UMEM Educational Pearls

Calciphylaxis is a rare disorder caused by systemic arteriolar calcification which leads to ischemia and necrosis.  It is characterized by painful ischemic necrotic lesions on adipose tissue areas such as abdomen, buttock and thighs.  This commonly occurs in patients with ESRD on hemodialysis or after transplant, but can also occur with other patients, such as those with hyperparathyroidism.

Diagnosis is made clinically, with the help of a skin biopsy as needed.  Differential diagnosis includes cholesterol embolization, warfarin necrosis, cryoglobulinemia, cellulitis and vasculitis.  There are no specific laboratory findings, although patients may manifest elevated PTH, phosphorous, calcium or calcium x phosphorous product. 

Infection is usually the cause of the high mortality rate of this condition, which has a reported mortality of 46%, or 80% if ulceration is present.

Treatment includes local wound care, trauma avoidance, electrolyte correction, increased frequency of dialysis or parathyroidectomy as needed.  Surgical debridement is controversial; as the risk of infection may outweigh the benefit in terms of outcome. 

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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!

Up to 10% of elderly patients in the ED meet criteria for acute delirium, though misdiagnosis rates are very common.
The most common cause of delirium in the elderly, overall, is medication effects. Other common causes are infections (UTIs most common), CNS abnormalities, cardiovascular abnormalities, electrolyte/metabolic abnormalities, and temperature abnormalities (fever or hypothermia).

Vision loss whether acute or chronic is a common presenting complaint to the ED.  This will be the first in a series of pearls on the subject.  This pearl will address the nomenclature used by ophthalmology based on the length of vision loss.

    •    Transient visual obscuration - Episodes lasting seconds. Usually associated with papilledema and increased intracranial pressure.
    •    Amaurosis fugax - Brief, fleeting attack of monocular partial or total blindness that lasts seconds to minutes
    •    Transient monocular visual loss  or transient monocular blindness - A more persistent vision loss that lasts minutes or longer
    •    Transient bilateral visual loss - Episodes affecting one or both eyes or both cerebral hemispheres and causing visual loss
    •    Ocular infarction - Persistent ischemic damage to the eye, resulting in permanent vision loss

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• Neuroleptic Malignant Syndrome (NMS) is a rare, but true neurological emergency which is today associated with much lower mortality given heightened awareness about the condition.

• It typically initially begins with muscle rigidity resulting in rhabdomyolysis, followed by high fever, and delirium.

• Always check creatinine phosphokinase (CPK) and white blood cell levels when concerned about NMS, as these typically elevate in response to muscle breakdown.

• The following mnemonic (FEVER) serves as a reminder of the signs and symptoms associated with NMS:

           F - Fever (anything over 100.4 F counts)

            E - Encephalopathy

           V - Vital signs instability

           E - Enzymes elevation (i.e. CPK)

            R - Rigidity of muscles

Spinal Epidural Abscess Pitfalls

• The classic triad of back pain, fever, and neurologic deficits are found in < 15% of patients at the time of presentation
• Up to 75% will be afebrile
• Up to 67% will have a normal initial neurologic exam
• < 40% have a WBC greater than 12,000 cells/mm³
• < 33% will have an abnormality on plain film in the first 7-10 days

Take Home Point: In the patient with risk factors for spinal epidural abscess (IVDU, DM, indwelling catheters, etc) do not exclude the diagnosis based upon the absence of a fever, a normal WBC count, and a normal neurologic exam.

Ring-removal is a dreaded problem in pediatric hand and finger injuries.  Removal can be difficult and time consuming.  The relatively recent introduction of Tungsten into the jewelry market has further complicated this problem:

• The hardest metal used in jewelry - cannot be scratched, much less cut, by common tools
• Cheap, easy to buy online, attractive to adolescents

However, it is:

• Extremely brittle
• May be safely and quickly broken with locking pliers (also cheap), by sequentially, gradually tightening the locking plier grip

This video explains how.  Of course, this works on adults as well.

http://www.youtube.com/watch?v=poM423pewRE

_{I have no relationship with the copany which made this video - it was simply chosen for its clear explanation of the solution described in this pearl.}

 Myocardial infarctions involving the left circumflex artery are often associated with ECGs that lack any ST-segment changes (38% in one representative study). Oftentimes when there are ST-changes, there may simply be anterior lead ST-segment depression. In these patients, acquisition of a few posterior leads frequently demonstrates STEMI. Some data does exist that failure to diagnose these posterior STEMIs (e.g. simply diagnosing anterior "ischemia" rather than posterior "STEMI") results in increased mortality.

