Enhancing diagnostic precision for acute chest syndrome in sickle cell disease: insights from dual-energy CT lung perfusion mapping.

PURPOSE: Acute chest syndrome (ACS) is secondary to occlusion of the pulmonary vasculature and a potentially life-threatening complication of sickle cell disease (SCD). Dual-energy CT (DECT) iodine perfusion map reconstructions can provide a method to visualize and quantify the extent of pulmonary microthrombi. METHODS: A total of 102 patients with sickle cell disease who underwent DECT CTPA with perfusion were retrospectively identified. The presence or absence of airspace opacities, segmental perfusion defects, and acute or chronic pulmonary emboli was noted. The number of segmental perfusion defects between patients with and without acute chest syndrome was compared. Sub-analyses were performed to investigate robustness. RESULTS: Of the 102 patients, 68 were clinically determined to not have ACS and 34 were determined to have ACS by clinical criteria. Of the patients with ACS, 82.4% were found to have perfusion defects with a median of 2 perfusion defects per patient. The presence of any or new perfusion defects was significantly associated with the diagnosis of ACS (P = 0.005 and < 0.001, respectively). Excluding patients with pulmonary embolism, 79% of patients with ACS had old or new perfusion defects, and the specificity for new perfusion defects was 87%, higher than consolidation/ground glass opacities (80%). CONCLUSION: DECT iodine map has the capability to depict microthrombi as perfusion defects. The presence of segmental perfusion defects on dual-energy CT maps was found to be associated with ACS with potential for improved specificity and reclassification.

Associating a standardized reporting tool for chest radiographs with clinical complications in pediatric acute chest syndrome.

BACKGROUND: Acute chest syndrome (ACS) is an important cause of morbidity in sickle cell disease (SCD). A standardized tool for reporting chest radiographs in pediatric SCD patients did not previously exist. OBJECTIVE: To analyze the interobserver agreement among pediatric radiologists' interpretations for pediatric ACS chest radiographs utilizing a standardized reporting tool. We also explored the association of radiographic findings with ACS complications. METHODS: This was a retrospective cohort study of pediatric ACS admissions from a single institution in 2019. ICD-10 codes identified 127 ACS admissions. Two radiologists independently interpreted the chest radiographs utilizing a standardized reporting tool, a third radiologist adjudicated discrepancies, and κ analysis assessed interobserver agreement. Clinical outcomes were correlated with chest radiograph findings utilizing Pearsons' χ2 , t tests, and Mann-Whitney U tests. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. RESULTS: Interobserver agreement was moderate to near-perfect across variables, with κ analysis showing near-perfect agreement for opacity reported in the right upper lobe (0.84), substantial agreement for right lower lobe (0.63), and vertebral bony changes (0.72), with moderate agreement for all other reported variables. On the initial chest radiograph, an opacity located in the left lower lobe (LLL) correlated with pediatric intensive care unit transfer (p = .03). Pleural effusion on the initial chest radiograph had a 3.98 OR (95% CI: 1.35-11.74) of requiring blood products and a 10.67 OR (95% CI: 3.62-31.39) for noninvasive ventilation. CONCLUSION: The standardized reporting tool showed moderate to near-perfect agreement between radiologists. LLL opacity, and pleural effusion were associated with increased risk of ACS complications.

