Deep Learning-based Prediction of Axial Length Using Ultra-widefield Fundus Photography

Purpose@#To develop a deep learning model that can predict the axial lengths of eyes using ultra-widefield (UWF) fundus photography. @*Methods@#We retrospectively enrolled patients who visited the ophthalmology clinic at the Seoul National University Hospital between September 2018 and December 2021. Patients with axial length measurements and UWF images taken within 3 months of axial length measurement were included in the study. The dataset was divided into a development set and a test set at an 8:2 ratio while maintaining an equal distribution of axial lengths (stratified splitting with binning). We used transfer learning-based on EfficientNet B3 to develop the model. We evaluated the model’s performance using mean absolute error (MAE), R-squared (R2), and 95% confidence intervals (CIs). We used vanilla gradient saliency maps to illustrate the regions predominantly used by convolutional neural network. @*Results@#In total, 8,657 UWF retinal fundus images from 3,829 patients (mean age, 63.98 ±15.25 years) were included in the study. The deep learning model predicted the axial lengths of the test dataset with MAE and R2 values of 0.744 mm (95% CI, 0.709–0.779 mm) and 0.815 (95% CI, 0.785–0.840), respectively. The model’s accuracy was 73.7%, 95.9%, and 99.2% in prediction, with error margins of ±1.0, ±2.0, and ±3.0 mm, respectively. @*Conclusions@#We developed a deep learning-based model for predicting the axial length from UWF images with good performance.

Voretigene Neparvovec for the Treatment of RPE65-associated Retinal Dystrophy: Consensus and Recommendations from the Korea RPE65-IRD Consensus Paper Committee

Mutations in the RPE65 gene, associated with Leber congenital amaurosis, early-onset severe retinal dystrophy, and retinitis pigmentosa, gained growing attention since gene therapy for patients with RPE65-associated retinal dystrophy is available in clinical practice. RPE65 gene accounts for a very small proportion of patients with inherited retinal degeneration, especially Asian patients. Because RPE65-associated retinal dystrophy shares common clinical characteristics, such as early-onset severe nyctalopia, nystagmus, low vision, and progressive visual field constriction, with retinitis pigmentosa by other genetic mutations, appropriate genetic testing is essential to make a correct diagnosis. Also, fundus abnormalities can be minimal in early childhood, and the phenotype is highly variable depending on the type of mutations in RPE65-associated retinal dystrophy, which makes a diagnostic difficulty. The aim of this paper is to review the epidemiology of RPE65-associated retinal dystrophy, mutation spectrum, genetic diagnosis, clinical characteristics, and voretigene neparvovec, a gene therapy product for the treatment of RPE65-related retinal dystrophy.

Current situation and control strategies of H9N2 avian influenza in South Korea

The H9N2 avian influenza (AI) has become endemic in poultry in many countries since the 1990s, which has caused considerable economic losses in the poultry industry. Considering the long history of the low pathogenicity H9N2 AI in many countries, once H9N2 AI is introduced, it is more difficult to eradicate than high pathogenicity AI. Various preventive measures and strategies, including vaccination and active national surveillance, have been used to control the Y439 lineage of H9N2 AI in South Korea, but it took a long time for the H9N2 virus to disappear from the fields. By contrast, the novel Y280 lineage of H9N2 AI was introduced in June 2020 and has spread nationwide. This study reviews the history, genetic and pathogenic characteristics, and control strategies for Korean H9N2 AI. This review may provide some clues for establishing control strategies for endemic AIV and a newly introduced Y280 lineage of H9N2 AI in South Korea.

Two Case Reports of Chronic Inflammatory Demyelinating Polyneuropathy After COVID-19Vaccination

The occurrence of chronic inflammatory demyelinating polyneuropathy (CIDP) related to coronavirus disease 2019 (COVID-19) has rarely been reported. We describe two patients who were diagnosed with CIDP after COVID-19 vaccination. A 72-year-old man presented with a progressive tingling sensation and weakness below both knees for two weeks. He had been vaccinated against COVID-19 (mRNA-1273 vaccine) a month before the appearance of symptoms. Demyelinating polyneuropathy was observed in the nerve conduction studies (NCS). Intravenous immunoglobulin (IVIg) was administered under the diagnosis of GuillainBarré syndrome (GBS), and his symptoms were improved. However, his symptoms relapsed at 10 weeks from the onset. Oral prednisolone, azathioprine, and IVIg were administered as treatment. The second case was a 50-year-old man who complained of a bilateral leg tingling sensation and gait disturbance lasting four weeks. He had received the Ad26.COV2.S vaccine against COVID-19 five weeks prior. Demyelinating polyneuropathy was observed in the NCS. He was treated with oral prednisolone, azathioprine, and IVIg for CIDP because his symptoms had lasted for more than 12 weeks from the onset. A causal relationship has not been established between COVID-19 vaccination and CIDP; however, CIDP may follow COVID-19 vaccination. As CIDP treatment is different from that for GBS, clinicians should closely monitor patients diagnosed with GBS associated with COVID-19 whether they deteriorate after initial treatment.

