with Rick Place, Inova Fairfax, on the Hot Seat
The Case
Here's how you answered our questions
Would you order a D-dimer on this patient?
Less than 3 years PEM (n=13)
The majority of both sets of providers would not have gotten a d-dimer on this patient, although a sizable minority would order one. See the clinical reasoning and Hot Seat response below on more of that discussion.
Would you use the Wells Criteria to risk stratify this patient?
Less than 3 yrs PEM (n=13)
The majority of both provider groups would not use the Wells criteria for risk stratification of this patient, with a fairly even split between either feeling its not useful in kids or just not generally not using it at all for management decisions. At the same time, about one third would use the Wells criteria. One other conceivable choice we didn't give was whether you thought that Well criteria didn't apply in this patient because the PE risk is low (thanks for making that note and mentioning PERC, Priya). If you're not sure which way you'd go personally, read below for an excellent discussion on the use of the criteria and risk stratification.
For those interested, an online Wells calculator can be found here (thanks for the link, Paul).
What imaging would you order FIRST for this patient?
Less than 3 years PEM (n=13)
Clinical Reasoning
Click here to read the excellent commentary in full. Below are excerpts on several themes for this case.
Is this an adult or a pediatric patient?
"While most of the DVT and PE literature is in adults, this adolescent is adult habitus and physiology (that is - can get pregnant - and worth checking urine-hcg right now in ED)." -Paul Mullan, Children's National
Risk stratification of this patient
"The Well's Criteria is really used for patients in which DVT/PE is high on the differential. Those patients are already stratified to "likely to have a DVT/PE". This patient is not in that population." -Priya Gopwani, Children's National
"Her only risk factor for a DVT is obesity and therefore possible sedentary lifestyle. But she hasn't been completely immobilized. Also, check her for pregnancy (incr coagulable state)." -Jennifer Chapman, Children's National
"This is a patient who is "unlikely to have a DVT", or "low suspicion", so something like the PERC criteria may be more appropriate here. The PERC criteria are:
Patients that meet ALL of the PERC criteria do not need further testing/imaging to eval for DVT or PE" -Priya Gopwani, Children's National
The diagnostic approach
"D-dimer not helpful since pre-test probably already high enough. If negative, first talk with the ultrasonographer to assess whether they were adequately able to see the entire vasculature and that the attending reviewed the images as well; if still negative, get an xray to r/o bone tumor." -Paul Mullan, Children's National
"Plain films to look for lytic lesions or the sunburst pattern of osterogenic sarcoma. Highest yield test will probably be an ultrasound, to look for a fluid collection- blood or pus. Duplex scan will need to be done since a DVT has the risk of extension and embolization. Labs: CBC, ESR, CRP, coags, BCx only if antibiotics are given for any reason." -Jennifer Chapman, Children's National
"What I would do is:
r/o DVT. Of course we're all going to do an US, so a D-dimer doesn't add anything here.
do labs for hypercoagulable (in case it's a DVT) and add CK and CBC/CRP to point towards potential infectious or muscle etiology
do XR to exclude bony origin
repeat clinical exam..........everything else (soft tissue tumor, cyst, hematoma, phlebitis, etc) should be differentiated on physical exam to dictate further workup. all of this can be followed outpatient."
-Dave Mathison, Children's National
"Would a D-dimer help you decide whether or not to transfer her to a site with immediately available ultrasound? Or is your level of concern for DVT so high that you would transfer regardless (as Dave said: "Of course we'll all do an US")?" -Emily Willner, Children's National
"I think you have to consider more systemic problems here. Why does a 14yo F have 1+ pitting edema bilaterally? She's too young for true venous stasis. Is her heart functioning? Her kidneys? Is her albumin zero? Or is this an inaccuracy in our physical exam and this is actually non-pitting edema?" -Priya Gopwani, Children's National
"IF she did not have the swelling, and IF she only had tenderness, and IF she only had symptoms for 1-2 days, and IF you were in a low resource setting without ultrasound, she would score 1 point (low risk) and you could consider starting with a d-dimer (if negative - send home with instructions to f/u if not resolving or PE signs; if positive - refer elsewhere for u/s)" -Paul Mullan, Children's National
From the Hot Seat
by Rick Place, Inova Fairfax
[Dr. Place is returning to pediatric emergency medicine in Fairfax after a year and a half treating mostly adults in New Zealand so has some unique insights on evaluating pulmonary embolism]
I would approach this patient with the primary intent of answering the question: what can I not afford to miss on this patient...on this visit.
