9.13.18 Conference Summary

Grand Rounds: Dr. Steven Curry

EM/Toxicologist, University of Arizona - Phoenix/Banner Medical Center

SNAKE BITES

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  • Viperidae Family (other main family in US is Elapidae - coral snakes)

    • Mobile front fangs that inject venom, triangular head, elliptical pupils

    • Subfamilies

      • Crotalinae: includes pit vipers and new world vipers (rattlesnakes, cotton mouths, cottonheads)

      • Viperinae

  • Clinical effects of rattlesnake bites

    • Soft tissue injury

      • Venom absorbed by lymphatics, and moves proximally, leading to pulmonary sequelae

      • Blebs - dark blood filled blisters, can track proximally

      • Distal injury ranges from partial thickness wound to complete amputation of digits

    • Myotoxicity

      • Local to more systemic necrosis

      • Can lead to renal failure (rhabdo)

    • Coagulopathy

      • Thrombin-like enzymes - deplete fibrinogen and lead to poorly formed fibrin chains—>poor ability to clot

      • Venom-induced thrombocytopenia

      • DIC is possible

    • Neurotoxicity

      • Venom affects NMJ, resulting in increased ACh release —> fasciculations —> weakness/paralysis (due to progressive increase in swelling)

    • Anaphylactoid syndrome

      • Angioedema, vascular leak (third-spacing), DIC, cardiovascular collapse

      • Rapid decompensation

      • Mechanism: mimic action of and increase production of bradykinin

    • Recurrent hematologic toxicity following antivenom administration; need close monitoring

  • Things to avoid for snake bite:

    • Ice, tourniquet (can worsen necrosis), ‘snake bite kits’, incisions

  • Management

    • Identify envenomation: look for presence of pain, swelling, n/v/d, hypotension, coagulopathy or thrombocytopenia (check labs), weakness

    • Supportive care

    • Monitor for minimum of 6 hours; if stable, may. discharge home

    • Always admit leg bites — often see delayed swelling —>splint/elevate extremities, monitor for compartment syndrome

    • Antivenom (CroFab) if moderate to severe toxicity

      • Initial dose: 4-6 vials

      • May need repeat dosing until adequate response

      • Very expensive

NERVE AGENTS

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History

  • Discovered in 1930s by researcher G. Schrader

  • Initially in form of tabun and sarin and, later, soman

  • Weaponized during WWII but not used

  • First used in warfare during Iran-Iraq war in 1980s



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  • Pharmacokinetics

    • Onset: minutes to hours

    • Mechanism of action: inhibits acetylcholinesterase, resulting in accumulation of ACh

    • Sympathetic and parasympathetic effects

  • Clinical Effects

    • Miosis, bradycardia/tachycardia, vomiting/diarrhea, urination, diaphoresis, bronchospasm, bronchorrhea—>pulmonary edema, seizure/lethargy/coma

    • Death primarily from respiratory failure

  • Treatment

    • Decon/remove clothing

    • Supportive care, resuscitate and manage airway as indicated

    • Atropine

      • 1-2mg/kg q2-5 min prn (Peds: 0.05mg/kg q2-5 min)

      • Endpoint: resolution of bronchorrhea +/- mydriasis, tachycardia, etc

    • 2PAM (pralidoxime):

      • Removes organophosphate from acetylcholineasterase, thereby ‘reactivating’ the enzyme

      • 1-2g IV over 10-15 min (Peds: 30-50mg/kg IV over 10-15 min)


EBM: Cellulitis - Dr. James Palmer

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  • Treatment = antibiotics

    • Consider keflex or amoxicillin if low suspicion for MRSA

    • MRSA coverage: bactrim/clindamycin —> vancomycin

  • Common mimics (28% misdiagnosis rate)

    • Stasis dermatitis —> good compression

    • Abscess —> drain

    • Bite wounds, gout, septic arthritis, etc.

  • Disposition to consider

    • Discharge… if: stable vitals + no/well-controlled comorbidities + no facial involvement

    • CDU … if: stable vitals/labs, anticipate response in <24 hours; mark boundaries

    • Admission… if: abnormal vitals, systemic signs of infection, h/o MRSA or concern for MRSA infx, failed outpatient therapy, poorly controlled comorbidities (incl dialysis-dependence)


Community EM Series: Pediatric Concussion - Dr. Arlene Losloso

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  • Concussion: synonymous with ‘mild TBI’

    • Associated with altered, but recoverable, brain physiology/function

  • Epidemiology

    • Common - at least 1 million children in US affected each year

    • More common in males

  • Risk Factors

    • Male gender, obesity, contact sports, prior concussions, mental disorder/cognitive delay

  • Clinical effects

    • Physical: headache, dizziness, ataxia, n/v, fatigue

    • Cognitive: forgetfulness, difficulty concentrating, slow to respond

    • Emotional/behavioral: mood lability, anxiety

    • Majority of symptoms resolve in 1 month

  • Diagnosis

    • Primarily made clinically (use age-appropriate measures) ; blood tests/imaging not effective

  • Initial management

    • PECARN - evidence-based decision rule to determine need for imaging and disposition; don’t routinely image

    • If in the community, consider urgent transfer to pediatric trauma center if concerned for severe injury

  • Management of stable patients (per CDC guidelines)

    • Physical and cognitive rest with gradual return to activities after 3 days

    • +/- targeted treatments based on symptoms

    • Reassurance and education —- start in the ED!

