Selvan, RPandey, NNandhini, MHrishikaanthan, SS.2025-06-182025-06-182025-06Selvan R, Pandey N, Nandhini M, Hrishikaanthan SS.. Chiari 1.5 malformation: a case report and review of literature. International Journal of Advances in Medicine. 2025 Jun; 12(3): 320-3222349-39252349-3933https://imsear.searo.who.int/handle/123456789/248366Chiari 1.5 malformation, a rare neurological disorder, involves cerebellar tonsil herniation and slight brainstem descent through the foramen magnum. A 25-year-old woman presented with recurrent headaches exacerbated by coughing, straining, and difficulty in maintaining head posture despite normal motor functions and reflexes. MRI revealed a Chiari 1.5 malformation with a 13.5 mm cerebellar tonsil herniation, minor brainstem descent, and C2-C3 vertebrae fusion. Suboccipital craniectomy with foramen magnum decompression significantly alleviated her symptoms. This case emphasizes the importance of recognizing Chiari 1.5 malformation as a cause of headaches in young adults and supports surgical intervention to prevent neurological decline. Although the aetiology is unknown, theories suggest a pressure differential between the cranial and spinal subarachnoid spaces during fetal development. Early diagnosis and posterior fossa decompression are crucial for symptom management and outcome improvement in CHIARI 1.5.Chiari 1.5 malformationHeadachesCerebellar tonsils herniationBrainstem descentJournal ArticleIndiaDepartment of General Surgery, Jeyasekharan Medical Trust and Hospital, Nagercoil, Tamil Nadu, IndiaDepartment of General Surgery, Jeyasekharan Medical Trust and Hospital, Nagercoil, Tamil Nadu, IndiaDepartment of General Surgery, Jeyasekharan Medical Trust and Hospital, Nagercoil, Tamil Nadu, IndiaDepartment of General Medicine, Chettinad Hospital and Research Institute, Tamil Nadu, India