UMEM Educational Pearls

The three factors that are most predictive of an arrhythmia as the cause of a syncopal episode are, in order:
1. abnormal ECG
2. history of CHF
3. age > 65

Overall, approximately 15-20% of cases of syncope are determined to be caused by an arrhythmia.

For those at the University of Maryland that got the chance to hear my lecture this week, you learned about Cubital tunnel syndrome [ulnar neuropathy], the second most common compressive neuropathy.  Carpal Tunnel syndrome remains the number one compressive neuropathy, and this pearl, for the sake of completeness, will address Radial tunnel syndrome.

Radial Tunnel Syndrome

• Believed to be due to overuse, frequently due to excessive elbow extension or forearm rotation.
• May actually just be an early stage of posterior interosseous nerve syndrome.
• Due to compression of the radial nerve as it passes a fibrous band that is attached to the radiocapitellar joint, and the tendinous origins of two muscles, extersor carpi radialis brevis and the supinator.
• Patients typically have l pain along the anteriolateral forearm.
• Pain is increased by extending the elbow and pronating the forearm.
• This syndrome is associated mostly with pain
• Weakness and numbness are not often seen.

Stay tuned for next week for Posterior Interosseous Nerve syndrome.

Pediatric Burns

• Burn Depth:
  • Avoid the traditional classification of 1st, 2nd, 3rd, and 4th degrees – they are imprecise.
  • Use modern classification:
    • Superficial, superficial partial thickness, deep partial thickness, full thickness, and Deep full thickness.
• Estimation of burn %:
  • Rules of 9 is NOT useful in pediatrics
  • Use the Lund-Browder Chart, which accounts for varying surface area percentiles by age.
  • If Lund-Browder Chart not available, use the area from the patient’s wrist to the tips of the fingers as being equivalent to 1% of his/her BSA.
  • Don’t include superficial burns in calculation of %TBSA burned.
  • Burn depth will often progress… anticipate this, as this will have implications on fluid management.
• Fluid Resuscitation
  • Parkland: Weight (kg) x %TBSA burned x 4ml = 24 hr total volume of Ringer’s Lactate
  • First ½ over the first 8 hours SINCE THE TIME OF THE BURN (not the arrival in the ED)
  • Second ½ over the next 16 hrs.
  • IF THE PT WEIGHS <30kg, this volume needs to be IN ADDITION to the child’s Maintenance fluids
  • Parkland gives you an estimate of the starting fluid requirements, but assessment of the Urine Output allows you to adjust it according to the pt’s needs:
    • Goal Urine Output = 1ml/kg/hr for pts <30kg; 0.5ml/kg/hr for pts >30kgs
    • Be careful not to fluid overload pt: decrease or increase IVF rate accordingly.
       

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Intra-aortic balloon pump counterpulsation

• It is possible that at some point in your career you may need to place an intra-aortic balloon pump (IABP) to temporarily stabilize a patient wth cardiogenic shock
• Optimal performance of the IABP is dependent upon proper positioning in the thoracic aorta
• Traditional teaching has been to insert the IABP via the femoral artery and advance to the level of the aortic knob (via CXR)
• A recent study suggests that using the aortic knob to position the IABP may result in occlusion of the left subclavian artery in a substantial portion of patients (16% in the study)
• Placing the IABP 2 cm above the carina may be a more reliable landmark that using the aortic knob

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Suspected Acute Leukemia in the ED

 Key ED Interventions for patients with astronomically high WBC counts:

• Usually talking about WBC counts over 200,000 or so (can be lower in lymphocytic leukemia)
• Hydrate aggressively
• Avoid PRBC transfusions as blood products will increase the patient's cytocrit (combination of WBC, platelets, and RBC) and predispose to organ malperfusion. This may lead to WBC (or blast) sludging in the microcirculation and may result in CNS bleeds. 
• Obviously, call for help immediately! Get a hematologist on the line quickly
• Assume the patient already has Tumor Lysis Syndrome and administer Allopurinol in a dose of 300 mg orally.
• Obtain a uric acid level, and if high, give an intravenous infusion of Rasburicase-eliminates preformed uric acid released from leukemia cell lysis. Renal failure results from high uric acid levels. We have this medication at University.
• The treatment of choice is initiation of definitive chemotherapy....clearly not an option for us in the ED. You can also do leukapheresis (where you take out WBC)....also not an option unless you have a special catheter and a perfusionist/nurse. BUT, you can take off a unit or two of blood (phlebotomy). This will potentially lower the patient's cytocrit. 

Infections occur in up to 8-9% of ICD sites. Early infections usually occur within the first 2 months of placement and are associated with typical findings...redness, tenderness, systemic symptoms, etc. Late infections, however, are often associated with nothing more than JUST pain.

