Category Archives: General

Subdural Hematomas and Hygromas Simplified

There’s a lot of confusion about subdural pathology after head trauma. All subdural collections are located under the dura, on the surface of the brain. In some way they involve or can involve the bridging veins, which are somewhat fragile and get more so with age.

Head trauma causes a subdural hematoma by tearing some of these bridging veins. Notice how thick the dura is and how delicate the bridging veins are in the image below.


When these veins tear, bleeding ensues which layers out over the surface of the brain in that area. If the bleeding does not stop, pressure builds and begins compressing and shifting the brain. A subdural hematoma is considered acute from time of injury until about 3 days later. During this time, it appears more dense than brain tissue.

After about 3-7 days, the clot begins to liquefy and becomes less dense on CT. Many hematomas are reabsorbed, but occasionally there is repeated bleeding from the bridging veins, or the hematoma draws fluid into itself due to the concentration gradient. It can enlarge and begin to cause new symptoms. During this period it is considered subacute.

It moves on to a more chronic stage over the ensuing weeks. The blood cells in it break down completely, and the fluid that is left is generally less dense than the brain underneath it. The image below shows a chronic subdural (arrows).


Hygromas are different, in that they are a collection of CSF and not blood. They are caused by a tear in the meninges and allow CSF to accumulate in the subdural space. This can be caused by head trauma as well, and is generally very slow to form. They can lead to slow neurologic deterioration, and are often found on head CT in patients with a history of falls, sometimes in the distant past. CT appearance is similar to a chronic subdural, but the density is the same as CSF, so it should have the same appearance as the fluid in the ventricle on CT.

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AAST 2013: Practice Guideline For Open Fractures

Evidence based guidelines continue to be part of the practice of medicine. They seek to standardize what we trauma professionals do to manage common clinical problems. A new orthopedic guideline was evaluated at the University of Michigan and the results are being reported at the upcoming AAST meeting in San Francisco.

There is considerable variation in the management of open fractures, ranging from timing of washout/repair, grading, and antibiotic management. The U of M group standardized the way they administered antibiotics in these patients. They implemented a protocol as follows:

  • Gustilo Grade I or II – cefazolin for 48 hours (clindamycin if allergic)
  • Gustilo Grade III – ceftriaxone for 48 hours (clinda or aztreonam if allergic)
  • No aminogyclosides, penicillin or vancomycin

They studied their results in 174 patients with open femur or tib/fib fractures (101 pre-protocol and 73 post; one apparently had both areas fractured). Risk adjusted surgical infection rates were calculated using the National Health Safety Index risk index, which is calculated using the ASA score, the wound classification, and the duration of the operative procedure. 

Here are the factoids:

  • The use of aminoglycosides and vancomycin decreased from 54% to 16%
  • Skin and soft tissue infection rates were not different (21% pre and 25% post)
  • People did not change their fracture grading to “game” the system
  • Infections with antibiotic resistant organisms or MRSA were similar in the two groups
  • The authors did not report time to operation in these open fractures

Bottom line: This is a good first shot at standardizing antibiotic use in patients with open fractures. The numbers are very small, and time to OR was not taken into account. Whereas the 8 hour rule for open fractures was dogma and has pretty much been discounted, antibiotic use is a case of “every man for himself.” It is important to continue this work, because I’m sure there will be cost and education benefits from following a protocol like this. More numbers need to be generated, and anyone who adopts this protocol now needs to closely watch their soft tissue and bone infection results in their PI process.

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Reference: Evidence-based protocol for prophylactic antibiotics in open fractures: improved antibiotic stewardship with no increase in infection rates. AAST 2013 Paper 62.

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The Newest Trauma MedEd Newsletter Is Here!

The August newsletter is now available! Click the image below or the link at the bottom to download. This month’s topic is trauma centers. 

In this issue you’ll find articles on:

  • The value of trauma center care
  • Benefit of transport to a trauma center
  • Going from Level II to Level I
  • Financial triage – the wallet biopsy
  • Is there a shortage of on-call specialists
  • Why do trauma patients get readmitted?

Subscribers had the newsletter emailed to them last weekend. If you want to subscribe (and download back issues), click here.


Download the newsletter here!

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Tomorrow! Trauma Education: The Next Generation

Thursday, September 5 – 8am to noon Central time (1-5pm GMT)

Conference details here!

Link to the live web stream here!

This conference is less than 24 hours away! It is designed to provide high quality trauma education for physicians, nurses, and paramedics in a fast paced and innovative format.

Presentations include:

  • You think you know… – why we still believe trauma myths and how to bust them
  • Dislocated hip reduction techniques
  • Field amputation: indications, challenges, techniques
  • Finger thoracostomy – from Scott Weingart!
  • Burn size estimation
  • Nursing considerations in burn patients
  • Keeping rare but critical knowledge fresh
  • Intraosseous tips
  • E-FAST
  • Disruptive innovation in education
  • Curbside consults – we ask specialists the questions you always with you had

All of this, delivered in short, easy to digest presentations and videos!

For those of you unable to attend the live event at the Minnesota History Center in St. Paul, join our live web stream. Submit questions or comments to the presenters in real time via #TETNG13 on Twitter. See you there!

Link to the live web stream here!

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