Isolated Tracheabronchomalacia Misdiagnosed for Years as Bronchial Asthma

Tracheomalacia (TM) is an abnormal collapse of the tracheal lumen, which often occurs when the cartilaginous part of the trachea has not developed. It is a rare condition but is seen often in infancy and childhood period. The incidence of primary airway malacia in children was estimated to be at least one in 2,100. It has a wide range of etiologies, and it is often localized but rarely generalized as in our case. It could be severe enough to indicate frequent admission and might expose the patient to multiple unnecessary medications. We are reporting a case with unusual primary tracheobronchomalacia (TBM) that was missed for several years with a huge burden on both families and healthcare providers. A five-year-old Saudi girl had multiple admissions to the intensive care unit with similar presentation each time, and she was misdiagnosed as having asthma exacerbation with an occasional chest infection. Bronchoscopy revealed the underlying condition, and the patient was kept on the minimal intervention of nasal continuous positive airway pressure (CPAP) and aggressive airway hydration therapy, all with the goal of improving the patient's outcome and reducing hospital admissions. We emphasize the importance of alerting physicians about malacia as an important cause of recurrent wheezy chest, which is one of the common asthma mimickers; in such cases, flexible bronchoscopy remains the gold standard diagnostic test, while the treatment remained supportive.

Dynamic Volumetric Computed Tomography Angiography is an Effective Method to Evaluate Tracheomalacia in Children

OBJECTIVE

Standard methods to evaluate tracheal pathology in children, including bronchoscopy, may require general anesthesia. Conventional dynamic proximal airway imaging in noncooperative children requires endotracheal intubation and/or medically induced apnea, which may affect airway mechanics and diagnostic performance. We describe a technique for unsedated dynamic volumetric computed tomography angiography (DV-CTA) of the proximal airway and surrounding vasculature in children and evaluate its performance compared to the reference-standard of rigid bronchoscopy.

METHODS

Children who had undergone DV-CTA and bronchoscopy in one-year were retrospectively identified. Imaging studies were reviewed by an expert reader blinded to the bronchoscopy findings of primary or secondary tracheomalacia. Airway narrowing, if present, was characterized as static and/or dynamic, with tracheomalacia defined as >50% collapse of the tracheal cross-sectional area in exhalation. Pearson correlation was used for comparison.

RESULTS

Over a 19-month period, we identified 32 children (median age 8 months, range 3-14 months) who had undergone DV-CTA and bronchoscopy within a 90-day period of each other. All studies were unsedated and free-breathing. The primary reasons for evaluation included noisy breathing, stridor, and screening for tracheomalacia. There was excellent agreement between DV-CTA and bronchoscopy for diagnosis of tracheomalacia (κ = 0.81, p < 0.001), which improved if children (n = 25) had the studies within 30 days of each other (κ = 0.91, p < 0.001). CTA provided incremental information on severity, and cause of secondary tracheomalacia.

CONCLUSION

For most children, DV-CTA requires no sedation or respiratory manipulation and correlates strongly with bronchoscopy for the diagnosis of tracheomalacia.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:410-416, 2023.

Pulmonary function of children with tracheomalacia and associated clinical factors

OBJECTIVES

Spirometry is easily accessible yet there is limited data in children with tracheomalacia. Availability of such data may inform clinical practice. We aimed to describe spirometry indices of children with tracheomalacia, including Empey index and flow-volume curve pattern, and determine whether these indices relate with bronchoscopic features.

METHODS

From the database of children with tracheomalacia diagnosed during 2016-2019, we reviewed their flexible bronchoscopy and spirometry data in a blinded manner. We specially evaluated several spirometry indices and tracheomalacia features (cross-sectional lumen reduction, malacic length, and presence of bronchomalacia) and determined their association using multivariable regression.

