Traumatic brain injury
CT scan of skull: Chihuahua with skull fractureA fracture is a break in a bone caused by physical force, such as a fall, blow, or accident. Fractures can range from simple breaks that do not require operative treatment to complex fractures that require surgical stabilization. and impression fractures after a bite injury
Traumatic brain injury (TBI)
A TBI is an injury to the brain caused by external force, e.g. a fall or car accident. It can lead to concussion, Bleeding, increased intracranialIntracranial refers to anything located within the skull. Intracranial conditions in dogs and cats include Tumors, infections, and cerebral edema, which can cause neurological symptoms. pressure and neurological deficits. The risk of secondary deterioration makes it an emergency.
Traumatic brain injury (TBI) is an acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. injury to the brain caused by external force to the skull. In dogs and cats, we distinguish between primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. and secondary brain damage. PrimaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. brain damage occurs immediately at the time of the TraumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. and includes direct tissue damage such as contusions, Bleeding or axon injuries. Secondary brain damage develops in the hours and days after the TraumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. and results from pathophysiological processes such as brain swelling (edemaAn edema is a buildup of fluid in the body’s tissues, leading to Swelling. Edema can be localized or generalized and is often a sign of an underlying condition.), inflammatory reactions, Circulatory disorders and metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. changes. These secondary processes can significantly increase the overall damage and are the main starting point for therapeutic interventions.
The severity of a traumatic brain injury is assessed in veterinary medicine using a modified Glasgow ComaA coma is a deep state of unconsciousness where an individual cannot be awakened and does not respond to stimuli. In dogs and cats, it can be caused by severe illnesses, poisoning, or neurological problems. Scale, which takes into account the animal’s state of consciousness, motor skills and brainstem reflexes. This classification is crucial for determining the Prognose and choosing the therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions..
Causes
Even minor injuries to the head can bleed heavily. However, they are usually harmless and heal quickly.
This results in a bruised skull without involving the brain.
Nevertheless, give your pet some rest as a precaution in the next few hours to days.
In the event of serious injuries, for example from a traffic accident or a fall with a severe traumatic brain injury, there is an emergency.
In addition to the injury to the skull, the brain is also involved, for example due to brain swelling or Bleeding in the brain.
The possible consequences range from a mild concussion to the Death of the animal.
The symptoms may not become clear until a few hours after the TraumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries. (Fig.).
Supplements
Traumatic brain injuries in pets are mainly caused by traffic accidents, which account for around 60% of cases. Other common causes include falls from a great height (especially in cats), kicks or blows, bite injuries from other animals and gunshot wounds. In small dog breeds and cats, even a fall from a low height can lead to significant injuries. Brachycephalic breeds such as pugs, French bulldogs or Persian cats have an increased risk of serious consequences from head injuries due to their skull anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues., as the altered skull shape offers less protectionProtection refers to safeguarding against diseases or harm. In veterinary medicine, this can include protecting animals through vaccinations, the use of parasite control products, or providing a safe environment. for the brain.
The injury mechanisms can be divided into acceleration/deceleration traumas (sudden acceleration or deceleration of the head), compression traumas (direct force on the skull) and penetrationPenetration describes the entry or permeation of a substance or organism into a body or material. In medicine, it can refer to the penetration of microorganisms into tissues or the insertion of instruments into the body. traumas (penetrating objects). Each of these mechanisms leads to different injury patterns in the brain tissue.