Letter to the Editor: Effectiveness of the Varicella Vaccine Among Korean Children: Suggestions for Future Research

no abstract available

Renal Infarction in Vascular Ehlers-Danlos Syndrome / 대한내과학회지

Renal infarction is a condition caused by sudden disturbance of renal arterial blood flow, which occurs frequently in cardioembolic disease, renal artery injury (trauma, Marfan syndrome, rarely Ehlers-Danlos syndrome), and in association with a hypercoagulable state. Ehlers-Danlos syndrome is a rare hereditary connective tissue disease characterized by skin fragility, hyperelasticity, hypermobility of small joints, and easy bruising. Among the subtypes, vascular Ehlers-Danlos syndrome is a very rare genetic disease caused by a mutation in the COL3A1 gene. As blood vessels are fragile due dysfunctional collagen synthesis, complications of bleeding due to arterial dissection or rupture are common in patients with this disease. Here, we report a case of vascular Ehlers-Danlos syndrome diagnosed based on a renal infarction caused by thrombus and renal artery injury; we also present a review of the relevant literature.

Immunoglobulin G4-Related Kidney Disease with Membranous Proliferative Glomerulonephritis Presenting with a Renal Pelvic Mass / 대한내과학회지

Immunoglobulin G4 (IgG4)-related kidney disease is a chronic immune-mediated fibro-inflammatory disorder characterized by multiple organ infiltration with IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis or tumefactive lesions. Previous studies have explored IgG4-related kidney disease, increasing our understanding of its clinical manifestations, and pathological and radiologic findings. However, IgG4-related kidney disease can be misdiagnosed since it mimics malignancies. We report a case of a 77-year-old Korean man diagnosed with IgG4-related kidney disease with membranous proliferative glomerulonephritis, presenting with a renal pelvic mass suspected of being malignant.

Nafcillin-Associated Hypokalemia / 대한내과학회지

Hypokalemia is a common finding in various clinical settings; it is associated with diuretic use and loss of potassium via the gastrointestinal tract. Less common causes are renal tubular acidosis, diabetic ketoacidosis, excess insulin, primary hyperaldosteronism, and medications, such as amphotericin B. Nafcillin, a narrow-spectrum penicillin class antibiotic, which is selectively prescribed for methicillin-susceptible Staphylococcal aureus infections, and is commonly associated with gastrointestinal side effects, such as nausea, vomiting, and abdominal pain. However, in rare cases it can cause hypokalemia, which is usually overlooked. Severe hypokalemia was detected in a 59-year-old male patient hospitalized due to traumatic cerebral hemorrhage who received 12 g of nafcillin per day for more than 2 weeks for sepsis caused by methicillin-sensitive Staphylococcus epidermidis. We confirmed the association between nafcillin and hypokalemia through further evaluation and a review of the relevant literature. Clinicians should be aware of hypokalemia as a complication when using high doses of nafcillin.

Genetic characterization of H9N2avian influenza virus previously unrecognized in Korea

In this study, we describe the isolation and characterization of previously unreported Y280-lineage H9N2 viruses from two live bird markets in Korea in June 2020. Genetic analysis revealed that they were distinct from previous H9N2 viruses circulating in Korea and had highest homology to A/chicken/Shandong/1844/2019(H9N2) viruses. Their genetic constellation showed they belonged to genotype S, which is the predominant genotype in China since 2010, where genotype S viruses have infected humans and acted as internal gene donors to H5 and H7 zoonotic influenza viruses. Active surveillance and control measures need to be enhanced to protect the poultry industry and public health.

