Humpty Dumpty had a Great Fall

Case:

A 54-year-old male presented to the ED after falling from a 10-foot ladder while painting his home. He complains of left foot pain, especially in the heel. Examination reveals edema of the left posterior foot, and he is unable to bear weight. 

Figure 1: Left foot physical examination findings. https://www.aofas.org/PRC/conditions/Documents/Calcaneal-fracture.pdf

Figure 1: Left foot physical examination findings. https://www.aofas.org/PRC/conditions/Documents/Calcaneal-fracture.pdf

Figure 2: Plain films of the left foot. http://radiopaedia.org/cases/calcaneal-fracture-and-associated-spinal-injury

Figure 2: Plain films of the left foot. http://radiopaedia.org/cases/calcaneal-fracture-and-associated-spinal-injury

A fracture of the calcaneus can be a painful and devastating injury. Although uncommon, calcaneal fractures can lead to long-term disability. Physical examination of the ankle can be misleading and radiographic evidence can be difficult to interpret making a high index of suspicion in the right clinical setting important. The most common mechanism for a calcaneal fracture is high-energy trauma to the foot. Seventy-two percent of these fractures result from falls,[i] but other high-energy mechanisms, such as motor vehicle crashes, can also cause calcaneal injury.  

Types of Calcaneal Fractures:

There are two broad categories of calcaneal fractures: extra-articular and intra-articular:

25-30% of fractures are extra-articular. All fractures that do not involve the posterior facet are included in this category. These include calcaneal tuberosity avulsion fractures and extra-articular Lover’s fracture. The name is derived from the fact that a suitor may jump from the bedroom window while trying to escape from the lover's spouse.    

Calcaneal fractures are more frequently intra-articular, involving the subtalar joint (the calcaneus and the talus form the subtalar joint). A lover fracture may be intra- or extra-articular.

Clinical Presentation:

Patients often present after a fall from a height with complaints of heel pain and swelling. Examination of the patient with a foot or ankle injury follows the standard approach; inspection, palpation, range of motion testing, etc.  The heel may appear short and wide when compared to the non-injured foot. A hematoma extending to the sole of the foot is called "Mondor Sign" and is highly suspicious for calcaneal fracture. Remember to closely examine the skin for lacerations, blisters, and tenting.

Imaging:

Fractures of the calcaneus can be very subtle, and these fractures often are missed on radiographs. When the mechanism of injury or exam is highly suggestive of calcaneus fracture, lateral radiographs should be evaluated by measuring Bohler's angle or the critical angle of Gissane. The axial (Harris) view of the foot may demonstrate widening of the heel or lateral wall displacement. This view should be obtained if the standard films are negative but strong clinical suspicion exists. Comparison views are helpful if the diagnosis remains in question.

It is also important to differentiate calcaneal fractures based on whether they are intra-articular or extra-articular, and displaced or nondisplaced, as these findings will dictate treatment. CT imaging is often necessary to better define the extent of the fracture. Multiple classification schemes have been used for calcaneus fractures, the most popular of which is the Sanders classification system used to describe intra-articular calcaneal fractures. This classification is based on the number of intra-articular fracture lines and their locations on CT imaging. Type I fractures are non-displaced. Type II have two articular fragments. Type III has three articular fragments. Type IV fractures have more than three articular fragments and are highly comminuted.[ii]  

MRI has a limited but potentially important role in select cases. If an occult non-displaced calcaneus fracture is suspected (e.g., persistent symptoms plus suggestive but indeterminate findings on CT), MRI may be used to confirm or rule-out a fracture. MRI is also sensitive for detecting stress fractures of the calcaneus.

Bohler's Angle:

On lateral radiograph, Bohler's angle is the angle between two tangent lines drawn across the anterior and posterior aspects of the superior calcaneus on the lateral view. A Bohler angle of less than 20° suggests calcaneal fracture[iii], though a normal Bohler angle does not exclude fracture.

Figure 3: Bohler's angle. http://www.wikiradiography.net/page/Calcaneal+Fractures

Figure 3: Bohler's angle. http://www.wikiradiography.net/page/Calcaneal+Fractures

Critical Angle of Gissane:

Measured on lateral radiograph, this “critical angle” is formed by the downward and upward slopes of the calcaneal superior surface. A normal angle of Gissane measures between 100 and 130 degrees, with a greater angle indicating fracture of the posterior subtalar articular surface.

