EM REMS

Fight broke out at the local prison and this man was shot in the face with a rubber bullet…

The “brain” weighting CT (first figure) shows a ruptured globe with hemorrhage into the orbit.  The remainder of the figures are in “bone” weighting and show various fractures:

1. Sagittal view of a comminuted fracture of the ethmoid sinus (medial orbital wall)
2. Sagittal view of a comminuted fracture of the maxillary sinus (inferior orbital wall)
3. Sagittal view of a posterior orbital fracture
4. Coronal view re-demonstrating the ethmoid and maxillary sinus fractures

This poor fellow ended up losing his eye and going back to prison.

Author:  Russell Jones, MD

A couple days ago I asked what other imaging modality is recommended with knee dislocations.  The answer is CT angiogram of the lower extremity.  As you recall we had an image of a patient with a knee dislocation, here is his CT angiogram of the left lower extremity:

This image shows no evidence of injury to the popliteal artery with contrast reaching the distal vasculature.  Please note that the bolus timing was optimized only for the left side thus the right side is not completely imaged.  Remember this imaging modality in knee dislocations to rule out vascular injury.

I came across an article written in 2007 published in Emergency Medicine Clinics of North America which has a good review section on knee dislocation (1).  The article also discusses other important emergency medicine orthopedic injuries.  According to the article, popliteal artery injury occurs in approximately 40% of high-energy knee dislocations.  Peroneal nerve injury occurs in 14-35% of cases.  Some classic mechanisms of dislocation include when a car bumper strikes the femur above a planted leg and when the knee strikes the dashboard in a high-energy frontal MVC.  Patients with findings consistent with arterial injury need emergent vascular surgery, ideally within 6 hours.  Compartment syndrome can occur and a delay in repair can result in need for amputation.  Furthermore, delayed spasm or compartment syndrome can occur and it is recommended that all patients be observed for 24 hours with serial clinical exams.

Author:  Russell Jones, MD

References

1.  Newton EJ, Love J.  Emergency Department Management of Selected Orthopedic Injuries.  Emerg Med Clin N Am 25; 2007: 763-793.

This patient has a knee dislocation with an avulsion fragment seen in the joint space.  The tibia/fibula are both rotated facing medial with the patella displaced to the medial side as well.  Lateral projections were unable to be obtained due to the patient being very uncomfortable however clinically the tibia seemed to be posterior to the distal femur. 

MRI later showed complete tears of the anterior and posterior cruciate ligaments as well as the medial collateral and fibular collateral ligaments.  It also showed the tibial plateu fracture and a compression fracture of the distal femur.

What other imaging would you recommend for this patient in the emergent setting?

Author:  Russell Jones, MD

This patient came in shortly after a high speed motor-vehicle collision.  Here is the patient’s CT abdomen with IV contrast:

This is an interesting CT as it demonstrates “active extravasation” of IV contrast.  The patient has a large left kidney fracture.  You can see a hematoma surrounding the area where you would expect the kidney.  In that hematoma there is a mix of low attenuation material and high attenuation material.  Both of these represent blood; the high attenuation is contrast material that leaking into the hematoma (some of the high attenuation includes perfusing kidney fragments but most of it is extravasating contrast).  The low attenuation is blood that collected before IV contrast administration.

Practically speaking, this means that there is active bleeding into this hematoma.  This is BAD and represents a large amount of bleeding that needs to be stopped.  The patient was actually relatively stable and was taken to interventional radiology where the offending lesion was embolized.

Author:  Russell Jones, MD

This is an image provided by one of our UC Davis resident physicians:

Great example of a lunate dislocation!

The key portion of the film above is the half-moon shaped bone (Lunate) which is dislocated in the palmar direction and has a “spilled teacup” appearance (it is rotated from its normal position with the concave portion of the bone facing the distal fingers).

The AP view on this patient is also interesting.  It shows a “Piece of pie” sign, also frequently found with lunate dislocation.  This is an abnormal triangular hyperdensity seen in the lunate on the AP projection (can also be seen in perilunate dislocation).

The distinguishing feature of this radiograph to differentiate between perilunate and lunate dislocation is the alignment on the lateral projection.  The capitate and distal radius are still aligned, the lunate is dislocated.  In a perilunate dislocation the lunate will not have a “spilled teacup” rotation and the capitate will be dorsally displaced off the alignment of the distal radius.  An example of a perilunate dislocation:

Tip:  on lateral wrist xrays, always draw a line through the distal radius, lunate, and capitate.  It should look like an apple sitting in a teacup on a saucer.

Author:  Russell Jones, M.D.

Image Contributor:  Dane Stevenson, M.D.

This gentleman was in a trauma and sustained an acetabular fracture.  Here is a standard AP pelvis, “Judet” view, CT with bone windows, and a CT 3-dimensional reconstruction image.  On the plain films you can see contrast in the bladder, this is residual from a urogram looking for bladder injury (no injury identified):

There are several ways to image acetabular fractures:

1.  Standard AP pelvis films:  this is a good screening imaging modality

2.  ”Judet” films:  xray images that can further delineate the extent, type of acetabular fracture.  wikiRadiography Judet Views

3.  CT pelvis with 3-dimensional reconstruction.  This is the “cadillac” of imaging that orthopedic surgeons get the most pre-operative information from.  Judet Views have largely been replaced by this imaging modality as it offers much more information for the surgeon.  On a PACS radiology system the images can be rotated, flipped to see the extent of the injury as if you were holding the pelvis in your hand.  Its pretty awesome.