Differentiation between Glioblastoma and Solitary Metastasis: Morphologic Assessment by Conventional Brain MR Imaging and Diffusion-Weighted Imaging

Purpose@#Differentiating between glioblastoma and solitary metastasis is very important for the planning of further workup and treatment. We assessed the ability of various morphological parameters using conventional MRI and diffusion-based techniques to distinguish between glioblastomas and solitary metastases in tumoral and peritumoral regions. @*Materials and Methods@#We included 38 patients with solitary brain tumors (21 glioblastomas, 17 solitary metastases). To find out if there were differences in the morphologic parameters of enhancing tumors, we analyzed their shape, margins, and enhancement patterns on postcontrast T1-weighted images. During analyses of peritumoral regions, we assessed the extent of peritumoral non-enhancing lesion on T2- and postcontrast T1-weighted images. We also aimed to detect peritumoral neoplastic cell infiltration by visual assessment of T2-weighted and diffusionbased images, including DWI, ADC maps, and exponential DWI, and evaluated which sequence depicted peritumoral neoplastic cell infiltration most clearly. @*Results@#The shapes, margins, and enhancement patterns of tumors all significantly differentiated glioblastomas from metastases. Glioblastomas had an irregular shape, ill-defined margins, and a heterogeneous enhancement pattern; on the other hand, metastases had an ovoid or round shape, well-defined margins, and homogeneous enhancement. Metastases had significantly more extensive peritumoral T2 high signal intensity than glioblastomas had. In visual assessment of peritumoral neoplastic cell infiltration using T2-weighted and diffusion-based images, all sequences differed significantly between the two groups. Exponential DWI had the highest sensitivity for the diagnosis of both glioblastoma (100%) and metastasis (70.6%). A combination of exponential DWI and ADC maps was optimal for the depiction of peritumoral neoplastic cell infiltration in glioblastoma. @*Conclusion@#In the differentiation of glioblastoma from solitary metastatic lesions, visual morphologic assessment of tumoral and peritumoral regions using conventional MRI and diffusion-based techniques can also offer diagnostic information.

Immunoglobulin G4-Related Kidney Disease with Membranous Proliferative Glomerulonephritis Presenting with a Renal Pelvic Mass / 대한내과학회지

Immunoglobulin G4 (IgG4)-related kidney disease is a chronic immune-mediated fibro-inflammatory disorder characterized by multiple organ infiltration with IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis or tumefactive lesions. Previous studies have explored IgG4-related kidney disease, increasing our understanding of its clinical manifestations, and pathological and radiologic findings. However, IgG4-related kidney disease can be misdiagnosed since it mimics malignancies. We report a case of a 77-year-old Korean man diagnosed with IgG4-related kidney disease with membranous proliferative glomerulonephritis, presenting with a renal pelvic mass suspected of being malignant.

Nafcillin-Associated Hypokalemia / 대한내과학회지

Hypokalemia is a common finding in various clinical settings; it is associated with diuretic use and loss of potassium via the gastrointestinal tract. Less common causes are renal tubular acidosis, diabetic ketoacidosis, excess insulin, primary hyperaldosteronism, and medications, such as amphotericin B. Nafcillin, a narrow-spectrum penicillin class antibiotic, which is selectively prescribed for methicillin-susceptible Staphylococcal aureus infections, and is commonly associated with gastrointestinal side effects, such as nausea, vomiting, and abdominal pain. However, in rare cases it can cause hypokalemia, which is usually overlooked. Severe hypokalemia was detected in a 59-year-old male patient hospitalized due to traumatic cerebral hemorrhage who received 12 g of nafcillin per day for more than 2 weeks for sepsis caused by methicillin-sensitive Staphylococcus epidermidis. We confirmed the association between nafcillin and hypokalemia through further evaluation and a review of the relevant literature. Clinicians should be aware of hypokalemia as a complication when using high doses of nafcillin.

Genetic characterization of H9N2avian influenza virus previously unrecognized in Korea

In this study, we describe the isolation and characterization of previously unreported Y280-lineage H9N2 viruses from two live bird markets in Korea in June 2020. Genetic analysis revealed that they were distinct from previous H9N2 viruses circulating in Korea and had highest homology to A/chicken/Shandong/1844/2019(H9N2) viruses. Their genetic constellation showed they belonged to genotype S, which is the predominant genotype in China since 2010, where genotype S viruses have infected humans and acted as internal gene donors to H5 and H7 zoonotic influenza viruses. Active surveillance and control measures need to be enhanced to protect the poultry industry and public health.