So what's the bottom line?
1. In patients with isolated anterior lead ST-segment depression, always check for posterior STEMI with a couple of posterior leads.
2. In patients with non-significant ECGs but concerning persistent symptoms, always check for posterior STEMI with a couple of posterior leads.

This is always a great time to use that 80-lead ECG if your ED has one.

Amal

MEWDS (Multiple Evanescent White Dot Syndrome)

• A rare, unilateral, self-limiting inflammatory disease
• Afflicts young women more than men in a 4:1 ratio.
• Patients typically present complaining of
  • Sudden, painless, monocular decline in central acuity
  • Photopsias-- def. appearance as of sparks or flashes in retinal irritation
  • Dyschromatopsia-- def> disorder of color vision
  • Central/paracentral scotomas
• Visual acuity usually in the  20/40-20/400
• Fluorescein angiography of active lesions typically demonstrate a "wreath-like" hyperfluorescence of the white dots
• Disease is usually self limited (resolves in weeks to months) with an excellent prognosis.
• There are no known treatment options.

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Global symptoms of elevated intracranial pressure (ICP) include:

• Headache (likely mediated via the pain fibers of cranial nerve V in the dura and blood vessels)
• Depressed consciousness (likely due to either the local effect of mass lesions or pressure on the midbrain reticular formation)
• Vomiting

There is no prospective, randomized study to elucidate propofol’s effect on the critically ill patient. By definition, Propofol Infusion Syndrome (PRIS) has the following characteristics:

• acute bradycardia progressing to asystole
• lipemic plasma
• fatty liver enlargement
• metabolic acidosis with negative base excess > 10
• rhabdomyolysis or myoglobinuria

It has been thought that PRIS was limited to patients with prolonged use, but we now know that this is not necessarily true.

It has been shown that PRIS is more likely with the following risk factors:

• <19 years old
• male
• received a vasopressor
• cardiac manifestations (including Brugada Syndrome)
• metabolic acidosis
• renal failure
• hypotension
• rhabdomyolysis
• dyslipidemia

The treatment for suspected PRIS is:

• Stop infusion
• Hemodynamic stabilization
• Carbohydrate substitution
• Hemodialysis or hemofiltration
• ECMO as necessary

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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/

During this season of the ever-present viral respiratory illness, we must be on the lookout for the potentially-deadly -entity of myocarditis. A recent study suggests some clues to when the diagnosis should more strongly be considered in patients presenting with viral respiratory symptoms.

1. Most cases of myocarditis were not initially recognized by primary care MDs or emergency health care providers. 84% of patients needed more than one visit within 2 weeks before the diagnosis was made. This highlights the difficulty in Dx and frequent misdiagnosis rate.
2. The most common presenting symptom was dyspnea (69%) and most common sign was tachypnea (60%).
3. Although resting tachycardia is often taught as a common finding, 66% of patients had a normal HR.
4. The most helpful findings in terms of helping distinguish myocarditis from benign common viral URIs was hepatomegaly (present in 50%) and cardiomegaly (present in 60%).
5. An abnormal ECG was present in 100% of cases. The most common abnormalities were tachycardia, ventricular hypertrophy, and ST or T wave changes.
6. 54% of patients had elevated troponin levels.

So what's the bottom line?
1. If your patient has tachypnea or dyspnea, strongly consider getting a CXR. In that case, look carefully for cardiomegaly.
2. Always assess for and document the presence or absence of hepatomegaly.
3. A completely normal ECG is strong evidence against myocarditis.

[Durani Y, Egan M, Baffa J, et al. Pediatric myocarditis: presenting clinical characteristics. Am J Emerg Med 2009;27:942-947.]

Scaphoid Fractures in Children:

1. Rare before the age of 11.
2. Make up less than 0.34% of all pediatric fractures
3. Scaphoid fractures may be missed 12.5% - 37% on the initial presentation.
4. 30% of patients will have an radiographically apparant fracture on repeat films done 2 weeks later.
5. These physical exam findings are more specific for fracture:
   1. Volar tenderness over the scaphoid
   2. Pain with radial deviation
   3. Pain with active wrist range of motion.  
6. Though snuff box tenderness was seen in 100% of patients eventually proven to have a fracture, it was also seen in 92% of the patients that did not have a fracture at follow-up making it non-specific but sensitive.
    

