• in the US, the right of an adolescent (<18yrs) to seek and receive treatment without parental consent varies from state to state.
• usually, the right to self-consent for treatment is specified through public health statutes when there is clinical suspicion of a STD
• many states allow minors to seek help for pregnancy, contraception, substance abuse, and mental health issues without parental consent

some absolutes or almost always cases include the following:

1. emancipated minors: moved outside of the home and support themselves financially, married, in the military, or has a child
2. emergencies: patient is unconscious or unable to give consent
3. mature-minor: possess the ability to comprehend the risks and benefits of treatment/therapy

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Scombroid is caused by ingestion of preformed histamine on skin of fish.

• Naturally occurring histidine on scaly fish converted to histamine by surface bacteria - often fish left out too long, refrigeration will prevent the conversion.
• Bacteria responsible are Morganelli morganii and K. pneumoniae
• Fish: tuna, mahi mahi, amberjack, bonito, mackerel, albacore
• Fish usually appears normal though meat may tast peppery
• Patient presents minutes/hrs flushed, urticaria, HA, N/V
• Self-limited and improve within hrs even without treatment
• Antihistamines and rarley epinephrine will be needed

• There are over 6 million stroke survivors in the United States, many of whom participate in helpful support groups, along with their loved ones and caregivers.

• Stroke recovery is often a lifelong journey.

• Prognosis and outcomes significantly improve with early, stroke rehabilitation at stroke-focused units.

• Stroke rehabilitation consists of several areas of focus such as physical, occupational, and visual therapies.

Postcardiac Arrest Syndrome: Controlled Reoxygenation

• In previous pearls, Dr. Marcolini has highlighted the poscardiac arrest syndrome (PCAS), comprised of brain injury, myocardial dysfunction, systemic ischemia/reperfusion response, and persistent precipitating disease.
• Not surprisingly, postcardiac arrest brain injury is a major cause of morbidity and mortality, accounting for > 60% of deaths in some studies.
• In addition to therapeutic hypothermia, consider "controlled reoxygenation" in order to optimize neurologic outcome.
• Animal data has demonstrated that too much oxygen may worsen neuronal damage during the initial resuscitation phase.
• Take Home Points:
  • Use a minimum amount of F_iO₂ to maintain S_pO₂ of 94-96%
  • Avoid unnecessary arterial hyperoxia

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Massive Pulmonary Embolism and Response to Fluids and Mechanical Ventilation

Massive pulmonary embolism leads to acute pulmonary hypertension and right ventricular overload. This leads to release of troponin and a "bowing" of the interventricular septum on echocardiography. Deviation of the septum then leads to a decrease in left-sided cardiac output. 

A few interesting clinical pearls:

• Administration of IV fluids to patients with massive PE often leads to a decrease in BP. This happens as a result of increasing preload causing further bowing of the septum and a subsequent further drop in left ventricular cardiac output, leading to hypotension. 
• Patients with massive PE who require intubation often demonstrate an increase in BP due to positive pressure ventilation causing a drop in preload and a reduction of septal bowing into the left ventricle.

Elderly patients have slightly lower body temperatures than younger adults, and as a result it has been suggested that "fever" be defined as anything > 99 degrees F. One study found that by lowering the definition to this number improved the sensitivity and specificity to 83% and 89%, respectively.

from Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department, part I. Emergency Medicine Reports 2010;31(9):101-110.

study referred to: Castle SC, et al. Fever response in elderly nursing home residents: are the older truly colder? J Am Geriatric Soc 1991;39:853-857.

Osteomyelitis:

• An acute or chronic inflammatory, infectious process of bone.  Can occur via hematogenous spread or direct innoculation of bone.
• Can be diagnosed on plain radiographs but bony changes might not be evident for 14-21 days.  By 28 days 90% of patients will demonstrate a bony abnormality.
• Initially plain radiographs will show periosteal elevation. Later cortical or medullary lucencies are seen.
• Additional tests to help make the diagnosis include:
  • Three phase bone scan: often not practical for the ED.
  • CT Scan: better in areas with complex anatomy [i.e.:spine, pelvis, ,mid and hind foot]
  • MRI: most effective in early detection and to guide surgical approaches.  Sensitivity is estimated at 90-100%.

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Hyperpronation: This reduction technique for a nursemaid's elbow (radial head subluxation)  has been found to have better first attempt success than classic supination/flexion technique.  (Pediatrics July '98).  Support the elbow with a finger on the radial head, and forcefully hyperpronate.  