RESULTS

Of 53 children with tracheomalacia, the mean (SD) peak expiratory flow (PEF) was below the normal range [68.9 percent of predicted value (23.08)]. However, all other spirometry parameters were within normal range [Z-score forced expired volume in 1 s (FEV₁ ) = -1.18 (1.39), forced vital capacity (FVC) = -0.61 (1.46), forced expiratory flow between 25% and 75% of vital capacity​​​​​​ (FEF_25%-75% ) = -1.43 (1.10), FEV₁ /FVC = -1.04 (1.08)], Empey Index = 8.21 (1.59). The most common flow-volume curve pattern was the "knee" pattern (n = 39, 73.6%). Multivariable linear regression identified the presence of bronchomalacia was significantly associated with lower flows: FEV₁ [coefficient (95% CI) -0.78 (-1.54, -0.02)], FEF_25%-75% [-0.61 (-1.22, 0)], and PEF [-12.69 (-21.13, -4.25)], all p ≤ 0.05. Other bronchoscopic-defined tracheomalacia features examined (cross-sectional lumen reduction, malacic length) were not significantly associated with spirometry indices.

CONCLUSION

The "knee" pattern in spirometry flow-volume curve is common in children with tracheomalacia but other indices, including Empey index, cannot be used to characterize tracheomalacia. Spirometry indices were not significantly associated with bronchoscopic tracheomalacia features but children with tracheobronchomalacia have significantly lower flow than those with tracheomalacia alone.

Tracheal cartilage growth promotion by intra-tracheal administration of basic FGF

PURPOSE

This study aimed to investigate whether intra-tracheal administration of basic fibroblast growth factor (b-FGF) promotes the growth of tracheal cartilage.

METHODS

Trachea of 4-week old mice were intubated and 2.5 μg b-FGF administered (Group 4) for periods from 1 to 5 days. Cervical tracheal outer diameter and tracheal ring length were compared in Group 1 (no intervention), Group 2 (tracheal intubation), Group 3 (intra-tracheal administration of distilled water) and Group 4, at 8 weeks of age. Outer diameter and tracheal ring length in Group 4 were also compared with that in Group 1 at 12 and 16 weeks of age.

RESULTS

At 8 weeks of age, tracheal ring length with b-FGF administration for more than 4 days in Group 4 was significantly increased over that following 1-day administration. At 8 weeks of age, mean outer diameter and the mean tracheal ring length in Group 4 were significantly greater than in the other groups. Mean outer diameter and mean tracheal ring length were significantly greater in Group 4 than in Group 1 at 12 and 16 weeks of age.

CONCLUSION

This study has shown that intra-tracheal administration of b-FGF enlarges the tracheal lumen.

ERS statement on tracheomalacia and bronchomalacia in children

Tracheomalacia and tracheobronchomalacia may be primary abnormalities of the large airways or associated with a wide variety of congenital and acquired conditions. The evidence on diagnosis, classification and management is scant. There is no universally accepted classification of severity. Clinical presentation includes early-onset stridor or fixed wheeze, recurrent infections, brassy cough and even near-death attacks, depending on the site and severity of the lesion. Diagnosis is usually made by flexible bronchoscopy in a free-breathing child but may also be shown by other dynamic imaging techniques such as low-contrast volume bronchography, computed tomography or magnetic resonance imaging. Lung function testing can provide supportive evidence but is not diagnostic. Management may be medical or surgical, depending on the nature and severity of the lesions, but the evidence base for any therapy is limited. While medical options that include bronchodilators, anti-muscarinic agents, mucolytics and antibiotics (as well as treatment of comorbidities and associated conditions) are used, there is currently little evidence for benefit. Chest physiotherapy is commonly prescribed, but the evidence base is poor. When symptoms are severe, surgical options include aortopexy or posterior tracheopexy, tracheal resection of short affected segments, internal stents and external airway splinting. If respiratory support is needed, continuous positive airway pressure is the most commonly used modality either via a face mask or tracheostomy. Parents of children with tracheobronchomalacia report diagnostic delays and anxieties about how to manage their child's condition, and want more information. There is a need for more research to establish an evidence base for malacia. This European Respiratory Society statement provides a review of the current literature to inform future study.

