The clinical significance of isolated traumatic subarachnoid hemorrhage

Mild traumatic brain injury is a clinical diagnosis predicated on a patient's neurologic status and encompasses a variety of pathologies on computed tomography. We wondered whether isolated traumatic subarachnoid hemorrhage (iSAH) without other intracranial pathologic diagnosis is a more benign form of minor head injury that does not warrant extensive (and expensive) observation and follow-up.

This is a retrospective review of patients identified prospectively via a trauma registry during a period of 7 years, who had the computed tomographic finding of iSAH on admission scan and a Glasgow Coma Scale (GCS) score of 13 or greater.

There were 478 patients identified, with a mean age 61 years, and 223 were male. Median Injury Severity Score (ISS) was 10 (range, 9-48), and the distribution was 415, 54, and 12 for those with GCS score of 15, 14, and 13, respectively. In-hospital follow-up imaging in nine patients demonstrated increased pathologic findings, but subsequent imaging showed stable or decreasing blood, and none experienced a neurologic decline or underwent a neurosurgical procedure.Among those with no other injuries (ISS = 9, n = 118) patients spent a mean of 2.0 (95% confidence interval, 1.1-2.9) days in intensive care unit and 4.9 (95% confidence interval, 3.9-6.0) days in hospital. The likelihood of discharge home was significantly related to age (p < 0.0001), ISS (p < 0.01), and admission GCS (p < 0.01) (stepwise logistic regression), but not progression of SAH.At 6-week follow-up, one patient (0.2%) developed bilateral chronic subdurals requiring drainage, without neurologic sequela.

In this largest reported series to date of iSAH in the setting of mild traumatic brain injury, the finding seems to be benign and can likely be managed without routine follow-up imaging or intensive care unit admission in the absence of other significant trauma.

Epidemiologic/prognostic study, level III; therapeutic study, level IV.