The Olfactory System: Basic Anatomy and Physiology for General Otorhinolaryngologists

Olfaction is one of the five basic human senses, and it is known to be one of the most primitive senses. The sense of olfaction may have been critical for human survival in prehistoric society, and although many believe its importance has diminished over time, it continues to have an impact on human interaction, bonding, and propagation of the species. Even if we are unaware of it, the sense of smell greatly affects our lives and is closely related to overall quality of life and health. Nonetheless, olfaction has been neglected from a scientific perspective compared to other senses. However, olfaction has recently received substantial attention since the loss of smell and taste has been noted as a key symptom of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Studies investigating olfaction loss in association with coronavirus disease 2019 (COVID-19) have revealed that olfactory dysfunction can be both conductive and sensorineural, possibly causing structural changes in the brain. Olfactory training is an effective treatment for olfactory dysfunction, suggesting the reorganization of neural associations. A reduced ability to smell may also alert suspicion for neurodegenerative or psychiatric disorders. Here, we summarize the basic knowledge that we, as otorhinolaryngologists, should have about the sense of smell and the peripheral and central olfactory pathways for managing and helping patients with olfactory dysfunction.

Chronic Obstructive Pulmonary Disease Is Not Associated with a Poor Prognosis in COVID-19 / 결핵및호흡기질환

Background@#The effect of underlying chronic obstructive pulmonary disease (COPD) on coronavirus disease 2019 (COVID-19) during a pandemic is controversial. The purpose of this study was to examine the prognosis of COVID-19 according to the underlying COPD. @*Methods@#COVID-19 patients were assessed using nationwide health insurance data. Comorbidities were evaluated using the modified Charlson Comorbidity Index (mCCI) which excluded COPD from conventional CCI scores. Baseline characteristics were assessed. Univariable and multiple logistic and linear regression analyses were performed to determine effects of variables on clinical outcomes. Ages, sex, mCCI, socioeconomic status, and underlying COPD were selected as variables. @*Results@#COPD patients showed older age (71.3±11.6 years vs. 47.7±19.1 years, p<0.001), higher mCCI (2.6±1.9 vs. 0.8±1.3, p<0.001), and higher mortality (22.9% vs. 3.2%, p<0.001) than non-COPD patients. The intensive care unit admission rate and hospital length of stay were not significantly different between the two groups. All variables were associated with mortality in univariate analysis. However, underlying COPD was not associated with mortality unlike other variables in the adjusted analysis. Older age (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.11–1.14; p<0.001), male sex (OR, 2.29; 95% CI, 1.67–3.12; p<0.001), higher mCCI (OR, 1.30; 95% CI, 1.20–1.41; p<0.001), and medical aid insurance (OR, 1.55; 95% CI, 1.03–2.32; p=0.035) were associated with mortality. @*Conclusion@#Underlying COPD is not associated with a poor prognosis of COVID-19.

COVID-19 International Collaborative Research by the Health Insurance Review and Assessment Service Using Its Nationwide Real-world Data: Database, Outcomes, and Implications / 예방의학회지

This article aims to introduce the inception and operation of the COVID-19 International Collaborative Research Project, the world’s first coronavirus disease 2019 (COVID-19) open data project for research, along with its dataset and research method, and to discuss relevant considerations for collaborative research using nationwide real-world data (RWD). COVID-19 has spread across the world since early 2020, becoming a serious global health threat to life, safety, and social and economic activities. However, insufficient RWD from patients was available to help clinicians efficiently diagnose and treat patients with COVID-19, or to provide necessary information to the government for policy-making. Countries that saw a rapid surge of infections had to focus on leveraging medical professionals to treat patients, and the circumstances made it even more difficult to promptly use COVID-19 RWD. Against this backdrop, the Health Insurance Review and Assessment Service (HIRA) of Korea decided to open its COVID-19 RWD collected through Korea’s universal health insurance program, under the title of the COVID-19 International Collaborative Research Project. The dataset, consisting of 476 508 claim statements from 234 427 patients (7590 confirmed cases) and 18 691 318 claim statements of the same patients for the previous 3 years, was established and hosted on HIRA’s in-house server. Researchers who applied to participate in the project uploaded analysis code on the platform prepared by HIRA, and HIRA conducted the analysis and provided outcome values. As of November 2020, analyses have been completed for 129 research projects, which have been published or are in the process of being published in prestigious journals.

IgG4-Related Disease with lymphadenopathy Presenting as a Cervical lymph node enlargement / 고신대학교의과대학학술지

During the course of evaluation and management of neck masses, consideration for Immunoglobulin G4-related disease (IgG4-RD) should be given. IgG4-RD is relatively a new growing entity of immune-mediated origin, characterized by a mass-forming lesion, the infiltration of IgG4-positive plasma cells and occasionally elevated serum IgG4. The most common manifestations are parotid and lacrimal swelling, lymphadenopathy and autoimmune pancreatitis. A previously healthy 72-year-old man was referred to our clinic with a 2-month history of left cervical lymph node enlargement without systemic manifestations . A cervical lymph node biopsy was planned because of elevated serum IgG4 levels. Pathological findings showed prominent infiltration of IgG4-postive plasma cells in the lymph node. After steroid therapy, a computed tomography scan revealed a decrease in the cervical lymph node size. This case illustrates the importance of including IgG4-RD in the differential diagnosis of a cervical lymph node enlargement.