Helical multi-detector CT scan as a tool for diagnosing tracheomalacia in children

BACKGROUND/AIMS

Tracheomalacia (TM) is not an unusual diagnosis in pediatric respiratory clinics. The aim of this study was to assess the accuracy of paired static end-inspiratory/end-expiratory helical multi-detector CT scan (MDCT) in detecting TM.

METHODS

FB was performed in 28 children suspected of TM on the grounds of presence of recurrent episodes of vibrating cough and a need for more specific diagnostic information. Children diagnosed with flexible bronchoscopy (FB) as having TM were further investigated with MDCT. The cross-sectional area ratio of the trachea during end-expiration and end-inspiration, at the level of maximum end-expiration collapse (CSR), determined the basis for the MDCT diagnosis of TM. FB and MDCT were also performed in five children who suffered from mainly dry-but not honking, barking, or vibrating-cough for more than 3 months, and served as controls.

RESULTS

The diagnosis of TM was established bronchoscopically in 26 out of 28 children. CRS was significantly smaller in patients (0.59 ± 0.14) compared with controls (0.85 ± 0.11) (P = 0.001). The optimal CSR cut-off point for TM diagnosis, as it was estimated by the ROC curve, was ≤0.705 (95%CI: ≤0.635-≤0.850) with a sensitivity 84.6% (95%CI: 65.1-95.6), and specificity 100.0% (95%CI: 47.8-100.0).

CONCLUSIONS

MDCT can effectively diagnose TM in the majority of children and can be used as an alternative to FB. In children, the established criterion of CSR ≤0.5 should be replaced by CSR ≤0.7 that seems to be a more appropriate threshold.

Expiratory central airway collapse in stable COPD and during exacerbations

BACKGROUND

Tracheal obstruction resulting from expiratory tracheal deformation has been associated with respiratory symptoms and severe airway exacerbations. In chronic obstructive pulmonary disease (COPD), acute exacerbations (AECOPD) create large intrathoracic pressure swings which may increase tracheal deformation. Excessive central airway collapse (ECAC) may be diagnosed when the tracheal area on expiration is less than 50% of that on inspiration. The prevalence of ECAC in AECOPD and its temporal course have not been systematically studied.

METHODS

We prospectively recruited healthy volunteers (n = 53), stable outpatients with COPD (n = 40) and patients with hospitalised acute exacerbations of COPD (AECOPD, n = 64). 17 of the AECOPD group returned for repeat evaluation when clinically well at 6-12 weeks. All subjects underwent dynamic 320-slice computed tomography of the larynx and trachea during tidal breathing, enabling quantitation of tracheal area and dimensions (mean ± SD).

RESULTS

No healthy individuals had ECAC. The prevalence of ECAC in stable COPD and AECOPD was 35% and 39% respectively. Mean tracheal collapse did not differ between stable COPD (57.5 ± 19.8%), AECOPD (53.8 ± 19.3%) and in the subset who returned when convalescent (54.9 ± 17.2%). AECOPD patients with and without ECAC had similar clinical characteristics.

CONCLUSIONS

Tracheal collapse in both stable and AECOPD is considerably more prevalent than in healthy individuals. ECAC warrants assessment as part of comprehensive COPD evaluation and management. Further studies should evaluate the aetiology of ECAC and whether it predisposes to exacerbations.

A comparison of virtual bronchoscopy versus flexible bronchoscopy in the diagnosis of tracheobronchomalacia in children

INTRODUCTION

Flexible bronchoscopy (FB) is the current gold standard for diagnosing tracheobronchomalacia. However, it is not always feasible and virtual bronchoscopy (VB), acquired from chest multi-detector CT (MDCT) scan is an alternative diagnostic tool. We determined the sensitivity, specificity, and positive and negative predictive values of VB compared to FB in diagnosing tracheobronchomalacia.

