UMEM Educational Pearls

Right heart endocarditis is much more common in patients that are injection drug users. Fortunately for them, they have a lower mortality than patients with left heart endocarditis because they have a lower rate of developing heart failure. This is a reminder that the most common cause of death from endocarditis is heart failure.

The Weber classification system

A commonly used, simple, easily remembered system used to describe ankle fractures. The system focuses on the integrity of the syndesmosis.

http://www.accessemergencymedicine.com/loadBinary.aspx?fileName=simo_c017f013t.gif

  - TYPE A:  fibula fracture below the ankle joint/syndesmosis (which is intact). Deltoid ligament intact. Medial malleolus can be fractured. Usually treated with closed reduction.

http://www.gentili.net/image1.asp?ID=-241442344&imgid=AnkleWeberAAP600.jpg&Fx=Weber+A+Fracture

  - TYPE B:  is a transsyndesmotic fracture with usually partial rupture of the syndesmosis (though may be intact). No gross widening to the tib/fib articulation.. Deltoid ligament intact. Medial malleolus often fractured.  Variable stability. Any clinical or radiographic injury to the medial joint complex make this an unstable fracture

http://www.gentili.net/image.asp?ID=145&imgid=AnkleWeberBmortise600.jpg&Fx=Weber+B+Fracture

  - TYPE C:  Fibular fracture above the level of the syndesmosis with usually a total rupture of the syndesmosis (seen as widening of the distal tib/fin articulation), resulting in instability of the ankle mortise. Associated with medial malleolus fracture or deltoid ligament injury. Unstable.

http://www.gentili.net/image1.asp?ID=146&imgid=anklewebcapoblx2600.jpg&Fx=Weber+C+Fracture

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Attachments

1111251332_2009_Red_Book.doc (384 Kb)

• Studies have shown that the natural history of Bell's Palsy without treatment is such that 85% show signs of recovery within 3 weeks of symptom onset, and 71% experience complete recovery.
• Of the remaining individuals who do not completely recover, 13% experience persistent mild sequelae and 16% have residual weakness, synkinesis, and/or contracture.
• Those with incomplete lesions (i.e. incomplete paralysis) are more likely to return to normal function (94%), while only 60% of those with clinically complete lesions return to normal function.
• Herpes zoster is associated with more severe paresis and a worse prognosis.  When little to no recovery is seen within the first 21 days following symptom onset, the prognosis is less favorable.

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Determining the exact etiology of hypotension / shock can sometimes be difficult in the Emergency Department.

The Rapid Ultrasound for Shock / Hypotension (RUSH) exam is a sequential, 5 step-protocol (typically requiring less than 2 minutes) that can be used to determine the cause(s) of hypotension.

The mnemonic for the exam is “HI MAP”, and is easy to remember because a "HI MAP" is our goal with hypotensive patients.

H - Heart (parasternal and four-chamber views)
I  - Inferior Vena Cava (for volume responsiveness)
M - Morrison’s pouch (i.e., FAST exam) and views of thorax (looking for free fluid)
A - Aortic Aneurysm (ruptured abdominal aneurysm)
P - Pneumothorax (i.e., Tension PTX)

Refer to the link for a more detailed discussion and podcast from the creators of this exam: emcrit.org/rush-exam

Reasons for acutely elevated troponins
ACS
Acute heart failure
PE
Stroke
Aortic dissection
Tachyarrhythmias
Shock
Sepsis
Perimyocarditis
Endocarditis
Tako-tsubo cardiomyopathy
Cardiac contusion
Strenuous excercise
Sympathomimetic drugs
Chemotherapy

I guess that means that your history, physical, and clinical judgment still supersede the lab test.

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Low Back is one of the most common complaints that we see in the Emergency Department.  Our first priority is to rule out those causes that can lead to paralysis or death (i.e.: epidural abscess, pathological fracture, cauda equina syndrome, etc…).  However, most of the back pain that we will see is musculoskeletal in origin.

The American College of Physicians (ACP) and the American Pain Society (APS)  released  joint recommendations on the evaluation of treatment of individuals with back pain in 2007.

In summary their key recommendations were:

1. Routine imaging is not required. However, diagnostic imaging and testing should be obtained for patients with low back pain when severe or progressive  neurologic deficits are present or when serious underlying conditions are suspected.
2.  For patients with low back pain, clinicians should consider the use of medications with proven benefits in conjunction with back care information and self-care. For most patients, first-line medication options are acetaminophen or nonsteroidal anti-inflammatory drugs.
3. Medications that have good evidence of short-term effectiveness for low back pain are NSAIDs, acetaminophen, skeletal muscle relaxants (for acute low back pain), and tricyclic antidepressants (for chronic low back pain).

Links to the Clinical Guidelines are listed below:

• Evaluation and Treatment
• Nonpharmacologic Therapies for Acute and Chronic Low Back Pain
• Medications for Acute and Chronic Low Back Pain

Child Passenger Safety.

