Edwin Chong Yu Sng

Primary Epstein-Barr virus (EBV) infection typically presents as infectious mononucleosis (IM), a clinical syndrome characterised by fever, pharyngitis and cervical lymphadenopathy. We describe a previously healthy 26-year-old woman who presented with fever and right-sided abdominal pain. There was no associated pharyngitis or enlarged cervical lymph nodes. Laboratory investigations demonstrated atypical lymphocytosis with a mixed hepatocellular-cholestatic pattern of liver enzyme derangement. Initial contrast-enhanced computed tomography of the abdomen and pelvis (CTAP) was unremarkable. As polymerase chain reaction was positive for EBV DNA (6290 copies/ml) in her serum, she was initially managed as for EBV hepatitis. Over 5 days, her abdominal pain worsened with development of positive Murphy’s sign and repeat CTAP demonstrated a distended gallbladder with diffuse mural oedema without cholelithiasis, suggestive of acute acalculous cholecystitis (AAC). She made a full recovery with supportive management alone. AAC is a rare complication of primary EBV infection and may occur without features of IM. Early in the course of AAC, Murphy’s sign may be absent, and CT may be non-diagnostic. Clinicians should maintain a high index of suspicion for AAC in patients with primary EBV infection who have right sided abdominal pain. Repeat imaging may be required if abdominal findings progress.

Background: Although endemic in surrounding countries, the true burden of histoplasmosis in Singapore is not well-defined and likely underestimated due to under-diagnosis. This case report describes a case of fatal chronic disseminated histoplasmosis in an elderly immunocompetent Singaporean male without recent travel. Case Report: A 77-year-old male presented with a 3-month history of generalised weakness and loss of weight. As investigations revealed bilateral calcified pulmonary nodules, bilateral adrenal enlargement, cytopenias, and non-parathyroid hormone-mediated hypercalcaemia, he was evaluated for tuberculosis. He later developed massive gastrointestinal bleeding and he underwent emergent endoscopy that revealed ulcerative nodular lesions in the duodenum and throughout the colon. Biopsies of the lesions showed numerous 2–4 μm intracellular yeasts within histiocytes in the lamina propria, suggestive of histoplasmosis. Based on the pathological finding, he was started on amphotericin B on day 26 of admission, but passed away 1 day later from refractory hypotension. Histoplasma capsulatum eventually grew on fungal blood culture. Conclusion: This case highlights the need for greater awareness of histoplasmosis among clinicians in Singapore. Because Histoplasma capsulatum can reactivate several years after exposure, and chronic disseminated histoplasmosis can occur in the immunocompetent elderly, histoplasmosis should be considered and specific diagnostic testing be undertaken whenever there is a compatible clinical syndrome, regardless of travel history and immune status. As disseminated histoplasmosis can be fatal, a high index of clinical suspicion is crucial to ensure timely diagnosis and treatment.

Brain abscess remains a serious infection with high morbidity and mortality despite advances in neuroimaging, molecular diagnostics and stereotactic neurosurgical techniques. Most large studies were based on European cohorts. Most Asian studies are single center, with smaller cohorts that consist almost entirely of patients with pyogenic brain abscess (PBA). Here, we present the results of our multi-center, retrospective study, representing the largest cohort of adults with brain abscess in Singapore. Radiological reports of patients who underwent neuroimaging between 1 Nov 2013 and 31 Dec 2024 at three tertiary hospitals in Singapore were filtered for terms indicating brain abscess. Infectious diseases physicians reviewed the electronic medical records to identify patients who fulfilled pre-determined criteria for "definite" or "probable" diagnosis. Over the 11-year-old study period, there were 106 patients with brain abscess. The diagnosis of 54 and 52 patients were assessed to be "definite" and "probable", respectively. The median age (interquartile) of the patients was 59 years (49-67), 62.2% (66/106) were male, and 95.3% (101/106) were Singaporeans. 60.4% (64/106) were immunocompromised. PBA (n = 65) accounted for more than half of the cases, followed by tuberculosis (TB) (n = 20), toxoplasmosis (n = 9), Nocardia brain abscess (n = 7), invasive mold infection (n = 3) and cryptococcosis (n = 2), respectively. Most patients with PBA had only one organism identified from microbiological investigations (53/65, 81.5%), among which Klebsiella pneumoniae (n = 21), Streptococcus anginosus (n = 12) and Staphylococcus aureus (n = 8) were most commonly isolated. 28 out of 65 (43.1%) patients had oral cavity bacteria identified from microbiological investigations. Diabetes mellitus was the leading cause of immunosuppression in patients with PBA, while HIV infection was the leading cause in those with TB. In this cohort, 7.5% (8/106) and 14.2% (15/106) died within 30 and 90 days from date of presentation, respectively. On multivariate analysis, having undergone external ventricular drainage was the only clinical parameter found to be associated with increased mortality (OR 6.26, 95% CI: 1.44-27.1, P = 0.0014). This study has provided valuable insights into the microbiology and clinical characteristics of brain abscesses in adults in Singapore and highlighted challenges in distinguishing between different etiologies. Further study with a larger, multicenter cohort and prospective design may aid to address study limitations.

