The Chart Decides a Missed-Bleed Case Before the Scan Does
A short read on what a defensible review of a missed subarachnoid hemorrhage case examines, and why it starts with the history. A composite of cases I see repeatedly, with no detail drawn from any actual matter.
A 38-year-old woman presents to a community emergency department with a severe headache that began suddenly that morning. The triage note records "headache, six hours, no trauma." She is discharged with a migraine diagnosis. Thirty-six hours later, she is found unresponsive at home. A CT scan (an X-ray-based brain image) shows a subarachnoid hemorrhage (SAH, bleeding into the space surrounding the brain, most often from a ruptured aneurysm, which is a balloon-like weakening of an artery wall). She survives surgery, but she does not return to her prior work.
Both sides will reach for the same record. The complaint will say the diagnosis was missed. The defense will say the presentation did not classically suggest a ruptured aneurysm. The chart sits in between, and the question this issue takes seriously is what it shows and what its silences carry.
A defensible reconstruction in a missed-SAH case is built from a small set of specific findings, most of them in the documented history rather than the imaging. One study of every Ontario hospital found patients triaged as low acuity (not urgent) were misdiagnosed at 2.65 times the odds (95% CI 1.46 to 4.80). Was the onset characterized (sudden versus gradual, time to peak), or was the duration reduced to hours? Was the comparison to prior headaches asked, or assumed away by a chronic-migraine label? Was CT obtained inside the six-hour window, in a patient without new deficits, where sensitivity (the share of true bleeds it detects; what a negative scan rules out depends on that share and on how strongly a bleed was suspected) is near complete, or beyond six hours, where a 2016 meta-analysis put pooled sensitivity at eighty-nine percent? Was it read on a high-quality scanner by a fellowship-trained, board-certified neuroradiologist, as the 2023 American Heart Association guideline requires for that window, or does the chart not say? When CT timing called for a lumbar puncture (a spinal tap sampling spinal fluid), was it performed at least twelve hours after onset, or at hour four, when a negative test for xanthochromia (yellow discoloration of that fluid as blood breaks down, measured by spectrophotometry, rare in American laboratories) proves nothing?
The Commentary in this month's Writings takes up the causation question this issue does not reach: whether earlier diagnosis would have changed a particular patient's course.
The point worth carrying into a file review is structural. Some files that look strong in the complaint dissolve against a chart that captures a careful onset history and a CT obtained at hour four. Others that look strong on the defense collapse against a chief complaint of "headache" that nobody pressed past, and a scan ordered too late to mean what it was read to mean. The CT shows the blood. The chart shows whether the question that should have ordered the CT was ever asked. In missed-SAH cases, the second record is the one worth reading first.
Primary source
Vermeulen MJ, Schull MJ. Missed diagnosis of subarachnoid hemorrhage in the emergency department. Stroke. 2007;38(4):1216-1221. doi:10.1161/01.STR.0000259661.05525.9a
The Commentary in this month's Writings
Missed Subarachnoid Hemorrhage: The Clock the Record Has to Establish — cortexion.co/writings/missed-subarachnoid-hemorrhage
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