Teen-agers and young adults (ages 15-24) suffer the highest rates of traumatic brain injuries, mostly due to motor vehicle accidents. Of this age group, males are nearly twice as likely to suffer a traumatic brain injury as females.
Primary brain injuries can be divided into two types of lesions: focal and diffuse. Focal lesion is typically associated with blows to the head that produce cerebral contusions and hematomas. Focal injuries can be life threatening. Diffuse axonal injury is caused by inertia forces commonly produced by motor vehicle accidents.These types of injuries can coexist.
Prevalent head injuries.
The more common types of primary head injuries include: (i) skull fractures, (ii) epidural hematomas; (iii) subdural hematomas; (iv) intracerebral hematomas; (v) diffuse axonal injury. Although the primary brain injury is the result of direct mechanical damage that occurs at the time of trauma, secondary brain injury occurs after the initial trauma and is defined as the damage to the neurons due to systemic responses to the initial injury.
Serverity of head injuries
The severity of a head injury is classified by the Glasgow Coma Scale. On that scale, a score of 13-15 is classified as a mild injury, a score of 9-12 as moderate and a score of less than or equal to 8 is considered severe. If a person is suspected to be intoxicated, a health care provider should exercise greater caution during the evaluation because such intoxication could be masking an expanding intracranial mass lesion.
The first priority in any injured patient is to stabilize the cervical spine, establish an adequate airway, ensure adequate ventilation and circulation. These steps are critical to avoid hypoxia and hypotension, the most important causes of secondary brain insults. Patients who have a Glasgow score less than or equal to 8 should be intubated early upon presentation to a health care professional.
A CT scan has become the ideal diagnostic procedure in evaluating acute head trauma. Generally, it is recommended that patients with a Glasgow score of 15 and a history of loss of consciousness be scanned. Once the patient is stabilized, a neurosurgical consultation is required. The critical factors in deciding whether to proceed directly with surgical evacuation of an intracranial hematoma include the patient’s neurologic status and CT findings.
Anoxic Brain Injuries
The brain requires oxygen in order to function normally. If the brain is deprived from a substantial lack of oxygen, a hypoxic event occurs. If the brain is completely deprived of oxygen, an anoxic event occurs. Oxygen is crucial to bodily functions, and the brain consumes approximately one-fifth (20%), of the body’s total oxygen.
If the brain is deprived from oxygen, a domino-effect of problems will occur. Oxygen is necessary to metabolize glucose. Glucose is used to provide energy for all living cells. Since 90% of the brain’s total energy is used to send electrochemical impulses and maintain the neuron’s ability to send these impulses, a deprivation of oxygen may produce profound thinking, movement, and emotional impairments.
The most common forms of anoxia are (i) anemic anoxia; (ii) ischemic anoxia; and (iii) anoxic anoxia. Anemic anoxia occurs when not enough blood or hemoglobin is making it to the brain. Hemoglobin is a chemical in red blood cells responsible for carrying oxygen throughout the body. This may occur when someone is hemorrhaging from a gunshot wound. Ischemic anoxia occurs when there is not enough cerebral blood flow to carry blood to the brain such as when a person suffers from an ischemic stroke. Anoxic anoxia occurs when not enough oxygen is present in the air to be absorbed by the body. An example of this occurs with high altitude sickness.
The most frequent causes of Ischemic anoxia include:
a. Anesthesia accidents-32%
b. Cardiovascular disease-29%
c. Asphyxia, such as drowning -16%
d. Chest trauma-10%
f. Severe bronchial asthma-3%
g. Barbiturate poisoning-3%
Symptoms of hypoxic-ischemic injury include: Cognitive deficits (thinking problems), weakness in all four extremities, abnormal movements, loss of coordination, visual disturbances, and the inability to follow a sequence of commands.
Direct treatment of anoxia is limited. The general consensus is one of maintaining the body’s general status, although some studies have suggested that the use of barbiturates may be helpful in the first 2-3 days of injury onset. Recovery may take months to years depending on the level of injury. Rehabilitation may include the need to consult professionals like a physical therapist, speech therapist and a neuropsychologist.
Brain Infection Injuries
There are many organisms, viruses, fungi and parasites which can cause infection in the brain and spinal cord. Some of the most commonly seen brain infections include:
Meningitis- is an inflammation of the membranes of the brain or spinal cord. It can be caused by a virus or by bacteria. Bacterial meningitis is a very serious disease.