METHODS

Children aged <18-years scheduled for FB and MDCT were recruited. FB and MDCT were undertaken within 30-min to 7-days of each other. Tracheobronchomalacia (mild, moderate, severe, very severe) diagnosed on FB were independently scored by two pediatric pulmonologists; VB was independently scored by two pairs (each pair = pediatric pulmonologist and radiologist), in a blinded manner.

RESULTS

In 53 children (median age = 2.5 years, range 0.8-14.3) evaluated for airway abnormalities, tracheomalacia was detected in 37 (70%) children at FB. Of these, VB detected tracheomalacia in 20 children, with a sensitivity of 54.1% (95%CI 37.1-70.2), specificity = 87.5% (95%CI 60.4-97.8), and positive predictive value = 90.9% (95%CI 69.4-98.4). The agreement between pediatric pulmonologists for diagnosing tracheomalacia by FB was excellent, weighted κ = 0.8 (95%CI 0.64-0.97); but only fair between the pairs of pediatric pulmonologists/radiologists for VB, weighted κ = 0.47 (95%CI 0.23-0.71). There were 42 cases of bronchomalacia detected on FB. VB had a sensitivity = 45.2% (95%CI 30.2-61.2), specificity = 95.5% (95%CI 94.2-96.5), and positive predictive value = 23.2 (95%CI 14.9-34.0) compared to FB in detecting bronchomalacia.

CONCLUSION

VB cannot replace FB as the gold standard for detecting tracheobronchomalacia in children. However, VB could be considered as an alternative diagnostic modality in children with symptoms suggestive of tracheobronchomalacia where FB is unavailable. Pediatr Pulmonol. 2017;52:480-486. © 2016 Wiley Periodicals, Inc.

Tracheal cartilage growth by intratracheal injection of basic fibroblast growth factor

BACKGROUND/PURPOSE

We have previously shown that intratracheal injection of slowly released (in gelatin) basic fibroblast growth factor (bFGF) significantly enlarged the tracheal lumen by a slight margin. This study aimed to investigate differences in tracheal cartilage growth by the intratracheal injection of bFGF doses in a rabbit model.

METHODS

Water (group 1; n=7; control) or 100μg (group 2; n=8) or 200μg (group 3; n=8) of bFGF dissolved in water was injected into the posterior wall of the cervical trachea of New Zealand white rabbits using a tracheoscope. All animals were sacrificed four weeks later.

RESULTS

The mean circumferences of cervical tracheas for groups 1, 2, and 3 were 18.8±0.83, 21.1±2.0, and 22.1±1.3mm, respectively. A significant difference was found between groups 1 and 2 (P=0.034) and groups 1 and 3 (P=0.004). The mean luminal areas of cervical tracheas for groups 1, 2, and 3 were 27.0±2.1, 32.2±4.8, and 36.3±4.6mm², respectively. A significant difference was found between groups 1 and 3 (P=0.001).

CONCLUSION

Intratracheal injection of bFGF in the dose range used significantly promoted the growth of tracheal cartilage in a rabbit model.

LEVELS OF EVIDENCE

Level II at treatment study (animal experiment).

Slow release of basic fibroblast growth factor (b-FGF) enhances mechanical properties of rat trachea

AIM

Severe tracheomalacia is a life-threatening disease, but symptoms usually improve with growth. The aims of this study were to investigate how slow release basic-Fibroblast Growth Factor (b-FGF) acts on tracheal cartilage, and whether growth-promoted trachea is more resistant against an increase in externally-applied pressure.

METHODS

Biodegradable gelatin hydrogel sheets soaked in 10 μl of distilled water (sham) or 0.5 or 5 μg/10 μl of b-FGF solution were inserted behind the cervical trachea of three-week-old male Wistar rats. The cervical trachea was harvested 4 weeks later. Extratracheal pressure was increased from 0 to 40 cmH2O in a chamber, while video-recording the internal lumen. The luminal area at each pressure was expressed as a proportion to that at 0 cmH2O. The amounts of collagen type II and glycosaminoglycan were measured by ELISA.

