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Doczilla
04-28-2008, 21:52
Another case. Bringin' the medicine...

32 yo obese but otherwise healthy female comes to the ED with a chief complaint of R leg pain and swelling for 1 day. She says that she noticed it was a little more swollen this morning, and gradually has worsened throughout the day. No fever, chills, chest pain, SOB, nausea, vomiting, diarrhea, dysuria, vaginal bleeding or discharge, or new rashes. No recent travel or immobility.

PMHx: Obesity
Meds: None
Allergies: NKDA
Social hx: Nonsmoker. Occasional social use of EtOH, denies drug use. Homemaker.
LMP: 1 week ago, normal time, normal flow, nothing remarkable

VS from triage: P 117 R 14 BP: 132/72 SaO2 99% on room air.
Exam: Alert, oriented, no apparent distress. Converses easily and pleasantly.
HEENT: Unremarkable. Oropharynx clear, no meningeal signs, no JVD.
Chest: Lung sounds clear and equal bilaterally. Heart sounds regular rate and rhythm, tachycardic, no murmurs, rubs, or gallops.
Abdomen soft, nontender, nondistended, with normal active bowel sounds.
GU/Pelvic: deferred.
Extremities: RUE, LUE, LLE unremarkable. Right leg noticeably swollen from mid-thigh to the foot, mildly tender to palpation. No obvious venous engorgement, no masses. 2/2 pulses. No erythema or warmth.

Differential diagnosis contains DVT, lymphedema, obstructing mass, cellulitis.

Concerning is her elevated heart rate, which I confirm by palpation at the bedside. Monitor shows a sinus tach at 110-115. Pulse ox remains 99% on room air. She again denies any chest pain, SOB, cough, or fatigue.

CBC is unremarkable. Normal WBC count with normal differential. Blood sugar normal. BMP normal.

At this particular facility, D-Dimer is not readily available (must be sent by courier to another hospital). I order ultrasound of her leg and CT scan of the chest with IV contrast (PE protocol). Ultrasound shows no DVT, but CT scan is positive for bilateral pulmonary emboli. We give the first dose of Lovenox 1mg/kg SQ, and admit her.

Important points from this case:
Vital signs are just that: vital. Her pulse was the only reason that we looked at her for PE. With a negative DVT screen, we otherwise would have sent her home for follow-up ultrasound as an outpatient.

Do not ignore abnormal vital signs. Be able to explain them clinically. If she was writhing in agony, then her elevated heart rate would not be unusual. In this comfortable-appearing patient, it doesn't fit.

DVT ultrasound is very good but not perfect. Likely the clot simply migrated to her lungs, leaving a radiographically insignificant amount of clot in the vein.

D-Dimer is helpful in patients with low pre-test probability of clot. She was moderate to high pre-test probability, so a D-dimer wouldn't add much to the diagnosis unless it, and the ultrasound and CT, were all negative.

'zilla

Semper gumby
04-29-2008, 07:52
Just a question about D-dimer, if the patient did have cellulitis, wouldn't that raise the D-dimer also? I know it's raised in rhuematoid disease, and some others...

A lot of the ER's I have worked next to don't put that much into D-dimer anyways. It's a good diagnostic tool, but has it's flaws. They order venous duplex of the legs/arms based off of clinical appearance. I'm sure some are just doing the CYA thing, not to say I don't blame them. (Good pick up with the tachycardia....)

Respectfully,

Mike

Red Flag 1
04-29-2008, 08:49
zilla,

Another great case! Were you suprised to see a 99% SaO2? I would have expected it to be lower with bilat PE. Did she have any orthopnea or DOE? Did not see ECG and I wonder if she had any history of atrial fib/flutter?

Thanks.

RF 1

Patriot007
04-29-2008, 09:32
Doczilla,

Thank you for taking the time to post these cases each with an important lesson. Looking forward to learning more from you.

swatsurgeon
04-29-2008, 17:04
just to extend this one alittle....troop transport, in a seat for several hours, dehydrated, anxious/stressed (circulating hormone levels not baseline). Same presentation, yet young healthy soldier....possible PE?
What do you think?

ss

Patriot007
04-29-2008, 18:39
Just a trainee but I'll take a stab.

Possible, yes if there is anything I've learned never say never.

Probable, I don't think so. It would be very low on my differential.

Major risk factors for PEs mainly consist of factors that would keep a soldier from duty- relatively recent surgery, chronic heart disease, deficiency of clotting inhibitors, ect...

I know there is evidence linking increased hormone levels to PEs but in a healthy young soldier I don't think it greatly increases the likelihood.

Sdiver
04-29-2008, 20:34
Doc,
Again, another GREAT case study. Thank you.