Figure 4: Gissane's Angle. https://dailyem.files.wordpress.com/2013/12/gissane.jpg

Figure 4: Gissane's Angle. https://dailyem.files.wordpress.com/2013/12/gissane.jpg

In 2006, Knight et al. published a randomized case-control trial evaluating the use and aid of Bohler’s angle and critical angle of Gissane. Of emergency department physicians studied, 97.9% were able to make an accurate diagnosis of calcaneus fracture without the benefit of measuring either angle on lateral radiograph.[iv]

Case Continued:

Our patient is also complaining of low back pain in addition to his heel pain. Examination of the lower back reveals axial lumbar tenderness without neurologic deficits.

Consider Associated Injuries:

Patients with calcaneus fractures often have concurrent injuries, and it is important to consider this possibility in their evaluation. Following major trauma, an obvious deformity of the hindfoot or ankle injury may distract us from these other injuries.  In addition to bony injuries, the amount of force required to fracture the calcaneus can cause damage to the surrounding soft tissues. Patients can develop compartment syndrome in the “calcaneal compartment” which, if left untreated, can lead to claw toe deformity. Up to 10% of calcaneal fractures will develop compartment syndrome and half of these can develop foot deformities, including clawing of the toes.[v]

High-energy impact to the feet can be accompanied by other lower extremity fractures in 25% of patients, vertebral injuries in 10% of cases, and contralateral calcaneus injuries in 7%.[vi] The mechanism of injury often involves a substantial load to the axial skeleton, such as jumping from a second story window. Therefore, a careful and focused spine evaluation is warranted. A thorough and focused tertiary survey should aim to rule out other injuries in common areas, in particular the thoracolumbar spine.

Figure 5: L1 Burst Fracture. http://radiopaedia.org/cases/calcaneal-fracture-and-associated-spinal-injury

Treatment:

Nondisplaced fractures (Sanders Type I) can be treated nonoperatively. In general, patients should be placed in a bulky compression dressing (Jones dressing) until the initial swelling subsides. The dressing can then be replaced by a removable splint or boot to begin range-of-motion exercises of the ankle and the subtalar joint. Non-weight-bearing for at least 6 weeks after injury is recommended.

Displaced intra-articular fractures require surgical intervention, and it is important to arrange for prompt orthopedic follow-up. Emergent orthopedic consultation is required for open fractures, fractures associated with neurovascular injury, fractures associated with dislocation (which must be reduced immediately), and suspicion or diagnosis of acute compartment syndrome.

Figure 6: Surgically repaired calcaneal fracture. http://orthoinfo.aaos.org/topic.cfm?topic=A00524

The Take Home:

  • Physical examination of the ankle can be misleading and radiographic evidence can be difficult to interpret. It is important to have a high index of suspicion for calcaneal fracture in the appropriate clinical setting.
  • Bohler’s angle can be used to identify subtle fractures. Less than 20 degrees is consistent with a calcaneus fracture.
  • CT is the imaging modality of choice in evaluating calcaneal fractures.
  • ED physicians should always consider the possibility that calcaneus fractures can be bilateral and associated with other lower extremity fractures and/or thoracolumbar spine fractures. 
  • An important early complication is acute compartment syndrome.
  • Emergent orthopedic surgery consultation is necessary for intra-articular, open, or displaced calcaneal fractures.
  •  

Reviewed by Dr Jeffrey Feden, Attending and Assistant Professor and Dr Neha Raukar, Attending, Assistant Professor and Director, Division of Sports Medicine, Department of Emergency Medicine, Alpert Medical School of Brown University.

References:

[i] Mitchell MJ, McKinley JC, Robinson CM. The epidemiology of calcaneal fractures. Foot (Edinb). 2009 Dec;19(4):197-200. doi: 10.1016/j.foot.2009.05.001. PubMed PMID: 20307476.

[ii] Daftary A, Haims AH, Baumgaertner MR. Fractures of the calcaneus: a review with emphasis on CT. Radiographics. 2005 Sep-Oct;25(5):1215-26. Review. PubMed PMID: 16160107.

[iii] Isaacs JD, Baba M, Huang P, Symes M, et al. The diagnostic accuracy of Böhler's angle in fractures of the calcaneus. J Emerg Med. 2013 Dec;45(6):879-84. doi: 10.1016/j.jemermed.2013.04.055. Epub 2013 Sep 17. PubMed PMID: 24054885.

