Machine-Learning-Based Approach to Differential Diagnosis in Tuberculous and Viral Meningitis / 감염과화학요법

Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.

Machine-Learning-Based Approach to Differential Diagnosis in Tuberculous and Viral Meningitis / 감염과화학요법

Background@#Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.Material and Methods: For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machinelearning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information. @*Results@#The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machinelearning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03). @*Conclusion@#The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.

Is the Initial Size of Tuberculous Lymphadenopathy associated with Lymph Node Enlargement during Treatment? / 감염과화학요법

There are little data on the changes in lymph node (LN) size during the treatment of tuberculous lymphadenopathy (TB LAP). This study aimed to provide data on LN changes during treatment. Between March 2014 and December 2015, 20 patients who were diagnosed with cervical TB LAP were enrolled. LN enlargement within two months (50%, 4/8 vs. 8.3%, 1/12; P = 0.04) was more frequently observed in patients with initial LN size ≥ 7.5 cm². Enlarged LNs were excised in three patients owing to pain and fistula formation. Initial LN size may be associated with LN enlargement during treatment.

Institutional Preparedness to Prevent Future Middle East Respiratory Syndrome Coronavirus-Like Outbreaks in Republic of Korea / 감염과화학요법

A year has passed since the Middle East respiratory syndrome (MERS) outbreak in the Republic of Korea. This 2015 outbreak led to a better understanding of healthcare infection control. The first Korean patient infected by Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was diagnosed on May 20, 2015, after he returned from Qatar and Bahrain. Thereafter, 186 Korean people were infected with the MERS-CoV in a short time through human-to-human transmission. All these cases were linked to healthcare settings, and 25 (13.5 %) infected patients were healthcare workers. Phylogenetic analysis suggested that the MERS-CoV isolate found in the Korean patient was closely related to the Qatar strain, and did not harbor transmission efficiency-improving mutations. Nevertheless, with the same infecting virus strain, Korea experienced the largest MERS-CoV outbreak outside the Arabian Peninsula, primarily due to the different characteristics of population density and the healthcare system. We aimed to review the epidemiological features and existing knowledge on the Korean MERS outbreak, and suggest methods to prevent future epidemics.

Characteristics of Device-Associated Cerebrospinal Fluid Infection in Adults

OBJECTIVE: Device-associated infections in the central nervous system are serious complications of procedures involving indwelling devices among neurosurgical patients. In this study, the clinical characteristics and outcome of microbiologically confirmed device-associated cerebrospinal fluid (CSF) infection were evaluated. METHODS: We performed a retrospective analysis of adult patients found to have a positive CSF culture result during a hospital admission between 1 January 2005 through 2 October 2010 in Soonchunhyang University Hospital. RESULTS: During the study period, all episodes (n=161 CSF specimens, 87 patients) involving a culture-positive CSF were enrolled. Thirty-two episodes of device-associated CSF infection were included in the analysis among the study group. Most device-associated infections were ventriculo-peritoneal shunt infections (14/32, 44%). Fever (>38degrees C) was present in 17 episodes (53%). Overall, the most common microorganism was coagulase-negative staphylococcus (7/32 [22%]). Gram-negative rods (Pseudomonas aeruginosa 6/32 [19%], Acinetobacter baumannii/haemolyticus 5/32 [16%]) were identified in culture in 16/32 (50%). Device was removed for the control of device-associated infection in 30/32 (94%). Cure rate was 69% (22/32). All patients with treatment failure (10/32, 34%) expired. CONCLUSION: It is difficult to diagnosis device-associated CSF infections early since those are frequently presented with nonspecific clinical signs and symptoms. In our study, gram-negative infections accounted for 50% of cases and the empiric antibiotics initially chosen were found to not be effective against the final identified pathogen in many cases. Device-associated CSF infections should be strongly considered a serious risk factor associated with CSF infections, and prompt initiation of broad coverage antibiotics should be started after appropriate assessment.