Keep in mind that fractures of the acetabulum can be occult.  If you obtain plain films that look normal and the patient cannot bear weight, consider CT imaging for a better look.  MRI can also be of value much like an occult femoral neck fracture.

Here is a free, extensive discussion of imaging acetabular fractures (including a discussion about types of acetabular fractures) available online from Radiographics:

Acetabular Fractures

Author:  Russell Jones, M.D.

References

1.  Judet Views.  http://www.wikiradiography.com/page/Judet+Views

2.  Potok PS, Hopper KD, Umlauf MJ.  Fractures of the Acetabulum:  Imaging, Classification, and Understanding.  Radiographics. 1995 Jan; 15(1), 7-23.

…and another head bleed!

This is a subdural hematoma with “midline shift.”  I posted late last year on the difference between subdural and epidural blood characteristics.  See GSW Head for the prior post. 

This is a good example of midline shift.  As you can see above the falx (linear hyperattenuated structure at midline) is bowing away from the subdural hematoma.  It is also compressing the ventricles (seen best on the second image).  What does this mean?  It means the subdural is taking up enough space in the closed intracranial vault to put pressure on the brain.  We don’t like pressure on the brain!  This can cause herniation.  Herniation is bad for one’s health.  Call Neurosurgery or get them to a hospital with neurosurgery capability STAT.

Author:  Russell Jones, MD

This person came in after a high speed motor vehicle collision.  Their main complaint was neck pain near C-7:

As you can see under bone windows there is a fracture of C7.  One could stop here and be satisfied that you see the primary pathology in which you were interested.  However, anytime you look at a CT you should pay attention to all parts of the image.  Secondary findings are very common, especially in trauma.  When assessing a CT image, one should change windows on the image to adequately look at all types of tissue that are present.  In a cervical spine CT, the top of the lungs are usually visualized in the catchment area as you get to the upper t-spine.  If you change the window to “lung” windows this is what you’ll see:

This person also has an anterior, small pneumothorax!  This could have easily been missed if not changing the window to look at the lungs.

One of the basics of CT imaging is to  change windows for all types of tissue.  In the head, your main window change will be from “brain” to “bone” to adequately visualize bony structures of the calavarium.  In the abdomen you should switch to “lungs” to visualize the lungs as well as switch to “bone” to visualize the ribs, pelvis, and spine.  There are many other examples of this principle, but we will leave it at this for now.

Author:  Russell Jones, MD

We’ve all seen it…the dude that had two beers after church and got jumped by a couple guys while he was minding his own business.

This Facial CT demonstrates several comminuted fracture lines through the mandible.  CT imaging is highly sensitive and specific for mandible fractures and is the imaging-of-choice in most emergency departments.  Plain films can also be obtained but subtle fractures can be missed; the extent and characterization of the fractures is much better identified on CT.

Its always difficult in the minor facial trauma to know when to pull the trigger and order a CT of the face…especially in the current environment of questioning CT utilization.  Some clinical exam findings that would increase your suspicion of mandibular fracture include (1):

1.  The patient having subjective feeling that their “teeth don’t fit.”

2.  Malocclusion.

3.  Anesthesia of the upper lip or chin (mental nerve distribution).

4.  Pain or tenderness near the anterior ear, especially with mandibular range-of-motion.  This is concerning for mandibular condyle fracture but also could represent TMJ strain, sprain, or dislocation.

An obvious deformity, laceration of the gingival area (indicating an open fracture), or severe mechanism are high concerns for mandibular fracture and CT imaging should be considered.  The “tongue blade test” (have the patient bite down on a tongue blade with their molars on both sides.  Negative test if the patient is able to break the tongue blade) has a 95% sensitivity in excluding injury in a patient with mild jaw pain and no obvious injury or instability (1).

Author:  Russell Jones, MD

References

1.  Bailitz J.  Trauma to the Face.  In:  Tintinalli JE, Stapczynski JS, et al.  Tintinalli’s Emergency Medicine:  A Comprehensive Study Guide.  7ed.

I admire radiologists for their medical vocabulary.  I was sent some images from one of my colleagues the other day demonstrating “pneumorrhacis.”  Being a simple minded ER doc, I had to look it up.

Pneumorrhacis:  air in the intra or extra dural space (1).  For a good, concise summary of this rare phenomena see Radiopaedia.org:

Pneumorrhacis

This patient was a trauma patient with a pneumothorax as the source of the air.  You can see on the CT there is air everywhere!  Its basically dissecting fasical planes in the neck, chest, and abdominal wall in addition to the extradural space.

Here is a brief review article discussing pneumorrhacis from the European Spine Journal (2).  It is available on PubMed for free download or from this link:

Pneumorrhacis article

Author:  Russell Jones, MD

Image Contributor:  Steve Glocke, MD

References:

1.  Pneumorrhacis.  www.radiopaedia.org

2.  Oertel MF, Kornith MC, Reinges MH, et al.  Pathogenesis, diagnosis, and management of pneumorrhacis.  Eur Spine J (2006) 15 (Suppl. 5):S636–S643