Hikikomori syndrome (HS), a phenomenon characterized by social withdrawal and isolation, has attracted significant attention in both academic and clinical settings. However, understanding the diverse nature of HS remains a challenge due to its multifaceted etiology and presentation. This paper aims to shed light on this phenomenon by examining three representative typologies of HS in clinical settings. Through detailed case analyses, we categorize HS into three main types: HS associated with neurodevelopmental disorders; HS triggered by the onset of mental illness; and HS emerging gradually with age-related challenges. By elucidating these typologies, we provide insights into the complex interplay of psychological, social, and developmental factors contributing to HS, thereby facilitating more tailored approaches for the evaluation of and intervention into this syndrome in clinical practice.

Background and Objectives: Early diastolic mitral annular tissue (e’) velocity is a commonly used marker of left ventricular (LV) diastolic function. This study aimed to investigate the prognostic implications of e’ velocity in patients with mitral regurgitation (MR). Methods: This retrospective cohort study included 1,536 consecutive patients aged <65 years with moderate or severe chronic primary MR diagnosed between 2009 and 2018. The primary and secondary outcomes were all-cause and cardiovascular mortality, respectively.According to the current guidelines, the cut-off value of e’ velocity was defined as 7 cm/s. Results: A total of 404 individuals were enrolled (median age, 51.0 years; 64.1% male; 47.8% severe MR). During a median 6.0-year follow-up, there were 40 all-cause mortality and 16 cardiovascular deaths. Multivariate analysis revealed a significant association between e’ velocity and all-cause death (adjusted hazard ratio [aHR], 0.770; 95% confidence interval [CI], 0.634–0.935; p=0.008) and cardiovascular death (aHR, 0.690; 95% CI, 0.477–0.998;p=0.049). Abnormal e’ velocity (≤7 cm/s) independently predicted all-cause death (aHR, 2.467; 95% CI, 1.170–5.200; p=0.018) and cardiovascular death (aHR, 5.021; 95% CI, 1.189–21.211; p=0.028), regardless of symptoms, LV dimension and ejection fraction. Subgroup analysis according to sex, MR severity, mitral valve replacement/repair, and symptoms, showed no significant interactions. Including e’ velocity in the 10-year risk score improved reclassification for mortality (net reclassification improvement [NRI], 0.154; 95% CI, 0.308– 0.910; p<0.001) and cardiovascular death (NRI, 1.018; 95% CI, 0.680–1.356; p<0.001). Conclusions In patients aged <65 years with primary MR, e’ velocity served as an independent predictor of all-cause and cardiovascular deaths.

Background: and Purpose We delineated the association between otolithic dysfunction and blood pressure (BP) variability. Methods: We prospectively recruited 145 consecutive patients (age=71 [59–79] years, median [interquartile range]; 76 females) with orthostatic intolerance between December 2021 and December 2023 at a tertiary hospital in South Korea. Each patient underwent evaluations of cervical and ocular vestibular-evoked myogenic potentials (oVEMPs), 24-h noninvasive ambulatory BP monitoring (ABPM), and a head-up tilt-table test using the Finometer device. As measures of BP variability, the standard deviations (SDs) of the systolic BP (SBP SD) and the diastolic BP were calculated based on serial ABPM recordings. Patients were divided into those with orthostatic hypotension (OH, n=68) and those with a normal head-up tilt-table test despite orthostatic intolerance (NOI, n=77) groups. Results: A multivariable logistic regression analysis showed that OH was associated with bilateral oVEMP abnormalities (p=0.021), SBP SD (p=0.012), and female sex (p=0.004). SBP SD was higher in patients with OH than in those with NOI (p<0.001), and was not correlated with n1–p1 amplitude (p=0.491) or normalized p13–n23 amplitude (p=0.193) in patients with OH.The sensitivity and specificity for differentiating OH from NOI were 72.1% and 67.5%, respectively, at a cutoff value of 12.7 mm Hg for SBP SD, with an area under the receiver operating characteristic curve of 0.73. Conclusions Bilaterally deficient oVEMP responses may be associated with OH regardless of 24-h BP variability, reflecting the integrity of the otolith-autonomic reflex during orthostasis. Alternatively, 24-h BP variability is predominantly regulated by the baroreflex, which also participates in securing orthostatic tolerance complementary to the vestibulo-autonomic reflex.

Hyperbaric oxygen therapy (HBOT) has garnered significant attention as a therapeutic modality with potential benefits across a variety of medical conditions, ranging from wound healing and ischemic conditions to neurologic disorders and radiation-induced tissue damage. HBOT involves the administration of 100% oxygen at higher-than-atmospheric pressures, which increases the amount of oxygen dissolved in body fluids and tissues. Those elevated oxygen levels are proposed to facilitate tissue repair, reduce inflammation, and promote angiogenesis. This case report presents a compelling instance of the usefulness of HBOT in promoting skin perfusion and healing following peripheral tissue injury caused by administration of inotropic and vasopressor agents to a septic shock patient.

Objective: The Korean National Fire Agency conducted a pilot project examining Advanced Life Support (ALS) protocols, including epinephrine administration, to improve survival among patients suffering out-of-hospital cardiac arrest (OHCA). In this study, we aimed to evaluate the effects of the Korean National Fire Agency ALS protocol on prehospital return of spontaneous circulation (ROSC) in patients with OHCA. Methods: This study included patients with adult-presumed cardiac arrest between January and December 2020. The main factor of interest was ambulance type according to ALS protocol, which was divided into dedicated ALS ambulance (DA), smartphone-based ALS ambulance (SALS), and non-DA, and the main analysis factor was prehospital ROSC. Multivariate logistic regression analysis was performed. Results: During the study period, a total of 18,031 adult patients with OHCA was treated by the emergency medical services, including 7,520 DAs (41.71%), 2,622 SALSs (14.54%), and 7,889 non-DAs (43.75%). The prehospital ROSC ratio was 13.19% for DA, 11.17% for SALS, and 7.91% for non-DA (P<0.01). Compared with that of the DA group, the odds ratios (95% confidence interval) for prehospital ROSC ratio were 0.97 (0.82–1.15) in the SALS group and 0.57 (0.50–0.65) in the non-DA group. The prehospital ROSC ratio of the DA group was higher than those of the non-DA group and the SALS group. Conclusion ALS protocol intervention was associated with prehospital ROSC rates. Therefore, continuous efforts to promote systemic implementation of the ALS protocol to improve OHCA outcomes are necessary.

