Clinical characteristics and risk factors for bilateral lateral geniculate body pathology: a systematic review of the literature.

BACKGROUND: Case presentation of acute onset bilateral painless vision loss caused by bilateral infarction of the lateral geniculate bodies (LGB) and a systematic review of the literature. METHODS: A descriptive case report is presented on a 17-year-old female diagnosed with acute pancreatitis who developed acute onset bilateral painless vision loss. A systematic literature review of cases with bilateral LGB lesions was conducted across three electronic databases (PubMed/PubMed Central/MEDLINE, Scopus, and ScienceDirect). The review was conducted in concordance with PRISMA guidelines and prospectively registered on PROSPERO (CRD42022362491). RESULTS: The reported 17-year-old female was found to have MRI findings consistent with bilateral hemorrhagic infarction of the LGB and Purtscher-like retinopathy. A systematic literature review of bilateral LGB infarction yielded 23 records for analysis. 19/23 (82.6%) of reported cases occurred in women. Bilateral vision loss was noted in all cases. The average reported age was 27 years old with a range from 2-50. Gastrointestinal pathology (e.g., pancreatitis, gastroenteritis) was present in 8/23 (34.7%) of cases. 8/23 (34.7%) cases had neuroimaging or pathological evidence of hemorrhagic transformation of the infarct. Most cases experienced partial recovery of visual loss; only one case (4.7%) had complete visual recovery. 9/23 (39.1%) cases were reported from the United States and 4/23 (17.3%) from India. CONCLUSIONS: Bilateral LGB lesion is a rare cause of vision loss, typically caused by systemic diseases and with female preponderance. Purported pathophysiology relates to increased vulnerability of the LGB to ischemic and metabolic stress.

Do the mammillary bodies atrophy with aging? A magnetic resonance imaging study.

PURPOSE: This retrospective study aimed to explore age-related atrophy of the mammillary bodies (MBs) based on their temporal change using magnetic resonance imaging (MRI). MATERIALS AND METHODS: The study included 30 adult outpatients who presented to the hospital and were followed for more than 100 months with annual MRIs. The bi-ventricular width (BVW), third ventricle width (TVW), and bi-mammillary dimension (BMD) were measured on axial T2-weighted imaging and analyzed. RESULTS: The 30 patients comprised 1 in their 40s, 5 in their 50s, 6 in their 60s, 11 in their 70s, 5 in their 80s, and 2 in their 90s. The MBs were consistently detected with left-to-right symmetry. The mean BVW was 32 ± 2.2 mm on the initial (BVW1) and 32 ± 2.4 mm on the last (BVW2) MRI. The mean TVW was 7.0 ± 2.3 mm on the initial (TVW1) and 7.6 ± 2.7 mm on the last (TVW2) MRI. Furthermore, the mean BMD was 9.9 ± 1.3 mm on the initial (BMD1) and 10 ± 1.3 mm on the last (BMD2) MRI. Statistically, no age ranges had a large dimension for BVW1, BVW2, TVW1, TVW2, BMD1, or BMD2. Changes between TVW1 and TVW2 were significantly different in the patients in their 80s; changes between BMD1 and BMD2 were not different for any age range or between sexes. CONCLUSIONS: Aging alone does not seem to promote MB atrophy. In healthy brains, the MBs may be stationary structures throughout life.

High ethanol preference and dissociated memory are co-occurring phenotypes associated with hippocampal GABAAR-δ receptor levels.

Alcohol use disorder (AUD) frequently co-occurs with dissociative disorders and disorders with dissociative symptoms, suggesting a common neurobiological basis. It has been proposed that facilitated information processing under the influence of alcohol, resulting in the formation of dissociated memories, might be an important factor controlling alcohol use. Access to such memories is facilitated under the effect of alcohol, thus further reinforcing alcohol use. To interrogate possible mechanisms associated with these phenotypes, we used a mouse model of dissociative amnesia, combined with a high-alcohol preferring (HAP) model of AUD. Dissociated memory was induced by activation of hippocampal extrasynaptic GABA type A receptor delta subunits (GABAAR-δ), which control tonic inhibition and to which ethanol binds with high affinity. Increased ethanol preference was associated with increased propensity to form dissociated memories dependent on GABAAR-δ in the dorsal hippocampus (DH). Furthermore, the DH level of GABAAR-δ protein, but not mRNA, was increased in HAP mice, and was inversely correlated to the level of miR-365-3p, suggesting an miRNA-mediated post-transcriptional mechanism contributing to elevated GABAAR-δ. The observed changes of DH GABAAR-δ were associated with a severe reduction of excitatory projections stemming from GABAAR-δ-containing pyramidal neurons in the subiculum and terminating in the mammillary body. These results suggest that both molecular and circuit dysfunction involving hippocampal GABAAR-δ receptors might contribute to the co-occurrence of ethanol preference and dissociated information processing.