Symptoms
Traumatic brain injury
Typical Symptoms:
- Change in consciousness, Drowsiness, Head shaking
- Staggering / ataxia, Disorientation
- Unconsciousness
- Pupil changes, Ataxia, Nystagmus
- Refusal to eat, Vomiting
- Head pressing, Pain
Alarm signs:
- Seizures, comaA coma is a deep state of unconsciousness where an individual cannot be awakened and does not respond to stimuli. In dogs and cats, it can be caused by severe illnesses, poisoning, or neurological problems., rapid neurological deterioration
- AnisocoriaAnisocoria is a medical term for unequal pupil sizes. It can be a harmless trait or indicate a number of underlying conditions., lack of pupillary response
- Blood/clear liquid from nose/ear, heavy Bleeding, open head injury,
- Bruising around the eyes
- Breathing pattern disorder, bradycardiaBradycardia refers to a slower than normal heart rate, typically below 60 beats per minute in adults. It can occur in healthy individuals, especially athletes, but can also be an indication of heart disease. + hypertensionHypertension, or high blood pressure, is a condition in which the blood pressure in the arteries is consistently elevated. In dogs and cats, this can lead to damage to organs such as the heart, kidneys, and eyes, and requires medical treatment. (Cushing’s reflex, a reflex increase in blood pressure when intracranialIntracranial refers to anything located within the skull. Intracranial conditions in dogs and cats include Tumors, infections, and cerebral edema, which can cause neurological symptoms. pressure increases)
Escalation/course:
- First 1–6 h: intracranialIntracranial refers to anything located within the skull. Intracranial conditions in dogs and cats include Tumors, infections, and cerebral edema, which can cause neurological symptoms. pressure can rise → monitor closely
- “Lucid interval” possible: short improvement, then crash
- 24–72 h: secondary brain damage (edemaAn edema is a buildup of fluid in the body's tissues, leading to Swelling. Edema can be localized or generalized and is often a sign of an underlying condition.) can escalate
The clinical signs of traumatic brain injury vary greatly depending on the location and severity of the injury. The most common neurological symptoms include impaired consciousness, which can range from mild Drowsiness to deep comaA coma is a deep state of unconsciousness where an individual cannot be awakened and does not respond to stimuli. In dogs and cats, it can be caused by severe illnesses, poisoning, or neurological problems.. Many animals show Coordination disorders such as Staggering / ataxia, circling, or the Inability to stand. Seizures also occur in approximately 30% of patients with severe TBI.
Changes in pupil size and reaction are important diagnostic clues: unequal pupils (AnisocoriaAnisocoria is a medical term for unequal pupil sizes. It can be a harmless trait or indicate a number of underlying conditions.) or lack of light reaction may indicate increased intracranialIntracranial refers to anything located within the skull. Intracranial conditions in dogs and cats include Tumors, infections, and cerebral edema, which can cause neurological symptoms. pressure or brainstem damage. Other signs include abnormal eye movements (nystagmus), altered posture and reflexes, and breathing difficulties.
Systemic symptoms include Vomiting, Cardiac arrhythmiaAn arrhythmia is a heart rhythm disorder in which the heart beats irregularly, either too fast (tachycardia), too slow (bradycardia), or with an irregular pattern. Arrhythmias can be harmless or a sign of serious heart problems., blood pressure changes and temperature regulation disorders. Externally visible injuries such as Bleeding from the nose or ears, bruising around the eyes or open skull fractures can indicate a TBI, but are not always present.
First Aid
- Keep your animal as calm as possible
- Do not move it unnecessarily
- In particular, do not move the head and neck area
- Carefully remove the collar
- Cover the source of the Bleeding with a clean cloth
- Do not apply pressure (skull fractureA fracture is a break in a bone caused by physical force, such as a fall, blow, or accident. Fractures can range from simple breaks that do not require operative treatment to complex fractures that require surgical stabilization.?)
- Keep your animal warm
- Transport your animal to a veterinary hospital immediately
- If possible, announce your arrival at the veterinary hospital.
When should you see a vet sooner?
→ Red in case of unconsciousness, seizures, unequal pupils, abnormal breathing patterns, or signs of shock.
Diagnosis
The Diagnose of a traumatic brain injury begins with a thorough neurological examination that assesses the state of consciousness, cranialCranial refers to a position that is closer to the head or towards the head of an animal. In veterinary medicine, the term is used to describe the location of structures or diseases in relation to the head. nerve reflexes, motor functions, and posture. The modified Glasgow Coma Scale for animals enables a standardized assessment of neurological function and a classification of the severity.