Differentiation between Glioblastoma and Solitary Metastasis: Morphologic Assessment by Conventional Brain MR Imaging and Diffusion-Weighted Imaging

Purpose@#Differentiating between glioblastoma and solitary metastasis is very important for the planning of further workup and treatment. We assessed the ability of various morphological parameters using conventional MRI and diffusion-based techniques to distinguish between glioblastomas and solitary metastases in tumoral and peritumoral regions. @*Materials and Methods@#We included 38 patients with solitary brain tumors (21 glioblastomas, 17 solitary metastases). To find out if there were differences in the morphologic parameters of enhancing tumors, we analyzed their shape, margins, and enhancement patterns on postcontrast T1-weighted images. During analyses of peritumoral regions, we assessed the extent of peritumoral non-enhancing lesion on T2- and postcontrast T1-weighted images. We also aimed to detect peritumoral neoplastic cell infiltration by visual assessment of T2-weighted and diffusionbased images, including DWI, ADC maps, and exponential DWI, and evaluated which sequence depicted peritumoral neoplastic cell infiltration most clearly. @*Results@#The shapes, margins, and enhancement patterns of tumors all significantly differentiated glioblastomas from metastases. Glioblastomas had an irregular shape, ill-defined margins, and a heterogeneous enhancement pattern; on the other hand, metastases had an ovoid or round shape, well-defined margins, and homogeneous enhancement. Metastases had significantly more extensive peritumoral T2 high signal intensity than glioblastomas had. In visual assessment of peritumoral neoplastic cell infiltration using T2-weighted and diffusion-based images, all sequences differed significantly between the two groups. Exponential DWI had the highest sensitivity for the diagnosis of both glioblastoma (100%) and metastasis (70.6%). A combination of exponential DWI and ADC maps was optimal for the depiction of peritumoral neoplastic cell infiltration in glioblastoma. @*Conclusion@#In the differentiation of glioblastoma from solitary metastatic lesions, visual morphologic assessment of tumoral and peritumoral regions using conventional MRI and diffusion-based techniques can also offer diagnostic information.

Autosomal Dominant Drusen Confirmed by Molecular Genetics

Purpose@#To report a case of autosomal dominant drusen confirmed by molecular genetic testing and the clinical features and findings of a multimodal diagnostic imaging study.Case summary: A 32-year-old male presented with decreased visual acuity in his right eye from 1 year prior to his first visit. On the first visit, his visual acuities were 0.3 in the right eye and 1.2 in the left eye. A fundus examination showed numerous drusen of various sizes widely distributed on the posterior pole of both eyes, as well as subretinal fibrotic change with pigmentation in the right eye. Optical coherence tomography showed extensive hyperreflective deposits beneath the retinal pigment epithelium in both eyes and small amounts of cystic intraretinal fluid in the right eye. Fluorescein angiography and fundus autofluorescence showed the drusen as multiple hyperfluorescent spots, while indocyanine green angiography indicated hypofluorescence corresponding to the drusen. Genetic sequence analysis revealed a pathogenic variant of the EFEMP1 gene, heterozygous c.1033C>T (p.Arg345Trp), which accords with the diagnosis of autosomal dominant drusen. Intravitreal bevacizumab injection was given in the right eye; however, there was no improvement in the amount of intraretinal fluid nor visual acuity. @*Conclusions@#Autosomal dominant drusen is a very rare disease. It is necessary to distinguish it from age-related macular degeneration, as the affected age and clinical features of drusen are different, including the response to anti-vascular endothelial growth factor treatment.

A Case of Sweet’s Syndrome with Acute Kidney Injury in a Patient with Myelodysplastic Syndrome / 대한내과학회지

Sweet’s syndrome (SS) is an autoimmune-mediated acute febrile neutrophilic dermatosis with a number of possible etiologies, including infection, malignancy, and drug reactions. In contrast to its original description, it can rarely involve extracutaneous organs, including the central nervous system, cardiovascular system, lung, liver, gastrointestinal tract, spleen, and bone. To our knowledge, there have been only three cases of SS accompanied by acute kidney injury worldwide, and this is the first report in which the patient recovered completely from acute kidney injury as well as cutaneous lesions with early steroid administration. Here, we report a case of SS with acute kidney injury in a patient with myelodysplastic syndrome (MDS) whose skin lesions and renal function recovered fully with early diagnosis and steroid therapy along with a review of the relevant literature.

Clinical Course and Outcomes of 3,060 Patients with Coronavirus Disease 2019 in Korea, January–May 2020

