14y.o. daughter blacked out, followed by confusion and lethargy. er dr. diangosis w/ sinusitis following ct scan, but no symptoms at all. should i seek 2nd ?

Yes: There are many reasons this could have occurred. There should be a report on the CT. The most important causes for these symptoms could be related to her neurological system such as seizures or a problem related to the electricity pathway in her heart. There may be other explanations. Follow up with your doctor for ongoing concerns or ask for another opinion.

Sinusitis: CT scan findings must be correlated with a person's symptoms and physical examination findings to diagnose a sinus infection. It's possible though, that she felt dizzy -a symptom of sinusitis-(specially after bending over and then standing up) and then blacked out. We see this scenario many times in acute sinusitis in teens. Follow up with her own Pediatrician.