Perhaps one of the greatest contributions emergency physicians can provide to society comes in the  form of anticipatory guidance. It is important to take the opportunity during the ED encounter to provide information to parents to prevent future injuries. Child passenger safety is one clear example. With over 330,000 pediatric visits to EDs  across the US annually attributed to motor vehicle collisions, the need to provide clear recommendations to parents on how to restrain their children in their vehicle is paramount. Despite a recent survey of over 1000 EPs in which 85% of respondents indicated child passenger safety should routinely be a part of pediatric MVC discharge instructions, only 36% of EPs knew the latest guidelines on child passenger safety.   The American Academy of Pediatrics provides such guidelines. These recommendations were recently adjusted in 2011.

(1) Infants up to 2 years must be in REAR-facing car seats
(2) Children through 4 years in forward-facing car safety seats
(3) Belt-positioning booster seat for children through at least 8 years old
(4) Lap-and-shoulder seat belts for those who have outgrown booster seats. How does one know when the child has outgrown the booster seat?
     a. Can the child sit with his/her knees bent at the edge of the seat?
     b. Does the shoulder belt lie across the middle of the chest/shoulder?
     c. Does the lap belt lie across the upper thighs and not the abdomen?
(5) Children younger than 13 should sit in the rear seats

Special Thanks to JV Nable, MD, EMT-P for writing this pearl.

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TEN is a rare, life-threatening dermatologic emergency characterized initially by erythema and tenderness. It is followed by a severe exfoliation that resembles a severe burn patient. Classically occurs within days of the exposure of the drug. Nikolsky's sign may be present - not pathognomonic.

The following is a short list of medications that can cause this lethal reaction:

allopurinol, bactrim, nitrofurantoin, NSAIDs, penicillin, phenytoin, lamotrigine, sulfasalazine

Treatment: transfer to a burn center may be needed, steroids are not generally recommended however immunomodulators are beginning to show promise - IVIG, cyclosporine and cyclophosphamide

See pic that is attached for example of the sloughing

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1111172057_TENPic.jpg (95 Kb)

• Myasthenia Graves (MG) is an autoimmune disorder wherein antibodies attack acetylcholine nicotinic postsynaptic receptors at the myoneural junction, resulting in muscle fatigue (commonly bulbar) that worsens with use and improves with rest.  MG flares are most commonly due to infection or inadequate treatment with cholinesterase inhibitors.

• The Tensilon (edrophonium) challenge test can be used to help distinguish an MG crisis from a cholingergic crisis.  Once the airway and ventilation are secure, escalating doses of edrophonium (i.e. 1 mg, then 3 mg, then 5 mg, up to a maximum of 10 mg total) can be administered with the goal of relieving the muscle weakness.  If a true MG crisis is present, patients usually respond with dramatic improvement within 1 minute.  Patients having a cholinergic crisis, on the other hand, typically respond with increased salivation, bronchopulmonary secretions, diaphoresis, and gastric motility.  

• Monitor closely as edrophonium can cause significant bradycardia, heart block, and asystole (only 0.16% risk by reports, but have atropine nearby). 

• Once the edrophonium wears off, patients having an MG crisis may develop increased secretions and respiratory distress as their muscle weakness returns, so manage expectantly and with caution.  

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Hypertensive Emergency Pearls

• Recent literature indicates that many patients with a true hypertensive emergency are mismanaged.
• Patients with a hypertensive emergency should have an arterial line placed and receive a continuous infusion of a short-acting, titratable medication to reduce blood pressure.  Avoid oral, sublingual, and intermittent IV bolus administration of antihypertensives. 
• Recall that most patients with a hypertensive emergency are volume depleted.  Providing IV fluids can help to prevent marked drops blood pressure when you start an IV antihypertensive medication.
• Avoid diuretics (due to volume depletion) and hydralazine.  Hydralazine can cause precipitous drops in blood pressure and is felt by many to have no role in the treatment of hypertensive emergencies.

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The 30-day mortality for patients < 65 years of age who are diagnosed with and treated for acute MI is 3%. In contrast, the 30-day mortality for patients > 85 years of age who are diagnosed with and treated for acute MI is 30%! Obviously the mortality is far higher if the patient's diagnosis is delayed or missed; or if the patient is not treated appropriately.

This simple statistic highlights the critical importance of being aggressive with diagnostic and therapeutic planning for elder patients with potential ACS. We cannot afford to be cavalier in their evaluation or treatment.

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Arthrocentesis of the Wrist

First locate and feel comfortable identifying two important landmarks:

1) Lister's tubercle is an elevation found in the center of the dorsal aspect of the distal end of the radius

http://www.aafp.org/afp/2004/0415/afp20040415p1941-f2.jpg

2) The extensor pollicis longus (EPL) tendon runs in a grove just radially to Lister's tubercle. Active extension of wrist and thumb aid with identification.

http://www.rad.washington.edu/academics/academic-sections/msk/muscle-atlas/upper-body/extensor-pollicis-longus/atlasImage

A) Positioning:  Place wrist in ulnar deviation and 20 - 30 degrees of flexion. Apply longitudinal traction to the fingers of the hand.

