Neurosurg Focus 9 (1):Article 8, 2000, Click here to return to Table of Contents Spontaneous spinal cerebrospinal fluid leaks: a review WOUTER I. SCHIEVINK, M.D. Cedars-Sinai Neurosurgical Institute, Los Angeles, and Department of Neurosurgery, University of California, Irvine, California Spontaneous intracranial hypotension has become a well-recognized clinical entity, but it remains an uncommonly, and probably underdiagnosed, cause of headache; its estimated prevalence is only one in 50,000 individuals. The clin- ical spectrum of spontaneous intracranial hypotension is quite variable and includes headache, neck stiffness, cranial nerve dysfunction, radicular arm pain, and symptoms of diencephalic or hindbrain herniation. Leakage of the spinal cerebrospinal fluid (CSF) is the most common cause of spontaneous intracranial hypotension. A combination of an underlying weakness of the spinal meninges and a more or less trivial traumatic event is often found to cause this event in these patients. Typical magnetic resonance imaging findings include diffuse pachymeningeal enhancement, sub- dural fluid collections, and downward displacement of the brain, sometimes mimicking a Chiari I malformation. Opening pressure is often, but not always, low, and examination of CSF may reveal pleocytosis, an elevated protein count, and xanthochromia. The use of myelography computerized tomography scanning is the most reliable method for the accurate localization of the CSF leak. Most CSF leaks are found at the cervicothoracic junction or in the tho- racic spine. The initial treatment of choice is a lumbar epidural blood patch, regardless of the location of the CSF leak. If the epidural blood patch fails, the blood patch procedure can be repeated at the lumbar level, or a blood patch can be directed at the exact site of the leak. Surgical repair of the CSF leak is safe and generally successful, although a dis- tinct structural cause of the leak often is not found. KEY WORDS • cerebrospinal fluid leak • Chiari malformation • headache • hypotension • intracranial pressure • Marfan syndrome When a person is in the upright position, intracranial ous intracranial hypotension, its clinical spectrum, meth- pressure is negative.9 Intracranial hypotension is defined ods of diagnosis, and approaches to treatment. as an abnormally low intracranial pressure, and it is char- acterized by headaches that worsen when standing and improve when lying down. The occurrence of such pos- EPIDEMIOLOGICAL CHARACTERISTICS ture-related headaches is well known to all physicians Spontaneous intracranial hypotension is an increasing- in individuals who have undergone lumbar puncture as ly diagnosed cause of headaches, and more than half of well as to neurosurgeons, in particular, who observe these documented cases have been reported during the last de- headaches in patients following craniospinal traumatic cade.4,8,15,21,29,30,36,38,40,49,54,62,63,68,70,81,84 In the past, sponta- injury or CSF shunt placement. Although a spontaneous neous intracranial hypotension was probably underdiag- form of intracranial hypotension was described more than 67 nosed, and it is not likely that there has been an actual 60 years ago, it has only been recently that this condition increase in its incidence, although that possibility cannot has become a well-recognized clinical entity. Spontaneous be excluded. Comprehensive epidemiological studies intracranial hypotension is also known as essential aliqu- have not been reported, but the prevalence of spontaneous orrhea, spontaneous hypoliquorrhea, and Schaltenbrand 67 intracranial hypotension in Olmsted County, MN, in 1995 syndrome. Georg Schaltenbrand was the German phy- was estimated at approximately one in 50,000 individu- sician who first described patients with spontaneously als.71 Spontaneous intracranial hypotension affects women occurring low CSF pressures, but his role in the Third Reich77 should preclude the eponym from being used. more frequently than men, and the onset of symptoms typ- ically occurs in the fourth or fifth decade of life.4,8,16,22,30, In this review I discuss recent developments in our un- 37,39,41,50,55,63,64,69,71,72,82,85 derstanding of the causes and pathogenesis of spontane- CAUSES AND PATHOGENESIS Abbreviations used in this paper: CSF = cerebrospinal fluid; CT = computerized tomography; MR = magnetic resonance. Spontaneous spinal CSF leaks are the most common Neurosurg. Focus / Volume 9 / July, 2000 1 Unauthenticated | Downloaded 09/29/21 02:02 PM UTC W. I. Schievink TABLE 1 Precipitating events in 29 patients with spinal CSF leaks and intracranial hypotension Cause No. of Cases roller-coaster ride 1 white-water rafting 1 bumped into table during a brawl 1 jet-skiing 1 childbirth 1 weight lifting 1 