Lumbar puncture rapidly improves olfaction in patients with idiopathic intracranial hypertension: A cohort study.

BACKGROUND: A lumbar puncture constitutes an important diagnostic procedure in the evaluation of idiopathic intracranial hypertension. Chronic overflow of cerebrospinal fluid into the sheaths of the olfactory nerves appears to be related to olfactory impairment in these patients. Here, we asked whether cerebrospinal fluid drainage in idiopathic intracranial hypertension patients improves olfactory function. METHODS: Fourteen idiopathic intracranial hypertension patients and 14 neurologic control patients were investigated before and after lumbar puncture using the extended Sniffin' Sticks procedure. We assessed odor threshold, discrimination, and identification. In idiopathic intracranial hypertension patients, cerebrospinal fluid was drained until cerebrospinal fluid pressure had normalized. In addition, a third group of 14 healthy controls participated in the two smell tests at similar intervals. RESULTS: Relative to healthy controls, threshold, discrimination, and identification composite scores before lumbar puncture were significantly lower in idiopathic intracranial hypertension patients and also in neurologic controls. Following lumbar puncture, threshold, discrimination, and identification scores for neurologic controls remained unchanged whereas idiopathic intracranial hypertension patients showed robust improvement on the composite score as well as on all three subscores (all changes: p < 0.003), quickly regaining olfactory function in the normal range. Cerebrospinal fluid opening pressure was significantly correlated with improvement in threshold, discrimination, and identification score upon cerebrospinal fluid drainage (r = 0.609, p = 0.021). CONCLUSION: Olfactory impairment is an important, yet underappreciated, clinical feature of idiopathic intracranial hypertension. Lowering of increased intracranial pressure improves hyposmia. Our findings shed new light on the pathophysiology of cerebrospinal fluid circulation in idiopathic intracranial hypertension.

The effect of CSF drain on the optic nerve in idiopathic intracranial hypertension.

BACKGROUND: Elevation of intracranial pressure in idiopathic intracranial hypertension induces an edema of the prelaminar section of the optic nerve (papilledema). Beside the commonly observed optic nerve sheath distention, information on a potential pathology of the retrolaminar section of the optic nerve and the short-term effect of normalization of intracranial pressure on these abnormalities remains scarce. METHODS: In this exploratory study 8 patients diagnosed with idiopathic intracranial hypertension underwent a MRI scan (T2 mapping) as well as a diffusion tensor imaging analysis (fractional anisotropy and mean diffusivity). In addition, the clinical presentation of headache and its accompanying symptoms were assessed. Intracranial pressure was then normalized by lumbar puncture and the initial parameters (MRI and clinical features) were re-assessed within 26 h. RESULTS: After normalization of CSF pressure, the morphometric MRI scans of the optic nerve and optic nerve sheath remained unchanged. In the diffusion tensor imaging, the fractional anisotropy value was reduced suggesting a tissue decompression of the optic nerve after lumbar puncture. In line with these finding, headache and most of the accompanying symptoms also improved or remitted within that short time frame. CONCLUSION: The findings support the hypothesis that the elevation of intracranial pressure induces a microstructural compression of the optic nerve impairing axoplasmic flow and thereby causing the prelaminar papilledema. The microstructural compression of the optic nerve as well as the clinical symptoms improve within hours of normalization of intracranial pressure.

Does IIH Alter Brain Microstructures? - A DTI-Based Approach.

INTRODUCTION: To investigate the correlation of microstructural parameters with CSF pressure and macroscopic changes assessed by diffusion tensor imaging (DTI) in patients with idiopathic intracranial hypertension (IIH). METHODS: Twenty-three patients with IIH as well as age-, sex-, and body mass index (BMI)-matched controls underwent high resolution MR imaging of the optic nerve sheaths (ONS), pituitary gland, and ventricles. For DTI data a voxelwise permutation analysis was performed for the whole brain and ROI analysis was performed for the optic nerve and optic radiation. DTI measurements were correlated to morphometric measurements, CSF opening pressure, and headache intensity. The reliability of diagnostic performance of DTI parameters was assessed using ROC analysis. RESULTS: Analysis of DTI metrics revealed a significant reduction in the fractional anisotropy (FA) of the optic nerve in patients with IIH. In contrast, systematic regional variations between IIH patients and controls were neither observed in the whole brain analysis nor in the optic radiation. FA values of the optic nerve show significant correlations with the optic nerve sheath diameter (P = .003, r = -.589). The correlation of the alterations of the FA values of the optic radiation and the whole brain do not show a significant association to morphometric alterations in the ONS diameter and hypophysis height as well as to CSF opening pressure and headache intensity. CONCLUSIONS: The results indicate that IIH is associated with microstructural changes in the optic nerve. These alterations may be the direct consequence of chronically elevated intracranial pressure.

Obesity and pituitary gland volume - a correlation study using three-dimensional magnetic resonance imaging.

PURPOSE: Obesity has become a major health problem and is associated with endocrine disorders and a disturbed hypothalamic-pituitary axis. The purpose of this study was to correlate pituitary gland volume determined by routine magnetic resonance imaging with patient characteristics, in particular body mass index and obesity. MATERIAL AND METHODS: A total of 144 'healthy' patients with normal findings in cerebral magnetic resonance imaging were retrospectively included. Pituitary gland volume was measured in postcontrast three-dimensional T1-weighted sequences. A polygonal three-dimensional region of interest covering the whole pituitary gland was assessed manually. Physical characteristics (gender, age, body height and body mass index) were correlated with pituitary gland volume. Multiple subgroup and regression analyses were performed. RESULTS: Pituitary gland volumes were significantly larger in females than in males (p<0.001) and young individuals (<35 years) versus middle-aged patients (35-47 years) (p=0.042). Obese patients (body mass index ≥30) had significantly larger pituitary gland volumes than overweight (250.05). Regression analysis showed that increased pituitary gland volume is associated with higher body mass index independent from gender, age and body height. CONCLUSION: Pituitary gland volume is increased in obese individuals and a high body mass index can be seen as an independent predictor of increased pituitary gland volume. Therefore, gland enlargement might be an imaging indicator of dysfunction in the hypothalamus-pituitary axis. Besides gender and age, body mass index should be considered by radiologists when diagnosing abnormal changes in pituitary gland volume.