B) Technique:  Insert a small needle (22g) just distal to the tubercle and on the ulnar side of the EPL tendon.

http://img.medscape.com/pi/emed/ckb/clinical_procedures/79926-79928-80032-1477044tn.jpg

http://www.youtube.com/watch?v=nlPdb_mymw4&feature=related

http://www.youtube.com/watch?v=UVG7fZvZD-s&feature=related

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• ocurs with significant lateral traction during vaginal delivery of an infant
• results in damage to the upper part of the brachial plexus, especially the 5th and 6th cervical roots
• results in paralysis of hte shoulder and arm
• the affected arm is held in adduction and internal rotation
• most resolve spontaneoulsy, but some may require physical therapy after 2 weeks
• surgery is rarely required, and has poor results
• always palpate for ipsilateral clavicel fractures!

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Several medications have been linked to causing idiopathic intracranial hypertension (pseudotumor cerebri). Be sure to record an accurate medication history in patients you suspect of having this diagnosis.

• Excessive doses of vitamin A
  • Other retinoids too: retinol, isotretinoin, and tretinoin
• Tetracyclines (tetracycline, doxycycline, minocycline)
• Growth hormone

Withdrawal of the offending agent will generally resolve the symptoms.

• Remember that lithium overdoses should not be treated with oral activated charcoal, as these charged particles are not adequately absorbed by this method.
• Instead, whole bowel irrigation using 500 mL to 2 liters of polyethylene glycol should be administered within the first 2-3 hours of presumed large ingestions (ie. at least 10 to 15 pills), with a goal of having the patient pass stool to the point of clear rectal effluent.
• Hemodialysis (HD) should be reserved to treat severe lithium toxicity, which is somewhat loosely defined as a serum level greater than 3.5 to 4 meq/L (mmol/L). 
• For levels > 4 meq/L, most experts agree that HD should be performed regardless of whether associated symptoms are present.  For levels > 2.5 meq/L with associated clinical signs/symptoms (i.e. tremulousness, dizziness, lethargy, seizure), conditions that would limit lithium excretion (i.e. renal insufficiency), or conditions that would limit ability to aggressively hydrate (i.e. CHF), HD should be performed.   

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Positive-pressure ventilation (e.g., mechanical ventilation) increases intrathoracic pressure potentially reducing venous return, right-ventricular filling, and cardiac output.

Pericardial tamponade similarly causes hemodynamic compromise through increased pericardial pressure which reduces right-ventricular filling and cardiac output.

When mechanically ventilating a patient with known or suspected pericardial tamponade the mechanisms above may be additive, causing cardiovascular collapse and possibly PEA arrest.

For the patient with known or suspected pericardial tamponade consider draining the pericardial effusion prior to intubation or delaying intubation until absolutely necessary.

If intubation is unavoidable, consider maintaining the intrathoracic pressure as low as possible (by keeping the PEEP and tidal volumes to a minimum) to ensure adequate cardiac filling and cardiac output.

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Blood pressure cuffs tend to OVERESTIMATE true blood pressure in obese patients. Even larger cuffs tend to do this as well. While low blood pressures are often reliable in diagnosing shock, be wary of  assuming a "normal" blood pressure (e.g. SBP 100-120s) rules out shock in an obese patient who is sick. A-lines might be necessary to accurately assess the blood pressure.

[adapted from ACEP talk by Dr. Tiffany Osborn]

A recent randomized trial compared nicardipine as a continuous infusion to labetalol boluses to determine which one was more effective at lowering blood pressure to a target range within 30 minutes.

Median initial SBP for the 226 patients was 212 mm Hg. Within 30 minutes, nicardipine patients more often reached target range than labetalol (91.7 vs. 82.5%, P = 0.039). Of 6 BP measures (taken every 5 minutes) during the study period, nicardipine patients had higher rates of five and six instances within target range than labetalol (47.3% vs. 32.8%, P = 0.026).

What this means: Nicardipine is a reasonable choice for patients needing acute lowering of blood pressure (e.g., ischemic stroke with tPa).  Nicardipine seems to achieve faster and smoother lowering of blood pressure than labetalol therapy with less blood pressure readings outside the target range.

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Salicylates:

• stimulate the respiratory center in the brainstem, causing respiratory alkalosis
• interfere with the Krebs cycle, limiting ATP production, leading to an anaerobic metabolism
• uncouple oxidative phosphorylation, causing accumulation of pyruvic and lactic acid and heat production, resulting in acidosis and hyperthermia
• increase fatty acid metabolism, generating ketone bodies

Overall, this results in a mixed respiratory alkalosis and metabolic acidosis. 

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