UMEM Educational Pearls

Myocarditis is a potentially fatal inflammatory disorder of the heart. Viral infection is the most common cause but can also result from toxic, autoimmune, or other infectious etiologies. Complications include life-threatening dysrhythmias, heart failure, and fulminant myocarditis. Typically affects young patients (20-50 years old).

• Diagnosis can be challenging. Presentation can range from nonspecific symptoms and normal hemodynamics to cardiogenic shock.
• Dyspnea was found to be the most common presenting symptom in one study
• Other symptoms include fever, malaise, chest pain, palpitations, fatigue, nausea, vomiting
• Consider the diagnosis in young patient with suspected sepsis but worsens with IV fluids with signs of volume overload
• Initial assessment should include ECG, CBC, CMP, inflammatory markers, cardiac biomarkers, CXR. Obtaining an echo is important. Perform POCUS to assess for global hypokinesis, reduced EF, wall motion abnormalities, pericardial effusion, B-lines.

ED management pearls

• Initiate vasopressors and inotropic support if hemodynamically unstable: norepinephrine + inotropic agent (e.g. milrinone, dobutamine) is recommended. In a few studies, epinephrine was associated with increased mortality when used in cardiogenic shock.
• Diurese if evidence of volume overload
• NIPPV or intubation if respiratory failure
• Avoid NSAIDs which may worsen mortality
• Consider mechanical circulatory support (e.g. ECMO, IABP, VAD) in refractory hypotension despite appropriate medical therapy

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Fever has long been understood to be associated with worse outcomes in patients post-cardiac arrest. Whether ascribing to the goal of 33-34°C, 36°C, or simply <38°C, close monitoring and management of core temperatures are a tenet of post-cardiac arrest care.

A recently published study compared the effectiveness of several methods in maintaining temperatures <38°C…

• Both ICHA and OHCA, shockable and unshockable, nontraumatic arrests
• Single center retrospective cohort study looking at 1/2012 – 9/2015
• Treatment and temperatures over first 48 hours

Results:

Maintenance of temp <38°C:

• Antipyretics only group: 57.7% 
• Invasive cooling by intravascular catheter +/- antipyretics:  82.1%

Mean change in temp from baseline:

• Antipyretics only: +1.1°C
• Intravascular alone: -3.4°C
• Antipyretics + Intravascular cooling: -5.2°C

Limitations:

• Varied range of antipyretic dosing per body weight
• No mention of noninvasive cooling methods (cooling pads, ice packs, etc.)
• Patients w/ intravascular cooling likely getting more aggressive care in general
• Not powered for clinical outcomes assessment

Bottom Line:

• Antipyretics alone greatly ineffective at preventing fever 
• Even with invasive cooling -- not meeting goal 18% of the time
• With longer ED boarding times nationwide, we must pay active attention to body temperature management and not assume that that we can set it and forget it, even with techniques as invasive as intravascular cooling.

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The classic mechanism for nursemaids elbow is axial traction on a pronated forearm and extended elbow.

The force allows a portion of the annular ligament to slip over the radius.

Consider this diagnosis with other mechanisms of injury especially if the exam is not suggestive of fracture.

Suspect in a patient in minimal distress with arm held semi flexed and pronated.

A recent retrospective study looked at other mechanisms of injury.

69 subjects with a median age of 2.5 years

The most common mechanisms of injury were fall (57%), direct hit to the elbow (16%), and rolling over (7%).

Some studies note the left elbow is more commonly involved but this is likely due to most guardians being right-handed, thereby holding the child’s left hand