• Technique may be less painful as well.  
• Reexamine after five minutes, and normal function should be returned
• Xrays are generally unnecessary unless history and physical are not consistent with nursemaid's elbow, symptoms for greater than 12 hours, or reductions attempts are unsuccessful
• Supination/Flexion may be attempted after two failed hyperpronation attempts 

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Stroke strikes F.A.S.T. and must be recognized quickly for optimized management.

The following Face, Arms, Speech test, known as F.A.S.T., is an easy and quick bedside teaching tool that can be used to spread awareness about how to recognize and respond to stroke symptoms:

F = Ask person to smile. Does one side of face droop down?

A = Ask person to raise both arms. Does one arm drift downward?

S = Ask person to say a simple phrase. Does speech sound slurred or strange?

T = If any of the above findings are observed, it's time to call 911 immediately.

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A single episode of hypotension portends a worse outcome for septic patients.  The restrospective analysis by Marchick et al of 700 patients showed that mortality was 10% vs 3.6% for septic patients whose SBP dropped below 100 even once.  It was also noted that the lower the SBP, the worse the in-hospital mortality.

So, not only do we need to remember to watch blood pressure closely for head-injured patients, but for septic patients as well!

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Teaching When Time is Limited

We all know how difficult it can be to teach in the ED when it is busy. So how do the experts do it when there is so little time?

Just a few considerations that might make your teaching more effective and easier to do when it is busy:

• Identify the learner's needs. The time-saving rule of thumb: target, then teach. After all, how do you know what to teach if you don't know what the learners knows or needs.
• Teach rapidly. And I mean rapidly. Many of us have really come to realize over the years that less is better. As Amal says, be a sniper and don't use a shotgun. Teach one thing quickly and move on. Pick a pearl (or pitfall, etc.), lock and load, then deliver it...then STOP teaching. Much more effective than spending 20 minutes talking about stuff nobody will ever remember!
• Provide some type of feedback. Feedback is one of the most underused yet powerful teaching tools available. 

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Elderly patients should be considered immunocompromised for several reasons:
1. T cell function and reduced cellular immunity occur as we get older.
2. B cell antibody production decreases.
3. Host defenses against infection are reduced with aging, such as reduced circulation and thinning skin.
4. Miscellaneous factors, such as malnutrition and co-existing illnesses contribute to increased risk of infection as well.

[Good reference and suggested reading: Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department: Part I. Emergency Medicine Reports 2010;31(9):103-111.]

Radial Head Fractures:

Radial head fractures can often be difficult to visualize on plain films especialing Mason Type 1 fractures (see prior pearl on classification system) which are nondisplaced. Often the only sign of a fracture will be a posterior fat pad sign which is always considered to be pathologic.  The posterior fat pad lies outside the synovium of the elbow joint and is normally hidden in the fossa of the distal humerus preventing it from being seen on lateral films of a normal elbow.  Trauma to the elbow that results in a intraarticular fracture (typically a radial head fracture) produces an intra-articular hemorrhage that distends the synovium and displaces the fat out of the fossa, producing the typical triangular radiolucent shadow posterior to the distal end of the humerus.

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Once you've made the presumptive diagnosis of cerebral edema in Pediatric DKA (refer to part 1), here's what's next:

• DO NOT GET A HEAD CT - this will only waste your time, recall that most children with DKA have subclinical cerebral edema
• Reduce the fluid rate by at least half
• Start mannitol at 0.25-1g/kg IV over 20 minutes (may repeat in 2 hours)
• OR (not and) 3% saline at 5-10mL/kg over 30 minutes (slightly less used and supported)
• If you intubate, DO NOT HYPERVENTILATE.  A pCO2 < 22 mmHg is associated with poorer outcomes, presumably secondary to ischemia from reduced bloodflow...

Mortality from cerebral edema in DKA is 20-25%, and 15-35% of survivors have permanent disability. 

The best strategy is to do your best to avoid cerebral edema in the first place, but if you do recognize it, this is a clinical diagnosis, and you should not delay treatment for radiographic studies.