Risk Factors for Mortality in Patients with Acinetobacter baumannii Bacteremia / 감염과화학요법

BACKGROUND: Acinetobacter baumannii, an opportunistic nosocomial pathogen that can cause significant morbidity and mortality, has emerged as a worldwide problem. The aim of this study was to evaluate the risk factors for mortality in patients with A. baumannii bacteremia. MATERIALS AND METHODS: We retrospectively evaluated 118 patients who had A. baumannii bacteremia between July 2003 and December 2011. The aim of this study was to identify the 30-day mortality in patients with A. baumannii bacteremia and relevant risk factors. RESULTS: The bacteremia-related 30-day mortality rate was 34.1%. Univariate analysis revealed that the risk factors for mortality included malignancy, longer hospital stay before bacteremia, intensive care unit (ICU) stay at the time of bacteremia, mechanical ventilation, use of a central venous catheter, unknown origin of bacteremia, bacteremia due to pneumonia, antimicrobial resistance to carbapenems, and elevated Acute Physiology and Chronic Health Evaluation II and Pitt bacteremia scores. Multivariate logistic regression analysis revealed that resistance to carbapenems (odds ratio [OR]: 4.01, 95% confidence interval [CI]: 1.51 to 0.68, P = 0.005), need for mechanical ventilation (OR: 3.97, 95% CI: 1.41 to 11.13, P = 0.005), and presence of malignancy (OR: 4.40, 95% CI: 1.60 to 12.08, P = 0.004) were significantly related to mortality risk. CONCLUSIONS: Risk factors such as resistance to carbapenems, mechanical ventilation, and presence of malignancy were found to be associated with high mortality rates in the patients with A. baumannii bacteremia.

Primary Hepatosplenic Tuberculosis in an Immunocompetent Adult and Domestic Literature Review

Hepatic or splenic involvement of tuberculosis without other disseminated lesions is a very uncommon form of extrapulmonary tuberculosis, especially in an immunocompetent adult. We report a case of a 25 year-old-man who developed primary hepatosplenic tuberculosis not associated with the lung or other distant organs. He was initially diagnosed with esophageal candidiasis in local clinic. A computed tomographic scan of the abdomen showed hepatosplenomegaly and multiple microabscesses in the spleen. Our initial diagnosis, based on the clinical feature and radiologic findings, was hepatosplenic candidiasis. However, histopathology of the liver specimens revealed chronic granuloma with central caseous necrosis, strongly suggestive of tuberculosis. Although rare, splenic tuberculosis should be considered in the differential diagnosis of splenic abscess, especially in countries where tuberculosis is endemic.

The Clinical Characteristics, Therapeutic Outcome and Prognostic Factors for Invasive Pulmonary Aspergillosis: A Single-Center Experience and Review of the Literature / 대한의진균학회지

BACKGROUND: Despite advances in microbiological diagnosis and effective antifungal treatment, invasive pulmonary aspergillosis (IPA) is a still major cause of mortality in immunocompromised patients. OBJECTIVE: The aim of this study is to analyze clinical characteristics, treatment outcome and prognostic factors for IPA. METHODS: Between May 2003 and March 2011, we retrospectively studied all patients with IPA in our facility. RESULTS: A total 37 cases were identified. Hematologic malignancies were the leading underlying disease for 27 (27/37, 73.0%) patients. Neutropenic period between the onset of neutropenia and the diagnosis of IPA was 15.0 days. The most common symptom was fever (35/37, 94.6%). The principal findings of chest computed tomography (CT) were segmental or air space consolidation (17/37, 45.9%) followed by halo sign (13/37, 35.1%), and ground-glass attenuation (11/37, 29.7%). Amphotericin B was the initial treatment for 36 (36/37, 97.3%) patients. Voriconazole was subsequently substituted for Amphotericin B in 25 (35/36, 97.2%) patients. The 30-day mortality rate was 24.3% (9/37). The 30-day mortality rate was associated with a failure to recover from neutropenia (p=0.048) or persistent fever during treatment (p=0.003). Two patients were lost to follow-up. Overall mortality was 62.9% (22/35). CONCLUSION: IPA remains a serious condition with failure to recover from neutropenia or persistent fever during treatment associated with a high 30-day mortality rate.