[iv] Knight JR et al. Boehler’s angle and the critical angle of Gissane are of limited use in diagnosing calcaneus fractures in the ED. 2006. Am J Emerg Med, Jul; 24 (4): 423-427.

[v] Germann CA, Perron AD, Miller MD, Powell SM, Brady WJ. Orthopedic pitfalls in the ED: calcaneal fractures. Am J Emerg Med. 2004 Nov;22(7):607-11. Review. PubMed PMID: 15666272.

[vi] Weedier IS, Charted J: Emergency Department Evaluation and Treatment of Ankle and Foot Injuries. Emergency Medicine Clinics of North America 2000;18:85-113.

 


 

Keep Your Eye on the Target: POCUS for Intussusception

Case:

HPI: An 18 month old previously healthy female with a history of mild intermittent constipation, but no prior abdominal surgeries presented to the ED with 3 days of non-bilious, non-bloody emesis and abdominal pain not responsive to laxatives and Zofran. On the day of presentation she developed multiple episodes of screaming associated with grabbing her stomach and pulling up her legs. Episodes lasted for 30 seconds to 1 minute and self-resolved. She was afebrile. Oral intake and urine output were decreased, and she had no stools on the day of presentation. Her last bowl movement was 1 day prior to presentation and was loose without blood. The patient had nasal congestion and rhinorrhea the prior week.

Vitals: Pulse 124 | Temp 98.7 °F (37.1 °C) | Resp 26 | Wt 15.7 kg | SpO2 98%

Exam: Unremarkable with the exception of diffuse abdominal tenderness and voluntary guarding, but no rebound. No hepatosplenomegaly was appreciated. Bowel sounds were diminished.

Given the story and exam, the clinical suspicion for intussusception was high, and an initial two view abdominal x-ray was obtained: 

Figure 1: Abdominal Xrays

Figure 1: Abdominal Xrays

2 View Abdominal x-ray revealed a soft tissue mass in the right upper quadrant concerning for intussusception (arrows). A comprehensive ultrasound confirmed ileocolic intussusception.

A bedside point-of-care ultrasound was performed while patient was awaiting comprehensive radiographic evaluation. A donut-shaped mass was visualized in the right lower quadrant, consistent with ileo-colic intussusception.

Figure 2a: Cross-sectional view of a donut-shaped mass, consistent with intussusception

Figure 2a: Cross-sectional view of a donut-shaped mass, consistent with intussusception

Figure 2b: Longitudinal view of the intussusception

Figure 2b: Longitudinal view of the intussusception

The patient underwent a successful air-enema reduction. Post air reduction, the left lateral decubitus film shows resolution of the paucity of gas previously seen in the RUQ.

Figure 3: Post reduction xray

Figure 3: Post reduction xray

Epidemiology of Intussusception:

Intussusception is the most common abdominal emergency in early childhood, particularly among children younger than 2 years of age. Approximately 60% of children with intussusception are less than 1 year old and 80-90% are less than 2 years old. Additionally, it is the most common cause of intestinal obstruction in infants between 6 and 36 months and there is a slight male predominance, with a male:female ratio of approximately 3:2.

Intussusception in this age group most often occurs at the ileocecal junction, leading to ileocolic intussusception. The intussusceptum, a proximal segment of bowel, telescopes into the intussuscipiens, a distal segment.

Approximately 75 percent of cases of intussusception in children are considered to be idiopathic because there is no clear disease trigger or pathological lead point. Mesenteric lymph nodes may act as a lead point and may occur in the setting of gastroenteritis (both viral and bacterial), viral upper respiratory illnesses, flu-like illnesses, and adenovirus. Henoch-Schönlein purpura, HSP, is also associated with intussusception, but more commonly ileo-ileal. Non-infectious causes of lead points include Meckels, polyps, tumors (lymphoma), hematomas, vascular malformations, duplication cysts, and post-operative scarring.

Clinical Features:

The classic presentation of intussusception includes sudden onset intermittent, severe, crampy, and progressive abdominal pain, accompanied by inconsolable crying and drawing up the legs towards the abdomen, with return to baseline between episodes. As lethargy may follow episodes of abdominal pain, intussusception should be on the differential diagnosis for any young child presenting with unexplained lethargy or altered mental status. Non-bloody, non-bilious emesis is often present. The classically described triad of pain, palpable abdominal mass, and currant jelly stool occurs in <15% of children.

