This is an interesting X-ray of a newborn with respiratory distress:
What are the findings in this picture?
Answer to follow.
Author: Russell Jones, MD
October 14, 2014
The Ottawa Ankle Rules are a set of criteria that are designed to help clinicians identify which patients that present with acute ankle injuries require imaging. The 1992 paper which outlined the criteria (PMID:1554175) consisted of a prospective study of 750 patients who came into the Ottawa Civic and Ottawa General hospitals with acute ankle injuries. The study was designed to record each patient’s particular presentation (area of tenderness, amount of swelling, ecchymoses, etc) and see if any aspect of their presentation correlated with a fracture identified on subsequent imaging (i.e. if a patient has pain over the medial malleolus, how likely are images of that ankle to show a fracture?).
MD Calc has a good summary picture of the criteria here. I’ll summarize it below as well:
A series of ankle x-rays is necessary if:
There is tenderness in the malleolar zone (lateral or medial) AND bony tenderness at the posterior edge of the medial malleolus OR bony tenderness at the posterior edge of the lateral malleolus OR an inability to bear weight immediately and in the ED
There is tenderness in the midfoot zone AND bony tenderness at the base of the 5th metatarsal OR bony tenderness at the navicular OR an inability to bear weight immediately and in the ED
The picture on the link above is probably more helpful to visualize the algorithm. They note that 102 patients out of the 750 cohort had “significant” fractures and these criteria would have led to imaging on all of those cases. Also, they report that this criteria would have led to a 32.3% decrease in the number of radiographs ordered. The algorithm’s sensitivity was 100% and specificity was 40% for identifying fractures that were later confirmed by imaging. In other words, it was touted as a great screening tool since it was highly sensitive in picking up an ankle fracture.
(Note: The original criteria included an age stipulation, so that every patient with ankle pain [but not midfoot pain] over the age of 55 was recommended to get imaging. Additional research and subsequent modification of the algorithm proved that age was actually not a predictive variable. [PMID: 8433468])
Now on to a case:
Homeless male, in his 50’s, with ankle and foot pain after falling 10 feet. Walked into the E.D. with some pain, but had the ability to bear weight. Pt had swelling on exam, but no tenderness at the lateral malleolus, medial malleolus, mid foot or lateral foot.
The question is, do you get imaging on this patient?
Oh, look, it turns out we have criteria for that! And, in short, if you follow the Ottawa Ankle Criteria, the answer is no. The patient can bear weight and has no tenderness at any of the 4 areas that the criteria specifies, therefore according to the algorithm, imaging should not be ordered.
But we have a twist! This patient did indeed get ankle x-rays.
Why did this patient end up getting ankle x-rays despite not having met the Ottowa Ankle criteria?
Dr. Jones plays “devil’s advocate” in arguing against the use of the Ottowa Ankle Rules:
“Despite high negative likelihood ratio’s found on creation and validation of the Ottowa Ankle Rules, ED physicians are still ordering x-rays for most traumatic ankle complaints. Why? Because they are immediately available, low cost, and low radiation. Many of our radiology decision rules pertain to expensive tests that are 10-100 times the amount of radiation (CT head, CT c-spine) and/or may not be readily available. It is less practical to try and decrease a test that has little downside…such as an ankle radiograph.
There is usually significant comorbidity associated with many different types of ankle fractures including calcaneal and talar fractures (I mention these because in my experience these are the two fracture patterns that are missed by the Ottowa Ankle Rules despite their reported 100% sensitivity…see the case above). In our medicolegal environment in the United States, it is very difficult to defend missing an ankle fracture when you have a low cost, low radiation, readily available test at your disposal. One must take into account that it is nearly impossible to recreate an exam with our current medical documentation. A radiograph is an objective picture of a non-fractured ankle while a nicely worded exam is not so defendable in the eyes of a layman jury. You open yourself up to legal problems if you miss a high-morbitidy injury because you used a rule that “decreases medical costs and increases efficiency” (these are the main benefits of the Ottowa Ankle Rules). Courts are more patient-centered, they don’t care about our waiting room times!