Lack of diagnosis of ICD site infections is associated with a mortality > 50%.

When infected, the entire ICD (including wires) must be replaced.

The most commor organisms associated with ICD infections are Staph and Strep. Treat them all with vancomycin.

Turf Toe:

Most commonly seen in atheletes who compete on artificial turf.  Presents as pain over the 1st Metatarsalphalangeal  (MTP) joint. 

• Due to a tear of the Metatarsal phalangeal Joint Capsule
• Results in subluxation or dislocation of the MTP joint
• Occurs due to:
  • Hyperextension (most common)
  • Hyperflexion
  • Valgus stress
• Treatment:
  • NSAIDS
  • Rest
  • Orthosis -- Prevents dorsiflexion during athletic activities

Pediatric Accidental Non-Fatal Injuries

• Every 1.5 minutes an infant 0-12 months is evaluated in an ED for nonfatal unintentional injuries
• “Falls” are the leading cause of injuries in all age groups (0-12mos)
  • account for ~51% of ED visits in this group
  • Only 2.6% required hospitalization
• “Drowning” was the least common cause of ED visit (0.2%), but
  • accounts for ~47% of the hospitalizations in this group
• “Poisoning” had a bimodal distribution between 0-12 months
  • more commonly seen in 1-3 mos (likely due to parents or siblings) and
  • also in 7mos to 12 mos (likely because of the kids – age when they put things in mouth)

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 How to recognize a truly toxic mushroom ingestion (remember one mushroom can be lethal!):

1) Onset of GI symptoms within 3 hours from time of ingestion: USUALLY NONTOXIC

- Control nausea and  vomiting

- Look for toxidrome: hallucinations, muscarinic symptoms, lethargy

2) Onset of GI symptoms greater than 5 hrs is associated with more toxic mushrooms

- High degree of suspicion for a cyclopeptide mushroom (Amanita phylloides)

- Follow liver enzymes and consier referral to liver transplant center

Bedside Glucometry in the Critically Ill

• Hyperglycemia is common in critically ill patients
• Depending on the underlying condition (e.g. DKA), you may be instituting an insulin drip and following frequent fingersticks in the ED
• A recent study indicates that bedside glucose values may not accurately reflect serum values in approximately 15% of critically ill patients
• This is more likely to occur in patients with poor peripheral perfusion
• Take Home Point: Interpret bedside glucose readings with caution especially in hypotensive critically ill patients

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Hemorrhage Volume on Head CT 

Ever wanted to speak the same language as our neurosurgical colleagues? Ever wonder what they are doing, calculating, or thinking about as they look at the head CT of the large intracranial hemorrhage? 

Most of the neurosurgeons want to know basic information about patients with head bleeds. One thing they always calculate is the hemorrhage volume...i.e. how many mLs of blood are in the bleed? This can be easily done in the ED by using the following formula: called the ABC formula. 

A X B X C/2 X 0.6= mL of blood

A= largest width of the bleed (in cm)

B=largest width perpindicular to A

C=number of cuts you see blood on

So, if A=2cm, B=2cm and the bleed is seen on 3 cuts.....

2 X 2 X 3/2 X 0.6=3.6 mL of blood (not very much in the opinion of a neurosurgeon)

Most of the big bleeds that neurosurgeons drain or take to the OR are 50 cc or so. So, when you call a neurosurgeon and tell them that the patient has 60 mLs of blood, you will definitely get their attention. 

Patients with ICDs presenting to the ED reporting that their ICD fired once do not need mandatory ICD interrogation, admission or an extensive ED workup purely based on the single shock. A workup should be initiated purely based on any other associated symptoms...chest pain, dyspnea, etc. If the patient was doing well and had no other symptoms prior to the shock, the patient should simply have close follow up with cardiology.

Patients presenting after multiple shocks, on the other hand, do need a workup and emergent ICD interrogation (most of these cases also are later deemed inappropriate shocks).

Achilles Tendon Rupture

• Most commonly occurs in males age 30-50 years that participate in occasional high intensity sports that are associated with jumping or quick starts.  [i.e.: Basketball, racquetball, tennis, squash, etc].
  • Exact mechanism is a sudden eccentric force that is applied to a dorsiflexed foot.
• Rupture is also associated with fluoroquinolone and glucocorticoid use.
• Patient will often hear or feel a sudden snap in the back of the ankle or calf.
• Typically ruptures 2-6cm proximal to its insertion on to the calcaneous where its blood supply is the least.
• On physical exam:
  • the patient is unable to plantar flex the foot, raise up on toes, and may have calf swelling. 
  • You may be able to palpate a gap in the achilles tendon.
  • Two specific tests for achilles tendon rupture.
    • Thompson test:  with the leg extended and the foot in neutral position, squeeze the calf muscles.  A positive test is when the foot does not plantar flex when the muscles are squeezed.
    • O’Brien needle test:  Insert a small gauge needle perpendicular to the skin into the proximal (about 10 cm from the calcaneous) achilles tendon. Passively dorsiflex and plantar flex the ankle and foot. If the needle moves in the opposite direction of the movement then the achilles tendon is intact.
• Treatment
  • Refer to orthopedics
  •  Place the patient in a posterior splint with the foot and ankle in slight plantar flexion. 
    • Ideally this will bring the two tendon ends together and speed healing.