A Case of Gastrointestinal and Cervical Lymph Nodal Kaposi's Sarcoma in a Patient with Acquired Immunodeficiency Syndrome

Kaposi's sarcoma was the first malignancy to be recognized as a cancer defining acquired immunodeficiency syndrome (AIDS). Kaposi's sarcoma, a rare tumor, usually presents itself with skin lesions but it may be widely disseminated internally such as digestive, respiratory organ, spleen, or lymph node. The incidence of Kaposi's sarcoma in patients with AIDS has declined in the era of effective antiretroviral therapy (ART), and cases of disseminated Kaposi's sarcomas have rarely been reported in Korea. Chemotherapy is usually used in symptomatic or rapidly progressive disease, and interferon-alpha can be applied as a treatment option. We report a successfully treated case of gastrointestinal and cervical lymph nodal Kaposi's sarcoma in a patient with AIDS who had combined treatment with ART, interferon-alpha, and paclitaxel.

Cytomegalovirus Infectious Mononucleosis in a Patient with a Gastric Ulcer / 대한소화기내시경학회지

Cytomegalovirus (CMV) is a prevalent pathogen, with 98~100% of Korean adults showing prior exposure by serology. A primary infection, such as CMV infectious mononucleosis, is very rare. CMV infectious mononucleosis often presents an initial diagnostic problem. Patients are often hospitalized with a wide variety of clinical diagnoses including fever of unknown origin without pharyngitis and lymphadenopathy. CMV gastrointestinal infections are rare in previously immunocompetent individuals. The most common sites involved are the colon and rectum, although lesions of the stomach have also been described. It is unusual to see CMV infectious mononucleosis and CMV gastrointestinal infection in the same patient. Our patient received symptomatic treatment and fully recovered. We present a case of CMV infectious mononucleosis with gastric ulcers in a previously healthy adult.

Clinical Characteristics and Outcome of Vascular Access Infections in Hemodialysis Patients / 감염과화학요법

BACKGROUND: Infections are the second leading cause of morbidity and mortality in hemodialysis patients. Vascular access is a major risk factor for infection-related hospitalization and mortality. This study aimed to characterize the presenting features and outcome of vascular access infection in hemodialysis patients. MATERIALS AND METHODS: Between May 2003 and March 2010, 224 patients admitted to a 750 bed tertiary care hospital for treatment of vascular access infection were retrospectively analyzed. Vascular access infections were defined by local infection signs (pus or redness) at the vascular access site or by a positive blood culture with no known source other than the vascular access. RESULTS: Of the 224 patients, 179 (79.7%) had an arteriovenous (AV) graft, 28 (12.5%) had a tunneled cuffed catheter, 12 (5.4%) had AV fistulas, and five (2.2%) had a temporary central catheter. The mean+/-SD time between the creation of each type of vascular access and onset of infection were as follows: temporary central catheter 46.6+/-36.9 days, tunneled cuffed catheter 180.3+/-168.8 days, AV fistulas 928.6+/-1,299.7 days, and AV graft 1,066.3+/-1321.1 days (P value=0.006). The most common causative organism was Staphylococcus aureus (62.5%; methicillin-susceptible 35.2%, methicillin-resistant 27.3%) followed by coagulase negative staphylococci (17.0%) and gram negative bacilli (15.9%). The involved vascular accesses in infected cases were: temporary central catheter (4/5, 80%), tunneled cuffed catheter (13/27, 48%), AV graft (68/179, 38%) and AV fistulas (4/12, 33%). The complications of vascular access infection included septic pulmonary embolism (n=9, 4%), pneumonia (n=9, 4%), endocarditis (n=6, 2.7%), osteomyelitis (n=3, 1.3%) and abdominal abscess (n=2, 0.9%). A multivariable analysis showed that Staphylococcus aureus was a risk factor of septic pulmonary embolism and osteomyelitis. The all-cause mortality was 8.4%, 30-day mortality was 2.2% and infection-related mortality was 5.4%. CONCLUSIONS: Staphylococcus was responsible for 79.5% of infections, with methicillin-susceptible S. aureus being the most commonly implicated strain. Temporary accesses have the potential to become infected earlier. Septic pulmonary embolism and pneumonia were common complications. Efforts should be focused on prevention and early detection of VA infection with pulmonary complications.