UMEM Educational Pearls - By Rob Rogers

Splenic Artery Aneurysm (SAA)

Ever scanned someone and the report says "incidental note of a splenic artery aneurysm"? Well, if it hasn't happened yet, it will sooner or later. This type of aneurysm isn't that rare and with the number of abdominal CTs we order we are bound to see this in clinical practice.

Some important points to remember about SAA:

• 3rd most common location of intra-abdominal aneurysm, 1st-aortic aneurysm, 2nd-iliac artery aneurysm
• Most common complication is sudden rupture and occurs in as many as 3-10% of cases
• 80% pf patients with SAA are asymptomatic
• Symptomatic aneurysms may present with left upper quadrant pain, nausea, and vomiting
• Splenic infarct is a rare complication
• Most important is followup: patients will need close followup for asymptomatic splenic artery aneurysms. Consultation with a surgeon will need to be arranged if it is thought that the patient has symptoms due to the aneurysm

Suspect your patient has an aortic dissection? Don't wait to lower the blood pressure.

A few considerations for the patient with suspected aortic dissection:

• If the patient is hypertensive AND you really think they could have the disease, start the drip then. Don't wait until the CT is done. Every second that goes by with extremely elevated BP may increase the dissection length.
• If you are really worried about a patient having a proximal aortic dissection, don't wait for the creatinine to come back...scan them without it. If you are really suspicious this is justified in many cases.
• There is very little (to no) role in performing a dry CT (because the patient's creatinine comes back elevated). Dry CT is very insensitive. Instead get a transesophageal echo or an MRI. 

Bleeding Dialysis Fistula?

Ever see a patient in the ED c/o "my fistula won't stop bleeding"? If you haven't, you probably will in the future.

Here are some helpful tips on getting these bad boys to stop oozing:

• Local pressure for 10 minutes will stop many of these bleeders
• Can also try locally applied gel foam/thrombin
• Pharmacologic adjuncts may be required, especially if the patient has missed dialysis-DDAVP can be given (makes platelets stickier by causing endothelial cells to release von Willibrand Factor). You can also give platelets, since platelets don't work well in a uremic state. Many dialysis patients are on coumadin because of chronic line clots, so don't forget to reverse this if present
• Probably as a last resort you can tie a superficial circular suture at the puncture site. This works quite well.

Altered Mental Status-Does Your Patient Have Non-Convulsive Status Epilepticus?

Ever intubated a patient in status epilepticus and wondered if they were still seizing after sedation and paralysis? Ever taken care of an altered patient and wondered if you should consult neurology and attempt to get an EEG?

NCSE is defined as continuous seizure activity without obvious outward manifestations of a seizure. This is important for emergency physicians to consider because it has to be detected early to prevent morbidity and mortality.

When to consider NCSE:

• Prolonged postictal period
• Unexplained altered mental status in a patient with a history of seizures
• Altered mental status associated with "eye twitching" or blinking
• Stroke patient who clinically looks worse than expected

Pulmonary Embolism-Myths and Misconceptions

Just wanted to mention a few myths/misconceptions about acute PE that I have recently heard discussed in the ED.

1. Emergency physicians have to "get help" to give thrombolytic therapy. Sure it makes sense that we consult critical care and perhaps interventional radiology in some cases. But we do not need permission to use this drug by ourselves if indicated. Consider using lytics ESPECIALLY if the patient is unstable or if there is evidence of RV dysfunction (elevated troponin, echo criteria for dysfunction, or CT with large RV and bowing of the septum). What about the patient with RV dysfunction and a normal BP? Evidence is mounting that lytics are indicated to reduce the severity of pulmonary hypertension. 

2. "Just get a d-dimer." Be very careful. Lots of false positives. D-dimer often clouds the picture more often than not. 

3. "The mortality rate of missed PE is high." Often quoted as a 30%+ mortality rate if missed. Recent data suggests that it is < 5%. 

Can you use a serum d-dimer to rule out aortic dissection?

The answer to the question, in 2010, is no.  

