A Unique Subset: Idiopathic Intracranial Hypertension Presenting as Spontaneous CSF Leak of the Anterior Skull Base

Abstract

Background Spontaneous cerebrospinal fluid (CSF) leaks represent a unique clinical presentation of idiopathic intracranial hypertension (IIH), lacking classical features of IIH, including severe headaches, papilledema, and markedly elevated opening pressures. Methods Following a single-institution retrospective review of patients undergoing spontaneous CSF leak repair, we performed a literature review of spontaneous CSF leak in patients previously undiagnosed with IIH, querying PubMed. Results Our literature review yielded 26 studies, comprising 716 patients. Average age was 51 years with 80.8% female predominance, and average body mass index was 35.5. Presenting symptoms included headaches (32.5%), visual disturbances (4.2%), and a history of meningitis (15.3%). Papilledema occurred in 14.1%. An empty sella was present in 77.7%. Slit ventricles and venous sinus stenosis comprised 7.7 and 31.8%, respectively. CSF leak most commonly originated from the sphenoid sinus (41.1%), cribriform plate (25.4%), and ethmoid skull base (20.4%). Preoperative opening pressures were normal at 22.4 cm H2O and elevated postoperatively to 30.8 cm H2O. 19.1% of patients underwent shunt placement. CSF leak recurred after repair in 10.5% of patients, 78.6% involving the initial site. A total of 85.7% of these patients were managed with repeat surgical intervention, and 23.2% underwent a shunting procedure. Conclusion Spontaneous CSF leaks represent a distinct variant of IIH, distinguished by decreased prevalence of headaches, lack of visual deficits, and normal opening pressures. Delayed measurement of opening pressure after leak repair may be helpful to diagnose IIH. Permanent CSF diversion may be indicated in patients exhibiting significantly elevated opening pressures postoperatively, refractory symptoms of IIH, or recurrent CSF leak.

Spontaneous rhinorrhea and idiopathic intracranial hypertension: a complex and challenging association

“…Leading Topic Editor: Olga P. Fermo, MD, Department of Neurology, Mayo Clinic, Jacksonville, Florida, United States unknown causes [1,2]. Primary spontaneous CSF leaks represent a unique subset of this condition, characterised by specific features including its target demographic and a high recurrence rate, of 2.9-46% after repair, compared to other types of CSF leak [3,4].…”

“…Although not all patients with SCSFR have idiopathic intracranial hypertension (IIH), the connection between them was first proposed in 1994 by Clark et al, who identified female gender and obesity as significant risk factors due to their potential to increase intraabdominal pressure, thereby impairing venous return and elevating intracranial pressure (ICP) [6]. Subsequent research has suggested a link between chronic elevated ICP and secondary skull base bony erosion leading to leakage [1,3,7]. Recognising and understanding this relationship is crucial for improving treatment outcomes.…”

Expanding the clinical spectrum of idiopathic intracranial hypertension

“…Chronic congestion of the lymphatic CSF as it travels through the sheaths of the cranial nerves, around the olfactory bulb, is thought to contribute to erosion of the cribriform plate [57 & ]. It is difficult to make a preoperative diagnosis of IIH in patients with spontaneous CSF leak, as 14% of patients have papilledema preoperatively and CSF pressure is frequently below the cut-off set out in the diagnostic criteria for IIH [58]. Postoperatively, not all patients with spontaneous CSF leak will develop papilledema or fulfil diagnostic criteria for IIH [53 & ].…”

“…It is difficult to make a preoperative diagnosis of IIH in patients with spontaneous CSF leak, as ∼14% of patients have papilledema preoperatively and CSF pressure is frequently below the cut-off set out in the diagnostic criteria for IIH [ 58 ]. Postoperatively, not all patients with spontaneous CSF leak will develop papilledema or fulfil diagnostic criteria for IIH [ 53 ▪ ].…”

“…Bilateral transverse venous sinus stenosis is a highly sensitive imaging marker of IIH found in almost all patients with IIH [ 6 ]; and venous sinus stenting (VSS) has emerged as an effective alternative treatment for a subset of patients with medically refractive IIH [ 62 ]. Some institutions have incorporated VSS into the management of patients with spontaneous CSF leak, either as a standalone procedure or as an adjunct to surgical repair as part of the treatment for elevated ICP [ 58 , 63 ]. There is insufficient evidence to support this practice in all patients with spontaneous CSF leak.…”