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the first-line treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and post-treatment management of patients.

Objective: This study aimed to investigate the association between gaming time and problematic game use (PGU) within a large sample of Korean male gamers and to examine the potential moderating effects of loneliness, living alone, and household size. Methods: This study employed data from 743 male gamers from the National Mental Health Survey 2021, a nationally representative survey of mental illness conducted in South Korea. Self-reported data on the average gaming time per day, severity of PGU, loneliness, living alone, and household size were used. Results: Gaming time was positively associated with PGU and this relationship was significantly moderated by loneliness such that the positive effect of gaming time on PGU was greater when the levels of loneliness were high. The three-way interaction effect of gaming time, loneliness, and living alone was also significant, in that the moderating effect of loneliness on the relationship between gaming time and PGU was significant only in the living alone group. However, household size (i.e., number of housemates) did not moderate the interaction between gaming time and loneliness among gamers living with housemates. Conclusion These results suggest the importance of considering loneliness and living arrangements of male gamers, in addition to gaming time, in identifying and intervening with individuals at heightened risk of PGU.

Hyperbaric oxygen therapy (HBOT) has garnered significant attention as a therapeutic modality with potential benefits across a variety of medical conditions, ranging from wound healing and ischemic conditions to neurologic disorders and radiation-induced tissue damage. HBOT involves the administration of 100% oxygen at higher-than-atmospheric pressures, which increases the amount of oxygen dissolved in body fluids and tissues. Those elevated oxygen levels are proposed to facilitate tissue repair, reduce inflammation, and promote angiogenesis. This case report presents a compelling instance of the usefulness of HBOT in promoting skin perfusion and healing following peripheral tissue injury caused by administration of inotropic and vasopressor agents to a septic shock patient.

Objective: The Korean National Fire Agency conducted a pilot project examining Advanced Life Support (ALS) protocols, including epinephrine administration, to improve survival among patients suffering out-of-hospital cardiac arrest (OHCA). In this study, we aimed to evaluate the effects of the Korean National Fire Agency ALS protocol on prehospital return of spontaneous circulation (ROSC) in patients with OHCA. Methods: This study included patients with adult-presumed cardiac arrest between January and December 2020. The main factor of interest was ambulance type according to ALS protocol, which was divided into dedicated ALS ambulance (DA), smartphone-based ALS ambulance (SALS), and non-DA, and the main analysis factor was prehospital ROSC. Multivariate logistic regression analysis was performed. Results: During the study period, a total of 18,031 adult patients with OHCA was treated by the emergency medical services, including 7,520 DAs (41.71%), 2,622 SALSs (14.54%), and 7,889 non-DAs (43.75%). The prehospital ROSC ratio was 13.19% for DA, 11.17% for SALS, and 7.91% for non-DA (P<0.01). Compared with that of the DA group, the odds ratios (95% confidence interval) for prehospital ROSC ratio were 0.97 (0.82–1.15) in the SALS group and 0.57 (0.50–0.65) in the non-DA group. The prehospital ROSC ratio of the DA group was higher than those of the non-DA group and the SALS group. Conclusion ALS protocol intervention was associated with prehospital ROSC rates. Therefore, continuous efforts to promote systemic implementation of the ALS protocol to improve OHCA outcomes are necessary.

Background: and Purpose We delineated the association between otolithic dysfunction and blood pressure (BP) variability. Methods: We prospectively recruited 145 consecutive patients (age=71 [59–79] years, median [interquartile range]; 76 females) with orthostatic intolerance between December 2021 and December 2023 at a tertiary hospital in South Korea. Each patient underwent evaluations of cervical and ocular vestibular-evoked myogenic potentials (oVEMPs), 24-h noninvasive ambulatory BP monitoring (ABPM), and a head-up tilt-table test using the Finometer device. As measures of BP variability, the standard deviations (SDs) of the systolic BP (SBP SD) and the diastolic BP were calculated based on serial ABPM recordings. Patients were divided into those with orthostatic hypotension (OH, n=68) and those with a normal head-up tilt-table test despite orthostatic intolerance (NOI, n=77) groups. Results: A multivariable logistic regression analysis showed that OH was associated with bilateral oVEMP abnormalities (p=0.021), SBP SD (p=0.012), and female sex (p=0.004). SBP SD was higher in patients with OH than in those with NOI (p<0.001), and was not correlated with n1–p1 amplitude (p=0.491) or normalized p13–n23 amplitude (p=0.193) in patients with OH.The sensitivity and specificity for differentiating OH from NOI were 72.1% and 67.5%, respectively, at a cutoff value of 12.7 mm Hg for SBP SD, with an area under the receiver operating characteristic curve of 0.73. Conclusions Bilaterally deficient oVEMP responses may be associated with OH regardless of 24-h BP variability, reflecting the integrity of the otolith-autonomic reflex during orthostasis. Alternatively, 24-h BP variability is predominantly regulated by the baroreflex, which also participates in securing orthostatic tolerance complementary to the vestibulo-autonomic reflex.