Imaging techniques are essential for precise Diagnose. Computed tomography (CT)Computed tomography (CT) is an imaging technique that uses X-rays and computer technology to create cross-sectional images of the body. It enables a detailed view of bones, organs, and other structures and is used for the diagnosis of injuries, diseases, and for planning medical interventions. is the method of choice in the acute phase because it can be carried out quickly and reliably shows skull fractures, acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. Bleeding and major tissue damage. Magnetic resonance imaging (MRI)Magnetic resonance imaging is an imaging technique that uses strong magnetic fields and radio waves to create detailed images of the inside of the body. It is used in veterinary medicine to diagnose diseases of the brain, spine, and other organs. offers a more detailed representation of the brain tissue and is particularly valuable for assessing edemaAn edema is a buildup of fluid in the body's tissues, leading to Swelling. Edema can be localized or generalized and is often a sign of an underlying condition., diffuse axonal injuries and smaller Lesions, but requires a longer examination time and is not available everywhere.
Laboratory tests are used to record systemic complications and include a complete blood count, ElectrolytesElectrolytes are minerals in the body that carry an electric charge and perform vital functions such as regulating fluid balance, acid-base balance, and nerve and muscle activity. The main electrolytes include sodium, potassium, chloride, and magnesium., blood gases and coagulationCoagulation is the process of blood coagulation, in which liquid blood is transformed into a solid clot. This process is crucial for stopping Bleeding and promoting wound healing. parameters. Biomarkers for brain damage such as the S100B proteinProteins are large molecules made up of amino acids and play an essential role in almost all biological processes. They are necessary for building body tissue, the function of the immune system, and as enzymes for metabolic reactions. or neuron-specific enolase are increasingly being researched in veterinary medicine, but are not yet routinely used.
Further veterinary measures
In the event of a serious traumatic brain injury, a computed tomography (CT) scan of the head is the most important measure.
Further injuries, such as an injury to the cervical spine, must be radiologically excluded and the patient must be kept as still as possible until then.
Depending on the results of the radiological examinations, operations may be necessary.
In patients with severe traumatic brain injury, heart activity, blood pressure, breathing and body temperature, as well as water and electrolyte balanceThe electrolyte balance refers to the balance of electrolytes in the body, which is essential for many physiological processes. Disturbances in the electrolyte balance can lead to serious health problems. must be monitored and therapeutically supported if necessary.
Infusion therapy and sometimes artificial nutrition are usually carried out.
Supplements
The treatment of traumatic brain injury is primarily aimed at minimizing secondary brain damage and ensuring basic care for the brain. Stabilizing the vital functionsVital functions are essential bodily functions necessary to sustain life. These include breathing, heart rate, blood pressure, body temperature, and level of consciousness. has the highest priority: securing the airways, supporting breathing and maintaining adequate blood pressure are crucial for cerebral blood flow.
Drug therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. includes several approaches. Osmotically active substances such as mannitol (0.5–1.5 g/kg i.v.) or hypertonic saline solution (3–5 ml/kg of a 7.5% solution) are used to control brain edema. The role of corticosteroidsCorticosteroids are a class of steroid hormones that occur naturally in the body and can also be produced synthetically. They have anti-inflammatory and immunosuppressive properties and are used in veterinary medicine to treat a variety of conditions. is controversial; current studies show no clear benefit in acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. TBI and point to possible side effects. In the event of Seizures, anticonvulsantsAnticonvulsants, also called antiepileptic drugs, are medications used to control or prevent seizures. They are used in dogs and cats with epilepsy or other conditions that cause seizures. such as diazepam are administered acutely and phenobarbital or levetiracetam for longer-term control.
Fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. must be carefully controlled to avoid both dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse. and increased edemaAn edema is a buildup of fluid in the body's tissues, leading to Swelling. Edema can be localized or generalized and is often a sign of an underlying condition.. Isotonic crystalloid solutions with a controlled infusion rate are standard. Monitoring intracranialIntracranial refers to anything located within the skull. Intracranial conditions in dogs and cats include Tumors, infections, and cerebral edema, which can cause neurological symptoms. pressure is technically challenging in veterinary medicine, but indirect parameters such as pupillary reactions and neurological status provide important clues.