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• Antimicrobial medications can be associated with neurological adverse reactions. 
• An individual’s risk is influenced by their age, weight, nutritional status, the medications they are taking concurrently, and pharmacological properties (dosage, half-life, CNS permeability). 
• Encephalopathy 
  • Seen with beta-lactams, fluoroquinolones, clarithromycin, and sulfamethoxazole-trimethoprim. 
  • Most commonly with cefepime. 
  • Higher risk in elderly, renal dysfunction, and preexisting CNS disease. 
• Seizures 
  • Beta-lactams block GABA receptors. 
  • Highest risk with cefepime and imipenem. 
• Peripheral neuropathy 
  • Associated with metronidazole, fluoroquinolones, linezolid, chloramphenicol, and isoniazid. 
  • Most cases are dose dependent. 
  • Some cases are irreversible. 
• Ototoxicity 
  • Aminoglycosides cause cochlear NMDA receptor excitotoxicity. 
• Weakness 
  • Fluoroquinolones, macrolides, and aminoglycosides inhibit acetylcholine release and bind neuromuscular junction receptors. 
  • Should be avoided in myasthenia gravis and Lambert-Eaton syndrome. 
• Movement disorders 
  • Tremors – sulfamethoxazole-trimethoprim 
  • Dyskinesia, dystonic reactions – fluoroquinolones, chloramphenicol 
  • Cerebellar syndrome – metronidazole, aminoglycosides 

Bottom Line: Recognition of antibiotic associated neurotoxicity reduces unnecessary workup and serious adverse effects. 

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The debate around post-arrest management recently has revolved around whether therapeutic hypothermia should go cold, or LESS cold.  But what if we went MORE cold?  While recent TTM trials have compared temps such as 33 to 36 and 33 to 37.5 or less, a recent trial called CAPITAL CHILL looked at 34C vs 31C.  There is a solid physiologic basis for cooling post-arrest patients, so do they do better if we lower their temp even further?  Maybe we're not going cold enough with 33?

Bottom Line: No, 31C is not better than 34C for post-arrest patients.  This study compared death and poor neurologic outcome at 180 days with 31 and 34C targets for post-arrest patients, and found no difference (in fact the 31C group did slightly, but not significantly, worse on the primary outcome, and worse on a few secondary outcomes).  

While debate remains for 33 vs 36 vs afebrile, the literature does not currently support consideration of temps below 33.  

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Kcentra (four-factor prothrombin complex concentrate, 4f-PCC) is approved for the reversal of warfarin using a weight-based dosing strategy based on INR. However, since the approval of Kcentra, data has shown a fixed-dose strategy and use for direct-acting oral anticoagulants (DOAC) is appropriate. There are even recommendations to use a fixed-dose for DOACs in some situations. Utilizing a fixed-dose strategy can help with decreasing drug preparation/delivery times and costs.

Our institution now only uses a weight-based Kcentra dose of 50 units/kg for patients on DOACs with ICH or trauma-induced coagulopathy. All other patients receive a fixed-dose of Kcentra 1,500 units or 2,000 units based on anticoagulant and other criteria.

Below is a diagram summarizing our current dosing strategy for Kcentra at our institution.

ICH=intracerebral hemorrhage

DOAC=direct-acting oral anticoagulant (rivaroxaban, apixaban, and edoxaban)

Other points of interest at our institution:

• Based on recommended monitoring parameters, patients may receive additional doses of Kcentra.
• Idarucizumab (Praxbind) is the preferred agent for dabigatran reversal.

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Incidence of T1DM is 1.93/1000 of youth <20 years old in the United States, with a bimodal distribution of onset. Onset peaks from ages 4-6 and again at puberty. 

Prior to the development of DKA, diabetes often has an insidious onset with symptoms of polydipsia, polyphagia and polyuria with weight loss in children. It can also be asymptomatic. 

When DKA is present, symptoms will include neurological manifestations (confusion, lethargy), GI symptoms (abdominal pain, nausea, vomiting), or respiratory abnormalities (Kussmaul respirations.) Polyuria and polydipsia are frequently present as well.

Diagnosis of DKA includes: serum glucose of >200 mg/dL, serum or urine ketones, and a pH <7.30 or bicarbonate <15 mEq/L. 

DKA is classified as mild, moderate or severe:

Mild: pH 7.21-7.30, HCO3 11-15 mEq/L

Moderate: pH 7.11-7.20, HCO3 6-10 mEq/L 

Severe: pH < 7.10, HCO3 <5 mEq/L

Initial treatment is 10 ml/kg of isotonic fluid bolus to a max of 500 ml, then reassess. Continue to replace fluids gradually to cover maintenance fluids as well as to treat dehydration. Do NOT bolus insulin. Rather, start a drip at 0.05-0.1 units/kg/hr. Continue insulin until acidosis has completely resolved. Once the serum glucose falls below 250 mg/dL, start dextrose to prevent hypoglycemia until the gap closes. 