Atrophy of the ipsilateral mammillary body in unilateral hippocampal sclerosis shown by thin-slice-reconstructed volumetric analysis.

PURPOSE: Conventional volumetric analysis could not detect ipsilateral atrophy of the mammillary body in patients with unilateral hippocampal sclerosis. By using thin-slice-reconstructed volumetric analysis, we investigated whether the mammillary body volume is smaller on the hippocampal sclerosis side than in healthy subjects or the non-hippocampal sclerosis side. METHODS: This retrospective study included 45 patients with unilateral hippocampal sclerosis and 30 healthy subjects. Three-dimensional T1WI of 1 mm thicknesses were oversampled to a thickness of 0.2 mm (thin-slice-reconstructed images), and the mammillary bodies were segmented manually to determine mammillary body volume on each side. Mammillary body volumes on the hippocampal sclerosis side were compared with those in healthy subjects or the non-hippocampal sclerosis side. RESULTS: In patients with right hippocampal sclerosis, right mammillary body volume was both significantly smaller than that in healthy subjects (30.3 ± 10.3 vs. 43.3 ± 8.07 mm3, P < 0.001) and significantly smaller than the left mammillary body volume in each patient (30.3 ± 10.3 vs. 41.4 ± 10.1 mm3, P < 0.001). Similarly, in patients with left hippocampal sclerosis, left mammillary body volume was both significantly smaller than that in healthy subjects (37.7 ± 11.2 vs. 47.0 ± 8.65 mm3, P < 0.001) and significantly smaller than right mammillary body volume in each patient (37.7 ± 11.2 vs. 42.5 ± 7.78 mm3, P = 0.044). CONCLUSIONS: In this study, thin-slice-reconstructed volumetric analysis showed that, in patients with unilateral hippocampal sclerosis, mammillary body volume on the hippocampal sclerosis side is smaller than that in healthy subjects and the non-hippocampal sclerosis side.

Isolated Mammillary Body Infarct Causing Global Amnesia: A Case Report.

OBJECTIVES: Mamillary bodies play an important role in human memory and emotions. Vascular lesions causing an isolated mammillary body lesion without affecting the surrounding structures are very rare. METHODS: A 53-year-old male was brought to the emergency department with acute-onset memory problems suggestive of partial anterograde and retrograde amnesia. RESULTS: Magnetic resonance imaging revealed an isolated left mammillary body infarct sparing adjacent structures. CONCLUSION: Mamillary bodies play an intrinsic role in memory formation and retrieval rather than acting as relay-only station for hippocampal projections. Non-hippocampal input from the limbic midbrain via the ventral tegmental nucleus of Gudden could be contributing to its function.

Mammillary body volume abnormalities in anorexia nervosa.

OBJECTIVE: Several case reports of Wernicke's Encephalopathy in anorexia nervosa (AN) caused by thiamine deficiency have described mammillary body (MB) injury, but systematic studies are lacking. Here we evaluated whether underweight and weight-restored individuals with AN demonstrate evidence of abnormal MB morphology, via retrospective examination of a previously collected data set. METHOD: Using standard-resolution T1-weighted magnetic resonance imaging at 3 Tesla, we measured MB volume and fornix area in a cross-sectional study of 12 underweight AN, 20 weight-restored AN, and 30 age- and sex-matched healthy comparisons. Because of the small size of these structures, a manual tracing approach was necessary to obtain accurate measurements. A blinded expert rater manually traced MB and fornix structures in each participant. RESULTS: We observed significantly smaller MB volumes in the underweight AN group. However, the weight-restored AN group exhibited significantly larger MB volumes. The right fornix was smaller in the weight-restored AN group only. DISCUSSION: These findings suggest the possibility that MB volume and fornix area could represent potential biomarkers of acute weight loss and restoration, respectively. Verification of this finding through prospective studies evaluating MB morphology, cognition, and thiamine levels longitudinally across individual illness trajectories might be warranted. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:920-929).

Acute Amnesia due to Isolated Mammillary Body Infarct.

BACKGROUND: There are limited reports describing acute amnesia after mammillothalamic tract infarction. Furthermore, acute infarction isolated to the mammillary body has never been reported. We present the first case of anterograde amnesia after isolated acute infarction of the mammillary body in a patient without concurrent or prior thalamic or mammillothalamic tract injury. METHODS: A retrospective review of the patient's electronic medical record including inpatient notes and all radiological examinations was performed. RESULTS: A 50-year-old woman presented with acute onset of confusion and constant repetition of the same questions. Magnetic resonance (MR) imaging of the brain showed isolated acute infarct of the left mammillary body without concurrent abnormality of the thalamus or mammillothalamic tract. MR angiography showed severe stenosis of the proximal posterior cerebral artery at the origin of the perforating mammillary artery. CONCLUSIONS: Isolated injury to the mammillary body is rare. In addition to recognized memory-related structures such as the thalamus and mammillothalamic tract, mammillary body injury may also play a role in memory dysfunction. Knowledge of the vascular supply of memory-related structures is important in diagnosing and understanding memory dysfunction.

