Glossary of Terms:

Compression ? the act of applying pressure to an area of the body. In this case, the term refers to "axial loading," in which the weight of the still-moving body is driven against the stationary part of the body, such as when the head hits the windshield of a vehicle.

Endotoxin ? a heat-stable toxin found primarily in the cell wall of gram-negative bacteria.

Flexion ? an inward movement of a skeletal joint that decreases the angle between two connecting bones, such as bending the elbow.

Gram-Negative/Positive ? a form of bacteria classified by its reaction to a dye known as the gram stain. A gram-negative bacterium has a single-layered cell wall that does not retain the stain. A gram-positive bacterium has a multi-layered cell wall that retains the stain and turns blue after the staining process.

Histamine ? released during allergic reactions, this compound acts as a vasodilator and decreases blood pressure. It also stimulates gastric secretions and constricts bronchial smooth muscle.

Hyperextension ? a position of extreme or abnormal extension.

Kawasaki Disease ? otherwise known as mucocutaneous lymph node syndrome, this is a febrile disease of unknown etiology that generally occurs in children less than 2 years of age.

Penetration ? injury created when an object pierces the skin and passes into the deeper tissues or into a cavity.

Peristalsis ? a wavelike contraction of smooth muscle that forces food and other substances through their respective systems.

Petechiae ? tiny red or purple spots that appear on the skin as a result of bleeding under the skin.

Rotation ? a basic motion allowed by many joints in the body, exemplified by the head turning on its axis.

Tachycardia ? an abnormal circulatory condition in which the heart contracts regularly but at a rate greater than 100 beats per minute.

Transection ? a cross section or cut across of tissue, an organ or other body part. In this case, the term refers to severance of the spinal cord.

LET?S TAKE A LOOK:

What thoughts race through your mind as you leave the station, and pull in behind the engine company? Are you wondering whether the injuries will be severe, or minor, as in most of the incidents you see? Or are you anticipating hemorrhagic shock, or perhaps head or chest injuries? Whatever your thoughts may be, you probably won?t be thinking of neurogenic shock?a form of vasogenic shock that results from injury to the spinal cord. But did you know that approximately 10,000 to 12,000 serious spinal injuries occur each year, nearly all of which result in permanent disability? And, sadly, the majority of these new victims are less than 30 years old.

Early recognition and prompt treatment of vasogenic shock can be crucial to patient outcome. This article reviews neurogenic shock, and septic shock, another type of vasogenic shock caused by overwhelming infection.

Case Presentation 1

On arrival at the scene, EMTs find the driver of the pickup truck standing by his vehicle, visibly upset but apparently not injured. The driver of the car is found slumped over the steering wheel, conscious but not moving. His respirations are rapid and shallow, and obvious use of accessory neck muscles is evident each time he takes a breath.

The patient?s head is immediately immobilized. Further examination reveals no obvious tracheal or chest injury, and lung sounds are decreased in the bases, with clear breath sounds in the upper lobes. His vital signs are: blood pressure ? 90/60; pulse ? 64/min.; and respirations ? 30/min. His extremities are warm and pink, while his face is pale, cool and clammy. No external bleeding noted. Capillary refill is slow, and a neurological check of all extremities reveals no response (flaccid).

The EMTs apply a cervical collar and rapidly but carefully extricate and immobilize the patient on a long backboard. They initiate oxygen via nasal cannula at 6 lpm with assistance from a bag-valve mask (BVM) and assist the patient?s respirations as needed enroute to the hospital. Cervical spine X-rays taken at the local community hospital reveal a C3-C4 fracture/dislocation. The patient remains immobilized, an IV is started, and he is flown to a regional trauma center, where the diagnosis of C3-C4 fracture is confirmed along with that of a completely severed spinal cord. Skull tongs are placed, and surgery is performed to fuse and wire the fractures. After a rocky course in the intensive care unit, where he develops an infection, the patient is transferred to a rehabilitation center and spends the following year in intensive therapy. He now lives with his parents, with his mother serving as his major caregiver.

Discussion

The cord itself ends at the L1-L2 position. Injury to a specific area results in loss in function below the level of injury. For example, a C2-C4 fracture results in total paralysis from the neck down (see figure 1 for specific areas). The following are different types of spine/spinal cord injuries:

• Flexion
• Penetration
• Flexion/rotation
• Hyperextension
• Compression

Pathophysiology

Sympathetic nervous system fibers are located in the spinal cord. Injury to the spinal cord can damage these fibers and interrupt nervous system control, which results in neurogenic shock. Unable to receive messages from the brain, the sympathetic system?s normal responses are lost. Without the balance of the sympathetic system, the parasympathetic system is left unchecked, causing bradycardia and vasodilation. This vasodilation leads to a pooling of blood in the extremities, which results in pink, warm, dry skin. If one contrasts neurogenic shock with hemorrhagic shock, the differences become apparent. (See Table 1.)

The pooling of blood also causes a backup in the cardiovascular system, and cardiac output (measured by taking the blood pressure) drops. Another effect of blood pooling is hypothermia. The patient will quickly become hypothermic as vasodilation and the resultant pooling of blood allows the body to "radiate" heat, leading to rapid cooling. If the injury is at C2-C4, loss of control also affects the phrenic nerve, which innervates the diaphragm, the major muscle of breathing. When this occurs, the diaphragm is unable to contract and relax normally, causing difficulty breathing.