MRI in spontaneous intracranial hypotension

Figure 3. Follow-up complete resolution subdural effusions.
axial T2 weighted scan showing of the previously demonstrated
Figure 2. Coronal spin echo T2 weighted MRI scan (TR 2000 ms, TE 90 ms) showing the high signal subdural fluid along the convexities and beneath the tentorium.
RAD
APHERS
Radiography
(1996)
4, 61-63
CASE REPORT
Байду номын сангаас
MRI in spontaneous
Cathy Johnston
intracranial
hypotension
and Terence Featherstone
Spontaneous intracranial hypotension is a rare event. In addition to the classic features of postural headacheand low cerebrospinal fluid (CSF) pressure,a caseis presented with subdural fluid collections demonstratedby magnetic resonanceimaging (MRI) together with a review of the literature.
MRI
in spontaneous
intracranial
hypotension
63
(after which it may persist for several years) [7]. Thus, although the MRI appearances are often distinctive, the diagnosis is still most reliably confirmed by measurements of CSF pressure. Spontaneous intracranial hypotension is probably misdiagnosed or overlooked frequently because patients with this disease usually lack objective signs. This syndrome is a benign, usually self-limiting condition which often responds to bed rest, high fluid intake and salt [5]. The headache may also take several months to resolve. In refractory cases, placement of an epidural blood patch may be required and rarely a sizeable CSF leak may be demonstrated which requires surgical repair [2]. In conclusion, MRI has a proven role in the diagnosis of this condition since its differentiation from more sinister meningitic processes is important to avoid unnecessary invasive investigations and to allow prompt diagnosis and effective treatment.
62
Johnston
and
Featherstone
Figure 1. Axial spin echo T2 weighted cranial MRI scan (TR 2000 ms, TE 90 ms) showing bilateral high signal intensity subdural effusions overlying the convexities without appreciable mass effect.
Darling~on MRI Centre, Darlington Memorial NHS Trust, Hollylrurst Road, Darlington, County Durham, DL3 6FlX, U.K. (Received 15 October 1996; accepted 19 June 1997)
Discussion
Since Schaltenbrand’s original study, at. least 76 cases have been reported in the literature, of these, 57 were women and 19 men. This indicates that spontaneous intracranial hypotensioti decks
ated nausea. The headache was alleviated by lying flat. There was no relevant previous medical history and no recent head trauma. Examination was normal. Lumbar puncture revealed a CSF pressure of 50 mm H,O, 4 lymphocytes mm3, no red blood cells and normal glucose and protein concentrations. Unenhanced cranial CT was normal. Cranial MRI showed small bilateral subdural effusions dverlying the convexities and under the tentorium (Figs 1 and 2). There was no associated mass effect or tonsillar hemiation. Intravenous Gadolinium vyas not administered. On the basis of the clinical presentation and the MRI findings a diagnosis of intracranial hypotension secondary to a spontaneous spinal CSF leak was made. Conservative management with bed rest and analgesics proved successful and the headache slowly resolved. A repeat cranial MRI Scan 6 weeks later was entirely normal (Fig. 3). The patient remains well.
0 1996 The College of Radiographers
Case history
A @-year-old previously fit woman developed severe frontal headache of rapid onset with associ1076-6174/96/010061+03 516.00
women more often than men by a ratio of 3:1 [3]. Presentation is commoner in people in the third and fourth decades. The headache produced by spontaneous intracranial hypotension shows many similarities to that seen following a lumbar puncture. It is thought to be the result of a spontaneous CSF leak. These leaks have been demonstrated by isotope cistemography [a]. Although a structural
Key words: magnetic resonance imaging; intracranial hypotension;
subdural eftkion.
Introduction
Less than 80 cases of spontaneous intracranial hypotension have been reported in the medical literature since the original description by Schaltenbrand in 1938 [I]. Following the advent of MRI, spontaneous intracranial hypotension is being recognised more frequently and is thought to be produced by leakage of CSF from a defect in the spinal meninges [2]. The cardinal feature of this syndrome is headache which is improved or eliminated by lying down. In addition to postural headache, patients may have nausea, vomiting, neck stiffness, vertigo, tinnitis and photophobia. By definition, the CSF pressure is low, 60 mm H,O or less, even without a history of previous dural puncture. The CSF is, often normal but an elevated protein content and mild lymphocytosis have been reported [2]. Spontaneous intracranial hypotension is often self-limiting and it is important to be aware of this condition because CSF analysis and MRI abnormalities in these patients may cause unnecessary concern and result in unwarranted invasive investigations.