Regional cerebral hypometabolism on 18F-FDG PET/CT scan in delirium is independent of acute illness and dementia.

INTRODUCTION: Delirium is associated with new onset dementia and accelerated cognitive decline; however, its pathophysiology remains unknown. Cerebral glucose metabolism previously seen in delirium may have been attributable to acute illness and/or dementia. We aimed to statistically map cerebral glucose metabolism attributable to delirium. METHODS: We assessed cerebral glucose metabolism using 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) in sick, older patients with and without delirium, all without clinical dementia (N = 20). Strict exclusion criteria were adopted to minimize the effect of established confounders on FDG-PET. RESULTS: Patients with delirium demonstrated hypometabolism in the bilateral thalami and right superior frontal, right posterior cingulate, right infero-lateral anterior temporal, and left superior parietal cortices. Regional hypometabolism correlated with delirium severity and performance on neuropsychological testing. DISCUSSION: In patients with acute illness but without clinical dementia, delirium is accompanied by regional cerebral hypometabolism. While some hypometabolic regions may represent preclinical Alzheimer's disease (AD), thalamic hypometabolism is atypical of AD and consistent with the clinical features that are unique to delirium.

Delirium in older adults is associated with development of new dementia: a systematic review and meta-analysis.

OBJECTIVES: Observational studies have examined the association between delirium and development of new dementia. However, no recent review has collectively assessed the available evidence quantitatively and qualitatively. We systematically reviewed and critically evaluated the literature regarding the association between delirium and dementia, and calculated the odds of developing new dementia after having delirium. METHODS: This systematic review and meta-analysis was conducted according to Preferred reporting items for systematic reviews and meta-analyses guidelines. MEDLINE, EMBASE and PsycINFO, were searched for English-language articles that compared the incidence of new dementia in older adult (≥65) inpatients with delirium, to inpatients without delirium. A random effects model was used for meta-analysis, and overall effect size was calculated using reported raw data of event counts. The Newcastle-Ottawa Quality Assessment scale assessed risk of bias. RESULTS: Six observational studies met eligibility criteria, with follow-up times ranging from six months to five years. Four looked at hip fracture surgical patients; one was on cardiac surgery patients and one examined geriatric medical patients. All studies excluded patients with pre-existing dementia. Pooled meta-analysis revealed that older adult inpatients who developed delirium had almost twelve times the odds of subsequently developing new dementia compared to non-delirious patients (OR = 11.9 [95% CI: 7.29-19.6]; p < 0.001). CONCLUSIONS: Older adult inpatients who develop delirium are at significant risk of subsequently developing dementia. This emphasises the importance of delirium prevention and cognitive monitoring post-delirium. The included studies mainly examined post-surgical patients-further research on medical and intensive care unit cohorts is warranted. Future studies should assess whether delirium duration, severity and subtype influence the risk of developing dementia.

Hyperthyroidism in gestational trophoblastic disease - a literature review.

OBJECTIVE: Gestational trophoblastic disease (GTD) is a group of pregnancy-related disorders that arise from abnormal proliferation of placental trophoblast. Some patients with GTD develop hyperthyroidism, a rare but potentially life-threatening complication requiring early detection and management. Existing literature on hyperthyroidism in GTD is scant. This review aims to analyse the epidemiology, pathophysiology and management of this phenomenon. METHODS: A comprehensive search of MEDLINE, EMBASE and Cochrane Library was performed to obtain articles that explored hyperthyroidism in GTD. A total of 405 articles were screened and 228 articles were considered for full-text review. We selected articles that explored epidemiology, pathophysiology and outcomes/management of hyperthyroidism in GTD. RESULTS: The pathophysiology of hyperthyroidism in GTD is well-investigated. Placental trophoblastic tissue secretes excessive hCG, which is structurally similar to thyroid stimulating hormone and also has enhanced thyrotropic activity compared to normal hCG. The incidence and prevalence of hyperthyroidism in GTD varies worldwide, with lower rates associated with high uptake of early antenatal screening and early GTD detection. No clear risk factors for hyperthyroidism in GTD were identified. While hyperthyroidism can be definitively managed with surgical evacuation of the uterus, severe complications associated with hyperthyroidism in GTD have been reported, including thyroid storm-induced multi-organ failure, ARDS, and pulmonary hypertension. CONCLUSION: Early detection of GTD is critical to prevent development of hyperthyroidism and its associated complications. Hyperthyroidism should be recognised as an important perioperative consideration for women undergoing surgery for GTD, and requires appropriate management. Future studies should explore risk factors for hyperthyroidism in GTD, which may facilitate earlier identification of high-risk women.