Pyoderma Gangrenosum Mimicking Necrotizing Fasciitis on Magnetic Resonance Imaging: A Case Report and Literature Review.

BACKGROUND Pyoderma gangrenosum (PG) is a sterile neutrophilic dermatosis that can be associated with systemic diseases, such as ulcerative colitis, polyarthritis, diabetes mellitus, myelodysplastic syndrome, and/or myeloid leukemia, and is often misdiagnosed as a necrotizing infection. Few reports have described imaging studies of PG; however, necrotizing fasciitis (NF) exhibits distinct imaging characteristics. If deep fascial involvement is not demonstrated on magnetic resonance imaging (MRI), NF is excluded. CASE REPORT We present a case of PG mimicking NF on MRI in a 67-year-old woman with acute myeloblastic leukemia. After undergoing a second cycle of decitabine therapy, she was admitted for pain in her lower left leg. The condition was initially misdiagnosed as NF because MRI findings demonstrated signal intensity in the fascia. MRI revealed fasciitis that exhibited linear fluid signal intensity in the fascia of lower left leg. Despite broad-spectrum antibiotics, the lesion rapidly progressed to a swollen hemorrhagic patch with bullae and an ulcer. Skin biopsy results ultimately led to the diagnosis of PG, based on histopathological findings. The patient was treated with intravenous steroids and regular wound dressing. The skin lesion on the lower left leg exhibited a good response. CONCLUSIONS Despite the presence of a lesion that invaded the fascia on MRI, our patient was diagnosed with PG following a skin biopsy and completely recovered with steroid treatment. To distinguish PG from NF, it is more important to identify the characteristic clinical features than to rely solely on imaging findings.

Performance evaluation of STANDARD Q COVID-19 Ag home test for the diagnosis of COVID-19 during early symptom onset.

BACKGROUND: Surveillance and control of SARS-CoV-2 outbreak through gold standard detection, that is, real-time polymerase chain reaction (RT-PCR), become a great obstacle, especially in overwhelming outbreaks. In this study, we aimed to analyze the performance of rapid antigen home test (RAHT) as an alternative detection method compared with RT-PCR. METHODS: In total, 79 COVID-19-positive and 217 COVID-19-negative patients confirmed by RT-PCR were enrolled in this study. A duration from symptom onset to COVID-19 confirmation of <5 days was considered a recruiting criterion for COVID-19-positive cases. A nasal cavity specimen was collected for the RAHT, and a nasopharyngeal swab specimen was collected for RT-PCR. RESULTS: Sensitivity of the STANDARD Q COVID-19 Ag Home Test (SD Biosensor, Korea), compared with RT-PCR, was 94.94% (75/79) (95% [confidence interval] CI, 87.54%-98.60%), and specificity was 100%. Sensitivity was significantly higher in symptomatic patients (98.00%) than in asymptomatic (89.66%) patients (p-value = 0.03). There was no difference in sensitivity according to the duration of symptom onset to confirmation (100% for 0-2 days and 96.97% for 3-5 days, respectively) (p-value = 1.00). The RAHT detected all 51 COVID-19 patients whose Ct values were ≤25 (100%), whereas sensitivity was 73.33% (11/15) among patients with Ct values >25 (p-value = 0.01). CONCLUSION: The RAHT showed an excellent sensitivity for COVID-19-confirmed cases, especially for those with symptoms. There was a decrease in sensitivity when the Ct value is over 25, indicating that RAHT screening may be useful during the early phase of symptom onset, when the viral numbers are higher and it is more transmissible.

Comparing Genomic Characteristics of Streptococcus pyogenes Associated with Invasiveness over a 20-year Period in Korea.

BACKGROUND: Few studies have investigated the invasiveness of Streptococcus pyogenes based on whole-genome sequencing (WGS). Using WGS, we determined the genomic features associated with invasiveness of S. pyogenes strains in Korea. METHODS: Forty-five S. pyogenes strains from 1997, 2006, and 2017, including common emm types, were selected from the repository at Gyeongsang National University Hospital in Korea. In addition, 48 S. pyogenes strains were randomly selected depending on their invasiveness between 1997 and 2017 to evaluate the genetic evolution and the associations between invasiveness and genetic profiles. Using WGS datasets, we conducted virulence-associated DNA sequence determination, emm genotyping, multi-locus sequence typing (MLST), and superantigen gene profiling. RESULTS: In total, 87 strains were included in this study. There were no significant differences in the genomic features throughout the study periods. Four genes, csn1, ispE, nisK, and citC, were detected only in invasive strains. There was a significant association between invasiveness and emm cluster type A-C3, including, emm1.0, emm1.18, emm1.3, and emm1.76 (P<0.05). The predominant emm1 lineage belonged to ST28. There were no associations between invasiveness and superantigen gene profiles. CONCLUSIONS: This is the first study using WGS datasets of S. pyogenes strains collected between 1997 and 2017 in Korea. Streptococcal invasiveness is associated with the presence of csn1, ispE, nisK, and citC. The emm1 lineage and ST28 clone are explicitly associated with invasiveness, whereas genomic features remained stable over the 20-year period.