Imaging Techniques:

Abdominal plain films: A two view abdominal x-ray can be used to evaluate the bowel gas pattern and to exclude perforation in patients with suspected intussusception. It is not the imaging method of choice, as a negative plain film cannot rule out intussusception. A plain film is less sensitive and specific than ultrasonography for intussusception, but may include the following suggestive findings:

  • Signs of intestinal obstruction (distended loops of bowel with absence of colonic gas)
  • Target sign (two concentric circles superimposed on the right kidney)
  • Crescent sign (soft tissue density projecting into the gas of the large bowel)
  • Obscured liver margin (as seen in the patient in this vignette)
  • Lack of air in the cecum
  • Pneumoperitoneum (RARE, secondary to perforation)

Ultrasonography:  Abdominal ultrasound is the modality of choice, with sensitivity and specificity approaching 100% when performed by experienced ultrasonographers. The classic imaging findings include a “target sign” or “bull’s eye” that occurs due to the layers of intestines within one another. This target is usually ≥3 cm in diameter.

Figure 4: Cross sectional view of intussusception

Figure 4: Cross sectional view of intussusception

Figure 5: Longitudinal view of intussusception

Figure 5: Longitudinal view of intussusception

Point of Care US (POCUS) for Intussusception:

Bedside ultrasound may lead to more expeditious diagnosis, particularly when pediatric radiology is not available, and may facilitate more rapid comprehensive radiographic and/or surgical evaluation. A 2011 study showed that 6 PEM physicians could perform the exam with a sensitivity of 85%, specificity of 97%, positive predictive value of 85%, and negative predictive value of 97% for diagnosing intussusception after just a 1 hour course!

Diagnostic pitfalls with ultrasonography include enlarged lymph nodes, non-pathologic ileo-ileal intussusception, the psoas muscle, colonic stool, and the kidneys, all of which may be misinterpreted as intussusception. Scan the entire abdomen and try to localize the actual kidneys. Confirm that the depth of the image and the diameter of the findings in question are consistent with the typical intussusception parameters, and observe for surrounding peristalsis to help decrease misinterpretation of findings.

Ultrasound Technique:

Using a linear probe, start by placing the probe transversely in the RLQ and attempt to identify the psoas muscle (semicircular structure with striations and iliac vessels just medial to it). Set the depth to at least 6 cm. Slowly sweep superolaterally until the liver and gallbladder are visualized. Proceed along the course of the large bowel as the intussusception may be seen in the LLQ. If seen, an intussusception should be imaged in two planes.

Figure 6: Ultrasound technique

Figure 6: Ultrasound technique

Treatment:

The preferred method of treatment for intussusception is nonoperative, with air or barium enema reduction, which is performed by radiology. Surgery should be close by in case of complication and/or need for urgent operative intervention. Operative intervention may be needed if non-operative reduction fails or if there is concern for a mass lesion as the pathological lead point, or if there is suspected or proven bowel perforation or necrosis.

Faculty Reviewer: Dr. Erika Constantine 

References:

1. KitagawS, Miqdady M. Intussusception in children. Uptodate.com. Accessed April 17, 2016. <http://www.uptodate.com/contents/intussusception-in-children source=search_result&search=intussusception&selectedTitle=1~102>.

2. Doniger SJ, Salmon M, Lewiss RE. Point-of-Care Ultrasonography for the Rapid Diagnosis of Intussusception: A case series. Pediatr Emergency Care. 2016 Feb 15. Epub ahead of print. PMID: 26890297.

3. Alletag MJ, Riera A,  Langhan ML, Chen L. Use of emergency ultrasound in the diagnostic evaluation of an infant with vomiting. Pediatr Emerg Care. 2011, Oct; 27(10):986-9.

4. Eshed I, Gorenstein A, Serour F, et al. Intussusception in children: can we rely on screening sonography performed by junior residents? Pediatr Radiol. 2004;34;134-137.

5. Ramsey KW, Halm BM. Diagnosis of intussusception using bedside ultrasound by a pediatric resident in the emergency department. Hawaii J Med Public Health. 2014 Feb;73(2):58-60.

6. Riera A, Hsiao AL, Langhan ML, Goodman TR, Chen L. Diagnosis of intussusception by physician novice sonographers in the emergency department. Ann Emerg Med. 2012 Sep;60(3):264–268. [PubMed].

7. Chang YJ, Hsia SH, Chao HC. Emergency medicine physicians performed ultrasound for pediatric intussusceptions. Biomed J. 2013 Jul-Aug;36(4):175–178. [PubMed]. 