We practice medicine taking into account more than just evidence-based medicine. Until the “standard of care” we are held up to in court is in line with evidence-based medicine, we will always have to take into account the burden of the medicolegal consequences. Be careful utilizing any clinical decision rules until they are universally accepted as standard of care among all ED physicians.
I personally use “shared decision making” with most of my decision rule utilization. My practice pattern using Ottowa Ankle Rules involves (1) A medical record documenting negative Ottowa Ankle Rules AND (2) a patient that understands the decision not to x-ray AND (3) the patient agrees. This situation is rare but I will sometimes not x-ray if all the above parameters are met. This is easier to defend if you happen to miss something by not getting an x-ray.
The above statement is of course my own opinion and practice pattern. Please utilize the Ottowa Ankle Rules as you feel fit and I appreciate any comments for and against their use in the ED.
-Russell Jones, MD”
So, there you have it. As is the case with many different areas of medicine, real-life practice varies from guidelines, rules and algorithms (even if they are backed up by multiple research studies) for various different reasons which include, but are not limited to differences in: availability of testing methods, medical setting, hospital policies, patient needs, legal considerations and the physician’s own interpretation of all of the above factors and the medical research/literature.
For students, this means that you’ll have to soon adapt yourself to an environment and way of thinking that takes multiple variables into account when it comes to decision making. Almost every patient is a different shade of grey, not black and white. After all, medicine is both art and science.
But, I digress from the patient. Can you spot the fracture in the above image? Answer below:
There is indeed a fracture of the calcaneus right around the inferior edge of the bone. Good thing this patient got imaging, right?
Author: Jaymin Patel
Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992 Apr;21(4):384-90. PubMed PMID: 1554175
Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J. Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA. 1993 Mar 3;269(9):1127-32. PubMed PMID: 8433468.
October 7, 2014
Back pain is one of the most frequent complaints in the ED. The vast majority of patients do not have a life threatening or highly morbid pathology. Unfortunately, this patient did:
This is a CT scan under bone windows. It shows erosive changes based around the L4-L5 disc, eroding into the inferior endplate of L4 and the superior endplate of L5. These findings are concerning for discitis-osteomyelitis. It is favored to have both acute
and chronic components.
Finding this pathology is somewhat like finding a needle in a haystack. However, pay attention to signs such as fever, repeat ED visits without a firm diagnosis, focal weakness, and predisposing factors such as IV drug abuse, history of endocarditis, or immunosuppression. Sedimentation rate and C-reactive protein are often elevated in this disorder (among others).
CT is a readily available, quick way to diagnose this pathology but it isn’t as sensitive as MRI. Plain films are not reliable but may show changes similar to the CT above. Nuclear medicine bone scans as well as PET scans can be used but are not commonplace in the ED.
Author: Russell Jones, MD
Image Contributor: Zachary Skaggs
September 30, 2014
This patient presented with wrist pain after a fall:
This is an example of a lunate dislocation. The lunate can be seen on the lateral view (blue arrow). It is dislocated quite a far distance. Also note that the lunate is not in its usual location on the AP view.
The above radiographs are not subtle. Keep in mind that lunate dislocation is sometimes not so obvious. We visited lunate and perilunate dislocation on a prior post (lunate). Stay tuned in the future for tips on reading wrist radiographs to avoid missing any subtle injuries.
Author: Russell Jones, MD
September 25, 2014
How many times have you had trouble with figuring out what type of cardiac device (e.g. pacemaker/defibrillator) a patient has implanted? A patient presented to our ED with chest pain, palpitations. He did not have his device card with them, no prior visits to our ED, and did not know the manufacturer of the device. How do you decide which company to call for interrogation?