Surgical interventions are indicated for skull fractures with impression, space-occupying Bleeding or open injuries. PostoperativePostoperative refers to the time after a surgical operation. This phase includes recovery and the management of possible complications after the procedure. intensive care includes regular neurological checks, pain management, nutritional support and avoidance of complications such as pressure sores or aspiration pneumonia.
Prognosis and aftercare
The Prognose after a traumatic brain injury depends largely on the initialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. severity of the injury, the time of the start of the therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. and the response to the treatment. Animals with mild TBI generally have a good Prognose with complete recovery within days to weeks. With moderate traumas, partial or complete recovery is possible, with the recovery phase lasting several weeks to months. Severe traumatic brain injuries have a cautious to poor Prognose; approximately 35–50% of patients do not survive or have to be euthanized due to severe neurological deficits.
Follow-up care includes regular neurological check-ups, adapted Physiotherapie and, if necessary, the long-term administration of anticonvulsantsAnticonvulsants, also called antiepileptic drugs, are medications used to control or prevent seizures. They are used in dogs and cats with epilepsy or other conditions that cause seizures.. A quiet environment is particularly important in the first few weeks after the TraumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries.; physical activity should be increased gradually. Approximately 10–20% of animals develop post-traumatic epilepsy, which requires lifelong drug treatment.
Home care is often challenging for pet owners. They must pay attention to signs of neurological deterioration, provide support for mobility restrictions and, if necessary, adapt the environment to avoid falls. The psychologicalPsychological refers to anything related to the mind or behavior. In veterinary medicine, this can include the study of animal behavior, including stress responses and behavioral disorders. support of the owners is also important, as caring for a neurologically impaired animal can be emotionally stressful.
Summary
Traumatic brain injury in dogs and cats is a medical emergency that requires immediate action. The injury is caused by external force and leads to primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. and secondary brain damage. Traffic accidents are the most common cause, with certain breeds and age groups being particularly at risk. The clinical symptoms range from mild Drowsiness to deep comaA coma is a deep state of unconsciousness where an individual cannot be awakened and does not respond to stimuli. In dogs and cats, it can be caused by severe illnesses, poisoning, or neurological problems. and include neurological and systemic manifestations.
The Diagnose is based on the neurological examination and imaging techniques, in particular CT and MRI. The therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. focuses on stabilizing the vital functionsVital functions are essential bodily functions necessary to sustain life. These include breathing, heart rate, blood pressure, body temperature, and level of consciousness., controlling intracranial pressure and avoiding secondary complications. The Prognose varies depending on the severity of the TraumaA trauma refers to a physical injury or damage caused by external force. Traumas can range from simple cuts to severe multiple injuries., with mild cases having a good chance of recovery, while severe injuries can often lead to permanent damage or Death.
Follow-up care and rehabilitation play a crucial role in long-term treatment success. Early detection, adequate first aid and professional veterinary treatment can significantly improve the survival rate and quality of life of affected animals.
Outlook on current research
Research in the field of traumatic brain injury in small animals is constantly evolving. Current studies focus on neuroprotective substances that can reduce the extent of secondary brain damage. Experimental approaches with antioxidants, growth factors and anti-inflammatory substances show promising results in preclinical models.
Stem cell therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. represents an innovative area of research. Mesenchymal stem cells have shown in initialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. studies that they can promote healing after brain injuries through their immunomodulatoryImmunomodulatory describes the ability of a substance to modify the reaction of the immune system. Immunomodulatory drugs can either stimulate the immune system to fight infections more effectively or suppress it to prevent overreactions. and regenerative properties. However, this form of therapy is still in the experimental stage.
Advances in imaging enable more precise Diagnose and follow-up monitoring. Special MRI examinations (functional MRI examinations and diffusion-weighted imaging) can show subtle changes in the brain tissue that are not recognizable with conventional methods. In addition, specific biomarkers are being researched that should enable early detection and Prognose assessment of brain injuries.