Cerebral edema can develop 4-12 hours after treatment has been initiated. Observe for change in mental status, posturing, decreased response to pain, cranial nerve palsy, bradycardia, or abnormal respiratory pattern. This is a clinical diagnosis! Although a head CT can be obtained, it is often negative and treatment with mannitol or hypertonic saline should be started as soon as there are clinical changes.

DKA has resolved when pH > 7.3 and HCO3 is >15.

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Substance use disorder contributes significantly to pediatric exposure/poisoning. There has been an increase in the opioid overdose deaths in the US, placing pediatric population to possible exposure. A retrospective study of fatal pediatric poisoning in the US was investigated using the National Violent Death Reporting System (NVDRS) from 2012-2017.

17 US states (AK, CO, GA, KT, MD, MA, NJ, NM, NC, OH, OK, OR, RI, SC, UT, VA, WI) reported to NVDRS from 2012-2017.   

Age was limited to 0-9 years

Results

1850 violent deaths were identified: n=122 (7%) were poisoning related

Characteristics

• Male: 49%
• Approximately 25% were homicide-suicides

Region

• Midwest: 25%
• Northeast: 5%
• South: 53%
• West: 17%

Most common exposure/etiology

1. Opioid (50%)
2. Benzodiazepines (8%)
3. Amphetamines (7%)
4. Antidepressants (5%)

Conclusion

• A large proportion of poisoning related pediatric fatality was due to opioid exposure
• Largest proportion of death was reported from the Southern US.

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Initial Mechanical Ventilation Settings for the Intubated Asthmatic

• Approximately 2% of adult patients who present with an acute asthma exacerbation will require intubation and mechanical ventilation.
• It is critical to provide the intubated asthmatic with sufficient time for exhalation.
• Initial recommended settings for mechanical ventilation include:
  • Tidal volume: 6-8 ml/kg ideal body weight
  • Respiratory rate: 6-10 breaths per minute
  • PEEP: 0-5 cm H2O
  • Inspiratory flow rate: 80-120 L/min
• Permissive hypercapnea is tolerated to a pH of approximately 7.15

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Background: A cornerstone of therapy for cardiogenic shock is inotropic support with medications including dobutamine, epinephrine and milrinone.  Few studies have examined these head-to-head and between dobutamine and milrinone (including only one RCT of 36 patients)

The investigators conducted a RCT of milrinone versus dobutamine for cardiogenic shock in a single quaternary care center cardiac ICU.

Inclusion: Patients over 18 with cardiogenic shock (largely clinical determination)

Exclusion: Out-of-hospital cardiac arrest, pregnancy, prior initiation of dobutamine or milrinone, or physician discretion.

Methods: 1:1 randomization stratified by affected ventricle (LV vs RV). Primary outcome was a composite of in-hospital death, resuscitated cardiac arrest, cardiac transplant, mechanical circulator support, nonfatal MI, TIA, stroke, or renal replacement therapy. Powered to detect a 20% improvement in this measure in the milrinone group (192 pts).

Results:  192 patients enrolled (96 in each arm). Average age was 70, 36% female, 90% LV dysfunction, 67% ischemic disease, 33% non-ischemic, average LVEF 25%, 68% on vasopressors. ICU admission to randomization was 23+/-92.6h for dobutamine and 17.6+/-50.6h for milrinone arms. 80% were SCAI class C shock.

Primary outcome for milrinone 49% versus dobutamine 54%, HR 0.9(0.69-1.19), p=0.47, death was the primary driver of the composite (37% vs 43%).  Arrythmia requiring intervention was not different between groups (50% vs 46%). No difference in a host of other endpoints including AKI (92% vs 90%), RRT (22% vs 17%), HR, lactate, MAP, UOP, and creatinine.

Discussion: No significant differences observed in outcomes for patients with cardiogenic shock randomized to milrinone versus dobutamine.  The trial addressed an important clinical question for management of cardiogenic shock and relied largely on clinical diagnosis for inclusion and likely reflected a somewhat broad range of patients. The trial was too small given observed treatment effects and few patients with RV failure. Notably, similar rates of adverse events observed in each group.  