Like many problems in medicine, the etiology could be something you simply can't prove, like a strained muscle (which is clearly not the case here, as it might be in real life). So testing must be directed at eliminating things that you CAN identify, things that are of relatively immediate clinical importance. The most obvious question is whether this patient has a DVT. As noted, the patient has no known risk factors, although some (adolescent) studies suggest that obesity may be a minor risk factor.
One approach when deciding whether to pursue further evaluation is to use the Well's criteria. Decision aids can be useful, but only when applied to the right patient. For instance, when deciding whether to send a d-dimer to identify (or rather to exclude) PE, I will rely on the PERC rule. But the PERC rule should ONLY be used in patients with a low pretest probability. Otherwise it is invalid. Similarly, I am more likely to use the Well's criteria to exclude further evaluation rather than help me to decide whether to drive further workup. In other words, if my pretest probability is reasonably low, and I do not want to image a patient or get stuck with a false positive test (i.e. d-dimer), I will use the decision rule to justify my medical decision-making (in case I am wrong). This may not be exactly how the Well's criteria is intended, but this is how I would use it.
(There is not room here for a complete discussion of decision rules, but many rules are subjective enough from the start that you can get the answer you want simply by interpreting the data the way you want. For instance, in a prior comment the patient is scored as 2, with one for tenderness and one for swelling. I would score the patient as zero. The swelling is not confined to the affected leg and the tenderness is not specifically localized to the deep venous system). My point is that I use decision aids as a guide, not a rule. In this case, I score the patient at zero but still believe the patient is at reasonable risk of DVT.
In this case, the patient has no clear alternative reason for calf pain, and a "low probability" Well's score still gives you a 3% probability; I would not say that my concern for DVT is exceptionally low. Furthermore, exam is of very limited utility in this patient, forcing us to rely even more heavily on diagnostic testing to sort this out.
If I had 24/7 ultrasound or unlimited resources (e.g. at Fairfax), I would probably go straight to doppler ultrasound to evaluate this patient. It may answer the question positively, or if not, may provide additional information, such as an abscess, hematoma, soft tissue mass, or Baker's cyst (in adults). (Incidentally, in Invercargill, after hours, we would risk stratify the patient and give a shot of enoxaparin and bring them back the next day for a sonogram. If they risk stratified low, I might still bring them back but pass on the LMWH).
I would also order a d-dimer on this patient as ultrasound has good but limited sensitivity for calf DVT (particularly in an obese patient). It is extremely good for proximal venous thrombosis but less sensitive for distal clots (the diagnosis of interest here). If the Doppler was negative (i.e. for proximal DVT), one would need to consider a repeat sonogram in a week or two as 30% of distal DVTs will migrate proximally. One advantage of a negative doppler AND a negative d-dimer is that the need for a follow up ultrasound is probably unnecessary.
Finally, since this patient could have practically anything (especially given that she is a hot seat patient) and since exam is so incredibly limiting, I would likely expand my workup to include screening labs for inflammatory markers (CBC/CRP) which might help suggest a myositis or osteomyelitits and an Xray to exclude occult fracture, some weird bony problem like malignancy or bone cyst (less likely given the calf pain).