RESULTS

The luminal areas at 40 cmH2O in the control (no intervention), sham, and each of the b-FGF groups were 0.65, 0.62, 0.72, and 0.73, respectively. The amounts of collagen type II and glycosaminoglycan in each group were 127, 136, 193, 249 μg/mg, respectively, and 15, 16, 19, 33 μg/mg, respectively. There were significant differences between the control group and the FGF 5 group (P=0.02, 0.01, 0.01, for luminal area, collagen, and glycosaminoglycan, respectively).

CONCLUSION

5 μg of slow-release b-FGF promotes matrix production (collagen type II and glycosaminoglycan). The growth-enhanced trachea was more resistant to collapse, suggesting that slowly released b-FGF might be useful in patients with severe tracheomalacia.

Promotion of tracheal cartilage growth by intra-tracheal injection of basic fibroblast growth factor (b-FGF)

PURPOSE

Basic fibroblast growth factor (b-FGF) is a very effective growth factor that induces the proliferation of chondrocytes. This study aimed to investigate whether intra-tracheally-injected b-FGF solution promotes the growth of tracheal cartilage.

METHODS

Group 1: 500 μl of distilled water was injected at the posterior wall of the cervical trachea of New Zealand white rabbits by using a tracheoscope (n=5). Group 2: 100 μg/500 μl of b-FGF solution was injected at the posterior wall of the cervical trachea (n=5). Group 3: Biodegradable gelatin hydrogel microspheres incorporating 100 μg/500 μl of b-FGF solution were injected at the posterior wall of the cervical trachea (n=5). All animals were sacrificed 4 weeks later, and the outer diameter and luminal area of the cervical trachea at the site of b-FGF injection were measured.

RESULTS

The cervical tracheas in the two b-FGF injection groups were spindle-shaped and had a maximum diameter at the injection site. The median outer diameter of the cervical trachea in Groups 1, 2, and 3 was 7.3, 8.0, and 8.0mm, respectively, showing a significant difference among Groups 1, 2, and 3 (P=0.04). The median luminal area in Groups 1, 2, and 3 was 27.4, 29.4, and 32.1mm(2), respectively. The ad hoc test showed a marginally significant difference only between groups 1 and 3 (p=0.056).

CONCLUSION

Intra-tracheal injection of slowly released b-FGF enlarged the tracheal lumen.

Chronic cough in preschool children

Cough may be the first overt sign of disease of the airways or lungs when it represents more than a defense mechanism, and may by its persistence become a helpful pointer of potential disease for both patient and physician. On the other hand, impairment or absence of the coughing mechanism can be harmful and even fatal; this is why cough suppression is rarely indicated in childhood. Pediatricians are concerned more with the etiology of the cough and making the right diagnosis. Whereas chronic cough in adults has been universally defined as a cough that lasts more than 8 weeks, in childhood, different timing has been reported. Many reasons support defining a cough that lasts more than 4 weeks in preschool children as chronic, however; and this is particularly true when the cough is wet. During childhood, the respiratory tract and nervous system undergo a series of anatomical and physiological maturation processes that influence the cough reflex. In addition, immunological response undergoes developmental and memorial processes that make infection and congenital abnormalities the overwhelming causes of cough in preschool children. Cough in children should be treated on the basis of etiology, and there is no evidence in support of the use of medication for symptomatic cough relief or adopting empirical approaches. Most cases of chronic cough in preschool age are caused by protracted bacterial bronchitis, tracheobronchomalacia, foreign body aspiration, post-infectious cough or some combination of these. Other causes of chronic cough, such as bronchiectasis, asthma, gastroesophageal reflux, and upper respiratory syndrome appear to be less frequent in this age group. The prevalence of each depends on the population in consideration, the epidemiology of infectious diseases, socioeconomic aspects, and the local health system.