Diagnostic Test Accuracy of Lung Ultrasound for Acute Chest Syndrome in Sickle Cell Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Acute chest syndrome (ACS) is a leading cause of death in patients with sickle cell disease. Lung ultrasound (LUS) is emerging as a point-of-care method to diagnose ACS, allowing for more rapid diagnosis in the ED setting and sparing patients from ionizing radiation exposure. RESEARCH QUESTION: What is the diagnostic accuracy of LUS for ACS diagnosis, using the current reference standard of chest radiography? STUDY DESIGN AND METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed for this systematic review and meta-analysis. Embase, MEDLINE, Web of Science, and Google Scholar were used to compile all relevant studies. Two reviewers screened the studies for inclusion in this review. Cases of discrepancy were resolved by a third reviewer. Meta-analyses were conducted using both metadta and midas STATA software packages to retrieve summary receiver operating characteristic curves, sensitivities, and specificities. Three reviewers scored the studies with QUADAS-2 for risk of bias assessment. RESULTS: From a total of 713 unique studies retrieved, six studies were included in the final quantitative synthesis. Of these, five studies were in pediatric EDs. Two studies were conference abstracts and not published manuscripts. Data were available for 625 possible ACS cases (97% of cases in patients aged ≤ 21 years) and 95 confirmed ACS diagnoses (pretest probability of 15.2%). The summary sensitivity was 0.92 (95% CI, 0.68-0.98) and the summary specificity was 0.89 (95% CI, 0.69-0.97) with an area under the curve of the summary receiver operating characteristic curve of 0.96 (95% CI, 0.94-0.97). INTERPRETATION: LUS has excellent sensitivity and very good specificity for ACS diagnosis and may serve as an initial point-of-care test to facilitate rapid treatment of ACS and spare pediatric patients from ionizing radiation; however, further research is warranted to improve the generalizability to the adult sickle cell disease population.

Point-of-care lung ultrasound is more reliable than chest X-ray for ruling out acute chest syndrome in sickle cell pediatric patients: A prospective study.

BACKGROUND: Acute chest syndrome (ACS) is a leading cause of morbidity and mortality in sickle cell patients, and it is often challenging to establish its diagnosis. PROCEDURE: This was a prospective observational study conducted in a pediatric emergency (PEM) department. We aimed to investigate the performance characteristics of point-of-care lung ultrasound (LUS) for diagnosing ACS in sickle cell children. LUS by trained PEM physicians was performed and interpreted as either positive or negative for consolidation. LUS results were compared to chest X-ray (CXR) and discharge diagnosis as reference standards. RESULTS: Four PEM physicians performed the LUS studies in 79 suspected ACS cases. The median age was 8 years (range 1-17 years). Fourteen cases (18%) received a diagnosis of ACS based on CXR and 21 (26.5%) had ACS discharge diagnosis. Comparing to CXR interpretation as the reference standard, LUS had a sensitivity of 100% (95% CI: 77%-100%), specificity of 68% (95% CI: 56%-79%), positive predictive value of 40% (95% CI: 24%-56%), and negative predictive value of 100% (95% CI: 92%-100%). Overall LUS accuracy was 73.42% (95% CI: 62%-83%). Using discharge diagnosis as the endpoint for both CXR and LUS, LUS had significantly higher sensitivity (100% vs. 62%, p = .0047) and lower specificity (76% vs.100%, p = .0002). LUS also had lower positive (60% vs.100%, p < .0001) and higher negative (100% vs.77%, p = .0025) predictive values. The overall accuracy was similar for both tests (82% vs. 88%, p = .2593). CONCLUSION: The high negative predictive value, with narrow CIs, makes LUS an excellent ruling-out tool for ACS.

Dual-energy CT evidence of pulmonary microvascular occlusion in patients with sickle cell disease experiencing acute chest syndrome.

PURPOSE: Acute chest syndrome (ACS), defined by the presence of a chest radiographic opacity in sickle cell disease patients experiencing respiratory symptoms is a leading cause of death in these patients. The etiology is ACS is not well understood however pulmonary microvascular occlusion has been postulated to be a major pathophysiologic driver. Our study aims to assess the value of dual-energy CT (DECT) as a marker of pulmonary microvascular occlusion. MATERIALS/METHODS: A search tool was used to identify CT angiography studies from 1/1/2017 to 9/15/2019 with any variation of the phrases "Acute chest syndrome" and "Sickle cell". These studies were manually reviewed for the use of DECT technique. An age-matched control group was created. DECT pulmonary blood volume (PBV) maps were reviewed semi-quantitatively for the presence of iodine defects and the number of involved bronchopulmonary segments were scored. Other recorded values included type of parenchymal opacities, diameter of main pulmonary artery (MPA) and presence of right ventricular dilatation. Mean values between cases and controls were compared using a two-sample t-test. RESULTS: Nine sickle cell DECT cases with PBV maps and nine age-matched controls were evaluated. Bronchopulmonary segments with iodine defects were significantly higher in cases vs controls (mean: 4.7 vs 0.3, p < 0.003). PBV defects were more extensive than parenchymal findings. MPA diameter was higher in cases (2.9 cm) vs control (2.4 cm), P < 0.03. CONCLUSIONS: DECT demonstrates abnormal PBV in sickle cell patients, often the predominant abnormality identified early, and likely reflects the presence of pulmonary microvascular occlusion.