There has been a flurry of recent literature about the use of serum d-dimer to rule out aortic dissection. Some studies have shown a sensitivity of nearly 100%, but other studies have shown sensitivities of only 60-70%....pretty abysmal sensitivities. And despite some of the authorities on the subject touting how good the test is, there is not firm literature to support it. Better yet, there are some active medical malpractice cases I am aware of in which the diagnosis of aortic dissection was missed based on a "negative d-dimer."

My suggestion, and the vascular pearl for the day, is to avoid using d-dimer as a aortic dissection rule out strategy until good evidence (if it ever becomes available) exists. I know that people are using this test to rule out the disease, just realize that EVERY time I have ever given a talk on acute aortic disasters, 2-3 people from the audience always share that they had a case of a "d-dimer negative dissection." 

Be careful....

Evaluation of the acutely ischemic limb

Some considerations when evaluating/treating patients with acute limb ischemia:

• Strongly consider anticoagulation (usually with Heparin) early
• Consider the source of the ischemia (LV/LA thrombus, AAA mural thrombus, in situ limb thrombosis)
• Always consider aortic dissection as an etiology of acute limb ischemia (chest pain and leg ischemia)
• Early vascular consult and/or transfer
• Obtain bedside ABIs on suspected cases and remember that diabetics may have normal to falsely elevated ABIs secondary to calcified vessels.
• Common theme in laws suits for missed or delayed cases of limb ischemia: failure to perform and document ABIs

Altered Mental Status-Three Diagnoses That Can "Bite You On The Buttocks"

When evaluating the patient who is altered, consider the following diagnoses:

1. DTs-seems simple enough, right? Remember that some altered patients will not be able to give a history of alcoholism. And this is definitely a diagnosis that can sneak up on you. Bottom line: consider DTs in ALL patients with a delirium.

2. Wernicke's encephalopathy-can also be very difficult to detect. Consider in ALL alcoholic patients with altered mental status and give Thiamine. 

3. Herpes encephalitis-speaking from personal experience, this diagnosis can be extremely tough to diagnose. Consider giving emperic Acyclovir in patients with WBCs in their CSF and a negative gram stain. And don't forget to send off a Herpes PCR. As far as clinical presentations, CNS Herpes can present with a wide spectrum of findings, from isolated headache, to new psychobehavioral changes, to severe depression of consciousness and coma. Be aware that this diagnosis isn't common but failure to initiate Acyclovir may be a fatal mistake. 

How to stop dialysis fistula/graft bleeding

The number of patients being placed on hemodialysis seems to be increasing. And the ED is where they will go when there is a any complication from their fistula or graft.

Hemodialysis shunts require cannulation with large bore instruments. This combined with heparinization may lead to prolonged bleeding from puncture sites. 

What to do when a patient shows up in the ED with persistent bleeding from a fistula puncture site:

• Simple pressure may be all that is required in many cases. 
• If this doesn't work, place a single circular suture around the puncture site/incision. In some small studies this has been shown to be very useful in stopping persistent oozing

Show References

 Wernicke's Encephalopathy

Wernicke's encephalopathy, considered a unique complication of alcoholism, is also seen in malnourished patients, bariatric surgery patients, and patients who have undergone bone marrow transplantation.

Some pearls about Wernicke's encephalopathy:

• The classic triad of confusion, ataxia, and opthalmoplegia is seen in only about 10-15% of cases
• The diagnosis is made before death in only about 10_15% of cases
• Most authorities on the disease have suggested that opthalmoplegia be replaced by ocular, since many ocular findings may be seen in these patients (nystagmus, retinal hemorhages, cranial nerve palsies)
• Essentially any alcoholic who presents with confusion (ever see these patients in your ED?) could have the disease, so give Thiamine liberally when the patient arrives. 
• It is a myth that administration of thiamine before glucose will precipitate Wernicke's. This dogma is based on a case series of 4 patients from the Irish Journal of Medical Sciences. 

Effort Thrombosis

Effort thrombosis, also called Paget von Schrotter disease, occurs when either the axillary and or subclavian veins thrombose. The condition is more common in young, healthy (>males) patients and presents with the usual DVT symptoms of arm pain, swelling, and pain.