Background/Objectives: Rapid and accurate classification of ring-enhancing brain lesions (REBLs) into infection or neoplasm is key to clinical triaging for expedited diagnostics in the former to enhance treatment outcomes, especially in the immunocompromised patients. High-resolution three-dimensional (3D) T1 post-contrast (T1+C) MRI provides high-dimensional volumetric data for radiomics analysis. While radiomics is useful in brain neoplasm characterization, its utility in central nervous system infection remains under-explored. In this exploratory study, we aim to determine if a radiomics-machine learning model, based solely on a 3D T1+C MRI dataset, can distinguish infective from neoplastic REBLs. Methods: 92 patients (infection, n = 26; neoplasm, n = 66) with 402 REBLs, who fulfilled criteria for “definite” or “probable” infective or neoplastic REBLs, were identified from scans performed at our hospital over four years and formed the training/validation dataset. All REBLs were manually annotated on T1+C MRI images under radiological supervision. In total, 1197 radiomics features were extracted, feature selection performed using mutual information, and nine machine learning classifiers applied to assess patient-level infection vs. neoplasm classification performance. End-to-end 2D CNN baselines and hybrid radiomics–CNN configurations were additionally evaluated under the same protocol for comparative benchmarking. Model performance was tested on an external holdout dataset of 57 patients (infection, n = 25; neoplasm, n = 32) with 454 REBLs from another hospital. Results: The Multi-layer Perceptron (MLP) model using the Original + LoG + Wavelet feature group demonstrated superior performance. In the cross-validation cohort, it achieved a mean AUC of 0.80 ± 0.02, sensitivity of 0.83 ± 0.09, specificity of 0.77 ± 0.08, and balanced accuracy of 0.80 ± 0.02. On external holdout data, the same configuration showed stable and sustainable performance with an AUC of 0.84, sensitivity of 0.84, specificity of 0.75, and balanced accuracy of 0.80. Conclusions: Our radiomics-machine learning model, based solely on a high-resolution 3D T1+C dataset, shows potential for distinguishing infective REBLs from neoplastic REBLs. Further study, with additional MR sequences and clinical data in a multimodal MRI radiomics-machine learning model, is warranted.

