Cerebral Venous Outflow Implications in Idiopathic Intracranial Hypertension-From Physiopathology to Treatment

Ultrasound-guided initial diagnosis and follow-up of pediatric idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension in children often presents with non-specific symptoms found in conditions such as hydrocephalus. For definite diagnosis, invasive intracranial pressure measurement is usually required. Ultrasound (US) of the optic nerve sheath diameter provides a non-invasive method to assess intracranial pressure. Transtemporal US allows imaging of the third ventricle and thus assessment for hydrocephalus.

OBJECTIVE

To investigate whether the combination of US optic nerve sheath and third ventricle diameter can be used as a screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure and exclude hydrocephalus as an underlying pathology. Further, to analyze whether both parameters can be used to monitor treatment outcome.

MATERIALS AND METHODS

We prospectively included 36 children with idiopathic intracranial hypertension and 32 controls. Using a 12-Mhz linear transducer and a 1-4-Mhz phased-array transducer, respectively, optic nerve sheath and third ventricle diameters were determined initially and during the course of treatment.

RESULTS

In patients, the mean optic nerve sheath diameter was significantly larger (6.45±0.65 mm, controls: 4.96±0.32 mm) and the mean third ventricle diameter (1.69±0.65 mm, controls: 2.99±1.31 mm) was significantly smaller compared to the control group, P<0.001. Optimal cut-off values were 5.55 mm for the optic nerve sheath and 1.83 mm for the third ventricle diameter.

CONCLUSIONS

The combined use of US optic nerve sheath and third ventricle diameter is an ideal non-invasive screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure while ruling out hydrocephalus. Treatment can effectively be monitored by repeated US, which also reliably indicates relapse.

Reversible Bilateral Transverse Sinus Occlusion Treated by Lumboperitoneal Shunt in Idiopathic Intracranial Hypertension: A Case Report

We report a patient with idiopathic intracranial hypertension (IIH) with bilateral transverse sinus occlusion treated by a lumboperitoneal shunt. A 45-year-old woman presented with visual disturbance and chronic headache. Magnetic resonance (MR) venography and three-dimensional computed tomography angiography (3D-CTA) showed occlusion of both transverse sinuses. After the surgery, MR venography and 3D-CTA showed no blockages in both transverse sinuses. This phenomenon reveals that obstruction of the bilateral transverse sinus is a consequence of intracranial hypertension, not just a single cause. Since many patients have an obstruction or stenosis of the venous sinus, there are some reports of endovascular treatment. Sinus reconstruction is usually effective, but it is not effective in some cases. Reversal of sinus occlusion suggests that endovascular therapy for IIH is inadequate in some cases.

Combined surgical repair and venous sinus stenting for patients with skull base encephaloceles secondary to dural venous sinus stenosis

BACKGROUND

Chronically elevated intracranial pressure (ICP) seen in idiopathic intracranial hypertension (IIH) can cause the development of skull base encephaloceles and cerebrospinal fluid (CSF) leaks. Surgical repair and ventriculoperitoneal shunt (VPS) placement are mainstays of treatment. Venous sinus stenting (VSS) is a newly accepted treatment modality. The goal of this study was thus to determine if VSS can be used to treat symptoms and prevent recurrence after surgical encephalocele repair.

METHODS

Retrospective chart review of patients that had surgical repair of encephaloceles followed by VSS for symptomatic stenosis with elevated pressure gradient.

RESULTS

A total of 13 patients underwent a combined encephalocele repair and VSS. Seventy-two percent were female; 46% had headaches, 69% pulsatile tinnitus, and 92% CSF rhinorrhea or otorrhea. One had seizures. Mean lumbar opening pressure was 23.3 ± 2.6 cm H2O; the average sagittal-to-jugular pressure gradient was 12.7 ± 1.8 cmH2O and was elevated in all patients. Four patients had middle fossa craniotomy for repair of tegmen defect (one bilateral); one had a retrosigmoid craniotomy for repair of a sigmoid plate defect. Eight had an endoscopic endonasal repair for sphenoid or cribriform plate encephalocele. There were no VSS procedural complications or complications associated with dual antiplatelet therapy. One patient had meningitis after endoscopic repair that was treated with antibiotics. One patient had recurrence of both CSF leak and venous stenosis adjacent to the stent requiring repeat repair and VSS. There was no further recurrence.

CONCLUSION

In patients with dural sinus stenosis and encephaloceles requiring repair, VSS can be performed safely within weeks of surgery for relief of symptoms, resolution of underlying pathology, and prevention of CSF leak recurrence.