The disease was originally described in patients performing vigorous activities, like weight lifting or repetitive over-the-head lifting. This type of activity has been reported to kink the subclavian vein and lead to clot formation.

Diagnosis and therapy is the same for any other type of DVT.

The Art of Pimping-And How to Protect Against

This monday's pearl (ok, I know, it's tuesday now) comes from Michelle Lin's blog: academic life in emergency medicine. It is more gem than pearl, and it discusses what medical students and residents do to avoid being pimped. It is a must read!

Here is the link to the discussion on Michelle Lin's blog:

http://academiclifeinem.blogspot.com/2009/11/trick-of-trade-essential-skills-for.html

Just a few note worthy "pimping protection procedures":

• The "Muffin"-person being pimped raises a muffin (or some other food item) to their mouth as they are being pimped. And if the person with the muffin stills gets the question, the pimpee pretends to choke, thus avoiding future pimp questions
• The "Eclipse"-eclipsing your head with someone in front of you, that way the pimper can't see you.
• The "Politician's" approach-answering the question you wished you were asked.

Happy pimping!

Well, this monday's pearl is a bit different than prior pearls. I wanted to let you know about a very cool website I came across recently called Clinical Reader. There is a whole lot in the recent medical education literature that discusses "Web 2.0." Web 2.0 involves learning through interactive websites, blogs, podcasts, etc. Medical education is really starting to head out of the classroom, and I wanted to mention a newer website that a lot of folks are talking about. 

Clinical Reader is a new medical RSS aggregator. What, you might ask, does this mean?

An RSS aggregator is a site that puts together information for you, that's right, for you. It actually does the work for you. Did I mention that it does the work for you? On this site, for example, if you are interested in "Emergency Medicine," the site finds all (or almost all) EM journals and brings you all of the latest information and updated articles. If you are into "Medical Education," you simply choose that category from a drop down menu and poof, you have all of the latest publications/reviews from the major medical education journals. Just choose your category and/or specialty and you are off and running. 

Try it out. It isn't 100% perfect, but it is very cool.

http://clinicalreader.com/

A varicocele is a collection of venous varicosities in the spermatic veins in the scrotum. This is caused by imcomplete drainage for the pampiniform plexus. This may be seen is up 20% of males and is asymptomatic most of the time. Most are found on the left side.

Why should you care, you might ask? Well, the right spermatic vein drains into the IVC and then into the renal vein, whereas the left spermatic vein drain drains directly into the renal vein.

In the patient with new onset, unilateral varicocele, consider an IVC thrombus/tumor if right sided and a left renal clot if left sided.

A case we had recently was a 30 yo male with nephrotic syndrome (a HUGE risk factor for renal vein thrombosis) who presented with left-sided scrotal swelling. He was found to have a left-sided varicocele. Based on this finding, a renal sono was performed and the diagnosis of left renal vein thrombosis was made.

Show References

Got some interesting info today on the costs of some commonly used antihypertensive medications. Keep in mind that in patients with severe hypertension, your options of IV drips are limited.

Here is some info from our hospital:

Fenoldopam - $113.28
Nicardipine - $94.67
Esmolol - $82.15
Nitroprusside - $20.86
Labetalol - $14.40
Nitroglycerin - $2.90

Although Fenoldopam (Corlopam), which has been around for years, is more expensive than Nitroprusside, it is just as effective and without the side effects.

A new drug on the market that we don't have yet, Clevidipine, is just as effective as the big guns Nipride and Fenoldopam. Costs at this point are unknown.

More on antihypertensive medications next week....

Management of Heparin-Induced Thrombocytopenia (HIT)

HIT occurs when antibodies form to a Heparin-Platelet Factor 4 (PF4) complex in patients who have been exposed to Heparin. 

The main clinical manifestation is thrombosis (arterial/venous). Treatment is unique in that only certain medications can be used.

