Venous thromboembolism (VTE) is the leading cause of morbidity and mortality among hospitalized patients. We searched the PubMed database and reviewed the articles published until June 2011. Articles related to the D-dimer and VTE were considered to write this paper. Many factors play a key role in changing the sensitivity and specificity of D-dimer testing, including the extent of thrombosis and fibrinolytic activity, duration of symptoms, anticoagulant therapy, comorbidity due to surgical or medical illnesses, inflammatory diseases, cancer, elderly age, pregnancy and the postpartum period, and previous VTE. Many previous studies have shown that the D-dimer test is highly sensitive (>95%) in acute deep venous thrombosis or pulmonary embolism, usually with a cut-off value of 500 μg FEU/l, which reasonably rules out acute VTE, particularly in patients with low clinical probability (LCP) or intermediate clinical probability. Patients with high D-dimer levels upon presentation may prompt a more intense diagnostic approach, irrespective of pretest probability. Studies performed after a negative D-dimer for 3 months proved the high negative predictive value (NPV) of D-dimer testing together with LCP in patients with suspected VTE. Among oncology patients, D-dimer testing has the highest sensitivity and NPV in excluding VTE. The new cutoff values of D-dimer testing were analyzed in a recent prospective study of pregnant women; they are 286 ng DDU/ml, 457 ng DDU/ml, and 644 ng DDU/ml for the first, second, and third trimesters, respectively.

Cerebral toxoplasmosis is a rare disease predominantly found in immunocompromised hosts. However, cerebral toxoplasmosis has not been frequently described in association with the use of immunosuppressive medications. We herein report a case of cerebral toxoplasmosis in a 76-year-old Caucasian woman on methotrexate and infliximab for rheumatoid arthritis. The patient presented with right facial droop, slurred speech and difficulty walking. In addition to receiving methotrexate and infliximab and owning a cat, she had no other obvious risk factors. Imaging studies were not conclusive; however, brain biopsy confirmed the diagnosis. Serology was positive for anti-toxoplasma immunoglobulin G. Cerebral toxoplasmosis should be included in the differential diagnosis of patients under immunosuppressive medication who present with neurological manifestations.

Geographical weighted regression (GWR) can be used to explore the COVID-19 transmission pattern between cases. This study aimed to explore the influence from environmental and urbanisation factors, and the spatial relationship between epidemiologically-linked, unlinked and imported cases during the early phase of the epidemic in Singapore. Spatial relationships were evaluated with GWR modelling. Community COVID-19 cases with residential location reported from 21st January 2020 till 17th March 2020 were considered for analyses. Temperature, relative humidity, population density and urbanisation are the variables used as exploratory variables for analysis. ArcGIS was used to process the data and perform geospatial analyses. During the early phase of COVID-19 epidemic in Singapore, significant but weak correlation of temperature with COVID-19 incidence (significance 0.5–1.5) was observed in several sub-zones of Singapore. Correlations between humidity and incidence could not be established. Across sub-zones, high residential population density and high levels of urbanisation were associated with COVID-19 incidence. The incidence of COVID-19 case types (linked, unlinked and imported) within sub-zones varied differently, especially those in the western and north-eastern regions of Singapore. Areas with both high residential population density and high levels of urbanisation are potential risk factors for COVID-19 transmission. These findings provide further insights for directing appropriate resources to enhance infection prevention and control strategies to contain COVID-19 transmission.