Spontaneous Retropharyngeal and Mediastinal Emphysema

A 14-year-old girl with no significant medical history presented at Emergency Department with sore throat and odynophagia after one episode of nonviolent coughing. She denied any respiratory distress, voice change, foreign body ingestion, retching, substance abuse, dental procedures, or trauma. She was afebrile with normal oxygen saturation and physical examination including the head and neck was unremarkable with the exception of bilateral neck crepitus without tenderness on palpation. Fiberoptic laryngoscopy revealed a patent laryngeal airway with normal vocal fold movement. Lateral neck X-ray demonstrated a linear air-column in the retropharyngeal space and computed tomography confirmed emphysema involving the retropharyngeal space and mediastinum with no evidence of fluid collection or abscess formation. Spontaneous retropharyngeal and mediastinal emphysema are clinical entities where free air is present within the confines of retropharyngeal space and mediastinum without obvious cause. It is benign and self-limited in nature and allows for conservative management. This case is presented with a review of literature.

Sentinel Lymph Node Radiolocalization with 99mTc Filtered Tin Colloid in Clinically Node-Negative Squamous Cell Carcinomas of the Oral Cavity

The objective of this study was to evaluate the feasibility of sentinel lymph node biopsy by using a radiotracer lymphatic mapping technique in patients with squamous cell carcinoma of the oral cavity, and the diagnostic value of this technique. We studied twenty patients with previously untreated squamous cell carcinomas of the oral cavity and N0 necks. After the peritumoral injection of 99mTc filtered tin colloid preop-eratively, lymphoscintigraphy and intraoperative mapping using a gamma detector were performed to localize sentinel nodes. An open biopsy of the sentinel node was followed by complete neck dissection. We identified the sentinel nodes in 19 of 20 patients (95.0%) by lymphoscintigraphy and in all (100%) by intraoperative gamma detector. In all cases, the status of the sentinel node accurately predicted the pathologic status of the neck with the false negative rate being 0%. The negative predictive value for the absence of cervical metastases was 100%. In conclusion, our radio-localization technique of sentinel nodes using 99mTc filtered tin colloid in N0 squamous cell carcinomas of the oral cavity is technically feasible and appears to accurately predict the presence of the occult metastatic disease.

A case of Peutz-Jeghers syndrome combined with metastatic adenocarcinoma with unknown primary origin / 대한내과학회지

The Peutz-Jeghers syndrome, characterized by mucocutaneous pigmentation and gastrointestinal polyposis, appeares to be transmitted in an autosomal dominant fashion. This syndrome is clinically important because of complications caused by gastrointestinal polyps, such as abdominal pain, gastrointestinal bleeding and intussusception often leading to intestinal obstruction. The possibility of malignany change in the polyp has been a controversial issue. The hamatomatous polyps is not regarded to be premalignanct lesion, generally. But in patients with this syndrome, increased rates of both intestinal and extraintestinal malignancies has been reported. This report is concerned with our experience with a case of 46-year old male patients with Peutz-Jeghers syndrome who had an metastatic adenocarcinoma with unknown primary origin.

Biological Analysis of a New Spontaneous Mutant Mouse Showing Deafness and Circling Behavior / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Deafness is the most common sensory deficit and hereditary defect in human populations. The present study investigated the causative gene in circling mice using the complementation test. In addition, the phenotypes and histopathologic findings in circler mice, spinner mice, and compound heterozygote mice were analyzed to elucidate the mechanism of causative gene in inner ear deafness. MATERIALS AND METHOD: In order to analyze inner ear pathology in time sequence for the circler mice, spinner mice, and compound heterozygote, five groups of the homozygous mutants of different ages were used: 10, 18, 21, 35, and 90 days old. The organs of Corti and spiral ganglion neurons in the basal and middle turns were included for quantification. For the preparation of genomic DNA, tail tissues were used. RESULTS: The hair cells in the organ of Corti degenerated in a time-dependent manner. In the basal and middle turns, the volume ratio of spiral ganglion neurons significantly decreased as the mutant aged. RT-PCR analysis indicated that transmembrane inner ear (Tmie) was absent in the case of circler mice, similar to spinner mouse of which is defective Tmie gene. Therefore the variations may be a result from strain-specific allelic differences of the Chr 9 Tmie gene itself (allelic heterogeneity). CONCLUSION: The cir mutant is a suitable mouse model for neuroepithelial defects. PCR and RT-PCR analyses suggest that the Tmie transcript is absent in circler mice. This model represents another candidate for human genetic hearing loss.

Normal Distribution of Nitric Oxide Synthase(NOS) in the Inner Ear of Guinea Pig / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study is to find out the exact distribution of nitric oxide synthase (NOS) in the cochlea and vestibular organ of normal guinea pig. Nitric oxide (NO) is synthesized from L-arginine catalyzed by NOS and it activates the soluble guanyl cyclase that activates cyclic GMP from GTP. These NO/cGMP pathways are involved in the neurotransmission of the inner ear and the regulation of cochlear blood flow in physiological condition. In addition, excess NO is involved in cytotoxicity. MATERIALS AND METHOD: Five normal guinea pigs were used. Antibodies to three isoforms of NOS (nNOS, eNOS, iNOS) were utilized to stain the paraffin sections of cochlea and vestibular organ (crista and maculae utriculi). Staining patterns were compared to previous reports. RESULTS: Neuronal NOS (nNOS) was constitutively expressed in the lateral cochlear wall (stria vascularis, spiral ligament), spiral ganglion, hair cells and supporting cells in the cochlea. In the vestibular organs, hair cells were well expressed. Endothelial NOS (eNOS) was expressed in the vascular endothelium, cochlear lateral wall, basal parts of hair cells and spiral ganglion in the cochlea. Vascular endothelium and nerve fiber including nerve calyx were also prominently expressed. No inducible NOS (iNOS) was identified in any sections. CONCLUSION: Neuronal and endothelial NOS were constitutively expressed in the inner ear of normal guinea pig. This distribution can explain the role of NO in physiologic conditions, which can be used as basic data in studying the role of NO in pathologic inner ear conditions.