playing volleyball 1 sexual intercourse 1 jogging 1 fall on buttocks while roller-blading 1 Fig. 1. Photograph showing a representative case of a general- ized connective tissue disorder in spontaneous intracranial hypo- 70 tension. Arachnodactyly and joint hypermobility were present in cause of spontaneous intracranial hypotension. Because this 30-year-old woman with a spontaneous CSF leak at the thora- these CSF leaks generally do not cause any other symp- columbar junction. toms, they often remain undetected. Other causes of symptomatic spontaneous intracranial hypotension, such as spontaneous CSF rhinorrhea or otorrhea, diabetic co- ma, or uremia, are less common, and their diagnosis is us- neous intracranial hypotension, and a decrease in CSF ually straight forward because of the obvious associated volume, rather than in CSF pressure, may be the final symptomatology. common pathway. The exact cause of spontaneous spinal CSF leaks large- ly remains unknown, but an underlying weakness of the spinal meninges is generally suspected,69–73 and a more or CLINICAL PRESENTATION less trivial traumatic event often precedes the onset of symptoms (Table 1).4,23,49,52,69 The structural dural weak- Posture-Related Headache ness predisposes to the formation of fragile meningeal The clinical hallmark of intracranial hypotension is the diverticula or simple dural rents that allow CSF to leak presence of an orthostatic headache that, according to the into the extradural space. There is good evidence to sug- criteria of the International Headache Society,27 should gest that a generalized connective tissue disorder may play “occur or worsen less than 15 minutes after assuming an important role in the development of spontaneous spi- the upright position, and disappear or improve less than nal CSF leaks and intracranial hypotension, as first report- 30 minutes after resuming the recumbent position.” The ed in 1994.72 In approximately one fifth of patients with onset of the individual’s headache generally is gradual or spontaneous CSF leaks and intracranial hypotension, sub- subacute and often is first noted upon arising in the morn- tle skeletal abnormalities are commonly observed such as ing. However, in some patients the onset is acute (“thun- those seen in Marfan syndrome—tall stature, joint hyper- derclap” headache), and such patients often will have mobility, and arachnodactyly—but no other stigmata of undergone cranial CT scanning and cerebral angiography the syndrome are found in these patients (Fig. 1).70,72,73 In to rule out an aneurysmal subarachnoid hemorrhage. The some of these patients an abnormality of fibrillin metabo- severity of the headache varies widely, and many mild lism is expressed.75 Another associated finding, suggest- cases undoubtedly are never diagnosed. On the other ing the presence of a generalized connective tissue dis- hand, the headaches may become quite incapacitating, order, is the occurrence of spontaneous retinal detachment preventing the patient from engaging in any useful activi- at an early age in patients with spontaneous CSF leaks.70 ty while in the upright position. Such patients will charac- Moreover, meningeal diverticula and spontaneous in- teristically present in a recumbent position to their physi- tracranial hypotension have been described in several cians’ offices. The headache may be generalized or it may well-characterized, generalized connective tissue disor- be localized to the frontal or (sub)occipital regions. The ders such as autosomal dominant polycystic kidney dis- headache most likely is a direct result of the decrease in ease,75 Marfan syndrome,13,18,22 neurofibromatosis type CSF volume and the downward displacement of the brain, 1,17,42 and Lehman syndrome.37,58 which causes traction on pain-sensitive structures, partic- In rare circumstances spontaneous spinal CSF leaks are ularly the intracranial dura that is supplied by the trigem- caused by an extradural pathological entity, such as a bone inal, glossopharyngeal, and vagal nerves, as well as the spur that pierces the dura.16,83 upper cervical nerve roots.19,33 In the past, some authors have speculated that spontane- Although all patients in all major series have presented ous intracranial hypotension results from decreased CSF with orthostatic headaches it is well known that this pos- secretion or generalized CSF hyperabsorption.34,35,40,67,68 ture-related component often becomes less prominent However, there are no data to support how these alternate or even disappears over time when the intracranial hypo- mechanisms lead to a decrease in CSF pressure. Much re- tension is left untreated and becomes chronic.49,70 Rarely, mains to be learned about the pathophysiology of sponta- patients with spontaneous intracranial