[The 2013 Sixto Obrador Award. A triple-axis topographical model for surgical planning of craniopharyngiomas. Part II: Anatomical and neuroradiological evidence to define triple-axis topography and its usefulness in predicting individual surgical risk]. / Premio Sixto Obrador 2013. Modelo topográfico de 3 ejes para el tratamiento quirúrgico de los craneofaringiomas. Parte II: Evidencias anatómicas y neurorradiológicas que definen el modelo de clasificación de 3 ejes y su utilidad para predecir el riesgo quirúrgico individual.

INTRODUCTION AND OBJECTIVES: This study evaluates the pathological and magnetic resonance imaging evidence to define the precise topographical relationships of craniopharyngiomas and to classify these lesions according to the risks of hypothalamic injury associated with their removal. MATERIAL AND METHODS: An extensive, systematic analysis of the topographical classification models used in the surgical series of craniopharyngiomas reported in the literature (n=145 series, 4,588 craniopharyngiomas) was performed. Topographical relationships of well-described operated craniopharyngiomas (n=224 cases) and of non-operated cases reported in autopsies (n=201 cases) were also analysed. Finally, preoperative and postoperative magnetic resonance imaging studies displayed in craniopharyngiomas reports (n=130) were compared to develop a triple-axis model for the topographical classification of these lesions with qualitative information regarding the associated risk of hypothalamic injury. RESULTS: The 2 major variables with prognostic value to define the topography of a craniopharyngioma are its position relative to the sellar diaphragm and its degree of invasion of the third ventricle floor. A multivariate diagnostic model including 5 variables -patient age, presence of hydrocephalus and/or psychiatric symptoms, the relative position of the hypothalamus and the mammillary body angle- makes it possible to differentiate suprasellar craniopharyngiomas displacing the third ventricle upwards (pseudointraventricular craniopharyngiomas) from either strictly intraventricular craniopharyngiomas or lesions developing primarily within the third ventricle floor (infundibulo-tuberal or not strictly intraventricular craniopharyngiomas). CONCLUSIONS: A triple-axis topographical model for craniopharyngiomas that includes the degree of hypothalamus invasion is useful in planning the surgical approach and degree of resection. Infundibulo-tuberal craniopharyngiomas represent 42% of all cases. These lesions typically show tight, circumferential adhesion to the third ventricle floor, with their removal being associated with a 50% risk of hypothalamic injury. The endoscopically-assisted extended transsphenoidal approach provides a proper view to assess the degree and extension of craniopharyngioma adherence to the hypothalamus.

[The 2013 Sixto Obrador Award. A triple-axis topographical model for surgical planning of craniopharyngiomas. Part I: historical review of the topographical diagnosis and classification schemes of craniopharyngiomas]. / Premio Sixto Obrador 2013. Modelo topográfico de 3 ejes para el tratamiento quirúrgico de los craneofaringiomas. Parte I: Evolución histórica del diagnóstico topográfico y métodos de clasificación de los craneofaringiomas.

INTRODUCTION AND OBJECTIVES: This study reviews the historical evolution of pathological, neuroradiological and surgical evidence that influenced the topographical concepts and classification schemes of craniopharyngiomas. MATERIAL AND METHODS: An extensive, systematic analysis of the surgical series of craniopharyngiomas reported in the literature was performed (n=145 series, 4,588 tumours) to describe the fundamental anatomical findings guiding the topographical classification schemes used for this tumour throughout history. These findings were compared with topographical relationships reported for well-described operated craniopharyngiomas (n=224 cases) as well as for non-operated cases studied in autopsies (n=201 cases). RESULTS: Two major variables define the topography of a craniopharyngioma: its position relative to the sellar diaphragm and its degree of invasion of the third ventricle floor. Suprasellar lesions displacing the third ventricle floor upwards (pseudointraventricular craniopharyngiomas) are amenable to safe, radical resection and must be differentiated from lesions developing primarily within the third ventricle floor (infundibulo-tuberal or not strictly intraventricular craniopharyngiomas). The latter group typically shows tight, circumferential adhesion to the third ventricle floor and represents approximately 40% of all cases. CONCLUSIONS: A triple-axis topographical model for craniopharyngiomas that includes the degree of hypothalamus invasion is useful in planning surgical approach and degree of resection. The group of infundibulo-tuberal craniopharyngiomas associates the highest risk of hypothalamic injury (50%). The endoscopically-assisted extended transsphenoidal approach provides a proper view to assess the topography of the craniopharyngioma and its degree of adherence to the hypothalamus.