Background@#The fatality rate of patients with coronavirus disease 2019 (COVID-19) varies among countries owing to demographics, patient comorbidities, surge capacity of healthcare systems, and the quality of medical care. We assessed the clinical outcomes of patients with COVID-19 during the first wave of the epidemic in Korea. @*Methods@#Using a modified World Health Organization clinical record form, we obtained clinical data for 3,060 patients with COVID-19 treated at 55 hospitals in Korea. Disease severity scores were defined as: 1) no limitation of daily activities; 2) limitation of daily activities but no need for supplemental oxygen; 3) supplemental oxygen via nasal cannula; 4) supplemental oxygen via facial mask; 5) non-invasive mechanical ventilation; 6) invasive mechanical ventilation; 7) multi-organ failure or extracorporeal membrane oxygenation therapy; and 8) death. Recovery was defined as a severity score of 1 or 2, or discharge and release from isolation. @*Results@#The median age of the patients was 43 years of age; 43.6% were male. The median time from illness onset to admission was 5 days. Of the patients with a disease severity score of 3–4 on admission, 65 (71.5%) of the 91 patients recovered, and 7 (7.7%) died due to illness by day 28. Of the patients with disease severity scores of 5–7, 7 (19.5%) of the 36 patients recovered, and 8 (22.2%) died due to illness by day 28. None of the 1,324 patients who were < 50 years of age died; in contrast, the fatality rate due to illness by day 28 was 0.5% (2/375), 0.9% (2/215), 5.8% (6/104), and 14.0% (7/50) for the patients aged 50–59, 60–69, 70–79, and ≥ 80 years of age, respectively. @*Conclusion@#In Korea, almost all patients of < 50 years of age with COVID-19 recovered without supplemental oxygen. In patients of ≥ 50 years of age, the fatality rate increased with age, reaching 14% in patients of ≥ 80 years of age.

The Difference in Intraocular Pressure before and after Visual Field Test Measured by Rebound Tonometer

PURPOSE: To investigate the effect of a visual field (VF) test on intraocular pressure (IOP) and relevant parameters in a normal group and an open-angle glaucoma group, and to determine the appropriate time of IOP measurements.METHODS: The IOP was measured by a rebound tonometer before and after a VF test for the normal, normal-tension glaucoma, and high-tension glaucoma groups, and IOP differences after the VF tests were compared among groups. Parameters including age, sex, axial length, central corneal thickness, IOP before the VF test, the VF index, mean deviation, VF test duration, and usage of IOP lowering medications were investigated, and the correlations of these parameters with IOP changes after VF tests were determined using linear regression analyses.RESULTS: A total of 232 participants (232 eyes) included 55 normal subjects, 131 normal-tension glaucoma patients, and 46 high-tension glaucoma patients. The IOP differences after VF tests were not statistically significant in the normal and high-tension glaucoma groups, and the difference was 0.31 mmHg in the normal-tension glaucoma group (p = 0.013). Multivariate regression analyses revealed that axial length (p = 0.005) and IOP before the VF test (p < 0.001) were relevant factors in the total number of patients, and the axial length (p = 0.017), IOP before the VF test (p = 0.001), and duration (p = 0.029) were found to be significantly associated with IOP differences in the normal-tension glaucoma group.CONCLUSIONS: The IOP changes after VF tests using the rebound tonometer were significant in the normal-tension glaucoma group, but were within an acceptable range. The IOP value measured after a VF test is clinically valid in clinical practice.

Acute Kidney Injury after Administering Dapagliflozin to a Diabetic Patient with Acute Cerebral Infarction / 대한내과학회지

Dapagliflozin is a recently developed oral anti-diabetic drug and SGLT2 inhibitor with well-known cardioprotective and renoprotective effects. Although a reduction of the glomerular filtration rate is induced by volume depletion and tubule-glomerular feedback during the early period after administering a SGLT2 inhibitor, the renal prognosis improves more with a decrease of proteinuria. However, the risk of acute kidney injury increases in heart failure and hypovolemia patients, and in those taking certain drugs, such as non-steroidal anti-inflammatory drugs, angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, or diuretics. We report acute kidney injury after dapagliflozin administration in a diabetic patient with acute cerebral infarction accompanied by right hemiplegia, motor aphasia, and dysphagia.

Minimal Change in Nephrotic Syndrome Associated with Mixed Connective Tissue Disease / 대한내과학회지

Mixed connective tissue disease (MCTD) is a rheumatologic disorder that has combined features of systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis with the anti-U1 ribonucleoprotein (RNP) antibody. Although renal involvement is not included in any of the diagnostic criteria, it has been observed in 20% of MCTD patients. The most common renal disease is immune complex nephropathy, histologically classified as membranous glomerulonephritis, but minimal change disease (MCD) is very rare and has only been reported once previously. A previously healthy 33-year-old woman presented with generalized edema, puffy hands, arthralgia, and Raynaud’s phenomenon. We diagnosed MCD with proteinuria (> 9 g/day) and hypoalbuminemia (< 1.0 g/dL) by renal biopsy, and MCTD with a simultaneously high titer of the anti-U1 RNP antibody. The patient was treated with 200 mg/day cyclosporine and 30 mg/day prednisolone. The proteinuria and hypoalbuminemia normalized 2 months later. We report a patient with severe MCD associated with MCTD.