The transfer of knowledge from human medicine to veterinary medicine remains an important area of research, whereby species-specific differences must be taken into account. Multimodal therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. concepts that combine drug treatment, neurosurgery and early rehabilitation are being increasingly evaluated and could further improve treatment results.
Frequently asked questions (FAQs)
- How do I know if my pet has suffered a traumatic brain injury?
Look for symptoms such as Drowsiness, Coordination disorders, unequal pupils, Vomiting, or Seizures after an accident or fall. Any change in the state of consciousness after a head injury should be taken seriously. - Is a traumatic brain injury always an emergency?
Yes, any suspected traumatic brain injury should be considered an emergency. Even if the symptoms initially appear mild, secondary brain damage can develop in the hours after the Trauma and worsen the situation. - How should I transport my animal if I suspect a traumatic brain injury?
Carefully transport the animal on a solid surface, stabilize the head and neck area and avoid unnecessary movements. Carefully remove the collar and be careful not to put pressure on the head. - Can my animal fully recover from a traumatic brain injury?
The chances of recovery depend on the severity of the injury. Complete recovery is likely with mild traumas, while severe injuries can lead to permanent neurological deficits. The first 48–72 hours are often crucial for the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop.. - How long does it take to recover from a traumatic brain injury?
The recovery time varies greatly: from a few days in mild cases to several months in severe traumas. The greatest progress is typically observed in the first 3–4 weeks, but improvements can occur over several months. - What long-term consequences can occur after a traumatic brain injury?
Possible long-term consequences include Behavioral changes, cognitiveCognitive refers to the mental processes of recognizing, thinking, learning, and understanding. Cognitive functions in dogs and cats include memory, perception, problem-solving, and decision-making. Cognitive dysfunction can occur in older animals and is similar to dementia in humans. deficits, Visual disturbances, balance problems, motor limitations and post-traumatic epilepsy. Approximately 10–20% of animals develop recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. Seizures. - Are certain dog or cat breeds more susceptible to severe traumatic brain injuries?
Brachycephalic breeds (e.g. pug, bulldog, Persian cat) have an increased risk of serious consequences from head injuries due to their skull anatomyAnatomy is the scientific study of the structure of living things. It deals with the construction and organization of organisms, including their systems, organs, and tissues.. Even very small breeds can suffer serious injuries in falls. - How can I prevent traumatic brain injuries in my pet?
Preventive measures include safe leash guidance in traffic, securing balconies and windows (especially for cats), avoiding falls and adequate supervision during interactions with other animals. - What role does Physiotherapie play in rehabilitation after a traumatic brain injury?
Physiotherapie can improve motor function, prevent muscle atrophyMuscle atrophy is the loss of muscle mass that can be caused by inactivity, malnutrition, or certain diseases. In dogs and cats, muscle atrophy can occur due to chronic diseases, aging, or after prolonged immobilization. and promote the animal’s independence. Techniques such as passive range of motion exercises, balance training and controlled activity increase are individually adapted. - Can a traumatic brain injury lead to personality changes in my pet?
Yes, injuries to certain areas of the brain can lead to Behavioral changes. Animals can become more anxious, aggressive or apathetic. These changes can be temporary or permanent, depending on the location and extent of the damage.
Literature
- Schmidt, M. and M. Kramer (eds.): MRT-Atlas CNS findings in dogs and cats. 328 pages, Enke 2015
- Löwe, G. and Löwe, O. (2021). Emergencies in dogs and cats – A veterinary Guide. Kynos-Verlag. 208 pp.
- Dewey CW, Fletcher DJ. Head Trauma Management. In: Dewey CW, da Costa RC, eds. Practical Guide to Canine and Feline Neurology. 3rd ed. Wiley-Blackwell; 2021:237-255.
- Kuo KW, Bacek LM, Taylor AR. Head Trauma. Veterinary Clinics of North America: Small Animal Practice. 2018;48(1):111-128.
- Sharma D, Holowaychuk MK. Retrospective evaluation of prognostic indicators in dogs with head trauma: 72 cases (January-March 2011). Journal of Veterinary Emergency and Critical Care. 2022;32(1):19-27.