Podcast # 373: Legionnaires Disease

Author:  Gretchen Hinson, MD

Educational Pearls:

  • Legionnaires disease refers to a severe pneumonia caused by Legionella pneumophilia and occurs typically at the extremes of age
  • Associated gastrointestinal symptoms (nausea/vomiting/diarrhea) may be present
  • Hyponatremia is a common laboratory finding
  • Legionella urinary antigen can be a convenient test to identify the infection
  • Treatment is with fluoroquinolones, macrolides and/or tetracyclines

 

 

References

Pierre DM, Baron J, Yu VL, Stout JE. Diagnostic testing for Legionnaires’ disease. Annals of Clinical Microbiology and Antimicrobials. 2017;16:59. doi:10.1186/s12941-017-0229-6.

Cunha BA, Cunha CB. Legionnaire’s Disease and its Mimics: A Clinical Perspective. Infect Dis Clin North Am. 2017 Mar;31(1):95-109. doi: 10.1016/j.idc.2016.10.008. Review.

Podcast # 340: Drowning

Author: Chris Holmes, MD

Educational Pearls:

  • Epidemiology: 80% male, ages 1-4 at greatest risk, African-American > Caucasian.
  • Freshwater and ocean water may have more bacteria than pool water.
  • Salt water is hyperosmolar, which theoretically increases risk of pulmonary edema.
  • Greatest physiologic insult is from hypoxia secondary to fluid aspiration or laryngeal spasm. Patient survival is related to presentation on arrival.
  • Workup includes CXR and ABG; consider C-spine immobilization/imaging when cervical injury is strongly suspected (i.e. diving injury).
  • Treatment consists of supplemental oxygen therapy. Consider CPAP or intubation.

References

Szpilman D, Bierens JJ, Handley AJ, Orlowski JP. Drowning. N Engl J Med. 2012. 366(22):2102-10. doi: 10.1056/NEJMra1013317.

Schmidt A, Sempsrott J. Drowning In The Adult Population: Emergency Department Resuscitation And Treatment. Emerg Med Pract. 2015. 17(5):1-18.

Podcast # 337: Airway Burn Inhalation

Author: John Winkler, MD

Educational Pearls:

  • Singed nasal hairs, soot around mouth, hoarse voice, drooling, and burns to head/face are signs suggestive of inhalation injury.
  • Early intubation is critical for these patients as the airway changes rapidly.
  • With inhalation injuries, the upper airway is burned while the lower airway is damaged by inhaled chemicals in the soot and can cause ARDS.
  • Carbon monoxide (CO) and cyanide (CN) poisoning can occur with inhalation injuries.
  • Treatment for CO poisoning is 100% oxygen and possible hyperbarics. Treatment for CN poisoning is cyanocobalamin.

 

References

Rehberg S, Maybauer MO, Enkhbaatar P, et al. Pathophysiology, management and treatment of smoke inhalation injury. Expert Rev Respir Med 2009; 3:283.

Woodson CL. Diagnosis and treatment of inhalation injury. In: Total Burn Care, 4 ed, Herndon DN (Ed), 2009.

Podcast #325: Vaping and Pneumonia

Author: Sam Killian, MD

Educational Pearls:

  • Being exposed to E-cigarette vapor may increase risk of pneumonia.
  • Recent study has shown e-cigarette vapor increases quantities of Platelet-activating-receptor factor in epithelial cells, which may aid pneumococcal bacteria in entering pneumocytes.

References:

Miyashita L, et al. (2018). E-cigarette vapour enhances pneumococcal adherence to airway epithelial cells. The European Respiratory Journal. 7;51(2).

Podcast #320: PE in Pregnancy

Author: Don Stader, M.D.