Resolution of opisthotonus in respiratory distress by aortopexy

We report a case of worsening respiratory distress associated with opisthotonus secondary to tracheomalacia, a rather unique pathophysiological phenomenon. A 2-month-old male baby was referred to our hospital for respiratory distress syndrome with a noticeable opisthotonus. Examination and investigation confirmed the presence of an aberrant innominate artery compressing the trachea. The infant underwent aortopexy and made a dramatic post-operative recovery. Of special note, the opisthotonus vanished soon after the operation. Opisthotonus is not always related to neurological impairment and may be a warning sign of mediastinal overcrowding in patients with respiratory distress syndrome secondary to vascular compression.

Slow release of basic fibroblast growth factor (b-FGF) promotes growth of tracheal cartilage

PURPOSE

Tracheomalacia is a major cause of morbidity in conditions such as oesophageal atresia. However, symptoms usually improve with age. A more rapid growth of tracheal cartilage can be induced by basic-Fibroblast Growth Factor (b-FGF). This study aimed to investigate whether slow-release b-FGF could act as a novel treatment for tracheomalacia.

METHODS

Biodegradable gelatin hydrogel sheets incorporating 0.5, 5, or 50 μg/20 μl of b-FGF solution were inserted between the cervical trachea and esophagus of rats. No intervention was performed in rats in a control group. All animals were sacrificed 4 weeks later, and the luminal area of the cervical trachea and the thickness of the cartilage were measured.

RESULTS

The mean luminal areas in the control group and in the b-FGF groups were 3.1, 3.2, 3.8, and 2.6mm(2), respectively, and showed a peak area at 5 μg of b-FGF. A significant difference was seen only between the control group and the b-FGF 5 μg group (p<0.05). The mean thickness of the tracheal cartilage was 0.12, 0.13, 0.19, and 0.32 mm in the control and the b-FGF groups, respectively, and showed a dose-dependent increase, which was statistically significant between the b-FGF 5 μg or 50 μg groups and the control group (p<0.01).

CONCLUSION

This study showed that slow-release b-FGF enlarges the tracheal lumen and thickens the cartilage in a dose-dependent fashion.

Interventions for primary (intrinsic) tracheomalacia in children

BACKGROUND

Tracheomalacia, a disorder of the large airways where the trachea is deformed or malformed during respiration, is commonly seen in tertiary paediatric practice. It is associated with a wide spectrum of respiratory symptoms from life-threatening recurrent apnoea to common respiratory symptoms such as chronic cough and wheeze. Current practice following diagnosis of tracheomalacia includes medical approaches aimed at reducing associated symptoms of tracheomalacia, ventilation modalities of continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP), and surgical approaches aimed at improving the calibre of the airway (airway stenting, aortopexy, tracheopexy).

OBJECTIVES

To evaluate the efficacy of medical and surgical therapies for children with intrinsic (primary) tracheomalacia.

SEARCH METHODS

The Cochrane Airways Group searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Airways Group's Specialised Register, MEDLINE and EMBASE databases. The Cochrane Airways Group performed the latest searches in March 2012.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of therapies related to symptoms associated with primary or intrinsic tracheomalacia.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted data from the included study independently and resolved disagreements by consensus.

MAIN RESULTS

We included one RCT that compared nebulised recombinant human deoxyribonuclease (rhDNase) with placebo in 40 children with airway malacia and a respiratory tract infection. We assessed it to be a RCT with overall low risk of bias. Data analysed in this review showed that there was no significant difference between groups for the primary outcome of proportion cough-free at two weeks (odds ratio (OR) 1.38; 95% confidence interval (CI) 0.37 to 5.14). However, the mean change in night time cough diary scores significantly favoured the placebo group (mean difference (MD) 1.00; 95% CI 0.17 to 1.83, P = 0.02). The mean change in daytime cough diary scores from baseline was also better in the placebo group compared to those on nebulised rhDNase, but the difference between groups was not statistically significant (MD 0.70; 95% CI -0.19 to 1.59). Other outcomes (dyspnoea, and difficulty in expectorating sputum scores, and lung function tests at two weeks also favoured placebo over nebulised rhDNase but did not reach levels of significance.

