How To Tell If A Dog Has A Concussion: Veterinary Assessment And Triage Guide

To tell if a dog has a concussion, immediately evaluate their eyes for unequal pupil sizes (anisocoria), rapid involuntary drifting (nystagmus), or a lack of light response, while checking for a loss of motor coordination (ataxia) or abnormal mental states like extreme lethargy. Any blunt force trauma to a canine's skull requires immediate veterinary evaluation, but tracking these baseline neurological biomarkers during transport is critical for emergency triage.

Canine traumatic brain injury (TBI), commonly referred to as a concussion, occurs when an external impact causes the brain to collide with the interior of the skull. Because dogs possess thick skull bones and strong temporal muscles, a force significant enough to cause a concussion often carries the risk of intracranial hemorrhage, cerebral edema, or secondary brain injury.

Identifying a concussion in a dog requires a systematic, clinical approach. Unlike humans, dogs cannot verbally communicate symptoms like headaches, dizziness, or blurred vision. As a pet owner or first responder, you must rely entirely on objective physiological and behavioral indicators to determine the severity of the trauma.

Pre-Assessment Protocol and Emergency Triage Requirements

Before attempting to evaluate a dog that has sustained head trauma, you must prepare the environment and yourself. An injured, concussed dog is likely in pain, disoriented, and experiencing a surge of epinephrine. This state can trigger unexpected defensive aggression, even in highly trained or gentle animals.

Required Assessment Tools and Materials

• Focal Light Source: A small medical penlight or a highly directional smartphone flashlight to evaluate pupillary light reflexes.
• Muzzle or Gauze Strip: For handler protection, provided the dog is not vomiting, exhibiting respiratory distress, or bleeding from the oral cavity.
• Rigid Transport Board: A flat wooden board, stiff cardboard, or a firm dog bed to act as a spinal board if neck or spinal injury is suspected.
• Blankets: To combat shock and stabilize body temperature during transport.
• Stopwatch or Timer: To measure heart rate, respiratory rate, and pupillary response times.

Baseline Prerequisite Standards

• Normal Canine Heart Rate: 70 to 120 beats per minute (bpm) for large dogs; up to 160 bpm for small dogs.
• Normal Canine Respiratory Rate: 15 to 30 breaths per minute at rest.
• Normal Mucous Membrane Color: Bubblegum pink with a Capillary Refill Time (CRT) of under 2 seconds.
• Estimated Evaluation Duration: 3 to 5 minutes. Do not delay emergency transport to complete a prolonged assessment.

Clinical Step-by-Step Evaluation for Canine Concussion

Perform these diagnostic checks in sequence, starting with the most critical life-safety measures and moving to specific neurological assessments.

Step 1: Secure the Patient and Stabilize the Spine

Minimize any sudden movements of the dog's head or neck. If the impact was severe enough to cause a concussion, there is a high probability of concurrent cervical spine trauma.

1. Approach the dog calmly at eye level, speaking in low, reassuring tones to minimize spike-inducing stress.
2. If the dog is conscious and not vomiting, gently apply a soft muzzle.
3. Place the dog in lateral recumbency (lying on their side) on a rigid board if they are non-ambulatory.
4. Keep the head and neck aligned with the spine. Do not flex or hyperextend the neck. Elevate the head slightly (approximately 30 degrees) using a folded towel under the board to help reduce intracranial pressure.

Warning: Never apply a muzzle if the dog is unconscious, vomiting, gasping for air, or exhibits bleeding from the mouth or nose. Doing so can cause aspiration pneumonia or asphyxiation.

Step 2: Conduct the Ocular (Eye) Assessment

The eyes are the direct window to the canine brainstem and cranial nerves. Changes in ocular symmetry and reactivity are the most reliable indicators of a concussion or severe brain injury.

1. Check Pupil Symmetry (Anisocoria): Compare the sizes of the left and right pupils in ambient light. Pupils of different sizes indicate unilateral brain injury or pressure on the oculomotor nerve.
2. Test the Pupillary Light Reflex (PLR): Direct your penlight into the right eye for 2 seconds, then remove it. Observe if the pupil constricts promptly and then dilates back when the light is removed. Repeat on the left eye. Direct and consensual (opposite eye) constriction must occur. Slow or absent constriction indicates midbrain damage.
3. Check for Nystagmus: Observe the eyeballs for rapid, involuntary, rhythmic oscillation (horizontal, vertical, or rotary movement). Nystagmus points to a disruption in the vestibular system or cerebellar pathways.

Pro-Tip: If both pupils are pinpoint (miotic) and do not respond to light, or if both are wide and fully dilated (mydriatic) and fixed, this indicates severe bilateral brain stem compression or herniation. This is a red-alert emergency.

Step 3: Assess Level of Consciousness and Mentation

A dog's mental status reflects the functional integrity of the cerebral cortex and the reticular activating system (RAS). Categorize the dog’s mentation into one of four clinical states:

1. Normal/Alert: The dog is responsive to their name, tracks movement with their eyes, and is aware of their surroundings.
2. Obtunded (Dull): The dog is conscious but shows a delayed response to vocal commands, touch, or environmental stimuli. They may appear unusually sleepy or depressed.
3. Stuporous: The dog is asleep or semi-conscious and will only respond to noxious or painful stimuli (such as a gentle pinch to the webbing between their toes).
4. Comatose: The dog is completely unconscious and unresponsive to all physical, vocal, or painful stimuli.

Step 4: Evaluate Motor Function, Balance, and Gait

If the dog is ambulatory, observe their movement on a flat, non-slip surface. Brain injuries frequently impair the cerebellum and vestibular tracts, leading to motor deficits.

