Quick Hit: D-Dimer false positives

30 Jun

Thinking about ordering a D-Dimer for PE rule-out? What are the clinical conditions to consider thatmay make your D-Dimer falsely elevated?

  • Myocardial infarction
  • Stroke
  • Atrial fibrillation
  • Preeclampsia and eclampsia
  • Cardiovascular disease
  • Congestive heart failure
  • Severe infection
  • Surgery/trauma
  • Sickle cell disease
  • Severe liver disease (decreased clearance)
  • Malignancy
  • Renal disease
  • Pregnancy

 

Source: uptodate.com; picture

 

Submitted by K Estes.

Hypertrophic Cardiomyopathy (HCM)

25 Jun

QUICK HITS:

-only about 50% of patients will have positive family history

-average age of diagnosis is 30-40 years -> not always a teenager or young adult!

-clinical features: syncope, chest pain, palpitations, dyspnea

systolic murmur at apex or LLSB

  • increases with valsalva and standing
  • decreases with trendelenburg and squatting

-ECG abnormalities present >85% of the time

            high left ventricular voltage, left atrial enlargement

            tall R wave in V1 (mimics posterior MI)

            deep, narrow Q-waves in inferior, lateral leads

-definitive diagnosis Doppler ECHO

-treatment: beta blockers, calcium channel blockers; these patients should be urgently referred to cardiology and be counseled to avoid strenuous activity

Source: lifeinthefastlane.com, Mattu A, Brady W. ECGs for the Emergency Physician 2, BMJ Books 2008.; picture

Submitted by K Estes.

Anbesol for babies: why worry?

23 Jun

Dapsone and topical anesthetic agents (benzocaine, the active ingredient in anbesol) are the most common causes of acquired methemoglobinemia

Acquired methemoglobinemia is a result of certain ingested drugs leading to a state of oxidized (ferric state Fe+++) of hemoglobin, which are unable to bind oxygen. The remaining hemoglobin groups have an increased oxygen affinity causing a left shift.

The overall result is a functional anemia.

There are two ways for methemoglobin to be reduced back to hemoglobin:

  1. NADH-dependent catalyzed by cytochrome b5 reductase (b5R)
  2. NADPH generated by glucose-6 phosphate dehydrogenase (G6PD), but in order for this pathway to be activated, an extrinsically administered electron acceptor is required (methylene blue and riboflavin)

Infants are more susceptible to the development of methemoglobinemia because their erythrocyte cytochrome b5 reductase activity is 50-60% of adult activity

Treatment includes administration of intravenous methylene blue, 1 to 2 mg/kg, given over five minutes

Source: uptodate.com

Submitted by K Estes.

Myth Buster: Egg allergies and Propofol

18 Jun

 

Bottom line: there is no confirmed report of propofol-induced anaphylaxis in egg-allergic patients.

 

Propofol is made up of an oil water emulsion using soybean oil (10%) and egg lecithin (1.2%).

 

Lecithin (from the Greek lekithos, which means egg yolk) is a purified phosphatide found in egg yolk.

 

Egg allergy is most common during childhood and is usually outgrown by adulthood. The five major allergens that have been characterized originate from the egg white. Chicken serum albumin is the major allergen that has been described from the egg yolk.

 

The cases documented of anaphylaxis that have been associated with propofol were never followed with formal skin testing.

 

Now that we are on the topic… what about allergies to soy? Should you be worried that patients with soy allergies will have anaphylaxis to propofol?

 

Refined soy oil, such that is used to make propofol, is safe for people with soy allergy because the allergenic proteins are removed during the refining process.

 

Source: Anesthesia in the patient with multiple drug allergies: are all allergies the same? Current Opinion in Anaesthesiology. June 2011. Issue: Volume 24 (3), p 320-325; picture

 

Submitted by K Estes.

A case of a chest pain zebra

16 Jun

Case: A 32 yo female 2 weeks post-partum who presents with sudden onset dull left anterior chest pressure and mild shortness of breath. No trauma or other sx. No PMH or significant FH.