Utility of Point-of-Care Lung Ultrasonography for Evaluating Acute Chest Syndrome in Young Patients With Sickle Cell Disease.

STUDY OBJECTIVE: Acute chest syndrome is a leading cause of mortality in patients with sickle cell disease (SCD). Because early detection of acute chest syndrome is directly tied to prognosis, young patients with SCD undergo countless chest radiography screenings throughout their lifetime for commonly occurring acute chest syndrome risk factors such as fever, chest pain, or cough. Chest radiography is not an ideal screening method because it is associated with radiation exposure, which accumulates with repeated imaging. Point-of-care lung ultrasonography is a nonradiating imaging modality that has been used to identify other lung pathology and may have a role in SCD. The goal of this study was to determine the accuracy of point-of-care lung ultrasound to identify an infiltrate suggestive of acute chest syndrome in patients with SCD compared to chest radiography as the gold standard. METHODS: This was a prospective observational study in 2 urban pediatric emergency departments to evaluate the accuracy of point-of-care lung ultrasonography in identifying patients with SCD who were aged 0 to 21 years and had an infiltrate suggestive of acute chest syndrome compared with chest radiography. Clinicians and trainees with point-of-care lung ultrasonographic training obtained informed consent and performed investigational point-of-care lung ultrasonography to evaluate for lung consolidation. A blinded point-of-care lung ultrasonographic expert reviewed results for quality assurance and agreement. Accuracy, sensitivity, specificity, likelihood ratios, and positive and negative predictive value were calculated for point-of-care lung ultrasonography test performance characteristics, with chest radiography as a reference standard. RESULTS: Point-of-care lung ultrasonography was performed on 191 SCD patients with a mean age of 8 years; 41% were female patients, and there was a 17% prevalence of acute chest syndrome. Accuracy of point-of-care lung ultrasonography to detected acute chest syndrome was 92%, sensitivity was 88%, and specificity was 93% compared with that for chest radiography. CONCLUSION: Point-of-care lung ultrasonography is a feasible alternative to chest radiography for screening for acute chest syndrome in young patients with SCD. Further studies are needed to determine how this test performs within clinical practice.

Acute Chest Syndrome in Sickle Cell Disease / Síndrome torácico agudo en la anemia de células falciformes

No disponible

Lung ultrasound in children: What does it give us?

Lung ultrasound (LUS), a non-invasive non-ionizing radiation tool, has become essential at the bedside in both adults and children, particularly in the critically ill. This manuscript reviews normal LUS patterns and the most important pathologies that LUS allows to diagnose. Normal LUS is represented by the pleural line, the lung-sliding and the A-lines and B-lines. These two last findings are artifacts derived from the pleural line. Pleural effusion appears as an anechoic collection. Pneumothorax is suspected when only A-lines are present, without lung-sliding and B-lines. Alveolo-interstitial syndrome is characterized by different degrees of confluent B-lines and can be present in different pathologies such as pulmonary edema and acute respiratory distress syndrome. The distribution of B-lines helps to differentiate between them. LUS is useful to evaluate the response to lung recruitment in pathologies such as acute respiratory distress syndrome or acute chest syndrome. The distribution of B-lines also appears to be useful to monitor the response to antibiotics in pneumonia. However, further studies are needed to further ascertain this evidence. LUS is also useful to guide thoracocentesis.

Successful Treatment of Acute Chest Syndrome with Manual Exchange Transfusion in a Patient with Sickle Beta+-thalassemia.