Encephalitis- is an inflammation of the brain itself. It can take many forms from many causes.
Myelitis- means an inflammation of the spinal cord
Abscess- a collection of pus appearing in an acute or chronic localized infection and associated with tissue destruction.
In the United States, about 25,000 new cases of meningitis are diagnosed each year. About 2/3 of all cases are in children. Recent statistics show that the incidence of bacterial meningitis is estimated to be more than 400 cases per 100,000 newborns. There are three types of bacteria which most commonly cause meningitis: (i) Streptococcus pneumonia, (ii) Neisseria meningitidis, and (iii) Haemophilus influenza type b.
Other common brain infections include (i) Toxoplasmosis, caused by a parasite, and acquired by eating unwashed vegetables or undercooked meat or direct contact with cat feces, (ii ) Cerebral cysticercosis, caused by the pork tapeworm, (iii) Trichinosis, caused by the roundworm parasite found in undercooked pork, (iv) Rubella (German measles) caused by the rubella virus, (v) Mumps, caused by a virus (vi) Rabies, a viral infection transmitted through animal bites, and (vii) AIDS or HIV, caused by the human immunodeficiency virus.
Various types of brain infections can develop different symptoms. However, in general, people older than 2 years with a bacterial infection might develop high fever, severe headaches, stiff neck, nausea and vomiting, discomfort looking into a bright light, a skin rash, confusion, sleepiness. Newborns may be unusually fussy, irritable, and sleepy. Seizures could also develop in the late stages of the disease.
Early diagnosis and treatment are extremely important with brain infections. The definitive diagnosis of meningitis is usually derived from a lumbar puncture, during which spinal fluid is obtained from a spinal tap and sent to a lab for analysis. A CT scan or other standard lab work and neurological examination may also be performed.
Treatment for the bacterial infection is usually accomplished through intravenous antibiotics. Steroids may also be given to reduce brain swelling. Acutely ill patients should be given I.V. antibiotics within 30 minutes of being evaluated in the emergency room.
Stroke Brain Injuries
What is a stroke? A stroke occurs when a blood clot blocks an artery or blood vessel in the brain or when a blood vessel breaks thereby interrupting the blood flow to an area of the brain.
When a stroke occurs, it kills brain cells in the immediate area. Death of these brain cells causes the release of chemicals that can kill brain cells in a larger surrounding area of brain tissue. This can happen at a fast pace. In fact, the “window” for interventional treatment of a stroke is about six hours.
There are two types of strokes: hemorrhagic strokes and ischemic strokes. Ischemic strokes occur when a blood clot blocks or plugs a blood vessel in the brain. A hemorrhagic stroke occurs when a blood vessel ruptures or breaks in the brain. Ischemic strokes occur in two ways:
Embolic stroke and Thrombotic Stroke. In embolic strokes, a blood clot forms in another part of the body (usually the heart), and travels through the bloodstream to the brain. When it arrives in the brain, the clot lodges in a blood vessel causing a stroke. In thrombotic strokes, blood flow is impaired because of a blockage to one or more of the arteries supplying blood to the brain.
Most stroke patients do not present until 24 hours or more after its onset. In fact, too few adults over the age of 50 cannot name a single symptom of stroke.
The five most common symptoms of stroke are (i) sudden weakness or numbness in the face or an extremity(especially on one side of the body) (ii) sudden vision trouble in one or both eyes; (iii) trouble speaking or understanding (sudden confusion); (iv) sudden severe headache of unknown origin; and (v) sudden dizziness or loss of balance or coordination.
Treatment of strokes may depend on the type of stroke. For instance, ischemic strokes are often treated with drugs called thrombolytics. This class of drugs help reestablish cerebral circulation by dissolving the clots that obstruct blood flow. Another class of drugs used to treat strokes are called neuroprotectives. These drugs work to minimize the effects caused by the release of chemicals following the death of brain cells. Another potential treatment for an acute stroke is called Oxygenated Fluorocarbon Nutrient Emulsion Therapy (OFNE). OFNE delivers oxygens and nutrients to the brain through the cerebral spinal fluid. Neuroperfusion is an experimental treatment for strokes that involves rerouting oxygen-rich blood through the brain to prevent damage from an ischemic stroke.
Use of diagnostic imaging devices such as an MRI or CT scan can help the physician determine whether the stroke is ischemic or hemorrhagic. This is an important determination to be made before therapy is instituted.