Head injuries are the most unexpected injury in the human population. It happens due to blow to the head usually associated with road traffic accident, fall from a height, assault, fall of a foreign object over the head. It is the most common cause of death in the adult population.
The impact of head injury varies from transient loss of consciousness to coma and death. It can be associated with facial injuries and injury to the other organs. Most common symptoms are transient loss of consciousness, vomiting, seizures, giddiness, loss of consciousness. Sometimes if the injury occurs in the vital parts of the brain, it can result in weakness of the limbs, hearing loss and vision loss, coma and death.
Head injury and its symptoms are because of the movement of brain inside the skull bone. The cerebrospinal fluid acts as a cushion and protects the brain from shock. Transiently brain stops to function, and it thereby causes loss of consciousness, memory loss, giddiness and vomiting.
Major types of head injury are Hematoma, Hemorrhage, Concussion, cerebral edema, Skull fracture, Diffuse axonal injury.
Head injury may cause blood clots in the brain. There are various types of blood clots in the brain.
- Extradural hematoma (EDH)
- Acute subdural hematoma (SDH)
- Chronic subdural hematoma
1. Extradural hematoma
It is an accumulation of blood between the inner table of skull and striped off dural membrane. It occurs following traumatic head injury and is often associated with skull fracture and arterial laceration. The blood vessel in proximity to the fracture is the source of blood. It is more common in young individuals because the membrane covering the brain is not as closely attached to the skull as in older people and in children younger than 2 years. It does not cause much damage to the underlying brain, and so the prognosis is excellent when treated early and aggressively. The requirement of surgery is based on the patient’s neurological condition.
2. Acute Subdural hematoma
It is a serious condition where in Blood collects between the skull and surface of brain. It occurs due to rupture of blood vessel and the clot may cause pressure on the brain. It occurs usually following a severe head injury. It can occur following a minor injury when the age of the patient is above 60 years or when the patient is on blood thinning medication for associated medical condition or with alcohol abuse. The surgical technique in the management of subdural hematoma are
- Burr hole
- Brain Contusion
It is a bruise of the brain tissue. Just like bruises that occur on other parts of the body, a brain contusion is caused by small blood vessel leaks. Because they involve structural brain damage, contusions are more serious than concussions.
Brain contusions are most often caused by an impact to the head, such as those sustained in a car accident, a fall, or a sports-related accident. In some cases the brain is injured right below the site of impact, while in other cases the injury occurs on the opposite side of the impact.
Contusions are most often found in cortical tissue, in areas that are near sharp ridges on the inside of the skull, such as under the frontal and temporal lobes and on the root of the ocular orbit. The prognosis for contusion depends upon the severity of the injury. Small contusions are able to heal on their own but larger contusions may need surgical interventions depends on patient’s condition. Extremely severe contusions can cause herniation of the brain, and eventually coma.
3. Chronic Subdural Hematomas
A chronic subdural hematoma (SDH) is an old clot of blood on the surface of the brain beneath its outer covering.
These liquefied clots most often occur in patients age 60 and older who have brain atrophy, a shrinking or wasting away of brain tissue due to age or disease. When the brain shrinks inside the skull over time, minor head trauma can cause tearing of blood vessels over the brain surface, resulting in a slow accumulation of blood over several days to weeks.
Because of the brain atrophy, the liquefied blood clots can become quite large before they cause symptoms. Less than half of patients remember the traumatic event itself because even relatively trivial trauma, such as a minor bump on the head, can produce these slow hemorrhages. Other risk factors include alcohol abuse, seizures, shunts that drain excess cerebrospinal fluid from the brain, and blood thinning medication.
Intracerebral hemorrhage is a common complication of traumatic brain injury. Intracerebral hemorrhage may result in a poor neurological outcome. In severe head injury if the hematoma is more than 50 ml it is associated with high mortality. It may expand over time. Contrast expansion on CT angiography is a strong and independent predictor of hematoma expansion. Aside from the direct damage to the brain tissue that was injured, swelling or edema is the major complication of an intracerebral bleed.
surgery is not often considered except in situations in which the pressure within the skull increases to the point at which part of the bone is temporarily removed to allow the brain to expand. When and if the brain swelling resolves, another operation replaces the piece of skull that was removed.
Although a number of factors contribute to increased mortality and morbidity in traumatic brain injury ,the development of cerebral Edema (brain swelling) is the most significant predictor of outcome. Altering the blood brain barrier has become a promising approach to manage brain Edema. It is also believed that the swelling contributing to Edema is derived from the vasculature. Targets aimed at reducing this at cellular level has been tried and research are being conducted in this concern.
The skull is made up of many bones that form a solid container for the brain. The face is the front part of the head and also helps protect the brain from injury. Fractures of the skull are described based on their location, the appearance of the fracture, and whether the bone has been pushed in.
Location is important because some skull bones are thinner and more fragile than others.
- Basilar skull fractures occur because of blunt trauma and describe a break in the bones at the base of the skull. These are often associated with bleeding around the eyes (raccoon eyes) or behind the ears (Battle’s sign). The fracture line may extend into the sinuses of the face and allow bacteria from the nose and mouth to come into contact with the brain, causing a potential infection.