Acute chest syndrome (ACS), characterized by fever, respiratory symptoms, and new pulmonary infiltration, is a serious complication of sickle cell disease (SCD). Regardless of the etiology, the conventional treatment options for ACS include empirical antibiotic therapy, the administration of analgesics, and red cell transfusion. The indications and methods of red cell transfusion are critical. We herein report the case of a 26-year-old African-American man with SCD who developed ACS and who was successfully treated with manual exchange transfusion. Despite increasing globalization, SCD remains extremely rare in Japan. Manual exchange transfusion can be performed easily anywhere and should be considered for treating SCD patients presenting with ACS.

ACS in children with sickle cell anaemia in Uganda: prevalence, presentation and aetiology.

ACS (ACS) is a serious complication of sickle cell anaemia (SCA). We set out to describe the burden, presentation and organisms associated with ACS amongst children with SCA attending Mulago Hospital, Kampala, Uganda. In a cross-sectional study, 256 children with SCA and fever attending Mulago Hospital were recruited. Chest X-rays, blood cultures, complete blood count and sputum induction were performed. Sputum samples were investigated by Ziehl-Nielsen staining, culture and DNA polymerase chain reaction (PCR) for Chlamydia pneumoniae. Of the 256 children, 22·7% had ACS. Clinical and laboratory findings were not significantly different between children with ACS and those without, besides cough and abnormal signs on auscultation. Among the 83 sputum cultures Streptococcus pneumoniae (12%) and Moraxella spp (8%), were the commonest. Of the 59 sputa examined with DNA PCR, 59·3% were positive for Chlamydia pneumoniae. Mycobacterium tuberculosis was isolated in 6/83 sputa. These results show that one in 5 SCA febrile children had ACS. There were no clinical and laboratory characteristics of ACS, but cough and abnormalities on auscultation were associated with ACS. The high prevalence of Chlamydia pneumoniae in children with ACS in this setting warrants the addition of macrolides to treatment, and M. tuberculosis should be differential in sub-Saharan children with ACS.

Bedside ultrasound as a predictive tool for acute chest syndrome in sickle cell patients.

BACKGROUND: Acute chest syndrome (ACS) is the leading cause of death for patients with sickle cell disease (SCD). Early recognition of ACS improves prognosis. OBJECTIVE: Investigate the use of bedside lung ultrasound (BLU) in identification of early pulmonary findings associated with ACS in SCD patients. METHODS: Prospective, observational study of a convenience sample of SCD patients presenting to the Emergency Department (ED) for a pain crisis. BLU interpretations were made by an emergency physician blinded to the diagnosis of ACS, and were validated by a second reviewer. The electronic medical record was reviewed at discharge and at 30 days. RESULTS: Twenty SCD patients were enrolled. Median age was 31 years, median hemoglobin was 7.7 g/dL. Six patients developed ACS. Five patients in the ACS group had lung consolidations on BLU (83%) compared to 3 patients in the non-ACS group (21%), p = 0.0181, (OR = 12.05, 95% CI 1.24 to 116.73). The ACS group was also more likely to have a pleural effusion and B-lines on BLU than the non-ACS group, p = 0.0175; 0.1657, respectively. In the ACS group, peripheral and frank consolidations on BLU was 83% and 50% sensitive, 79% and 100% specific for ACS, respectively; whereas an infiltrate on initial chest X-ray (CXR) was only 17% sensitive. BLU identified lung abnormalities sooner than CXR (median 3.6 vs. 31.8 h). CONCLUSIONS: Pulmonary abnormalities on BLU of an adult SCD patient presenting to the ED for a painful crisis appear before CXR, and highly suggest ACS. BLU is a promising predictive tool for ACS.

The McConnell Sign is Seen in Patients With Acute Chest Syndrome.

Bedside ultrasound is often used as a part of the evaluation of patients who are critically ill. The McConnell sign is an important echocardiographic finding in some critically ill patients with pulmonary embolism and an acute right ventricular infarct. We present 3 critically ill patients with confirmed acute chest syndrome who showed the McConnell sign on echocardiography. In patients with sickle cell disease presenting with chest pain and shortness of breath, the presence of the McConnell sign does not narrow the differential diagnosis between pulmonary embolism, an acute right ventricular infarct, and acute chest syndrome.