 

Other than HR 105, vitals are normal including bilateral BP’s.  Her exam is unremarkable.

 

Your Ddx is broad- you consider pericarditis, myocarditis, PE, cardiomyopathy, aortic dissection, ACS, gastritis, esophageal disruption, pneumothorax, pneumonia, substance use…

Her CXR is normal.

EKG is below:

ekg-sca

Her Tn returns at 4.58 and her other labs are unremarkable (including a negative d-dimer). Cardiology admits her, brings her to the cath lab and she is found to have a…

 

 

 

Spontaneous coronary artery dissection

This is very rare- about 300 documented cases according to 1 journal article in 2008, 70-90% reported cases are in women

Risk factors: Female, pregnancy or post-partum, fibromuscular dysplasia, extreme exercise, connective tissue disorder, cocaine use, marked HTN

Sx/presentation: Chest pain, diaphoresis, palpitations, shortness of breath- symptoms of ACS. Patients may present with an NSTEMI, STEMI, CHF, unstable angina, or even a pericarditis clinical syndrome.  Traditionally, patients will have ST elevation in the leads corresponding to the dissecting artery, but this is not always the case.

Dx: Many options for diagnostic studies: cardiac cath, coronary angiogram, intravascular US, optical coherence tomography, CTA

Tx: Given the low incidence, there is a significant amount of variability. Main options include medical management, coronary bypass, and stenting.

Bottom line: SCA is a very rare diagnosis with a high mortality. Consider in the ddx, particularly in young female patients with chest pain and an ACS picture. Classically, you will see ST elevations and an elevated troponin. For me the take away is keeping a high index of suspicion in patients with concerning histories or exams.

 

Submitted by Heather Groth.

 

References:

Cleveland Clinic http://my.clevelandclinic.org/services/heart/disorders/spontaneous-coronary-artery-dissection

Tweet, et al. Clinical Features, Management, and Prognosis of Spontaneous Coronary Artery Dissection. Circulation. 2012;126:667-670.

Vanzetto, et al. Prevalence, therapeutic management and medium-term prognosis of spontaneous coronary artery dissection: results from a database of 11,605 patients. European Journal of Cardio-thoracic Surgery. 2008: 35 (3), 205-254. 

Zampieri et al. Follow up after spontaneous coronary artery dissection: a report of five case series; Heart.1996: 75, 206-209.

picture 1, 2.

visual aid: mastoiditis

10 Jun

Not usually the focus of most of our head CT’s, but worth remembering what to look for, particularly for those with ear symptoms, and certainly if they have mastoid tenderness

 

QUICK HITS on MASTOIDITIS

rare complication of otitis media

more common in kids than adults

mastoid lies superior to the middle ear cavity

can have redness, swelling, tenderness over the mastoid process

pus entering mastoid cells under pressure -> dissolution of surrounding bone (not awesome)

infection can spread to nearby structures (e.g. neck, CNS)

treatment: IV abx

 

QUICK VISUALS

(opacification of mastoid air cells–tip: use bone windows)

 

 

mastoiditis

File it away in the mental Rolodex.

 

References: uptodate.com; mastoid process; picture 1; picture 2

cool resource: lacerationrepair.com

5 Jun

came across this website, which has a number of handy blog posts and procedure videos on a variety of laceration repair techniques.  Great for the novice learner, with added tips/tricks (subculticulars, nailbed repair, thin skin, etc.) for the experienced practitioner, too.

One highlight that I use quite often: V to Y conversion

Basically, for a big V-shaped lac, the goal is to approximate the corner/apex first, then the rest becomes easy.

QUICK STEPS:

  • often needs higher tension, so start it like a horizontal mattress
  • throw a subcuticular around the corner/apex
  • bring it back like finishing up the horizontal mattress.
  • voila!

 

If you only have 60-seconds: Start at the 0:40 mark.

 

Just one example, but a good thing to have in the back pocket.

Keep the site in mind as a resource, too. Check it out at your leisure.

 

References: lacerationrepair.com (+ picture & video).

 

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