Here is an article I found with radiologic characteristics of devices that can help identify which company produced the device. It has a great identification algorithm they coined the CaRDIA-X algorithm:
There are 5 major manufacturers currently: Medtronic, Boston Scientific, St. Jude, Biotronik, and Sorin Group. Each device manufactured by these companies have certain differentiating characteristics of can shape, battery shape, alphanumeric codes, capacitor shadows, coil types, etc. Turns out you can identify the manufacturer using the device characteristics on chest X-ray relatively easily.
In the case I was describing above the patient had an easily identifiable Medtronic device and we were able to get it interrogated. Our ED now has the algorithm posted at our doctor’s station so we can utilize it for device identification.
Author: Russell Jones, MD
Jacob S et al. Cardiac Rhythm Device Identification Algorithm Using X-Rays: CaRDIA-X. Heart Rhythm 2011; 8(6): 915-922.
September 15, 2014
This person fell from bike and won’t move their shoulder:
On initial evaluation we actually thought this person had a shoulder dislocation (glenohumeral dislocation) because of the significant deformity visible externally. They had the classic anterior “divot” on the shoulder and wouldn’t perform shoulder range of motion. We were somewhat surprised when we found an acromioclavicular (AC) separation instead.
This case is a good argument as to why often it is appropriate to obtain pre-reduction X-rays for possible shoulder (glenohumeral) dislocations. Unless the patient will allow a good exam, sometimes it is very hard to differentiate AC separation from glenohumeral dislocation without imaging. In this case, if we went directly to attempted “reduction” it would have been very difficult to “reduce” the shoulder! Hence the need for an X-ray.
There are six different types/degrees of AC separation that are summed up well on the following LearningRadiology.com webpage:
Author: Russell Jones, MD
1. Acromio-clavicular separation. www.LearningRadiology.com
September 11, 2014
This is a classic knee film in an elderly lady who fell. What is the finding and diagnosis?
Just anterior to the distal femur there is an example of lipohemarthrosis. Note the horizontal line seen in the suprapatellar pouch (blue arrow). This occurs when fat and blood have been released into the joint space and creates an interface (fats don’t mix with mostly water-based blood). The fat has been released from an occult fracture, most commonly a tibial plateau or distal femur fracture. If you can’t see the fracture it may be a good idea to obtain further imaging (CT or MRI) or refer the patient to an orthopedic surgeon.
Author: Russell Jones, MD
September 1, 2014
Here is the same CXR from last time.
Here’s some further information about the case:
Pt is a 52 y/o man with a history of smoking, atrial fibrillation, and HTN that presents to the ED today with a 2-3 day history of fatigue, weakness, fever, generalized body pains, drenching night sweats, increased urinary frequency, L ear discomfort, throat discomfort and blurry vision in the morning. The symptoms came on suddenly and have been constant since the beginning of the episode. The fatigue and weakness cause the patient to want to “drop into a hole” and sleep. His nightly sleep patterns have been disrupted by his night sweats and his increased urinary frequency. The night sweats are drenching and he often wakes up in the middle of the night with his shirt completely soaked. Around 8-9 AM in the morning he reports being cold and getting chills. He also has some lower sternal chest pain that occurs mostly with deep breathing. The pain does not radiate. The pt has a 30-35 year history of smoking cigarettes and drinking 15-20 alcoholic drinks/week. The pt stopped smoking yesterday with the intent to quit.
The pt has no change in appetite or weight, no new masses or lumps anywhere on his body and no syncope or LOC. The pt denies any history of similar symptoms. The pt denies any family history of these symptoms. The pt denies any sick contacts. The pt’s wife does not have similar symptoms. The patient has no N/V or history of recent travel. The pt was routinely tested for tuberculosis 2 years ago as part of an employment physical and the test was negative.