Postoperative Diabetes Insipidus Mimicking Radiological Findings and Symptoms of Intracranial Hypotension: A Case Report

Endocrine disturbances such as diabetes insipidus (DI) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) are recognized complications of craniopharyngioma surgery, which occur due to damage to structures that produce or store antidiuretic hormone (ADH). Intracranial hypotension is a clinical syndrome that presents with headache and typical radiological features and can occur due to a leak of cerebral spinal fluid (CSF) in operations that involve the opening of the arachnoid (e.g., craniopharyngioma surgery). We describe a patient presenting with headache, radiological evidence of intracranial hypotension, and chronic DI after craniopharyngioma surgery. This occurred in the absence of evidence of a CSF leak. The headache and radiological findings resolved after the identification and treatment of DI. Intracranial hypotension may have occurred secondary to dehydration in chronic DI. A 48-year-old woman presented with progressive visual field loss due to cystic recurrence of a craniopharyngioma. She underwent redo (second) extended endoscopic transsphenoidal surgery, having previously undergone an uncomplicated debulking procedure two years prior. Her redo operation was uneventful, and her vision improved postoperatively. A lumbar drain was placed preoperatively to protect the skull base repair and was removed after 48 hours. In the initial postoperative period, she developed a clinical (polyuria) and biochemical picture consistent with DI, subsequently reverting to a SIADH, after which fluid and sodium homeostasis appeared to normalize, and she was discharged. Two months after discharge, she re-presented with new headaches eased by lying flat. Magnetic resonance imaging (MRI) brain showed bilateral convexity subdural effusions and diffuse pachymeningeal enhancement, suggesting intracranial hypotension and raising concern for postoperative CSF leak. MRI spine did not show a CSF fistula at the site of the previous lumbar drain. Transsphenoidal examination under anesthesia showed a well-healed skull base repair and no evidence of CSF leak. She concurrently reported polyuria and polydipsia. A formal water deprivation test confirmed central DI. Treatment with desmopressin improved her headache, and a follow-up MRI brain showed resolution of the previous stigmata of intracranial hypotension. This case report reminds physicians and neurosurgeons that systemic disorders (such as dehydration) can cause intracranial hypotension.

Current and emerging diagnostic and management approaches for idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is characterized by raised intracranial pressure that triggers disabling headaches and can cause permanent visual loss. There is an increased incidence and prevalence of the condition linked to location-specific obesity rates. There are no licensed treatments for the condition. The majority of approaches to managing the disease prioritize resolution of papilledema. However, evidence is emerging that idiopathic intracranial hypertension is a systemic metabolic disease.

AREAS COVERED

The aim of this review is to present the emerging pathophysiology evidence which is leading to novel targeted therapeutics. The diagnostic pathway is outlined. The current and potential management approaches for idiopathic intracranial hypertension are also discussed.

EXPERT OPINION

Idiopathic intracranial hypertension is a condition with metabolic dysregulation with systemic manifestations that are present over and above what can be expl.ained by obesity alone. While most of the current management of this condition focuses on the eyes, future management needs to address the disabling headaches and the systemic risks of preeclampsia, gestational diabetes, and major cardiovascular events.

Pseudotumor Cerebri Postpartum: A Case Report

Idiopathic intracranial hypertension (IIH), called pseudotumor cerebri, could cause postpartum headaches. Generally, this diagnosis is idiopathic and treatment is mainly medical to avoid serious complications of possible vision loss. In this paper, we report the case of a 24-year-old lady who developed a similar constellation of symptoms and was diagnosed with this condition. Postpartum, the patient demonstrated symptoms of headache and vision disturbances. Workup ruled out infectious processes and intracranial pathologies. Normal cranial magnetic resonance imaging (MRI) and high cerebrospinal fluid (CSF) pressure during lumbar puncture led to a diagnosis of IIH. Initiation of medication allowed rapid improvement of symptoms and evaded imminent morbidity. Further discussion in light of the latest findings of the literature is held after the presentation of the case. This case sheds light on the importance on importance of fundoscopy in patients demonstrating new-onset headaches especially postpartum with the absence of intracranial pathologies.

Cerebrospinal fluid (CSF) and idiopatic intracranial hypertension (IIH): a critical review

Pseudotumor cerebri is a syndrome that results from increased intracranial pressure. The main symptoms are headache, vision disturbances, and pulsatile tinnitus. Definitive diagnosis requires the presence of clinical and/or radiological signs of intracranial hypertension, high opening pressure on lumbar puncture (LP), and normal CSF constitution. Several studies have evaluated new contributions of CSF in the clinical evaluation and the in understanding of the pathophysiology of pseudotumor cerebri. Such studies have included the analysis of inflammatory biomarkers, adipokines, proteomic analysis, and CSF flow studies. In this review, we present the main results obtained so far and critically discuss the present status and the potential role of research involving the CSF in this condition. Based on current knowledge, it is possible to conclude that CSF research with new biomarkers has not yet provided information that can be employed in clinical practice at this moment. However, a better understanding of the constitution and dynamics of CSF circulation in patients with pseudotumor cerebri has brought some information about this condition and can potentially improve our knowledge about this condition in the future.