- In infants and young children, whose skull bones have not yet fused together, a skull fracture may cause a diastasis fracture, in which the bone junctions (called suture lines) widen.
- Fractures can be linear (literally a line in the bone) or stellate (a starburst like pattern) and the pattern of the break is associated with the type of force applied to the skull.
- Penetrating skull fractures describe injuries caused by an object entering the brain. This includes gunshot and stab wounds, and impaled objects to the head.
- A depressed skull fracture occurs when a piece of skull is pushed toward the inside of the skull (think of pressing in on a ping pong ball). Depending upon circumstances, surgery may be required to elevate the depressed fragment.
- It is important to know whether the fracture is open or closed (this describes the condition of the skin overlying the broken bone). An open fracture occurs when the skin is torn or lacerated over the fracture site. This increases the risk of infection, especially with a depressed skull fracture in which brain tissue is exposed. In a closed fracture, the skin is not damaged and continues to protect the underlying fracture from contamination from the outside world.
Diffuse Axonal Injury or Shear Injury
A potentially devastating brain injury occurs when the brain injury occurs to the axons, the part of the neurons or brain cell that allows those cells to send messages to each other. Because of the damage of electrical flow between cells, the affected individual often appears comatose with no evidence of bleeding within the brain. The mechanism of injury is usually acceleration-deceleration, and the nerve endings that connect the brain cells rip apart.
Treatment is supportive, meaning that there is no surgery or other treatment presently available. The patient’s basic needs are met hoping that the brain will recover on its own, but most of them don’t.
Head Injury in Infants and Young Children
Infants often visit health care practitioner because of a head injury. Toddlers tend to fall as they learn to walk, and falls remain the number one cause of head injury in children. While guidelines exist regarding the evaluation of head injury victims, they tend to be applied to those older than 2 years of age.
A minor head injury in an infant is described by the American Academy of Pediatrics as the following: a history or physical signs of blunt trauma to the scalp, skull, or brain in an infant or child who is alert or awakens to voice or light touch.
Infants are usually unable to complain about headache or other symptoms. Therefore, basic guidelines as to when to seek medical care can include the following:
- Altered mental status. The child is not acting or behaving normally for that child.
- Scalp abnormalities including lacerations and swelling that may be associated with skull fracture Forehead contusions tend to be less worrisome than occipital (back of the head) contusions
Often a careful physical examination is all that is needed to assess the infant’s risk for intracranial hemorrhage, but some testing may be considered.
CT scan may be indicated based upon the health care practitioner’s assessment of the child. Plain skull X-rays may be considered to look for a fracture, as a screening tool to decide about the need for a CT scan.
Usually, if the health care practitioner finds no evidence for concern, the infant can be discharged home for observation. While parents may choose to, there is no need to keep the infant awake or waken them should they fall asleep.
Most of the pathology in case of traumatic brain injury can be easily detected by simple screening of the brain by CT scan. Most of the time all of the blood clots in the brain do not require surgery for the removal of the blood clot.
Whenever somebody suffers from a head injury, consultation by a Neurosurgeon is mandatory to assess the neurological status of the patient and get the necessary treatment.
If the Neurosurgeon feels that there is a significant head injury, the patient may require neuromonitoring.
The neuromonitoring includes
GCS score – Glasgow Coma Scale, Pupillary assessment, Pulse, Blood pressure, Respiratory rate, motor and sensory functions for 24 to 48 hours
During neuromonitoring if any change in any of the parameters is noticed, there may be a need to repeat CT scan -Brain to check for increase in the size of the clot in the brain.
Depending upon the size of the blood clot and if the blood clot is causing damage to the normal brain or the vital structures in the brain and also based on the status of the patient, neurosurgeon may advice surgery to prevent further damage to brain and it could be a lifesaving procedure for the patient.
This involves opening of a part of the skull bone and removal of the blood clots (EDH, SDH, contusion). This procedure is called Craniotomy and evacuation.
After the surgery depending on the neurological status, the patient may require neuro rehabilitation care, physiotherapy and medications.
Prevention of a head injury
It is always better to follow a preventive approach.
Falls are the most common cause of head injury. The elderly and the children need special attention and care. Some like toddler falling whole learning to walk are unavoidable ,but constant monitoring can prevent them sometimes.
Some tips on prevention are
- Proper flooring, installing window guards, non slip floor mats , handrails and safety gates can prevent head injury at home.
- Non slip mats in bathtub and shower floor and close monitoring in these high risk areas
- follow traffic signals and wearing helmet while driving bicycle/motorcycle/sporting activity
- Wearing seat belt
- Cars with airbag
- Avoid risky driving behavior like drunken driving or use of phone while driving Avoid arguments with unknown people while driving on road.
Preventing head injury in children especially during sports activity
- Obey all traffic signals and be aware of drivers when cycling or skateboarding.
- Avoid uneven or unpaved surfaces when cycling, skateboarding, or in-line skating.
- Perform regular safety checks of sports fields, playgrounds and equipment.
- Discard and replace sporting equipment or protective gear that is damaged.
- Never slide head-first when stealing a base.