Difficult Diagnosis of Spontaneous Intracranial Hypotension with Nausea and Lower Abdominal Pain as Main Complaints: A Case Report

<b>Background and Clinical Significance</b>: Symptoms of spontaneous intracranial hypotension include orthostatic headaches due to decreased cerebrospinal fluid (CSF) levels. Here, we present a 24-year-old female admitted to an obstetrics and gynecology department with primary complaints of lower abdominal pain and dysmenorrhea with subsequent diagnosis of spontaneous intracranial hypotension (SIH). <b>Case Presentation</b>: The patient had experienced nausea and lower abdominal pain independent of her menstrual cycle 5 days before admission, for which she visited the emergency department 3 days later. On admission, her symptoms were temporarily relieved by administering analgesics; thus, she was discharged. However, later, the symptoms worsened. Consequently, she returned to the emergency department for further evaluation, including blood tests, imaging, and endoscopy, which revealed no nausea- or abdominal pain-related organic abnormalities. On day 10, she developed a headache, aggravated by lying in the supine position and improved by sitting. Additional history revealed a diagnosis of SIH owing to the worsening abdominal pain in the supine position. An ¹¹¹In CSF cavity scintigram showed no spinal fluid leakage; early intrabladder radioisotope (RI) accumulation was observed, and the residual 24 h CSF cavity RI was >30%. At a referral specialist hospital, an epidural saline infusion test was performed, which improved her headache and lower abdominal pain. Blood patch therapy improved her lower abdominal pain, headache, and dysmenorrhea. <b>Conclusions</b>: The final diagnosis was SIH, with symptoms attributed to CSF depletion. The patient also experienced rare paradoxical postural-related headaches and lower abdominal pain, aggravated by lying in the supine position, contributing to the final diagnosis.