8. Halm BM. Reducing the time in making the diagnosis and improving workflow with point-of-care ultrasound. Pediatr Emerg Care. 2013 Feb;29(2):218–221. [PubMed].

CITW 18: A Swollen Leg

WELCOME BACK TO ANOTHER CLINICAL IMAGE OF THE WEEK FROM THE CASE FILES OF THE BROWN EM RESIDENCY!

HPI/ROS: A 24 year-old male presents to the ED with three days of right calf pain. He reports that the pain came on gradually and has been steadily worsening. Ambulating intensifies the sensation, which is further described as a cramping pain that does not radiate.  It is associated with right calf swelling and redness. This has never happened before. He denies fevers, chills, shortness of breath, chest pain, abdominal pain, numbness, tingling, or weakness. No history of trauma, although he is post-op day six from an appendectomy. There were no complications during the surgery, and he was discharged on day two following an uneventful post-operative course.

PMH: None

PSH: Appendectomy

Vital Signs: T 100.2, HR 82, RR 20, BP 117/72, SpO2 98% on RA

Pertinent physical exam: Patient is an uncomfortable appearing young male. Heart sounds are normal. Lung sounds are clear bilaterally. Abdomen is soft and non-tender. The right calf is noted to be moderately swollen as compared to the left. There is mild erythema overlying the right calf. There is tenderness to palpation of the right calf and a positive Homan’s sign. DP and PT pulses in the right lower extremity are intact. He has 5/5 strength throughout the right lower extremity with intact sensation as well. No other pertinent exam findings.

A bedside ultrasound of the right lower extremity was performed:

Figure 1: Right common femoral vein, with and without compression.

Figure 1: Right common femoral vein, with and without compression.

Figure 2: Right popliteal fossa axial view, with compression.

Figure 2: Right popliteal fossa axial view, with compression.

Figure 3: Right popliteal fossa, saggital view and with compression.

Figure 3: Right popliteal fossa, saggital view and with compression.

What's the diagnosis?

Deep Vein Thrombosis (DVT)

Hopefully this was not too tricky of a case! Note the non-compressible thrombus in the popliteal vein of this patient:

Figure 4: Non-compressible popliteal vein with internal thrombus.

Figure 4: Non-compressible popliteal vein with internal thrombus.

Figure 5: Just proximal to the image depicted in figure 4. Here the vein is no longer occluded by thrombus.

Figure 5: Just proximal to the image depicted in figure 4. Here the vein is no longer occluded by thrombus.

Let’s discuss the diagnosis and management of DVTs in the Emergency Department:

The Clinical Diagnosis:

  • A diagnosis of DVT should be suspected in patients with palpable cords (reflecting thrombosed veins) and/or ipsilateral calf swelling (>2 cm than the opposite calf, 10 cm below the tibial tubercle).  
  • One quarter of patients will have tenderness and redness in the swollen extremity, similar to findings seen in cellulitis.
  • Homan’s sign (calf pain elicited by passive foot dorsiflexion) has no predictive value for DVT secondary to low sensitivity and specificity.
  • It is recommended to implement a clinical decision rule such as the Well’s Criteria for DVT, which takes into account both physical examination findings, as well as other high risk criteria including history of malignancy, sedentary lifestyle, recent immobilization or surgery, and history of prior DVTs. 
  • The Well’s Criteria were derived in 2003, and then validated in 2006. They are supported by the American College of Chest Physician’s guidelines for the evaluation of DVT.
  • Interestingly, the incidence of DVT in patients with clinical concern for DVT was only about 15% in the original study, demonstrating that only a minority of these patients will have a DVT.
Figure 6: Well's Criteria. www.mdcalc.com.

Figure 6: Well's Criteria. www.mdcalc.com.

  • A score of 0 or less (pre-test probability <5%) should undergo D-dimer testing (either moderate or high sensitivity testing), and if positive, compressive ultrasonography should be utilized.
  • A score of 1-2 (pre-test probability 17%), should undergo high sensitivity d-dimer testing, and is positive, compressive ultrasonography should be utilized.
  • A score of 3 or higher (pre-test probability 17-53%) should go straight to compressive ultrasonography. If ultrasonography is negative in these patients, they should have a repeat ultrasound in one week.