Singapore has yet to conduct an HIV cure trial, and analytical treatment interruption (ATI) studies may face community scepticism. This study explores the perspectives of people living with HIV and healthcare providers in Singapore on participating in functional cure research involving ATI. Participants were recruited from four HIV care facilities through study advertisements. Healthcare providers were recruited via email. A self-administered survey gathered demographic data, views on ATI and HIV cure, acceptability of ATI, and tolerance for CD4 and viral load changes during ATI. Descriptive, univariate, and multivariable logistic regression analyses were used to identify barriers and motivators to trial participation. Among 200 people living with HIV, 116 (58%) expressed willingness to participate in a cure trial; 84 (42%) did not. Most (94.5%, 189/200) had never joined an HIV clinical study. No significant differences in age, gender, sexuality, or HIV duration were observed between the groups. Factors positively associated with willingness to participate included tertiary education (aOR 2.71, 95% CI 1.13–6.81), altruistic motivations (aOR 1.98, 95% CI 1.52–2.66), and financial compensation (aOR 3.55, 95% CI 1.36–9.88). Lower tolerance for viral load increases or CD4 declines was linked to reduced willingness (aOR 0.77, 95% CI 0.67–0.88). Monitoring frequency, self-testing, and home visits had no significant effect. Healthcare providers were more likely to recommend participation in cure trials if they demonstrated high tolerance for HIV viral load increases (p = 0.044), showed stronger interest in cure research (p = 0.009) and expressed greater acceptance of a functional HIV cure (p = 0.014). Willingness to participate in ATI cure trials is higher among individuals with more education, altruistic intent, and less concern about virologic or immunologic changes. Financial compensation is a strong motivating factor but should not play undue inducement in influencing decision to participate in an ATI cure trial. Community engagement and education are crucial to building support for future HIV cure research.

Background: The diagnostic evaluation of ring-enhancing brain lesions (REBLs) is challenging, especially in immunocompromised patients. We conducted a retrospective study to describe the clinicodemographic and radiological features among patients presenting with REBLs to a tertiary referral center. Methods: Radiological reports of all patients who underwent brain computed tomography or magnetic resonance (MR) imaging between 1 November 2013 and 31 October 2017 were filtered for terms indicative of REBLs. Infectious diseases physicians reviewed the medical records to confirm the diagnosis. Results: Over the 4-year study period, there were 42 patients with infective REBLs and 249 with neoplastic REBLs. Pyogenic brain abscesses (PBAs) (20 of 42 [47.6%]) were the most common cause of infective REBLs, followed by tuberculous brain abscesses (TBAs) (9 of 42 [21.4%]) and Nocardia brain abscesses (NBAs) (6 of 42 [14.3%]). The patients were predominantly male, with a mean age of 55.2 years. Fewer than half were febrile at presentation. Cerebrospinal fluid investigations established the microbiological diagnosis in fewer than half of those who underwent lumbar puncture or extraventricular drain insertion. Conversely, brain biopsy yielded the microbiological diagnosis in almost all patients (16 of 17) who underwent the operation. Median white blood cell counts and C-reactive protein were higher in those with PBAs or NBAs than in those with TBAs. All with PBAs and NBAs who underwent MR imaging had diffusion-weighted imaging–hyperintense lesions, compared with only about half of those with TBAs. Conclusions: Our study has revealed important distinguishing features between infective REBLs and neoplastic REBLs and between PBAs, TBAs, and NBAs.

Empyema necessitans is a rare complication of untreated/undertreated empyema characterized by the invasion and progression of empyema beyond the pleura into the chest wall. With the availability of antibiotics, empyema necessitans is now rarely seen in clinical practice. Effective treatment of empyema necessitans entails aggressive source control with surgical decortication in conjunction with prolonged culture‐directed antibiotics. The most common etiologies include Mycobacterium tuberculosis , Actinomyces , Staphylococcus aureus , and Streptococcus specie s. Here, we report a case of refractory nontyphoidal Salmonella empyema necessitans in a patient who is virologically suppressed on HIV treatment and highlight the challenges in management when surgical decortication could not be performed.

A liver abscess can be due to several different microbiological aetiologies. While pyogenic liver abscess is most frequently encountered, amoebic liver abscess and hydatid cyst caused by the parasites, Entamoeba histolytica and Echinococcus granulosus, respectively, should be considered whenever there is epidemiological exposure. As parasitic infections are now rarely seen in clinical practice in developed countries with improvement in sanitation, lack of clinical experience in managing amoebic liver abscesses and overlapping clinical and imaging features between amoebic and pyogenic liver abscesses may lead to delay in diagnosis. In particular, although amoebic liver abscesses respond well to treatment if diagnosed early, they can progress and rupture with high mortality if treatment is delayed. Hence, early diagnosis and prompt initiation of antimicrobials are crucial to prevent complications and death. This case report highlights a case of a very large 21 cm ALA in a young lady to illustrate the challenges faced during diagnostic evaluation.