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Second impact syndrome after a car accident: What is it, and what’s the typical treatment?

by | Nov 28, 2016

Second impact syndrome after a car accident

Concussions are the mildest form of traumatic brain injury, and they occur after an impact to the head. Car accidents victims often suffer concussions after hitting their heads during the crash or experiencing whiplash during the sudden deceleration, causing the brain to shake within the skull.

One concussion is bad enough, but fortunately it is usually not life-threatening. Most people recover fully within a month of the accident. A second concussion before the first brain trauma has fully healed, however, is quite serious, and it is often fatal. That next blow to the head can result in Second Impact Syndrome (SIS), in which the brain swells and/or hemorrhages.

The Second Impact

SIS is a catastrophic injury, and many victims do not survive. They succumb shortly after the second head injury, usually within five minutes as the respiratory system fails. Symptoms are immediate, and include:

  • Dilated pupils
  • Loss of consciousness
  • Respiratory problems

An SIS is always a medical emergency, with the victim requiring immediate treatment.

Emergency Treatment

If the victim gets to a hospital quickly enough, there is hope. Immediate stabilization is necessary, and physicians must focus on the victim’s respiratory distress and circulation. The patient may receive mannitol, a sucrose-like substance used to reduce pressure within the skull. Neurosurgery is often required. It’s a long, hard road ahead, and the patient may remain hospitalized for weeks or months. Even if the patient survives, virtually all SIS victims will suffer some sort of lifelong disability. Common impairments include:

  • Memory loss
  • Mobility problems
  • Neurological issues.


Anyone who has suffered a concussion in a car accident must take care to prevent a second head injury for the next several weeks. Of course, no one deliberately wants to cause head trauma, but it is imperative that victims take as few risks as possible until the doctor clears them. This means no playing sports, riding bicycles or participating in any activities that include the risk of falling. If the victim’s type of employment poses hazards, they should not perform those jobs without a physician’s approval.

If you or a loved has suffered traumatic brain injury or second impact syndrome after a car accident, a personal injury attorney may help you at this difficult time. Call us at 602-283-4122 to schedule a consultation.

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