Medical Management options in HIT:

• Direct thrombin inhibitors (DTI). The main ones used in clinical practice include Argatroban and Hirudin. These drugs work by directly binding to thrombin (fibrin bound) and inhibiting it. The drugs are reliable and safe. Hirudin may initiate an allergic reaction in patients who have been exposed and is renally cleared (so shouldn't be used in ESRD or lower GFRs)
• Fondaparinux (Arixtra). Can be given subcutaneously. More expensive. Also approved for once daily treatment of DVT/PE

So, when a patient with a history of HIT shows up in the ED with a DVT/PE or other thrombotic problem, these are your mainstay drugs.

Severe mitral regurgitation (MR) after MI, accompanied by cardiogenic shock carries a poor prognosis.

Severe MR in many cases is due to infarction of the posterior papillary muscle, and in these cases the area of infarction tends to be less extensive than in those with MR due to severe left ventricular dysfunction. 

Take Home Pearl:

The presence of pulmonary edema and/or cardiogenic shock in a patient with an inferior STEMI should prompt consideration for acute MR due to papilary muscle rupture. Get an echo as fast as you can to confirm or r/o the diagnosis. Treatment is afterload reduction, inotropic support, and urgent surgical repair. 

Herpes Encephalitis-When to Consider

Herpes encephalitis is a potential lethal condition with high morbidity. Obviously our job in the ED is to rule-out bacterial meningits. So, when should we consider the diagnosis of herpes encephalitis?

• High wbc in the CSF with a negative gram stain
• Lymphcytic predominance in the CSF
• Altered patient and abnormal CSF
• And, just about any of the softer "rule-out aseptic meningitis" patients

Although no great guidelines exist, consider ordering a herpes PCR when sending studies on the "rule-out meningitis" patient. What about emperically treating a patient with Acyclovir? Again, no great data. Consider treating with 10 mg/kg IV q 8 hours for patients with abnormal CSF (in addition to the Ceftriaxone/Vanc, etc.) if you are worried about them, if they are altered (or encephalopathic), and if the CSF is abnormal (elevated wbc) with a negative gram stain. Acyclovir can always be discontinued when the PCR returns negative.

This week's monday pearl is from our very own Azher Merchant....who recently gave an excellent talk on the risks of radiation.

Be afraid....be very afraid....

Radiation Risk:
Risk is based on acute exposure and is extrapolated largely from atomic bomb survivors.
Effective radiation dose = Sievert (Sv)

Adults:
Lifetime Attributable Risk of Cancer 1:1000 at 10mSv
Lifetime Attributable Risk of Cancer Mortality 1:2000 at 10mSv
 
Risk estimates follow a linear rate of change such that:
Lifetime Attributable Risk of Cancer in Adults = Radiation Dose (mSv) x 0.0001
Risk is Cumulative

Pediatrics:
Lifetime Attributable Risk of Cancer is greater than for adults and is age-dependent
Lifetime Attributable Risk of Cancer Mortality 1:1000 at 10mSv

Common Effective Dose Estimates (mSv)

Background radiation                     3.5/year (chronic exposure)
CXR                                             0.1
CT
    Head, Face                               2
    Neck, Cervical Spine                 2
    Chest, Thoracic Spine                8
    Abdomen                                7.5
    Pelvis                                     7.5
    Abdomen/Pelvis, Lumbar Spine 15
    Extremity                               0.5
 

Note that it doesn't take very much radiation to reach the 10 mSv level!

Bottom line: CT if you need to, but carefully consider whether it is worth it or not

One last pearl, carefully consider whether or not you want that d-dimer and don't order one unless you are prepared to order a CT scan.

Painless thoracic aortic dissection (TAD) and syncope

Patients with TAD do not always present with chest pain. In the International Registry of Aortic Dissection (IRAD) study, 2.2% of TAD cases were painless and approximately 13% of TAD cases presented with isolated syncope (i.e. NO PAIN). Other studies have shown that as many as 15% of TAD cases are painless.

Patients with TAD may present after a syncopal episode. The underlying pathophysiology of syncope is related to proximal rupture into the pericardium with resultant tamponade.

Add TAD to your differential diagnosis of unexplained syncope, especially in older folks and especially if a patient "looks bad" and you don't have a reason.