Posterior reversible encephalopathy syndrome secondary to asymptomatic poststreptococcal glomerulonephritis in a child with sickle cell anemia: a case report.

BACKGROUND: Posterior reversible encephalopathy syndrome is a neurotoxic condition that occurs as a result of the failure of posterior circulatory autoregulation in response to acute changes in blood pressure. Overperfusion with resultant disruption of the blood-brain barrier results in vasogenic edema, but not infarction. Posterior reversible encephalopathy syndrome can be the presenting feature of postinfectious glomerulonephritis, which has been reported in approximately 5% of hospitalized children, and it has been reported in very few cases of adult patients with sickle cell anemia. We report a very rare case of posterior reversible encephalopathy syndrome that occurred in a child with sickle cell anemia. This presentation should be differentiated from other neurologic manifestations that occur in patients with sickle cell anemia, because management is totally different. CASE PRESENTATION: We report what is to our knowledge the first reported case of a 9-year-old Saudi girl with sickle cell anemia who developed posterior reversible encephalopathy syndrome secondary to asymptomatic poststreptococcal glomerulonephritis. This occurred after full recovery from acute chest syndrome and severe vaso-occlusive crisis. CONCLUSIONS: The purpose of this report is to emphasize that all efforts should be made to explore the causes of different neurologic manifestations that occur in patients with sickle cell anemia, because this will require different pathways of management.

A multiscale analytical model of bronchial airway acoustics.

Sound transmission and resulting airway wall vibration in a complex multiscale viscoelastic model of the subglottal bronchial tree was calculated using a modified one-dimensional (1D) branching acoustic waveguide approach. This is an extension of previous work to enable use of complex airway trees that are partially derived from subject-specific medical images, without the need for self-similarity in the geometric structure. The approach was validated numerically for simplified airway geometries, as well as experimentally by comparison to previous studies. A comprehensive conducting airway tree with about 60 000 branches was then modified to create fibrotic, bronchoconstrictive, and pulmonary infiltrate conditions. The fibrotic case-systemic increase in soft tissue stiffness-increased the Helmholtz resonance frequency due to the increased acoustic impedance. Bronchoconstriction, with geometric changes in small conducting airways, decreased acoustic energy transmission to the peripheral airways due in part to the increased impedance mismatch between airway orders. Pulmonary infiltrate significantly altered the local acoustic field in the affected lobe. Calculation of acoustic differences between healthy versus pathologic cases can be used to enhance the understanding of vibro-acoustic changes correlated to pathology, and potentially provide improved tools for the diagnosis of pulmonary diseases that uniquely alter the acoustics of the airways.

Which Febrile Children With Sickle Cell Disease Need a Chest X-Ray?

OBJECTIVE: Controversy exists regarding which febrile children with sickle cell disease (SCD) should receive a chest x-ray (CXR). Our goal is to provide data informing the decision of which febrile children with SCD presenting to the emergency department (ED) require a CXR to evaluate for acute chest syndrome (ACS). METHODS: Retrospective chart review of children ages 3 months to 21 years with SCD presenting to the ED at one of two academic children's hospitals with fever ≥38.5°C between January 1, 2010, and December 31, 2012. Demographic characteristics, respiratory symptoms, and laboratory results were abstracted. The primary outcome was the presence of ACS. Binary recursive partitioning was performed to determine predictive factors for a diagnosis of ACS. RESULTS: A total of 185 (10%) of 1,837 febrile ED visits met ACS criteria. The current National Heart, Lung, and Blood Institute (NHLBI) consensus criteria for obtaining a CXR (shortness of breath, tachypnea, cough, or rales) identified 158 (85%) of ACS cases, while avoiding 825 CXRs. Obtaining a CXR in children with NHLBI criteria or chest pain and in children without those symptoms but with a white blood cell (WBC) count ≥18.75 × 109 /L or a history of ACS identified 181 (98%), while avoiding 430 CXRs. CONCLUSION: Children with SCD presenting to the ED with fever and shortness of breath, tachypnea, cough, rales, or chest pain should receive a CXR due to high ACS rates. A higher WBC count or history of ACS in a child without one of those symptoms may suggest the need for a CXR. Prospective validation of these criteria is needed.