1. Observe for Ataxia: Look for a drunken, uncoordinated gait. Concussed dogs may sway, stagger, lean to one side, or cross their paws while walking.
2. Identify Head Tilt: A persistent tilt of the head to one side suggests vestibular dysfunction caused by localized cranial trauma.
3. Watch for Extensor Rigidity: If the dog is lying down and cannot rise, observe their limb posture. Rigid, straight extension of all four limbs with the head arched backward (opisthotonus) indicates decerebrate rigidity, signifying a severe lesion in the midbrain.

Step 5: Monitor Systemic Vitals and Perfusion

A concussion can alter the autonomic nervous system, affecting cardiac output and respiratory patterns.

1. Check Capillary Refill Time (CRT): Press your finger firmly against the dog's upper gum line for two seconds to blanch the tissue. Release and time how long it takes for the pink color to return. A return time greater than 2 seconds indicates poor perfusion and shock.
2. Monitor Respiratory Patterns: Look for irregular, shallow, or rapid breathing. A classic sign of advanced intracranial pressure is Cheyne-Stokes respiration (periods of deep, fast breathing followed by temporary apnea).
3. Evaluate Heart Rate: Check for bradycardia (abnormally slow heart rate) combined with high blood pressure (which can present as strong, bounding femoral pulses). This combination, known as the Cushing's Reflex, indicates life-threatening elevated intracranial pressure.

Clinical Metrics & Modified Glasgow Coma Scale (MGCS) for Dogs

Veterinarians use the Modified Glasgow Coma Scale (MGCS) to objectively assess the neurological status of dogs following head trauma. This scoring system evaluates three categories: motor activity, brainstem reflexes, and level of consciousness. Each category is scored from 1 (worst) to 6 (best).

Understanding the Cumulative MGCS Score

• Score 15 to 18 (Good Prognosis): Mild concussion. Requires 24-to-48-hour monitoring and supportive therapy.
• Score 9 to 14 (Guarded Prognosis): Moderate traumatic brain injury. Requires aggressive medical intervention, oxygen therapy, and close monitoring for cerebral edema.
• Score 3 to 8 (Grave Prognosis): Severe traumatic brain injury. Requires immediate emergency intervention, advanced imaging, and intensive care unit (ICU) support.

Critical Neurological Complications and Field Actions

When managing a dog with a suspected concussion, you may encounter acute clinical emergencies. Knowing how to react in these scenarios can prevent permanent brain damage.

Scenario 1: The dog begins to seize post-impact

• Root Cause: Excitation of cortical neurons caused by localized trauma, intracranial hemorrhage, or sudden hypoxia.
• Actionable Fix: Clear the surrounding area of sharp objects to prevent secondary injuries. Do not attempt to restrain the dog's head or limbs. Keep the airway clear. Do not place anything in the dog’s mouth. Note the duration of the seizure and immediately transport the dog to the nearest emergency clinic for intravenous anticonvulsant administration (such as diazepam or phenobarbital).

Scenario 2: The dog’s level of consciousness deteriorates rapidly

• Root Cause: Progressive cerebral edema (brain swelling) or an active intracranial hematoma increasing intracranial pressure.
• Actionable Fix: Elevate the dog’s head at a 30-degree angle using a rigid transport board to promote venous drainage from the head. Ensure there is no pressure on the jugular veins (remove collars or harnesses immediately). Keep the dog cool using air conditioning to prevent hyperthermia, which increases brain oxygen consumption.

Scenario 3: Blood or clear fluid drains from the ears or nasal passages

• Root Cause: Basilar skull fracture causing leakage of cerebrospinal fluid (CSF) or rupture of local vasculature.
• Actionable Fix: Do not plug the ears or nostrils with cotton or gauze, as this blocks the escape of fluid and dangerously increases intracranial pressure. Allow the fluid to drain freely onto a clean, dry towel. Pack cold compresses around the base of the skull during transport to reduce local inflammation.

Scenario 4: Extreme respiratory distress or gasping (Apneustic breathing)

• Root Cause: Herniation of the brainstem through the foramen magnum due to severe pressure buildup.
• Actionable Fix: Provide immediate supplemental oxygen if available via a loose-fitting face mask. Avoid any restriction around the neck. Keep the head elevated and drive safely but rapidly to an emergency veterinary hospital.

Frequently Asked Questions

Can a dog sleep with a concussion?

It is a misconception that you should prevent a concussed dog from sleeping. Rest is essential for neurological recovery; however, you must monitor them closely. Wake the dog gently every 2 hours to check their pupillary reflexes, response to their name, and motor function. If they are difficult to arouse, stuporous, or disoriented upon waking, seek immediate emergency veterinary care.

How long does it take for a dog concussion to show symptoms?

While some symptoms appear immediately after the impact, secondary brain injuries such as cerebral edema or intracranial bleeding can develop slowly. Symptoms of a concussion can progress and become apparent 24 to 72 hours after the initial trauma. Continuous monitoring during this window is vital.

Can a dog recover from a concussion on its own?

A mild concussion can resolve with rest and supportive care, but a dog should never be left to recover without a professional veterinary assessment. What appears to be a minor concussion initially can quickly escalate into a life-threatening brain bleed or swelling. Early veterinary intervention is critical to prevent permanent cognitive or motor deficits.

What is the difference between a concussion and a traumatic brain injury (TBI) in dogs?

A concussion is technically a mild form of traumatic brain injury (TBI) that results in temporary disturbance of brain function without structural damage visible on standard imaging. TBIs encompass the entire spectrum of brain trauma, including severe cases involving skull fractures, contusions, lacerations, and active intracranial hemorrhaging.

Professional Veterinary Emergency Care

If your dog has sustained any form of head trauma, prompt medical evaluation is the single most important factor in their recovery. Contact an emergency veterinary hospital immediately to let them know you are on your way with a suspected head trauma patient.