Traumatic Brain Injury Health Article

Diagnosis

Recognizing a serious head injury, starting basic first aid, and seeking emergency medical care can help the injured person avoid disability or even death. When encountering a potential TBI, it is helpful to find out what happened from the injured person, from clues at the scene, and from any eyewitnesses. Because spinal cord injury often accompanies serious head trauma, it is prudent to assume that there is also injury to the spinal cord and to avoid moving the person until the paramedics arrive. Spinal cord injury is a challenging diagnosis; nearly one-tenth of spinal cord injuries accompanying TBI are missed initially.

Signs apparent to the observer that suggest serious head injury and mandate emergency treatment include shallow or erratic breathing or pulse; drop in blood pressure; broken bones or other obvious trauma to the skull or face such as bruising, swelling or bleeding; one pupil larger than the other; or clear or bloody fluid drainage from the nose, mouth, or ears.

Symptoms reported by the injured person that should also raise red flags include severe headache, stiff neck, vomiting, paralysis or inability to move one or more limbs, blindness, deafness, or inability to taste or smell. Other ominous developments may include initial improvement followed by worsening symptoms; deepening lethargy or unresponsiveness; personality change, irritability, or unusual behavior; or incoordination.

When emergency personnel arrive, they will stabilize the patient, evaluate the above signs and symptoms, and assess the nature and extent of other injuries, such as broken bones, spinal cord injury, or damage to other organ systems. Medical advances in early detection and treatment of associated injuries have improved the overall out-come in TBI. The initial evaluation measures vital signs such as temperature, blood pressure, pulse, and breathing rate, while the neurological examination assesses reflexes, level of consciousness, ability to move the limbs, and pupil size, symmetry, and response to light.

These neurological features are standardized using the Glasgow Coma Scale, a test scored from 1 to 15 points. Each of three measures (eye opening, best verbal response, and best motor response) is scored separately, and the combined score helps determine the severity of TBI. A total score of 3 to 8 reflects a severe TBI, 9 to 12 a moderate TBI, and 13 to 15 a mild TBI.

Imaging tests reveal the location and extent of brain injury and associated injuries and therefore help determine diagnosis and probable outcome. Sophisticated imaging tests can help differentiate the variety of unconscious states associated with TBI and can help determine their anatomical basis.

Until neck fractures or spinal instability have been ruled out with skull and neck x rays, and with head and neck computed tomography (CT) scan for more severe injuries, the patient should remain immobilized in a neck and back restraint.

By constructing a series of cross-sectional slices, or xray images through the head and brain, the CT scan can diagnose bone fractures, bleeding, hematomas, contusions, swelling of brain tissue, and blockage of the ventricular system circulating cerebrospinal fluid around the brain. In later stages after the initial injury, it may also show shrinkage of brain volume in areas where neurons have died.

Using magnetic fields to detect subtle changes in brain tissue related to differences in water content, the magnetic resonance imaging (MRI) scan shows more detail than x rays or CT. However, it takes more time than the CT and is not as readily available, making it less suited for routine emergency imaging.

For patients with seizures or for those with more subtle episodic symptoms thought possibly to be seizures, the electroencephalogram (EEG) may reveal abnormalities in the electrical activity of the brain or brain waves. Other diagnostic techniques that may be helpful include cerebral angiography, transcranial Doppler ultrasound, and single photon emission computed tomography (SPECT).