    • Keep in mind that pediatric athletes recover more slowly than college/professional athletes

  • Complications

    • Second impact syndrome - rare, usually fatal; diffuse cerebral edema from second head injury while still symptomatic from initial injury

    • Post-concussive syndrome (PCS)

    • Persistent post-concussive symptoms (PPCS)


Super Track Series: Approach to Sore Throat - Dr. Jordan HITCHENS

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  • Strep Throat

    • Modified Centor Score: 1 point for each of the following… if total is 3+, consider rapid testing/culture (empiric tx not recommended)

      • Age 3-14 yrs (if ≥ 45 yrs: -1 pt)

      • Tonsillar exudate

      • Tender/swollen anterior cervical lymph nodes

      • -Temp >38°C

      • Absence of cough

    • Treatment

      • Amoxicillin 500mg PO BID x 10 days

      • Penicillin G/Bicillin IM (IM not recommended currently due to shortage)

      • Steroids? - single dose shown to have two-fold reduction in pain; use judiciously if co-morbidities (i.e. diabetes) present

  • Viral pharyngitis

    • Supportive care

  • Herpangina

    • Cocksackie A virus (similar to HFM disease but only oral involvement)

    • Oral blisters/ulcers

    • Treatment: supportive care

  • Thrush

    • Often seen in chronic steroid use (inhaled steroids in COPD)

  • Oral gonorrhea (‘the clap’)

    • Sore throat is a common complaint

    • Treatment is the same as GU infection (ceftriaxone)

  • Epiglottitis

    • Less common in adults compared to kids; among adults, ‘sore throat’ is most common complaint

    • Thumbprint on xray

    • Treatment

      • Ceftriaxone (+ vanc in severe cases/MRSA concern)

  • Peritonsillar abscess

    • Common findings: asymmetric OP edema, uvula deviation, odynophagia, hot potato voice

    • Treatment

      • Antibiotics: Augmentin (oral), Unasyn (IV)

      • Needle aspiration

        • #protips

          • MAC blade to move tongue out of the way (have patient hold)

          • 3.5cm 18g spinal needle

          • Mark/cut needle cap 1cm from tip of needle to minimize risk of hitting carotid artery

          • Use ultrasound!!!


Consultant of the Month: Infectious Disease - Antibiotic Overview - Dr. Keith Armitage

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  • Cultures:

    • Always try to get two sets of blood cultures (from two sites) to increase sensitivity and specificity

    • Only reliable cultures are those obtained before antibiotic administration

  • Antibiotic selection based on efficacy/resistance, toxicity/side effects, convenience (especially if outpatient management), cost

  • Penicillins

    • Penicillin: still used to treat syphilis (first line), dental infections, strep pharyngitis (oral, IV, IM forms)

    • Ampicillin: gram neg coverage (klebsiella, proteus, listeria, etc)

    • Amoxicillin: better oral bioavailability compared to other penicillins —> most commonly prescribed oral antibiotic

    • Anti-Staph Penicillin (nafcillin, dicloxicillin): MSSA

    • Anti-Pseudomonal (PSA) Penicillin (piperacillin, ticarcillin)

    ***Addition of beta lactamase inhibitor (amox—> augmentin; ampicillin —> unasyn, piperacillin —> zosyn) significantly broadens coverage but diarrhea is common side effect

  • Cephalosporins

    • 1st generation (cefazolin - IV, cephalexin - PO): primarily gram positives —> SSTI, URI, surgery prophylaxis

    • 2nd gen (cefuroxime/cefoxitin/cefotetan): gram positive + some gram neg —> similar to 1st gen + some sinusitis/OM

    • 3rd gen (ceftriaxone/cefotaxime/ceftazidine): better gram neg + strep pneumo, good CSF penetration —> meningitis, CAP, UTI, gonorrhea, etc.

    • 4th gen (cefepime): covers pseudomonas

    • 5th gen (ceftaroline): broad spectrum, gram positive including MRSA

  • Tetracyclines

    • Black box warning for tendinopathy (reversible early on)

    • High resistance profile at UHCMC; avoid if severe intraabdominal infx (may consider if treating outpatient)

  • MRSA Coverage

    • Vancomycin is the best — use for MRSA infections unless known vanc-resistant

    • Linezolid: high toxicity profile (cumulative), expensive, good lung coverage

    • Daptomycin (IV only): very expensive

    • If milder infx and treating outpatient

      • Bactrim: sulfa allergy is an issue

      • Clindamycin: associated with cdif

  • Primarily need anaerobic coverage for lung abscesses; most ‘aspiration’ pneumonia can be treated with non-anaerobic antibiotics