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We are all familiar with the classic ECG abnormalities caused by the sodium channel blocking properties of tricyclic antidepressants (QRS interval widening, R wave in aVR, S wave in I and aVL, and rightward deviation in terminal 40 msec of QRS). Here are some other medications that also block cardiac sodium channels in a similar manner:

• Cocaine
• Diphenhydramine
• Cyclobenzaprine (Flexeril)
• Carbamazepine (Tegretol)
• Phenothiazines
• Propoxyphene
• Class 1A antidysrhythmics (quinidine, procainamide, disopyramide)
• Class 1C antidysrhythmics (encainide, flecainide, propafenone, moricizine)
• Amantadine

• May is Stroke Awareness Month;  Health care provider and patient education about how to prevent stroke is at least as important as treating it with cutting-edge therapies.
• Studies have shown that up to 80% of strokes could be prevented through recognition and management of risk factors, lifestyle changes, and compliance with recurrent stroke prevention treatments.
• Even in the emergency department, the opportunity to educate patients about the following stroke risk factors should be seized when possible:

              --  Hypertension                        

              --  Diabetes

              --  Atrial Fibrillation

              --  Hypercholesterolemia

              --  Physical Inactivity

              --  Tobacco Use

              --  Alcohol Use

              --  Obesity

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PRBC Transfusions in Neurocritical Care

• Historically, neurocritical care textbooks have favored a more liberal PRBC transfusion strategy, as the brain is very sensitive to decreases in oxygen delivery.
• Despite these recommendations, limited studies have failed to show a mortality benefit to PRBC transfusion in critically ill patients with neurologic illness.
• Postulated reasons for the lack of morbidity or mortality benefit center around the injured brain's response to attempts to increase oxygen delivery through transfusion.
  • TBI: PET studies have shown an overall lower level of metabolic activity along with a lower oxygen extraction and loss of autoregulation
  • SAH: transfusion may increase the risk of vasospasm in SAH and worsen flow
• Although the evidence is not overwhelming, current recommendations from SCCM-Eastern Society for the Surgery of Trauma recommend a restrictive PRBC transfusion threshold (Hgb < 7 gm/dL) even in neurocritical care patients.

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Some considerations in the patient with a penetrating vascular injury (gunshot, stab):

• Obtain ankle-brachial index on all patients and document
• An ABI <0.9 indicates the need to perform an arterial study
• Traditional approach to penetrating extremity injury has been to perform angiography
• Recent (good) studies have shown that CTA of the involved extremity is just as good if not better than angiography, and a lot of centers have moved to CTA
• Obtain vascular surgery consultation if there is any concern for an arterial injury. Never hurts to err on the side of caution. 

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The most likely considerations for a regular, narrow complex tachycardia are sinus tachycardia (ST), atrial flutter with 2:1 conduction, and supraventricular tachycardia (SVT, a generic terms that encompasses a few remaining rhythms originating above the ventricle). Atrial flutter is diagnosed when one sees atrial beats at a rate of 250-350/minute.

The distinction between ST and SVT can be difficult at very rapid rates. Here are a few clues that may help in this distinction:
1. Generally the maximal sinus rate that a patient produces will be 220-age. That means that a 20 year old can possibly have a ST up to 200 beats/min, but a 70 year old can only have a ST has fast as 150 beats/min. Rates that exceed that simple formula are extremely unlikely to be ST.
2. If the rate varies with respiration, with positional changes, with relaxation, or with fluid administration, these all favor ST.
3. If the rate reduces slowly, it favors ST. SVT, on the other hand, tends to "break" suddenly.
4. SVT generally will either have no P-waves visible or there may be P-waves just after the QRS complexes. These are referred to as retrograde Ps.
5. History, history, history. Is there a reason for tachycardia, for example a history consistent with dehydration or anxiety? That favors ST. If the patient reports palpitations or other symptoms that were of abrupt onset, that favors SVT.
6. Valsalva maneuvers may gently slow down ST but will either not affect SVT or will abruptly break the SVT....SVT shouldn't gently slow down.

Conservative Treatment of Back Pain:

Muscle relaxanats and benzodiazipnes are often used in the non-operative management of sciatica and non-specific low back pain.  In fact, a 2003 Cochrane review concluded that muslce relaxanats were effective in the management of non-specific low back pain. However, a recent analysis of randomized trials reported little efficacy or only  minor benefits with the use of benzodiazapines in treatment of low back pain.

A recent prospective, randomized, placebo-controlled, double-blinded trial conducted in Germany that enrolled a total of 60 patients found that the use of diazepam was equivilant to placebo in the reduction of distance of referred pain at day 7 of treatment.  Diazepam was also noted on average to increase the length of stay of those patients hospitalized by 2 days (median hospital days of 8 for placebo versus 10 for diazepam), and the probablility of pain reduction on a visual analog scale by more than 50% was twice as high in the placebo group (p< 0.0015).  Placebo reduced the patients pain more than diazepam.

Though the sample size was small; this study should really make one reevaluate the use of diazepam in the treatment of back pain.  Early movement and discouraging bed rest have been associated with decreased back pain, so one mechanism by which  benzodiazepines may make things work is by causing enough sedation to prevent early movement.

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