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Understanding head injuries

Posted By Jonathan Nadler, MD On January 18, 2017 @ 9:30 am In Brain and cognitive health,Injuries,Prevention,Safety | Comments Disabled

Ski season is here, and I am reminded of the story of Natasha Richardson (Liam Neeson’s wife), who tragically died of a head injury while skiing without a helmet in 2007. Here in the emergency department, we see many patients with concern for head injuries. We factor what may have caused the injury, your age, what we find when we examine you, the timing of the incident, the medicines you take, as well as some other factors, when deciding whether to do a CT scan or admit you to the hospital.

When a head injury causes bleeding in the brain

Ms. Richardson died of an epidural hematoma, one of several types of brain bleeding, but arguably one of the most severe.

Bleeding inside the skull can occur in several different areas. The brain is covered by three layers of tissue called the meninges. If bleeding occurs between the skull and the outermost brain tissue layer (the dura), it is called an epidural hematoma. These usually occur from high-pressure bleeding from an artery and can rapidly expand, putting pressure on the brain tissue and leading to death within hours. These types of bleeds are almost always treated surgically. Epidural hematomas usually result from high impact mechanisms, and trauma to the sides of the head, near where the larger arteries lie.

Bleeding underneath the dural layer of tissue, outside the brain tissue, is usually from a subdural bleed. This is generally a low-pressure bleed from a vein. When found, they may be monitored or treated surgically, depending on the size of the bleed as well as many other factors. This type of bleeding is more common after age 60, as the veins in the brain become slightly more taut due to natural shrinking of the brain tissue. These tight “bridging veins” are more easily sheared with a fairly low impact.

Bleeding inside the brain can be divided into subarachnoid or intraparenchymal, depending on the exact location. These bleeds, when caused by trauma, are generally treated without surgery unless they are very large.

Blood thinners such as Coumadin, Xarelto, Eliquis, Lovenox, or even Plavix put you at higher risk for dangerous bleeding after an injury. There are reversal agents for some of these medicines, but not all.

One thing to note is that while all of these types of bleeding can be seen on CT scanning, occasionally very small bleeds can be missed. Additionally, sometimes bleeding occurs several hours to days after the initial injury (delayed bleeding). Routine admission is not recommended, but if symptoms are suddenly worsening after being discharged from a hospital, please return to the emergency department for a repeat evaluation.


Many people are worried about concussions, in part because there has been much press about them in football players and children. I see many people come into the ED, requesting a CT scan to see if they have a concussion. Unfortunately, we can’t see a concussion on a CT scan. A concussion is defined by a constellation of symptoms, generally: headache, dizziness, nausea, difficulty focusing, light sensitivity, and problems with balance and coordination. Symptoms usually last a few days, but can sometimes last weeks or even months. The most important factor that we know of right now to prevent long term problems, is to rest your brain after a concussion, to allow it to heal, and to avoid another injury on an already bruised brain. It’s okay to sleep, and frequent awakenings are no longer routinely recommended.

If you unfortunately need to be seen in an emergency department after an accident, know that we have guidelines (such as the Canadian CT head rule) that help us determine who needs CT scanning. We factor the risks of radiation against the likelihood of an injury, and so please do not take personally when we decide that you do or do not need to have an imaging test.

Please wear a helmet when you’re out on those slopes. Stay safe!

Related Information: Harvard Health Letter

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