Introduction: Paradoxical brain herniation (PBH) represents a rare and potentially life-threatening complication observed in individuals following decompressive craniectomy. Its diagnosis necessitates a high level of suspicion, combined with clinical and imaging evidence, such as midline shift, herniation, and a decreased Glasgow Coma Scale (GCS). Given the rarity and severity of this condition, we conduct a comprehensive literature review to identify all documented predisposing factors, clinical presentations, and appropriate clinical management. This review will serve as a guide for effective treatment strategies.

Case presentation: In this report, we document three cases of post-traumatic PBH following decompressive craniectomy. The patient's predisposing factor was a lumbar puncture, with two cases resolving after Terendlenburg repositioning, hydration, and elective cranioplasty. The third case developed PBH after external ventricular drainage (EVD) insertion. Although the patient's GCS improved after clamping the EVD and hydration, the patient ultimately succumbed to meningitis.

Clinical discussion: The primary clinical manifestations of PBH often encompass a diminished GCS alongside radiographic evidence of midline shift and brain herniation. Various precipitating factors have been associated with PBH after decompressive craniectomy, including CSF drainage, dehydration, and upright positioning, although instances of spontaneous PBH have been documented. Reported therapeutic strategies encompass rehydration, Trendelenburg positioning, temporary cessation of CSF drainage, and cranioplasty.

Conclusion: Given the infrequency of PBH and the potential for misdiagnosis with brain edema, it is imperative to consider this condition in every patient who experiences a decreased level of consciousness following decompressive craniectomy.