Inhalation lung injury induced by smoke bombs in children: CT manifestations, dynamic evolution features and quantitative analysis.

BACKGROUND: This retrospective study aimed to investigate the computed tomography (CT) manifestations, short-term dynamic evolution features and quantitative lung CT analysis of inhalation lung injury induced by smoke bomb flare. METHODS: Eleven pediatric patients (aged 11 to 13) who inhaled the smoke of smoke bombs underwent several low-dose chest CT scans. The image characteristics and their dynamic changes were observed and quantitative CT values were analyzed. The quantitative CT indicators included lung injury CT score (LICTS), lung fibrosis CT score (LFCTS), mean lung density (MLD), normally aerated volume ratio (NAVR) and reductively aerated volume ratio (RAVR). Box-plot was used to analyze the dynamic changes of each indicator and Spearman statistical method was used to analyze the correlation between any two indicators. RESULTS: (I) In most cases, there were multiple consolidation and massive ground-glass opacities (GGOs) in the two lungs, which aggravated in the early stage and then gradually dissoluted in the later stage. LICTS was positively correlated with MLD (r=0.811, P=0.000), while it was negatively correlated with NAVR (r=-0.712, P=0.000). There existed interstitial fibrosis in the later stage, and LFCTS was positively correlated with RAVR (r=0.382, P=0.028). (II) In one case, the patterns were like layered cake, i.e., consolidation with air bronchus signs in the accumulation area, GGOs in the aforementioned area and normal lung in the top area. The patterns aggravated in the early stage and quickly dissolved in the later stage, and only a few residual fibrotic lesions existed on the final scan. (III) For severe cases, pneumomediastinum and subcutaneous emphysema aggravated in the early stage and then gradually dissolved in the later stage. CONCLUSIONS: The chest CT manifestations of inhalation lung injury induced by smoke bombs are predominantly GGOs and consolidation. They aggravate in the early stage and gradual dissolute in the later stage. CT quantitative values can contribute to evaluating the extent of this disease, and NAVR and RAVR can be used to assess pulmonary function.

Clinical characteristics of refractory melamine-related renal calculi.

OBJECTIVE: The melamine urinary stones are uric acid-based and amenable to alkalization and extracorporeal shock-wave lithotripsy (ESWL). However, a significant percentage of stones failed in alkalization and ESWL. To predict it before a likely deemed failed treatment, we attempt to confirm their clinical characteristics. METHODS: A total of 6 refractory- and 9 sensitive-melamine-related renal calculi were included from 15 children (age 6-51 months, mean 14). Renal function, and blood calcium and uric acid level were measured before treatment. Stone composition was determined qualitatively using Fourier transform infrared. Stone computed tomography (CT)-attenuation value, stone melamine and cyanuric acid level, and stone calcium level were performed quantitatively using spiral CT, high-performance liquid chromatography, and flame atomic absorption spectrum, respectively. RESULTS: Blood biochemical parameters in all children within the normal reference range and no difference was observed between refractory melamine stones and sensitive melamine stones (P >.05). Compared with sensitive melamine stones, stone calcium level and stone CT-attenuation value in refractory melamine stones were significantly higher (21.58 ± 5.76% vs 1.37 ± 1.47%, P = .000; 1037 ± 341HU vs 156 ± 61HU, P = 0.000). Multivariate regression analysis indicated stone calcium level had more impact on alkalization failure than other factors (P(children's age) = .670, P(feedingtime) = .826, P(stonesize) = .376, and P(stonecalcium level) = .000, and P(regressionmodel) = .000). CONCLUSION: Higher stone calcium level is the essential change of refractory melamine stones. The stones from children older than 2 years or stones with in vivo CT-attenuation value >700 Hounsfield units in clinical setting should be strong suspected for alkalization- and ESWL-resistance because they most likely contain >10.88% calcium level.

Study of stone composition changes in melamine-related urinary calculi and its clinical significance.

OBJECTIVES: To investigate the composition changes in melamine-related urinary calculi and their clinical significance. METHODS: A total of 49 melamine-related urinary calculi were included from 49 children (age 4-82 months, mean 22). The qualitative analysis of stone composition was determined using Fourier transform infrared. The quantitative analysis of the stone computed tomography (CT) attenuation value, stone uric acid level, and stone calcium level were measured using spiral CT, high-performance liquid chromatography, and flame atomic absorption spectrum, respectively. RESULTS: Fourier transform infrared showed that 41 (84%) of the 49 stones contained uric acid and 25 (51%) contained calcium compounds. The data from the qualitative and quantitative analysis were available for 15 stones because of sample consumption in the detection process (Fourier transform infrared, atomic absorption spectrum, and high-performance liquid chromatography). A negative correlation was observed between stone uric acid level and stone calcium level (n = 15, r = -0.629, P = .009). A positive correlation was observed between the stone calcium level and stone CT attenuation value (n = 25, r = 0.855, P = .000). Compared with the ≤1-year-age group and the 1-2-year-age group, the stone calcium level in the >2-year-age group was significantly greater (27.51% ± 12.65% vs 1.60% ± 1.68% or 10.12% ± 8.69%, P = .000 and P = .003, respectively). Compared with the alkalization-alone group, the stone calcium level in the nonalkalization-alone group was significant greater (19.83% ± 7.48% vs 1.25% ± 1.43%, n = 19, P = .000). CONCLUSIONS: The stones from children >2 years old were not amenable to medical treatment because they contained greater levels of calcium, which can be demonstrated by the radiologic "positive stone image" or stone CT attenuation value. We believe that surgical invention will be the best choice for such patients if extracorporeal shock wave lithotripsy has failed.