesthesia carries added risk in a cardiovascularly unstable patient.

When to seek help urgently

• Any animal struck by a vehicle, regardless of how normal it appears
• Pale gums, rapid breathing or a distended abdomen after impact
• Visible limb deformity or inability to bear weight
• Bleeding from the nose, mouth or a body opening after trauma

Every animal involved in a vehicle collision needs prompt veterinary examination, including chest and abdominal imaging, because your own vet can identify hidden injuries that are not apparent in the immediate aftermath, even when the pet seems to be walking normally.