One question I have............can I get CE hours for reading these ??? :D

Doczilla
04-30-2008, 00:02
The high SaO2 was a little surprising in light of the tachycardia. Near as I can figure, it's because she had bilateral PE, but not a "saddle embolus", so blood was still making it through to be well oxygenated by her non-smoker lungs. And she's young and otherwise healthy, so I would expect her to compensate well. I quizzed her pretty thoroughly, and she denied any SOB, orthopnea, dyspnea on exertion, chest pain, cough, or fatigue. I frankly don't know why she wasn't more symptomatic.

EKG showed sinus tachycardia without any other findings. Normal axis, normal R-wave progression. There is another lesson here; as much as we talk about the S1Q3T3 pattern in PE, the most common EKG finding is sinus tachycardia. A-Fib can present with a hemodynamically significant PE, since the right atrium can't empty (because the right ventricle can't empty) and will stretch out and start fibrillating.

D-dimer can be mildly elevated by cellulitis, but usually not to the same extent as you see with DVT or PE. The D-dimer can be markedly elevated by sepsis, shock, DIC, and trauma.

Here's the key thing with D-Dimer: there are 5 forms, and the most sensitive form is the ELISA D-dimer (it's a process, not a brand). This has a greater than 99% negative predictive value in patients without confounding factors, meaning that as long as certain criteria apply, you can virtually rule out a significant PE or DVT with it. This is good for the young, otherwise healthy person with chest pain where PE is unlikely but possible. If you have a high pretest probability, like a person with clinically apparent DVT and tachycardia, or sudden onset chest pain/SOB after a long flight, then you'd skip the D-Dimer and get the CT and US. It's great to use in concert with US as well. A negative D-Dimer and negative US rules out DVT to great clinical certainty. If you don't have the D-Dimer, and you have a negative US, you would have to do a repeat US in a few days. D-Dimer is decidedly NOT helpful in patients who are old, have multiple comorbid diseases, cancer, or recent trauma. In these cases, it means nothing if it is negative or positive.

The less sensitive forms, such as the latex agglutination D-dimer, have lower NPV, like 90%. This means that with a negative test, you still have a 10% chance of having a significant clot. Might as well flip a coin.

I don't think SS's question was directed at me, so I'll let others chime in on that.

We can give CEUs for this, but we'd have to devise a test at the end. ;)

'zilla

Red Flag 1
04-30-2008, 06:28
'zilla,

Thanks!

swatsurgeon
04-30-2008, 06:53
must be aware that saturation SaO2 does not equal PaO2. You can saturate well and have a low PaO2....carbon monoxide, methemaglobinemia and other hemoglobin-opathies can cause oxygen to bind well (too well) and never release from the hemoglobin, causing a low PaO2 with a 100% saturation.
Anemic patients that have PEs generally saturate well, welcome to your body's method of compensation. No rule is a 100% rule in the medical world.
"knowledge is the anti-ignorance medical providers seek"

ss

Semper gumby
04-30-2008, 08:00
I was in Kuwait in 05, and I actually did see some very young (early-mid 20's) with DVT up to mid SCV. Just because they are young, I wouldn't assume. In a relatively young, healthy individual It's not the first thing I would think about, but if another method of injury is not present, that would be on my mind.

Respectfully.......

Red Flag 1
04-30-2008, 08:16
As I recall, Hgb has an affinity 25 times greater for CO than O2, saturating the Hgb with CO.

Re: dvt's in young folks. I recall a patient 22yo enlisted airman living in barracks. He was admitted for acute gastroenteritis. His admission was primarily to keep him hydrated and nourished as he was unlikely to leave barracks to help himself. He was admitted on a Wednesday. I responded to a "code call " to ICU Saturday morning. The young man developed severe resp distress early Sat am...sent to ICU were he coded and we were not able to save him. On X-ray mid code, there was a large PE RLL and several smaller PEs' in both lung fields. On post dvt's were found. While not well documented in his inpatient chart, the patient was seldom seen out of bed.

If I remember correctly, Dan Blocker , of Bonanza fame, died under similar conditions following a Cholecystectomy.

RF

swatsurgeon
04-30-2008, 11:24
The reason I brought this up is that as medical providers, we sometimes have to step out of our 'comfort zone' and give advice where it typically wouldn't be asked for. Do flight surgeons require that all transported personnel stretch every 20-30 minutes while in flight, remain well hydrated, etc?????? The medic assigned to a unit may be the one to remind their team of similiar such 'needs'. The classic story is the person that drops from dehyration while working around water all day: lots of bottled water around, camelbak on but not used....you see my point.
ss