Whiplash

Definition

Whiplash is the mechanism that causes the neck injury often suffered in a rear-end automobile collision. People also use the same term, whiplash, to mean the resultant neck injury itself. Whiplash produces a wide range of symptoms, but almost all victims experience pain. About 1,000,000 whiplash injuries occur in the United States every year.

Description

An occupant of a car struck suddenly from the rear undergoes rapid acceleration and deceleration. The head and neck swing freely while the body remains supported by the seat and seatbelts. The rapid movement of the head causes variable amounts of hyperextension, hyperflexion, stretching, and twisting of neck structures, in a fashion similar to the snapping of a whip.

The structures often affected include muscles, ligaments, nerves, intervertebral disks, and spinal joints. Specific damage may range from minimal strains to complicated tears, hemorrhage, and joint injury, as shown by animal studies and autopsies of accident victims.

Causes and symptoms

Besides motor vehicle accidents, causes of whiplash include sports and other recreational activities, falls, and fights. Women tend to have more persistent symptoms than men do, perhaps because women's smaller neck muscles are more vulnerable.

Symptoms following a whiplash injury may begin immediately or any time up to a few days later. Symptoms include variable combinations of:

pain or stiffness in the neck, jaw, shoulders, arms, or back
dizziness
headache
loss of feeling in the upper extremities
problems with vision or hearing
problems with concentration
depression, anxiety, or other changes in mood

Symptoms may last for no more than a day or two, or may persist for months or years.

Diagnosis

Many patients with whiplash receive evaluation by emergency medical technicians (EMTs) at the scene of an accident, always starting with the ABCs of resuscitation: airway, breathing, and circulation. At the same time, in head or neck trauma, initial care providers always worry about the possibility of dangerous injury to the spine bones or spinal cord. Often, the EMTs will immobilize the neck in a stiff brace and strap the patient flat on a board, until a physician determines that it is safe for the neck to move. This minimizes the risk that any serious injury could progress and cause irreversible nerve damage. Unfortunately, this immobilization is usually very uncomfortable for the patient.

When such a patient arrives at the emergency department (ED), the nurse will further assess the patient for stable vital signs, proper alertness, and good ability to move and feel the extremities. A patient strapped to a spine immobilization board often demands to remove the neck brace and get up, but the nurse must ensure that the patient remains still until cleared by the physician. The nurse quickly asks the doctor to examine the patient.

Another danger is that a patient may vomit while immobilized. This presents a risk for aspiration of stomach contents, which can threaten breathing. The nurse must be alert to quickly turn the patient on the side, while still immobilized and with the neck brace still in place, to prevent this complication.

The physician obtains the patient's description of the event, then looks for injury to other organs, especially in the head, chest, abdomen, and back. The doctor will check for bony tenderness or limitation of movement, and examine the functions of deep tendon reflexes plus motor and sensory nerves. When the physician is confident that no injury threatens the spinal cord the patient is "cleared." The physician will remove the brace and free the patient from the rigid board.

The physician may order x-ray studies to exclude fracture or displacement of bone, but in typical whiplash these tests rarely show any abnormality. When there is severe or persistent pain or numbness, magnetic resonance imaging (MRI) may detect more subtle damage.

Treatment

Patients should apply ice in the first 24-48 hours. Physicians prescribe medicines such as ibuprofen (Motrin, Advil) or aspirin, acetaminophen, muscle relaxants, or narcotics (codeine, hydrocodone, Vicodin).

Use of soft cervical collars is controversial. Many doctors prescribe them, but some studies have shown that these devices prolong the return to normal activities. Physical therapy or exercises may reduce pain or limitation of movement.

Many patients use balms or salves, and seek alternative treatments such as chiropractic manipulation, biofeedback, acupuncture, or acupressure. In cases of protracted symptoms, patients may benefit from traction, ultrasound treatments, local injections of cortisone, or use of a nerve stimulator.

Prognosis

The course of an individual whiplash injury is unpredictable. Most people improve within a month, but 20% or more have symptoms that last longer than a year. The risk of greater symptoms increases for an unrestrained victim of a rear-end collision, or for one whose head is turned or tilted at the time of injury.

Controversy surrounds the role that accident-related litigation plays in delaying recovery from whiplash. An April 2000, article in The New England Journal of Medicine examined this issue. The authors showed a decreased incidence and improved prognosis of whiplash injury when the province of Saskatchewan changed to a new insurance claim system that eliminated payments for pain and suffering. However, other authors downplay the effect of psychosocial factors on recovery from whiplash.

Health care team roles

The EMT performs rescue, assessment, and initial treatment at the scene of an accident. A nurse in the ED or medical office also assesses the patient with whiplash. The nurse carries out physician orders for medication and treatments, monitors the patient throughout the stay, and instructs the patient and caregivers before discharge. The aide assists the nurse.

A radiology technician performs the x-ray or MRI studies. A physical therapist helps with exercise, massage, ultrasound, and other treatments. A social worker may coordinate later care.

Prevention

Proper adjustment of the automobile headrest is important to reduce the severity of a whiplash injury, because a headrest that does not come up behind the head offers no protection. Driving habits that reduce the frequency of abrupt stops make it less likely that a driver will suffer a rear-end collision.

KEY TERMS

Aspiration—The inhaling of stomach contents or other unwanted material, potentially leading to a form of pneumonia.

Hyperextension—Overstretching toward the back.

Hyperflexion—Overstretching toward the front.

Intervertebral disk—A cushioning structure between two adjacent spine bones.