Can an anti-Xa assay for unfractionated heparin be used to assess the presence of rivaroxaban in critical situations?

OBJECTIVE: Although rivaroxaban has recently become widely used for thrombosis treatment, it is difficult for clinicians to make clinical decisions in critical situations, such as emergent surgery or interventions, because a specific anti-Xa assay is not available in many laboratories. This study assessed the relationships between rivaroxaban-specific anti-factor Xa activity (AXA) and unfractionated heparin (UFH)-specific AXA and determined the cutoff level for UFH-specific AXA in critical situations for patients undergoing rivaroxaban therapy. METHODS: Thirty-eight blood samples were collected from patients with cancer-associated thrombosis receiving rivaroxaban therapy. All samples were assessed using both rivaroxaban-specific and UFH-specific anti-Xa assays. Routine coagulation studies, including prothrombin time (PT) and activated partial thromboplastin time, were also conducted on the samples. RESULTS: A positive dose-dependent correlation between rivaroxaban-specific and UFH-specific AXA was evident (R = 0.97; P < .0001). Rivaroxaban-specific AXA was also positively correlated with PT (R = 0.95; P < .0001) but only weakly with activated partial thromboplastin time (R = 0.67; P < .0001). Patients with plasma rivaroxaban concentrations <100 ng/mL were found to have UFH-specific AXA <1.41 IU/mL and PT <17.3 seconds, with sensitivities of 100% and 93.3% and specificities of 87.0% and 95.7%, respectively. CONCLUSIONS: Our study demonstrates that UFH-calibrated AXA correlates strongly with plasma rivaroxaban concentration. This assay appears to be sensitive to the presence of rivaroxaban, which may be advantageous in the setting of assessing drug levels for critical events. These findings suggest that if a rivaroxaban-specific anti-Xa assay is unavailable, the chromogenic anti-Xa assay for UFH may be useful to assess the anticoagulant effects of rivaroxaban.

Parvovirus B19 infection presenting with neutropenia and thrombocytopenia: Three case reports.

RATIONALE: Parvovirus B19 (PV) infection is usually symptomless and can cause benign, short-lived conditions. Anemia associated with PRCA is the most representative hematologic manifestation, but neutropenia and thrombocytopenia have been rarely reported. PATIENT CONCERNS: Three patients were admitted to the hospital with neutropenia and thrombocytopenia. The accompanying symptoms were fever, myalgia, rash, or arthralgia, and all patients were previously healthy. DIAGNOSIS: Patients were positive for PV PCR and diagnosed with PV infection. Before the diagnosis of PV infection, 2 patients underwent BM study and almost absence of erythroid progenitor cells in BM aspiration were a clue for the PV infection. Other BM findings were hypocellular marrow and a few hemophagocytic histiocytes. INTERVENTIONS: Patients received supportive care with follow-up of CBC. OUTCOMES: All 3 patients spontaneously recovered from neutropenia and thrombocytopenia within 3 weeks without severe complications. LESSONS: The evaluation of PV infection should be considered in situations where there is neutropenia and thrombocytopenia in healthy individuals even without anemia as a differential diagnosis.

Laboratory measurement of apixaban using anti-factor Xa assays in acute ischemic stroke patients with non-valvular atrial fibrillation.

Apixaban is effective and safe for preventing stroke, and its usage has increased exponentially in recent years. However, data concerning the therapeutic range of apixaban is limited. This study determined the trough and peak levels of apixaban-specific anti-factor Xa activity (AFXaA) in acute ischemic stroke patients with non-valvular atrial fibrillation (NVAF) in Korea. The study included 85 patients who received apixaban. Blood samples were taken to measure the trough and peak levels of AFXaA using a chromogenic anti-factor assay, as well as prothrombin time (PT) and activated partial thromboplastin time (aPTT). We also reviewed complications such as major bleeding of patients treated with apixaban. In patients given a 5.0-mg apixaban dose, the median trough and peak levels of AFXaA were 104.5 and 202.0 ng/mL. In patients given a 2.5-mg apixaban dose, the median trough and peak AFXaA levels were 76.0 and 151.0 ng/mL. The PT showed a positive correlation with increased AFXaA activity at both levels (Trough R = 0.486, Peak R = 0.592), but the aPTT had no relationship with AFXaA activity at both levels (Trough R = 0.181, Peak R = 0.129). Two cases with intracranial bleeding belonged to the highest AFXaA quartile (Trough, p = 0.176; Peak, p = 0.053). In conclusion, we determined the trough and peak levels of AFXaA in patients with NVAF while being treated with the apixaban in Korea. Our results could be used as a starting point when setting the reference ranges for laboratories using anti-Xa assay. Large-scale studies are needed to establish the reference range for AFXaA in patients with NVAF.