Two cases of cerebrospinal fluid hypovolemia that had been interpreted as orthostatic dysregulation

Children with cerebrospinal fluid (CSF) hypovolemia can exhibit various symptoms, with the most common ones being headache and vertigo; further, it is often misdiagnosed as orthostatic dysregulation (OD). This article describes two cases of CSF hypovolemia that were interpreted as OD. Both patients, including a previously healthy 13-year-old boy and an 11-year-old girl, presented with orthostatic headaches and participated in sports activities, such as tennis and basketball. Both patients were considered to have OD given their diagnosis of postural orthostatic tachycardia syndrome using a new orthostatic test. However, the symptoms did not improve after OD treatment; they were diagnosed with CSF hypovolemia based on radioisotope cisternography and computed tomography myelography. Both patients were treated with epidural blood patches (EBPs), which significantly improved their prognoses. We report two cases of cerebrospinal fluid hypovolemia that improved with treatment with EBP. When a patient is diagnosed with OD and shows no response to lifestyle guidance and medication, considering cerebrospinal fluid hypovolemia as one of the differential diseases is essential.