Analysis Of Clinical Characteristics Of Spontaneous Intracranial Hypotension And Cerebrospinal Fluid Leakage

ObjectiveThe aim of the study is to reveal the clinical features of spontaneous intracranial hypotension（SIH）by retrospectively analyzing the data of hospitalized SIH patients in a single center.This can enhance our understanding of manifestation,prognosis,as well as optimized treatment strategy for SIH.MethodsThe study is of retrospective,observational design.SIH was diagnosed according tocriteria.SIH patients admitted to the Department of Neurology,Fujian Provincial Hospital between March 2010 and October 2020 were recruited.The clinical data including symptoms,neurology imaging data,RNC,treatment and short-term prognosis was analyzed.Results1.A total of 52 SIH patients were hospitalized during the study period,including22 males and30 females,with the gender ratio of 1:1.36.The age of the patients ranged from 21 to 81 years,with an mean age of 42.37±14.30years,The population aged between 26 and 45 years accounted for 57.7%.An acute or sub-acute onset was seen in 80.8%of the patients,and most patients had not any clear preceding cause.SIH is mainly manifested by orthostatic headache（78.8%）accompanied by nausea and vomiting（65.4%）,dizziness（30.8%）and other symptoms.Some patients had atypical symptoms.Neck stiffness（23.1%）was the most common neurological finding..On admission,11 patients（21.2%）were misdiagnosed,most of which were misdiagnosed as intracranial infection（36.4%）,subarachnoid hemorrhage（SAH）（36.4%）,intracranial venous sinus thrombosis（cerebral venous sinus thrombosis,CVST）（18.2%）and so on.2.Cerebrospinal fluid（CSF）and other laboratory examination:routine blood test and blood biochemistry was generally normal.Some patients have mild hypokalemia and low sodium manifestations.CSF pressure lower than 60mm H₂O,60-70（not including 70）,70-80（not including 80）and 80-180mm H₂O was seen in 30 cases（57.7%）,,8 cases,3 cases,and 11 cases respectively.There were 24 cases with elevated cerebrospinal fluid red blood cell counts,14 cases with elevated white blood cell counts,and 27 cases with elevated cerebrospinal fluid biochemical total protein results;all patients had normal chloride and glucose tests,ink staining and acid-fast staining results.3.Routine imaging examination:The most common changes in brain imaging of SIH patients are pachymemningeal thickening and enhancement（34.6%）and subdural fluid collection（19.2%）.Other common manifestations include pituitary hyperemia and sagging of the brain.Spinal MRI imaging manifestations include:spinal dural enhancement（13.0%）,epidural fluid collection（4.3%）,nerve root sleeve sheath expansion（4.3%）,etc.Cerebrospinal fluid leakage in patients with SIH can not be detected by MRI.4.RNC combined with SPECT/CT to determine the site of leakage:Among 23 patients who underwent RNC with SPECT/CT examination,cerebrospinal fluid leakage was reveal in 18 cases,with a positive rate of 78.3%.Among them,direct cerebrospinal fluid leakage was found in11 cases（61.1%）,after SPECT/CT positioning,the most common cerebrospinal fluid leakage site was located in the thoracic spinal cord（45.5%,5/11）,and 7 cases were indirect evidence of cerebrospinal fluid leakage.5.RNC’s identification of different types of cerebrospinal fluid leakage:according to the number of cerebrospinal fluid leakage sites and the quantitative results of radionuclide leakage,the cerebrospinal fluid leakage of SIH patients can be classified as:high-flow cerebrospinal fluid leakage（1 case）,multiple low-flow cerebrospinal fluid leakage（2 cases）,single low-flow cerebrospinal fluid leakage（8 cases）,intermittent cerebrospinal fluid leakage（1 case）,and indirect cerebrospinal fluid leakage（7 cases）.The RNC results of the other 5 patients were unremarkable.6.Treatment and prognosis:52 patients were treated conservatively,with large amounts of fluid admininstration daily,and some use small doses of dexamethasone in combination.The course of treatment lasted from 1 to 33 days,with an average lenghth of 13.8±8.0 days.51 patients had a good prognosis at discharge.Only 1 patient with high-flow cerebrospinal fluid leakage was admitted to the hospital for a second time due to headache.Conclusion1.Orthostatic headache is a common manifestation of SIH patients,but some patients are not typical and easy to be misdiagnosed.Clinically,attention should be paid to differential diagnosis.For patients with atypical symptoms,lumbar puncture should be performed as soon as possible.2.Low CSF pressure in the lateral position can be absent in SIH.For suspected patient with normal CSF pressure,neuroimagng should be performed to determine the presence of cerebrospinal fluid leakage.3.Cranial MRI has high sensitivity for SIH patients,and it can reveal secondary abnormalities of low intracranial pressure such as dural enhancement,sagging of brain,dural thickening,and subdural fluid collection.It is the first line technique to recognize SIH.Spinal MRI examination is not sensitive to spinal cerebrospinal fluid leakage,and it is not used to make quantitative measurement the leakage and determine the site of the leakage.4.RNC with SPECT/CT is currently a more suitable imaging method to determine whether patients have cerebrospinal fluid leakage.Compared with RNC alone to detect cerebrospinal fluid leakage,RNC with SPECT/CT scan can improve the diagnostic accuracy of SIH,by complementing the lack of spatial resolution of RNC and take advantage of its higher time resolution as well.5.RNC can detect different types of cerebrospinal fluid leakage,and has unique advantages in detecting intermittent cerebrospinal fluid leakage.It has the advantages of easy procedure,low radioactivity,and causing less discomfort to the patients.Moreover,in the process of identifying cerebrospinal fluid leakage,the clinical treatment and prognosis of SIH patients can be evaluated at the same time.6.The vast majority of SIH is self-limited,and the recovery is good after timely conservative treatment.Only one case of high-flow cerebrospinal fluid leakage in 52cases has poor prognosis despite of conservative treatment.RNC with SPECT/CT can be useful for selecting patients with high-flow leakage patients who need intervention.