Vitals: BP 142/106 | Pulse 105 | Temp(Src) 100.6 °F (38.1 °C) (Oral) | Wt 228 lb (103.42 kg) | BMI 31.36 kg/m2 | SpO2 99%
General appearance – alert, well appearing, and in no distress; slightly pale
Eyes – PERRLA, EOMI
Ears – bilateral TM’s and external ear canals normal
Mouth – mucous membranes moist, pharynx normal without lesions
Neck – supple, no significant adenopathy
Lymphatics – no palpable lymphadenopathy, no hepatosplenomegaly
Chest – clear to auscultation, no wheezes, rales or rhonchi, symmetric air entry
Heart – normal rate, regular rhythm, normal S1, S2, no murmurs, rubs, clicks or gallops, no pericardial rub on auscultation with patient leaning forward
Abdomen – mild suprapubic ttp without rebound/guarding
Neurological – alert, oriented, normal speech, no focal findings or movement disorder noted, CN 2-12 grossly intact
Skin – normal coloration and turgor, no rashes, no suspicious skin lesions noted
With all of that in mind, let’s take a look at the x-ray again. The last post went through the ABCDE methodology to review the image and the A through D aspect was pretty well outlined there. The airway is patent, there is no obstruction and it lines up with the cervical spinous processes. The bones have no step-offs or other evidence of fractures and there are 10 ribs visible. The cardiac silhouette is not enlarged (in other words, not more than twice the width of the chest cavity) and the AP window sits between the aortic arch and pulmonary artery. The diaphragm has normal contour and the costo-vertebral angle is sharp.
The E is where things get interesting. One of the ways I like to do it is to try and look for asymmetry in the lung fields. And I think I see something!
The blue circle seems like a focal area of consolidation (either liquid or solid). That same “opacity” is not present on the corresponding place on the L lung field. I think its important to note that this finding has a large differential diagnosis attached to it, even if you put the finding on the x-ray in context with the case presentation. Most of the diagnoses on the list would be infectious, like TB or pneumonia, but other possibilities include lung cancer, edema, hemorrhage and systemic inflammatory conditions like sarcoidosis.
The radiologist read that image as most likely a case of lobar pneumonia. There was some hedging by the radiologist on the read because the lateral film was taken from L to R, therefore the opacity in the R lung field was very hard to see (that’s why I didn’t include a lateral view as well, but we can save that particular x-ray type for another post). In general, you want to get two views on any pathology on x-ray because it’s important to try and construct a 3D image in your head about where the pathology is located.
In any case, his patient presented with fever, cough, loss of energy, chills and body aches, with all of those symptoms having an acute onset. This makes an infectious process more likely (I say “more likely” because as everyone in medicine learns at some point or another, it is very dangerous to talk and think in absolutes). He was treated empirically with antibiotics for pneumonia.
Hopefully this example helps you to have a system in place when you look at any chest x-ray. If you have any questions, feel free to drop them in the comments and I’ll do my best to answer them. Also, if you have any requests for certain types of images you would like to see for the next post, also let me know in the comments. Until next time!
Author: Jaymin Patel
August 25, 2014
In these “Student Corner” pieces, we will go over certain aspects of radiology in EM that are of interest to medical students. Topics will include: common (and interesting) case presentations with accompanying imaging, schematics for how to read different types of imaging in various anatomical locations, discussions on what types of imaging to order and when in the EM setting, and others.
In this inaugural edition of the Student Corner, we’ll take a look at how to tackle reading an anterior-posterior chest x-ray.
For starters, it is important to understand that having a “gameplan” for reading any type of image is key when you first start out trying to decipher radiological images. As a reader and interpreter, you must be systematic in your thought process as you analyze the image in front of you. For chest x-rays, there is a classic schematic: ABCDE. Any medical student will tell you that this is not the only time you will see “ABC…” used as a way to quickly memorize something, but at least it’s easy to remember.
Here’s the image we are going to use and let’s start to dissect it using the mnemonic:
Note: For the purpose of keeping this a short piece, we’ll only focus on the anterior-posterior view only.
Legend: Red Arrows–trachea; Blue Arrows–carina; Green arrows–L and R main bronchus
The upper airway, including the trachea, carina and both main bronchi, should all be visible on an AP view. Things to look for include deviation of the trachea away from the midline (there is some deviation to the patient’s right in this image, but this is due to the aortic arch, which passes to the left of the trachea as it passes posteriorly in the mediastinum), obstruction due to aspiration of a foreign object and obscuring of the upper airway due to enlarged mediastinal lymph nodes.