Because of the high (30%) fracture rate seen on followup films it is recommended that all children be placed into a thumb spica splint until followed up.

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The newest antidote for cyanide poisoning, hydroxocobalamin, has several advantages over the older Cyanide Antidote Kit (amyl nitrite, sodium nitrite, sodium thiosulfate).  Hydroxocobalamin works rapidly, does not induce methemoglobinemia, and does not cause vasodilation/hypotension.

• The first is self-limiting hypertension. However, think about the patient population you are treating.  They are most likely hypotensive from the cyanide/carbon monoxide poisoning.  Increased blood pressure is a welcome adverse effect in these cases.
• The second is red discoloration of the skin and urine, secondary to the red color of hydroxocobalamin (see attached picture).  This effect can be quite pronounced, especially if you aren’t prepared for it. There is no harm to the patient although it can last up to 8 days.

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Attachments

0911120826_Cyanokit_red_skin.jpg (107 Kb)

• Guillain-Barre’ syndrome can be associated with marked neuropathic pain which is best described as having “burning” skin.

• Additionally, these patient may develop hemodynamic instability and adynamic ileus, both related to autonomic dysfunction.

• Classically, GB patients present with a foot drop several days after an episode of food poisoning, most commonly from Campylobacter jejuni.

Severe Acute Pancreatitis

• Patients with acute pancreatitis are considered to have severe acute pancreatitis (SAP) if they manifest signs of shock, respiratory failure, renal faliure, or GI bleeding.
• SAP is almost universally associated with pulmonary dysfunction, typically manifested as an S_pO₂ < 90% in the first few hours of illness.
• In fact, ARDS develops in at least one-third of patients with SAP.
• Take Home Point: Pay close attention to the patient with acute pancreatitis and a low pulse oximetry reading, as many will rapidly deteriorate from ARDS. In those who deteriorate, early intubation with implementation of lung protective ventilatory strategies is indicated.

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Slipped Capital Femoral Epiphysis (SCFE)

SCFE can present as hip, thigh or knee pain in the young adolescent. Risk factors include hypogonadism, hypothyroidism, hypopituiratism, and obesity. One way to make the diagnosis is to obtain a AP view of the pelvis and draw a line(Klein's line) along the superior border of the neck of the femur.  This line should intersect the femoral epiphysis. If it does not the diagnosis of SCFE can be made.

However, this is only about 40% sensitivity. Green et al recently published a study that demonstrated that if you measure the distance from Klein's line and the lateral edge of the femoral epiphysis on both sides, and the difference between the two is more than 2mm you can make the diagnosis of SCFE more accurately and sooner.

FIGURE 1. Measurement methods on an anterior-posterior radiograph of a right slipped capital femoral epiphysis. White lines indicate Klein’s line for each hip. A and B, indicate maximum epiphyseal width lateral to Klein’s line. As A is 2mm narrower than B, the right (A) hip qualifies as a slip using our modification but not Klein’s original definition.

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Conjunctivitis in Children:

• Usually a self-limiting process, very common in school-aged children and children in daycare or group home settings
• Crusting/swelling treated with warm compresses
• Antibiotics are not necessary outside of the neonatal period, but they do speed recovery
• Neonates with conjunctivitis - send cultures (gonococcal ophthalmia neonatorum);  all others - no cultures necessary
• Treatment with erythromycin ointment, Polytrim solution, ciprofloxacin solution (usually practicioner preference unless dealing with a recurrent/resistant case)

HOWEVER... remember to consider other common etiologies of a red eye in a child!

• Corneal abrasions
• Acute angle closure glaucoma (sickle cell patients)
• Allergic sources

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• Infections induce activated T cells and antibodies, which within the context of an influenza syndrome, are thought to cross react with axonal antigens and macrophages, resulting in demyelination.  This process likely triggers a subsequent Guillain-Barre’ syndrome (GBS).

• Presumably, influenza vaccine induces a similar response in susceptible individuals.

• Juurlink and colleagues found there to be a 1.45 relative risk, which equals a 1.7-fold adjusted relative risk for contracting GBS, associated with influenza vaccination.

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