Saturday, March 2, 2013

Blunt Trauma in a Child

For a related tragic case, click here.

A child between the ages of 5 and 10 was restrained in a motor vehicle collision and sustained multiple chest injuries.  Therefore, an ECG was recorded:

There is sinus rhythm.  The axis is about -50 (left axis), whereas normal for this age is 0 to +90.  So there is left axis deviation.  In V1, there is a tiny r-wave, followed by an s-, an r-, and an S' wave.  Normally there is an RS-wave, and at age 8 the S-wave is more prominent, as in adults.  The QRS duration is 102 ms, which is long for this age (normal, 80-85 ms, see:  Rijnbeek PR.  European Heart Journal (2001) 22, 702–711.  Thus, there is an abnormal conduction delay.  This is probably an atypical RBBB, given that there is an rsrS'.   Furthermore, R-wave progression in children is much earlier than in adults, so the R-wave in V2 should be more well developed.  There are no apparent repolarization abnormalities (ST elevation, depression, or T-wave inversion)  The QTc is 373 ms.

Thus, the ECG is abnormal, and this prompted a troponin measurement, the initial one of which was normal.  The 6-hour troponin was the first detectable and first positive one at 0.044 ng/ml (Ortho Clinical Diagnostics, 99% reference = 0.034 ng/ml).  Serial troponin I  peaked at 0.927 ng/ml. 

A transthoracic echocardiogram showed thinned and dilated right ventricle with poor function and some tricuspid regurgitation. 

A followup ECG 36 hours later was recorded:

The QRS is still prolonged (106 ms) and there are new repolarization abnormalities (T-wave inversion).  The QTc is 396 ms.
Echo was repeated due to the ECG changes and troponin elevation and this showed less tricuspid regurgitation.  There was RV dilation and significant thinning of the apical RV freewall which was akinetic and moved paradoxically.  There was a very small amount of pericardial fluid (blood?--uncertain). There was also some abnormal movement of the septum.

An ECG was recorded at t = 60 hours:
QRS is 107 ms and QTc is 486 ms.  There is bizarre T-wave inversion.

This child did well in the hospital, with no hypotension, tachycardia, or dysrhythmias, and the child was transferred to the care of a pediatric cardiologist.  This is essential, as myocardial contusion with ECG abnormalities can have disastrous outcomes.  See this tragic case.

For a nice review article by Bill Brady on the normal pediatric ECG, look here (full text pdf).

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