|Year : 2019 | Volume
| Issue : 3 | Page : 693-700
Role of thoracic ultrasound in children with chronic kidney disease
Saneya Abd El-Halim Fahmy1, Naglaa Abd El-Moneam Abd Allah1, Amira I Al-Masry1, Eman Sobh2
1 Department of Pediatric, Faculty of Medicine for Girls (Cairo), Al-Azhar University, Cairo, Egypt
2 Department of Chest Diseases, Faculty of Medicine for Girls (Cairo), Al-Azhar University, Cairo, Egypt
|Date of Submission||15-Oct-2019|
|Date of Decision||15-Oct-2019|
|Date of Acceptance||17-Nov-2019|
|Date of Web Publication||10-Feb-2020|
MD Eman Sobh
Chest Diseases Department, Faculty of Medicine for Girls, Al-Azhar University, Al-Zahraa University Hospital 11517, Cairo
Source of Support: None, Conflict of Interest: None
Background Chronic kidney disease (CKD) and dialysis may affect different body systems such as the cardiovascular, respiratory, and musculoskeletal system dysfunction. Pulmonary complications reported in patients with CKD include pulmonary edema, pleural effusion, pulmonary hypertension, respiratory infections, pulmonary fibrosis, and hypoxemia. Ultrasound (US) is a simple noninvasive method that is available at the bedside. It can be used to guide diagnostic and therapeutic decisions and monitor efficacy of treatment; in addition, sonographic signs are simple to learn.
Aim The aim of the work was to evaluate thoracic ultrasound (TUS) findings in children of CKD and those on regular hemodialysis.
Patients and methods This was a cross-sectional comparative study that was carried out on 90 children; their age ranged from 4 to 17 years. We included two groups: the first group comprised 60 patients with CKD: 30 of them on regular hemodialysis and the other 30 children with CKD not on hemodialysis. The second group was the control group (30 children). Medical history, clinical examination, anthropometric measurement, and routine laboratory studies were done. Chest radiograph and TUS were done for all patients. Computed tomography (CT) chest was done when indicated, whereas TUS in dialysis cases was done before and after dialysis. All groups were age and sex matched.
Results Among the dialysis group patients, there was no significant difference between CT, US, and radiograph regarding lung congestion, consolidation, pericardial effusion, and pleural effusion. On the contrary, air trapping, cavity, granuloma, and calcified nodules were detected only with CT. US was sensitive to detect fluid overload even when body weight was below the estimated dry weight by 300 g, and B-lines more than 14 is a cutoff point with high sensitivity. In patients with CKD not on dialysis, there was no significant difference between radiograph, CT, and US chest findings regarding lung congestion, consolidation, pleural effusion, and atelectasis.
Conclusion Chest US is a useful tool for the detection of pulmonary complications in pediatrics on regular hemodialysis. The technique is sensitive for detecting fluid overload and can be used for follow-up.
Keywords: chest ultrasound, chronic kidney disease, hemodialysis
|How to cite this article:|
El-Halim Fahmy SA, El-Moneam Abd Allah NA, Al-Masry AI, Sobh E. Role of thoracic ultrasound in children with chronic kidney disease. Sci J Al-Azhar Med Fac Girls 2019;3:693-700
|How to cite this URL:|
El-Halim Fahmy SA, El-Moneam Abd Allah NA, Al-Masry AI, Sobh E. Role of thoracic ultrasound in children with chronic kidney disease. Sci J Al-Azhar Med Fac Girls [serial online] 2019 [cited 2020 Oct 22];3:693-700. Available from: http://www.sjamf.eg.net/text.asp?2019/3/3/693/278049
| Introduction|| |
Chronic kidney disease (CKD) is a growing global health problem. It has significant effect on health-related quality of life. Systemic effects of CKD and hemodialysis include cardiovascular, respiratory, and musculoskeletal system dysfunctions . Respiratory complications are usually underevaluated in patients with CKD on hemodialysis . These effects may be acute, such as acute respiratory distress syndrome, pulmonary edema, recurrent infections, and pleural effusions, or chronic, such as pulmonary fibrosis, respiratory infections, pulmonary hypertension, decreased pulmonary capillary blood flow, and hypoxemia . Various diagnostic imaging modalities are used to demonstrate respiratory problems. Plain chest radiograph (CXR) is the first diagnostic tool. However; the sensitivity of CXR is low, so chest high-resolution computed tomography (CT) has been described as the gold standard diagnostic tool . CT has some limitations including the risk of ionizing radiations; this mandates the need for a safe, noninvasive diagnostic tool for patients with suspected chest findings. Recent studies demonstrated that thoracic ultrasound (TUS) can be used as an alternative imaging modality to diagnose pulmonary complications in patients with CKD. Lung US is preferred because it is a simple, easy to learn, noninvasive radiation-free tool. The cost is very low, and the results are immediate . Respiratory complications are prevalent in children with CKD; volume expansion is the most common complication of patients with end-stage renal disease (ESRD) on regular dialysis. It has been proposed as a strong prognostic factor. It can be clinically evident or occult . Assessment of volume status in patients with ESRD is a challenging process . Clinical examination, CXR, and CT can be used; however, none is completely accurate . Recent studies reported that lung US is an effective bedside tool for volume status assessment in patients with ESRD .
| Aim|| |
The aim of study was to evaluate TUS findings in children of CKD and those on regular hemodialysis.
| Patients and methods|| |
This was a cross-sectional comparative study that was carried out on 90 children. The study sample was selected from the Pediatric Nephrology and Hemodialysis Unit and from Outpatient Clinic of Al-Zahraa University Hospital during the period from May 2018 to May 2019.
