Tag Archives: aneurysm

General

When To Worry About Subarachnoid Hemorrhage

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Neurosurgeons tend to worry about aneurysms a lot. They can cause devastating and lasting neurologic dysfunction. The most common diagnostic finding, besides the classic “worst headache of my life” complaint, is subarachnoid hemorrhage (SAH). And one of the more common CT findings after head trauma is also SAH. 

For that reason, CT angiography tends to get added on to the trauma workup from time to time. Trauma professionals are faced with the “chicken or the egg” question, trying to figure out if a leaking aneurysm caused the subarachnoid blood and then the fall/crash, or the fall/crash caused the blood.

A group at St. Luke’s Hospital in Bethlehem PA looked at this question using 5 years worth of retrospective data from their Level I trauma center. They noted a significant increase in the number of CT angiographic (CTA) studies being ordered in their head trauma patients and wanted to determine which patients would benefit most from this study.

Here are the factoids:

  • 617 patients were identified with traumatic SAH during the study period, and 186 of them (30%) underwent CTA
  • 13 patients (7%) who had CTA actually had an aneurysm
  • Of these 13 patients, 8 were believed to have presented with trauma caused by the aneurysm because they were found to be ruptured

  • All patients who had a ruptured aneurysm had a pattern of central subarachnoid hemorrhage on CTA

  • Of the patients who were “found down”, none had an aneurysm

Bottom line: Pre-existing aneurysms are not any more common in TBI patients than they are in the general population. However, they may be the cause of trauma on occasion. Contrary to what many think, they seem to be uncommon in cases of patients who are found down; it looks like the trauma usually comes first. However, a pattern of central subarachnoid hemorrhage is reasonably predictive of this uncommon yet dangerous problem, so addition of CT angiography of the head when it is seen on non-contrast CT appears to be warranted.

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Reference: Selected computed tomographic angiography in traumatic subarachnoid hemorrhage: a pilot study. J Surg Research, in press, 2015.

General

CT Angiography Of The Head In TBI?

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Trauma professionals rely heavily on diagnostic tests these days, particularly CT after blunt trauma. Apparently, the neurosurgeons at the Massachusetts General Hospital are asking for CT angiography of the brain on occasion in patients with TBI. Ostensibly, this is to rule out cases when a brain aneurysm causes a car crash or other blunt trauma.

WTF? Now, I know that we occasionally agonize over older victims of blunt trauma who come in pre-terminal or in arrest. Did they have an MI which caused the event, or did the trauma stop their heart? I had no idea that a ruptured/rupturing aneurysm was such a problem in blunt trauma.

So the surgeons at the MGH decided to critically look at this issue to see if the extra head scan was warranted. 

Here are the factoids:

  • 600 patients with blunt TBI over a one year study period were reviewed
  • 22% underwent CT angio in addition to the normal head CT
  • 66% had the CT angio immediately, 27% within 24 hours, and 7% beyond 24 hours after arrival
  • Specialists who requested the study were neurosurgeons (23), radiologists (15!), neurologists (7!!)
  • Reasons for getting the study: look for cause of subarachnoid hemorrhage (aneurysm) in 43, look for vascular injuries near a skull fracture in 14, rule out stroke in 4, and no particular reason in 71
  • Head CTA changed management in only 1 patient, prompting a formal angiogram which was negative
  • 33 patients (25%) had incidental findings on CTA, but none required any intervention in the hospital or on later followup

Bottom line: There is no value to adding CT angio of the head to the usual scan protocols. Having said that, if the patient was witnessed to lose consciousness prior to the event, and the CT shows subarachnoid hemorrhage in a more typical middle cerebral artery distribution, you might consider it to look for an aneurysm. That’s a lot of if’s. Just move the zebra off the CT scanner first. And as you can see from the last factoid above, if we scan it, we will find stuff. Fortunately, most of that stuff doesn’t need further workup or treatment.

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Reference: Is CT angiography of the head useful in management of traumatic brain injury? J Am Col Surg 220(6):1027-1031, 2015.