What is Contrecoup Brain Injury?
A contrecoup brain injury is a specific kind of brain damage. It occurs on the side of your brain opposite to where your head was hit. The word ‘contrecoup’ comes from French and means ‘counterblow’. This term was first utilized by the ancient Greek physician Hippocrates to describe a fracture that happens on the opposite area from the impact. It has been mentioned in various documents from the 16th to the 19th centuries.
Sometimes, you might hear people use the term ‘countercoup’ to describe this kind of injury. Medical professionals have been examining and debating the cause and significance of this type of injury for many years.
Unlike broader brain injuries, such as diffuse axonal injury or brain swelling, which can cover large areas and also be caused by head trauma, a contrecoup injury is more localized. It’s also worth mentioning that this type of injury could contribute to vision problems after minor head injuries.
What Causes Contrecoup Brain Injury?
A contrecoup injury typically happens when the moving head, or the brain inside, hits a stationary object. Conversely, a coup injury happens when a moving object hits a stationary head. Signs of both these types of injuries usually include blood or damage in a specific area of the brain, which can be seen on a CT scan or an MRI. Contrecoup injuries come from forces inside the skull that aren’t directly related to the site of the hit, but rather, are linked to strain on the brain and its structure caused by the hit on an already moving head. This leads the brain to bounce back in the opposite direction after the impact.
There are four theories as to why contrecoup injuries occur. In the “positive pressure” theory, the injuries result from the brain’s delay in following the skull’s initial movement, which leads to the brain getting compressed against the stationary skull. The brain then hits the other side of the skull, creating a bruise. The “negative pressure” or cavitation theory suggests that when the brain moves in one direction, stress is put on the opposite side, damaging the brain tissue there. The “rotational shear stress” theory includes the brain rotating, along with moving along the injury’s axis. The “angular acceleration” theory suggests that certain areas of the brain have the potential for greater acceleration and deceleration, causing these injuries.
The difference in density between the brain and the cerebrospinal fluid (CSF) can also play a role in contrecoup injuries. The thought here is that, during an impact, the denser CSF moves in the direction of the impact, which forces the lighter brain to move in the opposite direction where it gets injured. This could suggest that a combination of these mechanisms leads to contrecoup injuries. The biggest damage often occurs in the irregular surfaces in the temporal and frontal areas of the brain. It’s even possible that a contrecoup injury can be more severe than the coup injury, and there have been cases of patients having contrecoup injuries without any coup injuries.
Risk Factors and Frequency for Contrecoup Brain Injury
Contrecoup brain injury is a type of traumatic brain injury. It often happens alongside other types of brain injuries. Falls and car accidents are the most common causes. This type of injury is most commonly seen in young males, but is fairly evenly distributed between the genders in older people.
- Between 13% and 48% of adults with a traumatic brain injury will also have intracerebral hemorrhage.
- Of these patients, 13% to 77% have contrecoup hemorrhages. This type of brain bruising often happens after a blow to the back or side of the head.
- Contrecoup injuries in children under four are rare. However, after age four, they become much more common. This is mainly due to how flexible and unformed an infant’s skull is.
Signs and Symptoms of Contrecoup Brain Injury
When taking a patient’s history, it’s important to get detailed information about the trauma and any other important aspects of their history. Usually, the area of the brain that’s injured is on the opposite side of where the impact happened. This can sometimes be subtle and not easy to identify. Neurological signs can vary depending on the exact location of the injury. It’s quite common to see changes in mental status. Many injuries to the frontal lobe don’t show specific signs, but patients might seem disoriented and confused. If the temporal lobe is injured, patients might have changes in speech or weakness on one side of the body. Some patients also have seizures.
Testing for Contrecoup Brain Injury
Patients who have experienced a traumatic brain injury need to undergo a complete trauma evaluation. This means they should receive advanced trauma support and a comprehensive neurological exam. A CT (computed tomography) scan of the head is typically done as the first step in assessing the extent of the brain injury. It’s also important to check for possible associated neck fractures, which are common in injuries resulting from falls. This is usually done using X-rays or a CT scan focused on the cervical region of the spine.
Treatment Options for Contrecoup Brain Injury
The treatment for contrecoup brain injuries, which are a type of traumatic brain injury, will vary based on how severe the injury is. In cases where surgery isn’t urgently needed, patients will be closely monitored and will usually have a repeat head CT scan after 12 or 24 hours.
If a patient’s neurological status decreases and they score 8 or lower on the Glasgow coma scale (which measures consciousness levels), it’s important to monitor their intracranial pressure (pressure inside the skull). These patients will receive treatment following trauma guidelines.
The extent of the damage and the results of neurological exams will decide if a patient needs surgery, and if so, what kind. At its simplest, the procedure might involve draining a blood clot (hematoma) from the brain. However, in more serious cases, surgery may require the removal of part of a lobe of the brain (lobectomy) or a procedure to relieve pressure inside the skull (decompressive hemicraniectomy).
Patients will also typically take antiepileptic medications for seven days in accordance with standard guidelines. Treating contrecoup brain injury often involves taking into account other types of brain injuries and injuries to other parts of the body.
What else can Contrecoup Brain Injury be?
When diagnosing contrecoup injuries, it’s important to also consider a condition called diffuse axonal injury (DAI). This condition is marked by small spots of bleeding in certain areas of the brain, specifically where the brain’s grey and white matter meet, the corpus callosum, and the brainstem. Rather than being caused by a direct hit to the skull, DAI often results from a sudden acceleration, deceleration or rotational injuries, such as those endured in a severe car accident.
It’s worth noting that DAI is often a reason why patients end up in a long-term, unresponsive state where they’re awake but not aware of their surroundings or ability to interact.
What to expect with Contrecoup Brain Injury
The outlook for recovery from a contrecoup injury can greatly depend on how severely the brain is damaged and whether other types of head injuries are present, such as subarachnoid hemorrhage, DAI, and various forms of traumatic brain injury. According to one study, a positive recovery was seen in 48% of cases six months after the injury.
Possible Complications When Diagnosed with Contrecoup Brain Injury
A traumatic brain injury can lead to many neurological problems. Some of these problems may last forever and depend largely on the region of the brain affected by the injury. If the injury, known as a “contrecoup” injury, isn’t treated quickly and correctly, it can have very serious effects. These can be extreme to the point of causing a coma or even resulting in death.
Preventing Contrecoup Brain Injury
It’s important to educate patients and their families about the wide-ranging effects of a traumatic brain injury, including the potential for contrecoup injury (an injury on the opposite side of the area of impact). This knowledge will help them understand how such injuries can lead to significant life changes and also encourage them to avoid behaviors that may increase the risk of injury. After the immediate crisis phase has passed, some patients may still experience ongoing mental and emotional difficulties that need to be managed.