The studied population was 90 children divided into two groups:
- Group I (patient group): it include 60 children who were classified into two subgroups:
- Group Ia (dialysis group): it included 30 children with ESRD [estimated glomerular filtration rate (eGFR) <15 ml/min/1.73 m2] according to KDOQI 2018 , on regular hemodialysis for more than 3 months three times weekly.
- Group Ib (CKD group): it included 30 children with CKD according to KDOQI 2018  not on dialysis.
- Group II (control group): it included 30 apparently healthy children age and sex matched with group I.
The study included children 4–17 years old, of either sex, who fulfill the diagnostic criteria of CKD (GFR <60 ml/min/1.73 m2) for more than 3 months according to KDOQI 2018  either with ESRD on regular hemodialysis or not on hemodialysis yet.
Patients with chronic illness other than CKD or severe malnourishment were excluded from the study.
The study protocol was approved by research ethics committee of Pediatric Department and the Faculty of Medicine for Girls, Al-Azhar University (Cairo) before starting of the study. Informed consent was obtained from the parents of all the children. All data were kept anonymous, and all participants had the right to withdraw at any time.
The enrolled children were subjected to the following:
- Full detailed medical history with stress on pulmonary symptoms, including cough, dyspnea, hemoptysis, and chest wheezes. Details of renal disease, cause and duration of CKD, and family history were recorded.
- Complete examination; all anthropometric measures were recorded, and signs of hypervolemia such as congested neck veins, lower limb edema, and fine basal crepitation. Vital signs and body weight were taken before and after dialysis for the dialysis group.
- Routine laboratory investigations data were recorded.
- Radiological investigations: CXR, high-resolution CT (when indicated), and TUS (before and after dialysis for dialysis group) were done.
The machine used was Ultrasound Scanner (Sonoscape SSI6000, equipped with a 3.5 MHz curvilinear and 8 MHz linear probes, Nanshan, China). All patients were examined in the supine or semisetting position, starting with right anterior chest, followed by the right lateral chest, and ends with a careful examination of the lower lung and the costophrenic recesses. Each hemithorax is divided into six areas, and each area is examined for the presence of consolidation, atelectasis, pleural effusion, and pericardial effusion . For the evaluation of extravascular lung water (EVLW), the anterolateral chest was scanned on a total of 28 scanning sites on the right and left hemithorax, from the second to the fourth (on the right side to the fifth) intercostal spaces along the parasternal, midclavicular, anterior axillary, and mid-axillary lines  and by eight zones sector method . The number of B-lines per scan was recorded, and the total number was calculated . B-lines are well-defined, laser-like, vertical, hyperechoic, dynamic lines originating from the pleural line reaching the edge of the screen . The lung comet score was grouped into grades of severity: ‘mild’ with less than 15 B-line, ‘moderate’ with 15–30 B-lines, and ‘severe’ with more than 30 B-lines . This technique was performed before and after dialysis for the dialysis group.
| Results|| |
[Table 1] shows that among the 30 children with ESRD, most of them were males (17; 56.7%), and their age ranged from 7 to 17 years. Most of them (8.26.7%), have chest symptoms at the time of scan in the form of dyspnea (43.3%), cough (50%), hemoptysis (3.3%), and chest wheezes (40%). We did not find any significant difference among the three studied groups regarding sex, age, and symptoms. Family history of dialysis was evident in the dialysis group and the CKD group, and both height and BMI were significantly lower in the dialysis group.
[Table 2] show that platelet count, red blood cells (RBCs), hematocrit, white blood cells, and eGFR were significantly lower in the dialysis group. Serum creatinine and urea in dialysis were significantly elevated in the dialysis group.
[Table 3] show that there was no significant difference between radiograph and chest US in the detection of lung congestion, consolidation, atelectasis, and pleural effusion in children with CKD.
|Table 3 Comparison between radiograph and ultrasound chest finding in children with chronic kidney disease|
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[Table 4] shows that no significant difference was detected among the three imaging modalities in the detection of lung congestion, consolidation, and atelectasis. However, other findings were detected mainly by CT (air trapping, nodules, and cavity lesions), whereas pleural effusion in the dialysis group was detected only by US.
|Table 4 Comparison among chest radiograph, high-resolution computed tomography chest, and ultrasound chest findings in patients with end-stage renal disease|
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[Table 5] shows that B-lines in each area and the total number of B-lines (28 spaces) were significantly decreased after dialysis in children with CKD on hemodialysis (15–44 predialysis and 10–22 postdialysis).
|Table 5 Comparison between the number of B-lines before and after dialysis in children with end-stage renal disease|
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[Table 6] shows that there was improvement in total number of B-lines (17.5%).