Educational Pearls:

  • Pulmonary embolism is one of the leading causes of maternal mortality.
  • There is disagreement among different medical societies about the value of D-dimer as a screening modality. If you use it, consider the rational D-dimer approach whereby you add 250 to your cut-off for every trimester.
  • A useful screening modality is an ultrasound of bilateral lower extremities looking for DVT.
  • Keep in mind, both a V/Q scan and CT scan have a significant amount of radiation. CTA is probably the right diagnostic test (less radiation than CT w&w/o).
  • Always use the shared decision-making model and clinical acumen to choose your tests.

References:

Leung AN, et. al. (2011). An official American Thoracic Society/Society of Thoracic Radiology clinical practice guideline: evaluation of suspected pulmonary embolism in pregnancy. American Journal of Respiratory and Critical Care Medicine. 184(10):1200-8

 

Polak JF, Wilkinson DL. (1991). Ultrasonographic diagnosis of symptomatic deep venous thrombosis in pregnancy. American Journal of Obstetrics and Gynecology. 165(3):625-9.

Sachs BP, et. al. (1987). Maternal mortality in Massachusetts. Trends and prevention. New England Journal of Medicine. 316(11):667-72.

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Podcast #268: Poiseuille’s Law

Author:  Dave Rosenberg, M.D.

Educational Pearls

  • Poiseuille’s Law addresses the flow of a fluid through a tube.
  • Many common ED presentations involve alterations in flow: asthma, MI, ischemic stroke, etc.
  • According to the law, flow increases with the 4th power of the radius. That is to say, doubling the radius of the tube will increase the flow by 16x.
  • Therefore, in situations that require re-opening of an anatomic tube (artery, airway), small changes in the size of the opening will result in dramatic effects.

References: https://www.openanesthesia.org/poiseuilles_law_iv_fluids/

Podcast #262: Pertussis

Author: Julian Orenstein, M.D.

Educational Pearls

  • Colorado has a high population of unvaccinated children, and is at increased risk for pertussis outbreaks.
  • The causative organism is Bordetella pertussis. It causes  causes respiratory epithelial necrosis leading to congestion of the bronchioles, leading to cough.
  • The cough is unique – it is usually a series of expiratory coughs followed by one deep inspiration
  • The clinical presentation is divided into 3 phases:
    • Catarrhal: cough and congestion with low-grade fever and coryza.
    • Whooping: characteristic cough.
    • Resolution: recovery with persistent cough.
  • Infants may not get this presentation, but may get apnea and nonspecific cough.  
  • Tongue depressor can be used to elicit cough for diagnosis.

References: Tozzi AE, Pastore Celentano L, Ciofi degli Atti ML, Salmaso S. Diagnosis and management of pertussis. CMAJ?: Canadian Medical Association Journal. 2005;172(4):509-515. doi:10.1503/cmaj.1040766.

Podcast #260: Preoxygenation

Author: David Rosenberg, M.D.

Educational Pearls

  • Preoxygenation is done before rapid sequence intubation, and should be done even if SaO2 is at 100%.
  • Preoxygenation is done to fill the lungs with oxygen rather than ambient air, which is only 20% O2. While the patient is paralyzed, the O2-filled lungs will continue to oxygenate venous blood, buying you more time for intubation.  
  • BiPAP is an effective tool for pre-oxygenation.

References: https://lifeinthefastlane.com/ccc/preoxygenation/

Podcast #247: D-Dimer

Author: Michael Hunt, M.D.

Educational Pearls

  • In the recent YEARS study, investigators checked every patient with suspicion for PE with a D-dimer, using a modified Wells score for risk stratification. The goal of the study was to show that CT scan usage could safely reduced using this screening method.
  • The Wells Criteria measures they used to stratify risk were: PE mostly likely dx, hemoptysis, and evidence of DVT. If the d-dimer was 1, but the patient had none of the Wells criteria, the patient did not get a CT. If the patient had any of the criteria, but the d-dimer was only 0.5, the patient did not get a CT scan.
  • The investigators reduced  CT usage by 14% using the new criteria, with no significant increase in morbidity and mortality.

References: van der Hulle et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study. The Lancet. 2017