Gunshot wounds causing trauma to the head are considered as one of the most potentially fatal firearm injuries. In the past few years, the incidence has increased noticeably and gunshot wounds to the head are one of the leading causes of head injury in many urban cities1 as there is a direct wound into the head causing brain injury, there are higher chances of mortality or severe disability in survivors. Most of the cases are related to intentional violence, while others arise out of suicidal intention and inadvertent accidents.
In the U.S. around 35% of all deaths related to traumatic brain injury are gunshot wounds to the head. The mortality rate of head trauma due to gunshot wound is around 90%, and in many cases, death occurs before reaching the hospital.
Head Injury Caused By Gunshot
Gunshot wound to the head when caused by a bullet that is traveling at high velocity and force results in two types of injuries of the skull bone. The strike of smaller bullet over the skull causes penetrating cone shape aperture of the bone and larger bullet causes bullet entry surrounded by fracture of skull bone. The bullet always causes entry wound. Bullet may or may not exit the skull. The bullet wound is identified as penetrating wound when the bullet enters the skull but does not exit and shows only entry wound. Similarly the bullet injury is diagnosed as perforating wound when the bullet enters the skull and exits from another end showing both entry and exit wounds.
In either case, the bullet can cause significant injury to skull bone and brain tissue. The brain damage depends on following factors-
- The distance bullet travels through brain tissue
- The direction of passage of bullet
- The distance of the shooting range
- Projectile path prior to bullet strike to skull bone and
- Type of bullet fired.
The injuries caused by the gunshot wound to head include following injuries-
- Skull fracture like bullet aperture or shattered bone
- Injury of brain tissue
- Injury of blood vessel resulting in internal bleeding
- Tears brain sinuses and brain tissue surrounding sinuses2
- Injuries of cranial nerves resulting in facial palsy and hearing loss3
- Injury of vital centers like breathing center, blood pressure center, heart monitoring center and various brain coordinating centers.
Symptom And Signs Of Gunshot Wound To The Head
When cases of gunshot wound to the head arrive at the hospital, aggressive treatment for resuscitation is required. The victim may present with following abnormalities-
- Brain Swelling
- Brain Hemorrhage- Bleeding within brain or between skull and brain
- Cerebral Ischemia- lack of blood supply to brain and
- Increased Intracranial Pressure- Increased pressure within skull resulting in displacement or compression of brain inside the skull.
Diagnostic Studies For Gunshot Wound To The Head
- X-ray of Skull- To rule out fracture
- CT Scan and MRI- Diagnose fracture, bleeding, shifting of brain tissue and brain tissue injury
- Ultrasound Study- Ultrasound study of brain and skull is performed to evaluate brain hemorrhage and shifting of brain tissue.
- Electrocardiogram (EKG)- EKG abnormalities are observed when brain tissue is shifted following internal bleeding. Heart function is controlled by the cardiac center in brain. Function of Cardiac center is compromised when blood supply is obstructed or squeezed by shifting of the brain.
- Blood Examination- Loss of blood often causes low hemoglobin and anemia. Blood oxygen level is low when respiratory center function is compromised by lack of blood supply.
Glasgow Coma Scale (GCS)-
- Most patients may have altered consciousness and assessing the level of consciousness using Glasgow Coma Scale (GCS) is essential.1
- GCS helps to determine the patient’s neurological condition and level of alertness to assess the severity of head injury.
- GCS parameters include eye opening, verbal response and motor response to various stimuli and the quality of the responses is noted according to the given scale.
- GCS score guides the severity of the head injury. Severity is classified as mild, moderate and severe.
Brain Injury As A Result Of Gunshot Wound To The Head
Severe brain injury is suspected when MRI or CT scan does not show significant hematoma, and following symptoms are observed-
- Patient is in coma.
- Abnormal breathing or being unable to breath- Patient needs endotracheal tube as well as external breathing machine to support breathing.
- Cardiac Arrhythmia- Heart rate slow or extremely fast resulting in ventricular tachycardia.
Emergency Treatment For Gunshot Wound To The Head
Life saving initial treatment by EMT technician or ER nurses-
- Establish Normal Breathing
- Positioning the head so that patient can breathe through nose or mouth without obstruction
- Clear oral cavity by removing denture, blood or vomitus.
- Nasal oxygen if patient is breathing but looks bluish or cyanotic.
- Oral airway or insert endotracheal tube in trachea to support breathing using Ambu Bag.
- Cardiovascular Stability-
- Check EKG
- Heart rate
- Blood pressure
- Treat with appropriate medications
- Intravenous fluid.
- GCS Score-
- The patient’s level of consciousness as per the GCS score
- Stabilize patient then get brain CT scan or MRI.
Treatment For Gunshot Wound To The Head
Head trauma from gunshot is considered as serious situation and life saving procedures may be necessary. Treatment includes-
- Intensive care admission
- Intermittent positive pressure ventilation
- Cardiac support by using intravenous medications
- Emergency surgery is performed to remove bullets, remove blood clots and repair brain tissue.
- Surgery during early stages often is life saving.4
In order to reduce the intracranial pressure, a procedure called craniectomy, in which a part of skull is temporarily removed, may also be performed if found appropriate. For patients having a better motor response on GCS, immediate and intensive neurological management is warranted.
Prognosis Of Gunshot Wound To The Head
The overall effect of the gunshot wound to the head depends on the type of injury, the amount of brain damage and the response of the patient.
Hemorrhage is an important outcome of tissue damage. It can result into immediate death if major blood vessels are damaged and bleeding cannot be stopped in time. In cases where the patient survives the initial stage of blood loss, the pressure inside the skull keeps increasing, causing brain swelling which can create significant damage and even death before medical care is obtained.
Outcome And Recovery Of Gunshot Wound To The Head
The outcome and recovery from brain injury due to gunshot wound is variable and some indicators of neurological function help in determining the outcome of gunshot wound to the head. Some indicators influencing the neurological outcome include initial score on Glasgow Coma Scale, age and health status of the patient, insufficient oxygen supply during initial phase, low blood pressure, brainstem reflexes and reaction of pupils on examination.
Other factors that determine the severity of brain injury and the resultant outcome include the type of wound (penetrating or perforating), the injured areas in the brain and the amount of tissue destruction, features of the bullet and type of gun, the distance from which the bullet was shot and the timely provision of medical care.
As gunshot wounds to the head can affect the brain in varying degrees, the outcome too varies. In cases, where only some part of the brain is damaged; there may be impairment of the particular functions that the part is responsible for. Immediate medical care and intensive rehabilitation can help in limiting the damage in such patients.
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J Neurosurg. 2014 May;120(5):1138-46.
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Beaty NB1, Diaz C, Crandall K, Sansur C.
BMJ Case Rep. 2012 Sep 17;2012. pii: bcr2012006679.
3. Gunshot injuries to the temporal bone.
Moore PL1, Selby G, Irving RM.
J Laryngol Otol. 2003 Jan;117(1):71-4.
4. Craniocerebral gunshot injuries in preschoolers.
Irfan FB1, Hassan RU, Kumar R, Bhutta ZA, Bari E.
Childs Nerv Syst. 2010 Jan;26(1):61-6.