[Figure 1] shows that the number of patients with moderate and severe lung congestion significantly decreased after dialysis.
|Figure 1 Distribution of patients according to the degree of pulmonary congestion by B-lines number.|
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Receiver operating characteristic curve analysis shows that in children with CKD on hemodialysis, total B-line can detect excess EVLW when body weight is below the estimated dry body weight by 300 g (area under the curve, 0.538) with sensitivity of 100%, specificity of 70%, positive predictive value of 47.1%, and negative predictive value of 100%.
[Figure 2] show that the cutoff point of total B-lines was more than 14 to detect excess EVLW with sensitivity of 100%, specificity of 94.44%, positive predictive value of 92.3%, and negative predictive value of 100%, with the area under the curve of 0.956.
|Figure 2 Receiver operating characteristic curve for sensitivity of B-lines to detect excess lung water.|
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[Figure 3] shows that there was a significant positive correlation between the total number of B-lines before dialysis and excess body weight (r=0.487, P=0.006).
|Figure 3 Correlation between the total number of B-lines before dialysis and excess body weight (BW).|
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| Discussion|| |
Various imaging modalities have been used for the detection of pulmonary complications in children with CKD. However, the main challenge was the radiation exposure and the availability . So, in this study, we tested US as a noninvasive bedside tool for detection of pulmonary complications and to evaluate the efficacy of hemodialysis.
This study showed that platelet count, RBCs, hematocrit, white blood cells, and eGFR were significantly lower in the dialysis group. Serum creatinine and urea were significantly elevated in the dialysis group ([Table 2]). This is in agreement with Bendapudi and McCaffrey  who reported that uremic plasma increases the expression of phosphatidylserine on the outer cell surface in RBCs, and this enhances the recognition of damaged RBCs by macrophage, leading to their destruction.
Moreover, Safouh et al.  reviewed the records of 1018 Egyptian patients with CKD, and the mean eGFR was 12.5 ml/min/1.73 m2.
This study showed that among the dialysis group, no significant difference among CT, US, and radiograph regarding lung congestion, consolidation, and atelectasis, whereas pleural effusion was detected only by US ([Table 4]). Other findings such as air trapping, cavity, granuloma, and calcified nodules could only be detected by CT in children with CKD whether on dialysis or not. This may be attributed to low number of cases and to the fact that the size of consolidation was large enough to be evident on radiograph and CT. Mohsen et al.  reported that US is better than CXR and can be used as alternative to CT in detection of lung pathologies.
In hemodialysis group, our work revealed excess B-lines, which decreased significantly after dialysis ([Table 5] and [Table 6], [Figure 1]), that is, 17.5% improvement, and the predialysis total number of B-lines correlated with excess body weight. The number of patients with severe and moderate lung comets score significantly decreased after dialysis ([Figure 4]). The same results were reported by Vitturi et al.  who found a strong significant difference in the number of B-lines before and after dialysis.
|Figure 4 Receiver operating characteristic curve for sensitivity of B-lines to detect excess body weight (BW).|
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The average number of B-lines before dialysis in our patients was higher than the average number in the study by Vitturi and colleagues, which can be explained by the different hydration state and hemodynamic state. The presence of lung comets in most of our patients, even in those who are asymptomatic, underlines the capability of lung US to detect the signs of pulmonary congestion even in a subclinical phase .Receiver operating characteristic curve analysis showed that US B-lines have greater sensitivity for detection of excess lung water even when body weight was below the estimated dry body weight by 300 g; although the specificity is low still, this can be used as a follow-up tool for the efficacy of hemodialysis in some cases . Similar results were found in the study by Youssef et al.  who assessed volume status in patients with CKD on regular hemodialysis by US and bioimpedance technique.
In our study, the cutoff point of total B-lines to detect excess lung water was 14, with sensitivity of 100%, specificity of 94.44%, positive predictive value of 92.3%, and the negative predictive value of 100% in the diagnosis of postdialysis lung water excess. Previous studies ,, reported similar results that lung US is sensitive in detecting fluid overload in the absence of fluid-related symptoms.
| Conclusion|| |
In conclusion, this study found lung US is a practical, sensitive, radiation-free method for detection of extrapulmonary complications and for quantifying fluid overload in children with CKD on dialysis. B-lines are a sensitive method for follow-up of efficacy of hemodialysis. Lung US can be a useful tool for nephrologists to evaluate volume status of each patient before and after dialysis sessions for accurate assessment of volume status.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]