Accuracy of Point-of-care Lung Ultrasonography for Diagnosis of Acute Chest Syndrome in Pediatric Patients with Sickle Cell Disease and Fever.

OBJECTIVES: The objective was to determine the test performance characteristics for point-of-care lung ultrasonography (LUS) performed by pediatric emergency medicine (PEM) physicians compared with radiographic diagnosis of acute chest syndrome (ACS) in patients with sickle cell disease (SCD) and fever. METHODS: This was a prospective study of patients up to 21 years with SCD and fever requiring chest X-ray (CXR) evaluation for ACS. Before obtaining CXR, a blinded PEM physician performed LUS using a standardized scanning protocol. Positive LUS for ACS was defined as lung consolidation. All patients received CXR and follow-up. The criterion standard for ACS was consolidation on CXR as determined by a blinded radiologist. LUS clips were reviewed by a blinded expert PEM sonologist. RESULTS: A total of 116 febrile events from 91 patients with a median age of 5.7 years were enrolled by 15 PEM sonologists. CXR was positive for ACS in 15 (13%) patients, and LUS was positive for ACS in 19 (16%) patients. Positive LUS had a sensitivity of 87% (95% confidence interval [CI] = 62% to 96%), specificity of 94% (95% CI = 88% to 97%), positive likelihood ratio of 14.6 (95% CI = 6.5 to 32.5), and negative likelihood ratio of 0.14 (95% CI = 0.04 to 0.52) for ACS. The interobserver agreement (kappa) was 0.77. There were two missed cases of ACS on LUS. CONCLUSIONS: LUS may be sensitive and specific for diagnosis of ACS in pediatric patients with SCD and fever. LUS may reduce the need for routine CXR and associated ionizing radiation exposure in this population.

Utilidad de la ecografía en la patología respiratoria / Utility of ultrasound in respiratory disease

No disponible

Bedside Lung Ultrasound During Acute Chest Syndrome in Sickle Cell Disease.

Lung ultrasound (LU) is increasingly used to assess pleural and lung disease in intensive care unit (ICU) and emergency unit at the bedside. We assessed the performance of bedside chest radiograph (CR) and LU during severe acute chest syndrome (ACS), using computed tomography (CT) as the reference standard. We prospectively explored 44 ACS episodes (in 41 patients) admitted to the medical ICU. Three imaging findings were evaluated (consolidation, ground-glass opacities, and pleural effusion). A score was used to quantify and compare loss of lung aeration with each technique and assess its association with outcome. A total number of 496, 507, and 519 lung regions could be assessed by CT scan, bedside CR, and bedside LU, respectively. Consolidations were the most common pattern and prevailed in lung bases (especially postero-inferior regions). The agreement with CT scan patterns was significantly higher for LU as compared to CR (κ coefficients of 0.45 ±â€Š0.03 vs 0.30 ±â€Š0.03, P < 0.01 for the parenchyma, and 0.73 ±â€Š0.08 vs 0.06 ±â€Š0.09, P < 0.001 for pleural effusion). The Bland and Altman analysis showed a nonfixed bias of -1.0 (P = 0.12) between LU score and CT score whereas CR score underestimated CT score with a fixed bias of -5.8 (P < 0.001). The specificity for the detection of consolidated regions or pleural effusion (using CT scan as the reference standard) was high for LU and CR, whereas the sensitivity was high for LU but low for CR. As compared to others, ACS patients with an LU score above the median value of 11 had a larger volume of transfused and exsanguinated blood, greater oxygen requirements, more need for mechanical ventilation, and a longer ICU length of stay. LU outperformed CR for the diagnosis of consolidations and pleural effusion during ACS. Higher values of LU score identified patients at risk of worse outcome.