Many limitations for practice including a single specialized ICU setting, limited information on events leading to ICU admission including invasive or medical interventions during the index visit and no long term follow-up.  Time to randomization, exclusion of cardiac arrest, and lack of reporting pre-ICU setting (ED, floor, cath lab) also significantly limits utility in an emergency setting.

Bottom Line: 192 patient single-center cardiac ICU-based trial shows no difference in composite or secondary endpoints between milrinone and dobutamine for cardiogenic shock, adds to a body of very limited RCTs comparing inotropes in cardiogenic shock but provides no practice changing evidence.

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Ventriculoperitoneal (VP) shunts are common. Unfortunately shunt complications are also common! 

There are 3 major categories of shunt complications:

1. Mechanical Failure - obstruction, fracture, disconnection, migration, perforation
2. Functional Failure - overdrainage, slit ventricle syndrome, pseudocyst, ascites, meastasis
3. Infection - may occur in  up to 10% of patients (bacterial, fungal, parasitic)

Shunt series are helpful, but are NOT 100% sensitive. If you have a clinical concern for a shunt complication, make sure to involve neurosurgery.

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The total number of concussions tripled among female athletes aged 14 to 18 years during a 20-year period from 2000 to 2019.

Query of National Injury Surveillance System

Female athletes with sports-related concussions or closed head injuries who presented to the ED

In 14- to 18-year-old females the number of concussions increased from 9,000 in 2000 to 32,000 in 2019.

65% of all concussions among female athletes occurred in soccer, basketball, cheerleading, softball, and volleyball.

Association between an increase of 308.7 annual concussions per 10,000 annual female participants.

In a study of more than 80,000 teenage players across US high schools, female athletes are 1.9 times more likely to develop a sports-related concussion than are their male counterparts in comparable sports.

In boys, the most common way of becoming concussed was through direct contact with another player (50%)

In girls, the most common way of becoming concussed was after colliding with another object (ball/goalpost).

This mechanism may partly explain another finding:  Boys were also more likely to be removed from play immediately after a suspected head injury than were girls

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This was a retrospective, noninferiority analysis looking at patients 14 years old and younger treated for nontraumatic seizures by EMS with a midazolam dose of 0.1 mg/kg (regardless of route).  There were just over 2000 patients with a median age of 6 years included in the study.  Midazolam redosing occurred in 25% of patients who received intranasal midazolam versus only 14% who received midazolam via intramuscular, intravenous, or intraosseous routes.
Bottom line: In the prehospital setting, intranasal midazolam at a dose of 0.1 mg/kg was associated with an increased need to redose compared to other routes.  This dose may be subtherapeutic for intranasal administration.

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Your patient presents with a large traumatic subdural hematoma with midline shift and clinical evidence of herniation.  Your nearest neurosurgeon is several hours away, what do you do?

Initial resuscitation should follow ATLS.  Treatment of intracranial hypertension and herniation includes elevating the head of bed, administering osmotic therapies, optimizing analgesia/sedation, and hyperventilation.  If all measures have been exhausted and there is a delay to definitive neurosurgical intervention, an emergency department burr hole may be considered.

Indications:

• GCS < 8, dilated and nonreactive pupil(s), posturing suggestive of uncal or transtentorial herniation 
• Radiographic evidence of an extra-axial (subdural/epidural) hematoma causing midline shift and brainstem compression
• Lack of timely neurosurgical intervention
• Procedure will not delay transfer to definitive care

Contraindications:

• Neurosurgical intervention available within reasonable time frame
• Skull fracture at site of planned burr hole

Equipment:

• Razor
• Surgical marker
• Sterile prep and drape
• Syringe, needle, lidocaine
• Scalpel, forceps, retractor, sharp hook, scissors
• Hand drill, hex wrench, drill bit with guard
• Sterile saline, gauze, dressing

Transtemporal Approach:

• Measure skull thickness on CT for depth of drill guard.
• Position patient supine and elevate the ipsilateral shoulder with a shoulder roll.  Utilize tape or have assistant hold the head in place. 
• Shave the hair.
• Mark the point 2 cm superior and 2 cm anterior to the tragus.
• Sterile prep and drape.
• Inject local anesthetic and then make a 3 cm vertical skin incision down to the periosteum.  Dissect and use a retractor to expose the skull.
• Drill with steady pressure perpendicular to the skull.  Irrigate with sterile saline to remove bone fragments.
• Once the skull is penetrated:
  • If an epidural hematoma, blood should be released.  Can use sterile saline to facilitate drainage of clotted blood.
  • If a subdural hematoma, use a sharp hook to tent the dura and make a small cruciate incision.
• Place loose sterile dressing.
• Transfer to definitive care.

