Low-Pressure Hydrocephalus After Traumatic Brain Injury: A Case Series and Scoping Review

Background/Objectives: Low-pressure hydrocephalus (LPH) is an underappreciated pathology in which patients present with ventriculomegaly and intracranial pressures (ICPs) below normal, making traditional pressure-driven cerebrospinal fluid diversion treatment strategies challenging. LPH has been observed in patients following traumatic brain injury (TBI), often within the neurocritical care unit (NCCU). However, its presentation and associated patient characteristics remain unclear. Thus, we sought to compile patients from our institution and the literature to characterize LPH after TBI. Methods: Eleven patients were identified from our institutional chart review. Additionally, we performed a scoping review using PRISMA guidelines, which yielded eight publications, resulting in a total of 46 patients with LPH after TBI. Results: The median age was 34 years (IQR 23 to 50.75), with 86.96% male. When used, ventriculoperitoneal shunt (VPS) valves were programmed to a median pressure setting of 45 mmH₂O (IQR 22 to 45). The median Glascow Outcome Scale-Extended (GOSE) score at 2-6 months post-shunt was 3 (IQR 2.25 to 4), indicating lower-severe disability and a 16.28% mortality. Conclusions: To our knowledge, this is the largest curation of TBI patients with LPH to date. From this pooled cohort, we observed that patients affected by LPH after TBI are often young to middle-aged and undergo multiple neurosurgical procedures prior to LPH diagnosis. Outcomes were poor with significant long-term disability and mortality. Clinicians should consider LPH diagnosis in TBI patients with hydrocephalus, especially if they have undergone prior neurosurgical procedures. Additionally, providers should recognize that these patients may potentially require lower opening pressures or certain pharmacological interventions compared to those with traditional post-traumatic hydrocephalus. Improved recognition of LPH after TBI can advance the understanding of the underlying mechanisms and inform treatment strategies.