Bedside Ultrasound: 

  • Poley, et al. compared limited compression ultrasound (bedside) versus the gold standard of comprehensive ultrasound.
  • They attempted to incorporate limited compression ultrasound into the diagnostic workup of lower extremity DVT in an attempt to determine if they could reduce the rates of imaging (comprehensive ultrasound), d-dimer testing, and unnecessary anti-coagulation.
  • Patients with Well’s scores less than 2 and a negative limited compression ultrasound were considered negative for DVT.
  • Patients with Well’s scores greater than or equal to 2 and a negative limited compression ultrasound, had d-dimer testing, and if positive then had confirmatory comprehensive ultrasounds.
  • Any positive limited compression ultrasounds underwent confirmatory comprehensive ultrasounds.
  • The sensitivity and specificity of limited compression ultrasound was 91% and 97% respectively.
  • They determined that they could have reduced the rate of comprehensive ultrasound imaging from 70% to 43% and d-dimer testing from 100% to 33%.
  • Performing a limited compression ultrasound is quick and easy, involving compression ultrasound at the femoral vein where the saphenous vein inserts (see figure 1), and compression ultrasound in the popliteal fossa (see figure 2).
  • For a nice review of this study, check out episode 10: 
    http://www.ultrasoundpodcast.com/tag/dvt/
  • Newer studies have also investigated the diagnostic accuracy of 5 point compression ultrasound versus the current standard of 2-point compression ultrasound. We’ve discussed this previously on our previous blog. Check it out here: http://blogs.brown.edu/emergency-medicine-residency/eus-comprehensive-le-dvt-studies-lp-guidance/ 

ED Management and Disposition:

  • The decision to anticoagulate and what agent to use (including for how long) is a highly individualized decision taking into account the nature and cause of the DVT (clot burden, provoked or not, etc), patient co-morbidities, age, risk of bleeding, social concerns, costs of treatment, patient follow up, as well as patient and physician preferences.
  • Initial anticoagulation (0-10 days since diagnosis) should be started immediately in a patient with a confirmed DVT, assuming the risk of bleeding is not high.
  • There are no well validated tools for estimating bleeding risks in patients being anticoagulated for VTE.
  • Options include low-molecular weight heparin (LMWH), oral Xa inhibitors (rivaroxaban or apixaban), or unfractionated heparin (UFH), with the novel oral anticoagulants now being the preferred treatment as per the American College of Chest Physicians.
  • IVC filters should be considered for patients in which the bleeding risk outweighs the benefits of anticoagulation or continued clot formation while on anticoagulants.
  • Patient’s with massive clot burden (iliofemoral DVT or phlegmasia cerulean dolens) should be considered for catheter directed thrombolysis and/or mechanical extraction. 
  • Outpatient management should be considered in low risk patients who are ambulatory, hemodynamically stable, have appropriate follow up and living situations, and are understanding of the management plan (including return precautions).
  • Long term anti-coagulation (minimum of three months, up to 6-12 months) includes agents such as Coumadin and direct thrombin inhibitors (dabigitran).

Case Resolution:

A hypercoagulable workup was initiated and low molecular weight heparin was started. The patient was admitted to the medicine service for further evaluation and management.

References:

  • Bauer, Kenneth. Approach to the Diagnosis and Therapy of Lower Extremity Deep Venous Thrombosis. UptoDate. 2016.
  • Lip G, Hull R. Overview of the Treatment of Lower Extremity Deep Vein Thrombosis. UptoDate. 2016. 
  • Poley, Rachel et al. Estimated Effect of an Integrated Approach to Suspected Deep Venous Thrombosis Using Limited Compression Ultrasound. Academic Emergency Medicine. 2004 Sep;21(9):971-80.
  • Scarvelis D, Wells PS. Diagnosis and treatment of deep-vein thrombosis. CMAJ. 2006 Oct 24;175(9):1087-92. Review. Erratum in: CMAJ. 2007 Nov 20;177(11):1392.
  • Slovis, Benjamin. Wells Criteria for DVT. 2016. <http://www.mdcalc.com/wells-criteria-for-dvt/>.
  • Tintinalli, et. al. Emergency Medicine. 8th Edition. 2016. 391.
  • Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, Kovacs G, Mitchell M, Lewandowski B, Kovacs MJ. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. 2003 Sep 25;349(13):1227-35.

The contents of this case were deliberately altered to protect the identity of the patient. All content in this report are for educational purposes only. The patient consented to the use of these images.

Faculty Reviewer: Drs. Alyson McGregor, Otto Liebmann, and Frantz Gibbs

See you again soon!