AUTHORS' CONCLUSIONS

There is currently an absence of evidence to support any of the therapies currently utilised for management of intrinsic tracheomalacia. It remains inconclusive whether the use of nebulised rhDNase in children with airway malacia and a respiratory tract infection worsens recovery. It is unlikely that any RCT on surgically based management will ever be available for children with severe life-threatening illness associated with tracheomalacia. For those with less severe disease, RCTs on interventions such as antibiotics and chest physiotherapy are clearly needed. Outcomes of these RCTs should include measurements of the trachea and physiological outcomes in addition to clinical outcomes.

Tracheobronchomalacia in children: review of diagnosis and definition

Tracheobronchomalacia is characterised by excessive airway collapsibility due to weakness of airway walls and supporting cartilage. The standard definition requires reduction in cross-sectional area of at least 50% on expiration. However, there is a paucity of information regarding the normal range of central airway collapse among children of varying ages, ethnicities and genders, with and without coexisting pulmonary disease. Consequently, the threshold for pathological collapse is considered somewhat arbitrary. Available methods for assessing the airway dynamically--bronchoscopy, radiography, cine fluoroscopy, bronchography, CT and MR--have issues with reliability, the need for intubation, radiation dose and contrast administration. In addition, there are varying means of eliciting the diagnosis. Forced expiratory manoeuvres have been employed but can exaggerate normal physiological changes. Furthermore, radiographic evidence of tracheal compression does not necessarily translate into physiological or functional significance. Given that the criteria used to make the diagnosis of tracheobronchomalacia are poorly validated, further studies with larger patient samples are required to define the threshold for pathological airway collapse.

A comparison of fluoroscopic airway screening with flexible bronchoscopy for diagnosing tracheomalacia

BACKGROUND

Flexible bronchoscopy (FB) is the gold standard method of diagnosing tracheomalacia but it is not always feasible in settings with limited resources. Fluoroscopy is sometimes performed as an alternative diagnostic tool but there are no prospective studies that have evaluated the diagnostic accuracy of airway fluoroscopy for tracheomalacia using a-priori definitions. We determined the sensitivity, specificity, and likelihood predictive ratio of airway fluoroscopy compared with FB in children suspected of having an airway abnormality.

METHODS

Airway fluoroscopic examination was undertaken within 2-weeks of a FB in children aged <18-years and reported by a pediatric radiologist blinded to FB data. Fluoroscopic and FB methods and diagnostic criteria were standardized and defined a-priori. Tracheomalacia diagnosed by FB were independently scored (mild, moderate, severe) by 2 pulmonologists in a blinded manner.

RESULTS

In 22 children (median age 33 months, range 1-187) evaluated for airway abnormality, tracheomalacia was found in 21 children at bronchoscopy. Of these, fluoroscopy detected tracheomalacia in five children. Airway fluoroscopy was poorly sensitive (23.8%) but highly specific (100%), positive likelihood ratio was 8.6. However, in moderate-severe tracheomalacia, the sensitivity improved to 57.1% but the specificity reduced (93.3%). The agreement between bronchoscopists for tracheomalacia severity was excellent, weighted kappa 0.74 (95% CI 0.77, 0.98).

CONCLUSION

Airway fluoroscopy cannot replace FB which remains the tool for definitively diagnosing airway malacia. However, in absence of other modalities for diagnosis fluoroscopy should be considered in the setting of persistent respiratory symptoms compatible with the clinical picture of tracheomalacia.