Additional Points:

• Neurosurgery consultation before performing this procedure is recommended. 
• Antibiotic prophylaxis with gram-positive coverage is recommended.
• In extenuating circumstances, this may be considered without CT confirmation of the location of the extra-axial hematoma.  However, there is risk of a negative exploratory burr hole due to a hematoma not in the temporal location or due to a false localizing sign.

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The Role of Active Rehabilitation in Concussion Management: A Systematic Review and Meta-analysis

Concussions make up 70% to 90% of all traumatic brain injuries

During the recovery process, prolonged rest has been shown to slow recovery and precipitate secondary symptoms of fatigue, reactive depression, anxiety and physical deconditioning.

As a result, a gradual increase in low-level activities has been encouraged after 24-48 h of rest.

23 articles for a total of 2547 concussed individuals, 49% female, both kids and adults. Included both sport related and non-sport related concussion.

None of the studies reported any adverse events in symptomatic participants after subthreshold exacerbation aerobic exercise.

Duration ranged from 15-20 minutes per session or until symptom exacerbation.

Subthreshold activity generally targeted 80% of max heart rate achieved during a graded symptom threshold test.

Every study showed improved concussion symptom scores with a physical activity intervention.

Most common treatment duration was 6 weeks (Range 1-12 wk)

Best outcomes if initiated with 2-3 weeks after injury but intervention beneficial in chronic phases of recovery as well.

The intervention of physical activity decreases post concussion symptom scores and the overall effect across studies was large and positive.

Optimal intensity, duration and time to initiation of exercise intervention needs further investigation.

Exercise effect is likely multifactorial including:

1. Improvement in cerebral autoregulation
2. Increases levels of brain-derived neurotrophic factor which promotes neuron growth and repair
3. May reduce fear of exercise and perception of illness and injury
4. Reintegration with social environments and support

One of the best effects I have seen in treating these patients is that active exercise allows a proactive approach to patient recovery. Patients become less focused on every minor symptom or irregularity.

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What they are: Clinical practice guidelines put together by an AAP subcommittee over a span of several years based on changing bacteriology and incidence of illness, advances in testing, and evidence that has accumulated

Includes: Healthy infants 8 to 60 days of life with an episode of temperature greater than or equal to 38.0 C who at now at home after being born at home or after discharge from the newborn nursery, born between 37 and 42 weeks, without focal infection on exam (cellulitis, vesicles, etc)

Recommendations:

For the well appearing 8-21 day old:

• Obtain UA (and culture if + UA), blood culture, CSF (including enterovirus PCR if pleocytosis in CSF or seasonal periods), inflammatory markers are optional
• Start empiric antimicrobials regardless of results of UA/CSF or any inflammatory markers
• Infant should be admitted

For well appearing 22- 28 day olds:

• Obtain UA (and culture if +UA), blood culture, and inflammatory markers
  • procalcitonin preferred over CRP if available, ANC is helpful but less so than others
  • several studies used in making these guidelines used more than 1 inflammatory marker
    • Temp >38.5 is considered an inflammatory marker
• If any inflammatory marker is abnormal:
  • Obtain CSF and start empiric antibiotics
    • CSF is optional if no inflammatory markers are abnormal (provider judgment/risk assessment)
  • If CSF is not obtained, infant should be hospitalized for observation
• Discharge home is acceptable if all of the following are true: UA is normal, CSF is normal or enterovirus +, no obtained inflammatory marker is abnormal (or if abnormal they have subsequently had normal CSF testing), return precautions are discussed and follow up is assured within 24 hours for clinical re-examination
  • Infants being discharged home should receive empiric parental antibiotics prior to discharge
• If the infant is hospitalized antibiotics should be started if: CSF with pleocytosis or uninterpretable or if UA is +
  • If workup is normal, antibiotics optional
  • If CSF not obtained, may start antibiotics but not required
• Shared decision making with parents is recommended for decisions regarding LP and disposition in this group

