>EM Reflections – February 2019

Thanks to Dr. Joanna Middleton for leading the discussions this month

Edited by Dr David Lewis 


Discussion Topics

  1. Can diagnostic ultrasound reliably rule out appendicitis?
  2. Do mandibular fractures need to be admitted?
  3. Can neuromuscular disorders alone result in symptoms of dyspnoea?

Can diagnostic ultrasound reliably rule out appendicitis?

  • Accuracy depends upon the skill and experience of the sonographer – when the appendix is visualized the accuracy of ultrasound is equivalent to CT – sensitivity and specificity of 91-98% and 86-92%
  • Inaccurate examinations were significantly associated with high body mass index (≥85th percentile, primarily false-negative results) 

In this case, a patient with clinically suspected appendicitis, had an ultrasound that was reported normal i.e the appendix was visualized and appeared normal. A subsequent CT confirmed the diagnosis of appendicitis.

Take Home Point: All diagnostic tests have a false negative rate. If it looks like a sock, even if the test says it isn’t, it still might be.


Do mandibular fractures need to be admitted?

  • Must assess open vs closed – open needs ABx
  • Consider MOI/associated injuries
  • Bilateral #’s – airway obstruction 
    • Posterior displacement of the tongue
    • Bleeding – tearing of the periosteum and muscles attached to the mandible – sublingual hematoma, swelling and life-threatening airway compromise
    • Edema
    • FB

Admission Criteria:

Admit (ENT, OMFS, Plastics) for:

  1. Airway compromise (e.g when lying flat)
  2. Unable to tolerate PO or secretions
  3. Inadequate pain control
  4. Open and/or unstable fractures

Useful review article here

In this case the patient was admitted to Family Medicine after discussion with other relevant specialties.

Recommended Disposition Guidelines for Trauma Patients:

Take Home Point: Mandibular fractures are usually indicative of significant force. They are usually fractured in 2 places and therefore unstable. Disposition to appropriate specialist and level of care is recommended.


Can neuromuscular disorders alone result in symptoms of dyspnoea?

Consider all the common causes of dyspnoea first

“No single abnormality is diagnostic of respiratory muscle weakness; rather, diagnosis is based on a constellation of abnormalities. The use of single tests tends to overdiagnose respiratory muscle weakness, whereas use of combinations of tests increase diagnostic accuracy.”

And interesting case report here

Take Home Point: A differential diagnosis should always include the common conditions, but also consider the rarer conditions. Online tools are available to help with rare disease diagnosis – see this article

Some online differential diagnosis tools:

http://www.findzebra.com/

https://www.isabelhealthcare.com/

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