Pearls From the Emergency Medical Literature

October 29, 2013

Here: tips from top articles culled from the emergency medical literature, with take-home lessons for primary care.

In the type of discussion for which they are famous, Dr Jerome Hoffman and Dr Richard Bukata covered a variety of recent articles in the medical literature that related to emergency medicine at the American College of Emergency Physicians 13th annual symposium in Seattle (ACEP13) entitled “Clinical Pearls From the Recent Medical Literature.”

TBI in children. The first article addressed clinically important traumatic brain injuries in children who clinically appeared well, but had a concerning mechanism of injury. Results supported that mechanism alone is not a good predictor of important brain injury. Other predictors of severity, such as the intensity or headache progression, vomiting, altered mentation, loss of consciousness, or clinical evidence of skull fracture are more important to consider in deciding who needs a head CT.

For a solid background on this topic the audience was referred to the PECARN (Pediatric Emergency Care And Research Network) study, which provides clinical guidelines that help limit the number of unnecessary CT scans in children and thereby reduce both cost and radiation exposure to pediatric patients with head trauma.

Neck Injury: Which imaging study? Another article reviewed the use of plain films vs CT for neck injuries. Findings showed that CT was much more sensitive for injury, but that adequate plain films did not miss any important injuries except in high-risk patients.

The speakers opined that when imaging of the neck for trauma is indicated, plain films are acceptable in most patients. CT should be considered in patients with high-risk mechanisms, altered mental status, focal neurologic deficits, abnormal or inadequate plain films, or in the elderly.

Readers are referred to the NEXUS study and/or the Canadian C-spine rules to determine who needs no imaging at all.

Pulmonary embolism and the ECG. A key article was about a specific ECG finding in acute pulmonary embolism (PE). This article showed that simultaneous anterior and inferior T-wave inversion, although not very sensitive for PE, was 90% specific. The take-home message? New anterior or anterior plus inferior T-wave inversion should be added to the list of findings that prompt consideration of PE rather than just ischemia in the appropriate clinical scenario. Although non-sensitive for small PE’s, it is critical to be aware of the fact that a large PE can cause both EEG changes and a troponin leak that mimics an acute coronary syndrome.

Staying with the theme of PE, two very provocative essays recommended raising the threshold for testing for PE, in that very small PE’s are rarely dangerous and the risk of testing-ie, radiation and IV contrast and risk of treatment with anticoagulants-may outweigh the risk of the disease. Because of broader availability of advanced testing to diagnose milder and milder disease, “overdiagnosis” may occur: the result is treatment of conditions that would otherwise resolve on their own or never cause any important clinical harm.

Dr Hoffman mentioned that the same phenomenon likely occurs with PSA testing and prostate cancer. Clinical decision rules, like the PERC criteria, which recommend that no testing in very low–risk patients may be the best solution and provide the best way to substantiate decreasing the number of patients who are tested without increasing medico-legal risks or patient morbidity.

Heart disease. Another article showed that both the sensitivity and specificity of chest pain response to nitroglycerine was not very useful in determining the cause of the pain. It was only about 50% sensitive and 50% specific for coronary disease. Dr Hoffman mentioned that the chest pain response to a GI cocktail was similarly useless on its own and should not be used to make treatment decisions. Although these “therapeutic challenges” will likely continued to be used clinically, it is important not to place too much confidence in them. It is important to realize that the pain from many conditions may abate on its own and the apparent response to medication may sometimes represent nothing more than a coincidence in timing. In addition, other conditions such as biliary colic and esophageal spasm often improve after the administration of nitroglycerin.

Overdiagnosis of CAD. Finally, another series of provocative essays shows that we may not only be over-diagnosing clinically unimportant prostate cancer and very small PE’s, but also over-diagnosing incidental stable coronary artery disease in patients with non-cardiac chest pain who are found to have coronary stenosis when they are worked up. A large percentage of older individuals have coronary disease, much of which is not the cause of acute symptoms at the time of evaluation. If these patients present with gastritis or acid reflux, the ensuing workup may lead to a coronary intervention or even a cardiac bypass, which they may not have needed, since much chronic coronary disease does not cause morbidity or mortality if it is stable and/or asymptomatic.