For well appearing 29-60 day olds:

• Obtain UA ( and culture if +UA), blood culture, and inflammatory markers
• If inflammatory markers are normal LP does not need to be performed, antibiotics do not need to be administered (unless UTI present), and patient can be monitored closely at home with follow up in 24-36 hours
• If positive UA in this group with normal inflammatory markers, obtain cath urine culture and start oral antibiotics
• Consider obtaining CSF if abnormal inflammatory markers
• If CSF obtained and normal antibiotics are optional, may be observed in hospital or closely at home
• If CSF is not obtained or is uninterpretable with abnormal inflammatory markers, administer parenteral antibiotics
  • May be observed in hospital or closely at home

Notable changes:

• UTIs have been differentiated from bacteremia and bacterial meningitis, the guideline discourages the use of the historic “serious bacterial illness”
• A 2 step process where decision for catheretized urine culture is based on UA is suggested, UA to be obtained by bag or stimulated void

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Intubation considerations

• Use large ET tube (at least 8.0 if possible): minimizes airway resistance, facilitates aggressive pulmonary toilet and bronchoscopy if needed
• Consider using ketamine as induction agent as it has bronchodilator properties and can maintain blood pressure
• Appropriate choices for initial sedation includes propofol, fentanyl, and ketamine

Vent management strategies

• No overall outcome differences between volume vs pressure control modes. Volume control has been recommended as initial mode due to familiarity and ensures your set tidal volume will be delivered.
• Goal is to minimize autoPEEP, which occurs from incomplete exhalation prior to initiation of next inhaled breath. This can be achieved by adjusting a few vent settings: decreasing RR, decreasing I:E ratio, decreasing inspiratory time, or increasing inspiratory flow rate. Allow for permissive hypercapnia, pH >7.2 has been advocated though precise target is unknown.
• If patient becomes hemodynamically unstable, consider first disconnecting the ventilator from the ET tube and manually decompress the chest to facilitate exhalation.
• Peak inspiratory pressures are expected to be high in the acute severe asthmatic. More important is to keep plateau pressures <30 cm H₂O to prevent lung injury.
• Don't forget to continue asthma-directed therapy. Administer albuterol via in-line nebulization unit of the vent.

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Exertional Heat Stroke at the Boston Marathon

Study goal: To assess for possible associations between exertional heat stroke (EHS) and sex, age, prior performance and environmental conditions

Data sourced from 2015-2019 Boston Marathon races.

Why Boston:  The Boston marathon is one of the only marathons that require qualifying times for entry for a majority of runners which yields a high proportion of faster than average runners. The race is frequently characterized by extreme weather conditions, including warm and humid days.

Results: 136,161 race starters. Incidence of EHS was 3.7 cases per 10,000 starters.

                Note: Twin Cities Marathon found 3 cases per 10,000 runners.

Mean age of runners was 43.3. Female 45%, male 55%.

Significant associations between sex and age, sex and start wave and age group and start wave.

Sex not associated with increased EHS incidence.

Age < 30 and assignment to the first 2 waves (faster runners) was significantly associated with increased EHS.

All cases of EHS occurred with average wet bulb globe temperatures (WBGT) were 17° – 20° C.

Linear correlation between EHS and incidence in addition to increases in WBGT from start to peak.

72.5% of cases were race finishers. Non finishers presented after mile 18.

Almost 30% developed post treatment hypothermia.

Almost 2/3rds were discharged directly, the remainder required hospital transport.

Authors estimate needing at least 4 ice water immersion tubs per 10,000 runners with potential of needing 8-10 if race day is humid.

Conclusions: Overall, EHS represented a small percentage of medical encounters but required significant resources.

Younger and faster runners are at high risk of EHS.

Greater increases in heat stress from start to peak worsens risk.

Definitions: WGBT - The Wet Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: ambient temperature, relative humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. 

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