The Denouement
by Lenore Jarvis, Children's National
This patient was seen at a satellite site where we do not have ready access to ultrasound. The differential diagnosis was electrolyte imbalance, trauma, musculoskeletal, myositis, and DVT. We felt she was "Moderate Well’s," but looking back, one could also make the argument for "Low Risk" or not applicable to peds. I'm interested to see what people have to say about this point. D-dimer, CBC, ESR/CRP, chemistry, CK were order and within normal range. D-dimer was at the upper limit of normal, though. XR normal. We questioned whether to send the main campus for US with Doppler to evaluate for DVT. A brief literature search concluded that D-dimer not sensitive in pediatrics. We sent the patient to the main campus for an ultrasound via private vehicle. That ultrasound was negative and the patient was discharged with a diagnosis of musculoskeletal related pain with instructions for supportive care with continued motrin. The patient has not returned to our ER to seek care since being discharged.
Editors Note: This is a great illustration of the amount of learning that can be had from a seemingly simple decision dilemma. Since we don't see pulmonary embolism and DVT often in PEM, it's helpful to hear from a wide range of experiences and refresh our memory on available decision rules.
The Hot Seat is a recurrent online case series aimed at facilitating asynchronous sharing of PEM knowledge and experience. Faculty are placed on The Hot Seat and publish their opinions without knowing the case or its outcomes. Cases are based on real cases and written by PEM fellows at Children's National in DC, Johns Hopkins in MD, and INOVA Fairfax in VA to highlight teaching points. Emily Willner is the faculty advisor for the Hot Seat.
"D-dimer not helpful since pre-test probably already high enough. If negative, first talk with the ultrasonographer to assess whether they were adequately able to see the entire vasculature and that the attending reviewed the images as well; if still negative, get an xray to r/o bone tumor." -Paul Mullan, Children's National
"Plain films to look for lytic lesions or the sunburst pattern of osterogenic sarcoma. Highest yield test will probably be an ultrasound, to look for a fluid collection- blood or pus. Duplex scan will need to be done since a DVT has the risk of extension and embolization. Labs: CBC, ESR, CRP, coags, BCx only if antibiotics are given for any reason." -Jennifer Chapman, Children's National
"What I would do is:
"Would a D-dimer help you decide whether or not to transfer her to a site with immediately available ultrasound? Or is your level of concern for DVT so high that you would transfer regardless (as Dave said: "Of course we'll all do an US")?" -Emily Willner, Children's National
"I think you have to consider more systemic problems here. Why does a 14yo F have 1+ pitting edema bilaterally? She's too young for true venous stasis. Is her heart functioning? Her kidneys? Is her albumin zero? Or is this an inaccuracy in our physical exam and this is actually non-pitting edema?" -Priya Gopwani, Children's National
"IF she did not have the swelling, and IF she only had tenderness, and IF she only had symptoms for 1-2 days, and IF you were in a low resource setting without ultrasound, she would score 1 point (low risk) and you could consider starting with a d-dimer (if negative - send home with instructions to f/u if not resolving or PE signs; if positive - refer elsewhere for u/s)" -Paul Mullan, Children's National
From the Hot Seat
by Rick Place, Inova Fairfax
[Dr. Place is returning to pediatric emergency medicine in Fairfax after a year and a half treating mostly adults in New Zealand so has some unique insights on evaluating pulmonary embolism]
I would approach this patient with the primary intent of answering the question: what can I not afford to miss on this patient...on this visit.
Like many problems in medicine, the etiology could be something you simply can't prove, like a strained muscle (which is clearly not the case here, as it might be in real life). So testing must be directed at eliminating things that you CAN identify, things that are of relatively immediate clinical importance. The most obvious question is whether this patient has a DVT. As noted, the patient has no known risk factors, although some (adolescent) studies suggest that obesity may be a minor risk factor.
One approach when deciding whether to pursue further evaluation is to use the Well's criteria. Decision aids can be useful, but only when applied to the right patient. For instance, when deciding whether to send a d-dimer to identify (or rather to exclude) PE, I will rely on the PERC rule. But the PERC rule should ONLY be used in patients with a low pretest probability. Otherwise it is invalid. Similarly, I am more likely to use the Well's criteria to exclude further evaluation rather than help me to decide whether to drive further workup. In other words, if my pretest probability is reasonably low, and I do not want to image a patient or get stuck with a false positive test (i.e. d-dimer), I will use the decision rule to justify my medical decision-making (in case I am wrong). This may not be exactly how the Well's criteria is intended, but this is how I would use it.