This addition was sent in my Dr. Andrew Milstein:

Thanks for the Orthopedics update.  A few pearls for Achilles Tendon Rupture --> often these patients may present like a typical ankle sprain patient and are placed in a hallway chair.  You can't do an adequate Thompson Test while someone is sitting in a chair.  If you're concerned, lay them down on a stretcher to do the test.

Acute Chest Syndrome

• ACS is the leading cause of morbidity and mortality in children and adults with Sickle Cell Disease.
• Definition: ==> A new infiltrate on CXR (excluding atelectasis) PLUS one or more of the following:
  • Tachpnea
  • Fever (>101 degrees F)
  • Chest Pain
  • Cough
  • Wheezing
  • Hypoxemia
• Treatment
  • Bronchodilators
    • Trial of beta-agonists for clinical response is advocated even in those without wheezing.
  • Antibiotics
    • Broad Spectrum: Ceftriaxone PLUS Azithromycin
    • Evidence demonstrates a significant amount of these patients have atypical bacterial infections
    • Vanco is warranted for severe disease unresponsive to therapy
  • Steroids
    • Use for patients with Reactive Airway Disease or severe distress
    • They may cause a rebound of Vaso-occlusive Crisis and need to be tapered.
    • Prednisone 2mg/kg/Day x 5 then taper
  • Pain Control
    • Need to optimize pulmonary toilet by providing adequate pain management, but avoid over-sedation leading to hypoventilation.
    • NSAIDs have proven to be useful in conjunction opiods.
  • Transfusion of PRBCs
    • Simple
      • For pts who have a >10-20% drop from their baseline Hgb
      • For pts who are symptomatic, but not in impending respiratory failure
      • Try not to EXCEED Hgb of 10g/dL post transfusion
    • Exchange
      • For pts with impending respiratory failure
      • For pts with Hgb > 10g/dL and significant symptoms (to avoid hyperviscosity)
    • The decision to transfuse these patients needs to be made in conjunction with the consulting Hematologist.

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 Hemodialysis

• Ethylene Glycol
• Methanol
• Lithium
• Salicylate
• Theophylline (Hemoperfusion)
• Ethanol (rarely needed but can be done)
• Isopropanol (rarely done)

CAVH or CVVH: Lithium, Procainamide, Aminoglycosides, Methotrexate

Exchange Transfusion (pediatrics mostly): Salicylate and Theophylline

• Intracranial hemorrhage (ICH) can expand for the first 24 hours after onset.
• Peak ICH expansion occurs at 6 hours.
• REMEMBER:  The heads of patients with ICH should be elevated (~30 degrees) for at least 24 hours after the onset of bleeding to decrease the extent of expansion.  This is a simple, but too often neglected, clinical measure that potentially offers great benefit to the patient.

 PEA Arrest...Look for AAA rupture and Cardiac Tamponade

If a patient presents in cardiac arrest (particularly PEA), consider the following diagnoses in addition to the causes commonly taught in ACLS:

• AAA with rupture
• Aortic Dissection complicated by tamponade

A 2004 study in Resuscitation by Meron et al. showed the following:

• Approximately 50% of the patients who presented in PEA arrest from a AAA rupture did NOT have abdominal or flank pain prior to arrest
• Approximately 50% of the patients who presented in PEA arrest from cardiac tamponade (from aortic dissection) did NOT have chest pain prior to arrest
• Bedside US was diagnostic in all cases in this subset of patients with PEA arrest of unknown cause

Take home point for the emergency physician:

• Pull the US machine out very early on in the resuscitation of the PEA arrest patient....get the probe on as soon as you can. 

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Vasopressin for Sepsis

• The VASST trial was recently published in NEJM comparing vasopressin vs. norepinephrine for septic shock
• Unfortunately, there are some issues with the study which I will clarify/expand upon in the next Critical Care Literature Update
• There was a trend towards improved mortality in the vasopressin group receiving low doses of norepinephrine (5 - 14 mcg/min)
• Take Home Point: If you are thinking about adding vasopressin to norepinephrine in patients wtih refractory septic shock, do it early.  In other words, add vasopressin when you find yourself titrating norepinephrine doses to 6, 7, 8 mcg/min