Let’s explore tracheal deviation a bit further. Deviation from the midline is not associated with a defect in the trachea itself, but with a force from either the R or L side of the chest cavity that is pulling or pushing the trachea to one side or the other. For example, introduction of air into one side of the chest cavity will cause that lung to collapse due to the loss of negative intrapleural pressure. The collapsed lung will shrink to the size of a ball and “push” the trachea to the opposite side. You can think of the two lungs like bungee cords that put roughly equal force on the trachea in each direction. If one of the cords snaps or is released from where it is attached to, the cord that is still intact will pull the trachea towards one side, resulting in a deviation that will show up on a CXR.
Legend: Numbers–ribs; Red Arrow–clavicle; Blue Arrow–medial border of scapula
A CXR offers a good view to look for rib fractures and clavicle fractures. Clavicular fractures are usually easy to spot, as they usually reveal distinct fracture lines in the middle 3rd of the clavicle. Hairline fractures are less common. Rib fractures are sometimes hard to spot, but each rib should be followed across it’s length to look for fracture lines or step-offs (disruptions in the normal curve of the rib) that could indicate a fracture.
The number of ribs is also important to assess because it is an indirect measurement of the volume of the chest cavity. Hyperinflated lungs are usually the result of obstructive disease where the patient is unable to fully expel the air that is inhaled with every breath they take–this increase in residual volume will build up over time and overinflate the chest cavity. This overinflation will result in a greater-than-normal number of ribs being visible on an AP view. Normally, you should expect to see 8-10 ribs on an upright chest X-ray, depending on whether the patient was instructed to exhale or inhale before the picture was taken.
Legend: Red Dashed Lines–heart borders
This part of the mnemonic involves the heart and surrounding structures. The silhouette of the heart should be identified and the heart borders should be clear. A general rule of thumb is that the heart base should not be wider than 1/2 the total width of the diaphragm. As with a lot of “general rule of thumb”s in medicine, it’s not quite clear whether this has any diagnostic value–for example, if the heart base is indeed 1/2 the width of the diaphragm on CXR, is that really sensitive for cardiomegaly? In any case, it’s something to keep in mind.
The aortic arch and the L pulmonary artery should be visible as two semi-circles above the left atrium. There is a space called the “AP Window” that has the following borders: ascending aortic arch (anterior), descending aortic arch (posterior), L pulmonary artery (inferior), inferior border of aortic arch (superior). The window should be “concave” in the sense that the lateral border should be caved in medially. If it is not, things like mediastinal lymphadenopathy and aorta/pulmonary artery aneurysms are possible.
Legend: Blue Arrow–gastric air bubble; Red Arrow–costophrenic angle
The diaphragm has 3 major characteristics which you look for on CXR. One is the gastric air bubble, which allows you to identify that the stomach is on the left (as opposed to the right, as in situs inversus). Another is the contour of the diaphragm, which should be a “dome” shape. The right side should be a little higher than the left, thanks to the liver. The third is perhaps the most important: the costophrenic angle. It is the lateral point of attachment for the diaphragm and it should be a sharp, triangle-shaped region at either end. The angle should be acute. If the angle is closer to 90 degrees, then one possible explanation is that the lungs are hyperexpanded (perhaps because of COPD) and pushing the diaphragm down into the abdomen. “blunting” of the angle refers to a radio-opaque marking of the angle that usually is indicative of pleural effusion.
Everything else is…everything else. Mostly this means the lung parenchyma itself. For this, asymmetry is key. Compare left and right and see whether there is a difference. More on this particular section of the read later.
Now you should try to read the above x-ray for yourself and type your own version of the read in the comments if you’d like. If not the entire read, then try to identify the pathology in the x-ray and post your answer in the comments. Any questions/comments would also be appreciated.
I’ll post the answer with the “correct” read a bit later on the site.
Author: Jaymin Patel