(There is not room here for a complete discussion of decision rules, but many rules are subjective enough from the start that you can get the answer you want simply by interpreting the data the way you want. For instance, in a prior comment the patient is scored as 2, with one for tenderness and one for swelling. I would score the patient as zero. The swelling is not confined to the affected leg and the tenderness is not specifically localized to the deep venous system). My point is that I use decision aids as a guide, not a rule. In this case, I score the patient at zero but still believe the patient is at reasonable risk of DVT.
In this case, the patient has no clear alternative reason for calf pain, and a "low probability" Well's score still gives you a 3% probability; I would not say that my concern for DVT is exceptionally low. Furthermore, exam is of very limited utility in this patient, forcing us to rely even more heavily on diagnostic testing to sort this out.
If I had 24/7 ultrasound or unlimited resources (e.g. at Fairfax), I would probably go straight to doppler ultrasound to evaluate this patient. It may answer the question positively, or if not, may provide additional information, such as an abscess, hematoma, soft tissue mass, or Baker's cyst (in adults). (Incidentally, in Invercargill, after hours, we would risk stratify the patient and give a shot of enoxaparin and bring them back the next day for a sonogram. If they risk stratified low, I might still bring them back but pass on the LMWH).
I would also order a d-dimer on this patient as ultrasound has good but limited sensitivity for calf DVT (particularly in an obese patient). It is extremely good for proximal venous thrombosis but less sensitive for distal clots (the diagnosis of interest here). If the Doppler was negative (i.e. for proximal DVT), one would need to consider a repeat sonogram in a week or two as 30% of distal DVTs will migrate proximally. One advantage of a negative doppler AND a negative d-dimer is that the need for a follow up ultrasound is probably unnecessary.
Finally, since this patient could have practically anything (especially given that she is a hot seat patient) and since exam is so incredibly limiting, I would likely expand my workup to include screening labs for inflammatory markers (CBC/CRP) which might help suggest a myositis or osteomyelitits and an Xray to exclude occult fracture, some weird bony problem like malignancy or bone cyst (less likely given the calf pain).
The Denouement
by Lenore Jarvis, Children's National
This patient was seen at a satellite site where we do not have ready access to ultrasound. The differential diagnosis was electrolyte imbalance, trauma, musculoskeletal, myositis, and DVT. We felt she was "Moderate Well’s," but looking back, one could also make the argument for "Low Risk" or not applicable to peds. I'm interested to see what people have to say about this point. D-dimer, CBC, ESR/CRP, chemistry, CK were order and within normal range. D-dimer was at the upper limit of normal, though. XR normal. We questioned whether to send the main campus for US with Doppler to evaluate for DVT. A brief literature search concluded that D-dimer not sensitive in pediatrics. We sent the patient to the main campus for an ultrasound via private vehicle. That ultrasound was negative and the patient was discharged with a diagnosis of musculoskeletal related pain with instructions for supportive care with continued motrin. The patient has not returned to our ER to seek care since being discharged.
Editors Note: This is a great illustration of the amount of learning that can be had from a seemingly simple decision dilemma. Since we don't see pulmonary embolism and DVT often in PEM, it's helpful to hear from a wide range of experiences and refresh our memory on available decision rules.
The Hot Seat is a recurrent online case series aimed at facilitating asynchronous sharing of PEM knowledge and experience. Faculty are placed on The Hot Seat and publish their opinions without knowing the case or its outcomes. Cases are based on real cases and written by PEM fellows at Children's National in DC, Johns Hopkins in MD, and INOVA Fairfax in VA to highlight teaching points. Emily Willner is the faculty advisor for the Hot Seat.
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