Whiplash

Whiplash, a colloquial term, describes a range of injuries to the neck caused by a sudden distortion, commonly associated with motor vehicle accidents. The medical terms "Cervical acceleration–deceleration" (CAD) and "whiplash associated disorders" (WAD) are used to describe the injury mechanism and subsequent symptoms.

Signs and Symptoms

Symptoms of whiplash include neck and back pain, referred pain to the shoulders, sensory disturbances like pins and needles, and headaches. Symptoms may appear immediately or days after the injury, often affecting the neck and middle of the spine. Cognitive symptoms such as distraction and irritability are common and may indicate a poorer prognosis.

Cause

Whiplash injuries result from forceful hyperextension followed by hyperflexion of the cervical vertebrae, primarily affecting the nuchal and Anterior Longitudinal Ligaments. Common causes include rear-end vehicle collisions, sports injuries, and other high-impact activities. Severe cases may involve a coup contrecoup brain injury, where the brain is jolted within the cranium.

Mechanism

Whiplash involves a sudden strain on the neck's muscles, bones, and nerves. The injury process includes four phases: initial position, retraction, extension, and rebound. During the retraction phase, the spine forms an S-shaped curve, causing most injuries in the lower cervical vertebrae (C-5 and C-6). The extension phase involves full extension of the cervical vertebrae and head, limited by the head restraint.

Pathophysiology

The interaction sequence in a collision can be detailed as follows:

• 0 ms: Vehicle impact begins, occupant remains stationary.
• 100 ms: Seat accelerates, pushing the torso forward while the head remains stationary.
• 150 ms: Torso accelerates forward, lower neck pulled forward, head hyper-extends.
• 300 ms: Head and torso move forward, neck hyper-flexes.

Diagnosis

Diagnosis involves patient history, head and neck examination, and X-rays to rule out fractures. The Québec Task Force (QTF) categorises whiplash-associated disorders into five grades, from no symptoms (Grade 0) to severe neck complaints with fractures or dislocations (Grade 4).

Prevention

Preventive measures focus on car seat design, particularly head restraints. Effective head restraints limit rearward head displacement to minimise neck hyperextension. Types of head restraints include integrated, adjustable, active, and automatically adjusting variants. Proper adjustment of head restraints by vehicle occupants is very important. For optimal protection, the restraint should be at least as high as the head's centre of gravity and positioned close to the head.

Management

Rehabilitation

Rehabilitation aims to prevent chronic whiplash syndrome. Early mobilisation is recommended over using a soft collar. Active treatments involve light exercises to maintain normal neck function. Passive treatments like acupuncture and massage may complement active exercises. For chronic whiplash, a structured rehabilitation programme helps manage pain and improve daily activities.

Medications

Non-narcotic analgesics and non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed for grades 1-3 of whiplash-associated disorders, with NSAIDs limited to three weeks. Botulinum toxin A can be used for muscle spasms but requires repeated injections.

Prognosis

Whiplash outcomes range from mild pain to severe disability, with around 50% of individuals experiencing lingering symptoms. Chronic pain after whiplash is linked to persistent inflammation and altered cerebral blood flow. There is moderate evidence that temporomandibular joint dysfunction (TMD) may occasionally follow whiplash injuries.

Epidemiology

Whiplash is a common nonfatal injury from car crashes, with more than one million cases annually. It can occur at low speeds and is more frequent in middle-aged individuals. Long-term outcomes show that many patients remain symptomatic, with significant economic costs associated with whiplash injuries.

Incidence

Whiplash incidence varies globally, influenced by access to healthcare and insurance. Studies indicate that compensation expectations may affect the reporting and prognosis of whiplash injuries.

---

Self-assessment MCQs (single best answer)

Which term is NOT commonly used to describe whiplash injuries?

Which symptom is NOT commonly associated with whiplash?

What is the most common cause of whiplash injuries?

During which phase of the whiplash mechanism does the spine form an S-shaped curve?

In the diagnosis of whiplash, what does Grade 4 in the Québec Task Force (QTF) classification indicate?

Which of the following is a recommended preventive measure for whiplash?

What is the primary goal of rehabilitation in whiplash management?

For which grades of whiplash-associated disorders are non-narcotic analgesics and NSAIDs commonly prescribed?

Which of the following is NOT a factor influencing the global incidence of whiplash?

Which statement is TRUE about the prognosis of whiplash?