Demographic characteristics
A total of 164 patients with airway malacia complicated by pneumonia were recruited to the study (Table 1). Of these 164 patients, 123 (75%) were male and 41 (25%) were female. The male-to-female ratio was 3:1. The age of the patients ranged from 1 month to 4 years old. Ninety (54.88%) patients were aged ≤6 months, 42 (25.61%) patients were aged 6–12 months, and 32 (19.51%) patients were aged ≥12 months, The median age was 6 (3–10) months.
There were 34 (20.73%), 88 (53.66%), and 42 (25.61%) patients with tracheomalacia, bronchomalacia, and tracheobronchomalacia, respectively. Of the 88 children with bronchomalacia, 44 (50%) had right-sided disease, 25 (28.41%) had left-sided disease, and 19 (21.59%) had bilateral disease. In all cases of pneumonia with airway malacia, 24/164 (14.63%) were complicated by other airway dysplasia, most frequently laryngomalacia (12/24, 50%), followed by bronchial stenosis (6/24, 25%), abnormal opening of the bronchus (4/24, 16.67%), and tracheal bronchus (2/24, 8.33%); 40.85% (67/164) of patients had mild airway malacia, 43.29% (71/164) of patients had moderate airway malacia, and 15.86% (26/164) of patients had severe airway malacia.
Table 1. Airway malacia in patients with CAP
Patient characteristics
|
Case
|
sex(Male/Female)
|
123/41
|
Mean age (months)
|
6(3~10)
|
Age group n (%)
|
|
≤6 months
|
90(54.88%)
|
6~12 months
|
42(25.61%)
|
≥12 months
|
32(19.51%)
|
Part of malacia
|
|
tracheomalacia
|
34(20.73%)
|
bronchiomalacia
|
88(53.66%)
|
racheobronchiomalacia
|
42(25.61%)
|
Degree of malacia
|
|
mild malacia
|
67(40.85%)
|
moderate malacia
|
71(43.29%)
|
severe malacia
|
26(15.86%)
|
Range of malacia
|
|
single malacia
|
95(57.93%)
|
double malacia
|
37(53.62%)
|
multiple malacia(≥3)
|
32(46.38%)
|
Pathogens
Overall, because more than one pathogen could be detected in a patient, a total of 119 different pathogens were detected (Fig. 1). The most commonly detected pathogen was MP (25/164, 15.24%). Meanwhile, among the detected viruses, RSV (16/164, 9.76%) was the most common, followed by PIV3 (7/164, 4.27%), HBoV (7/164, 4.27%), ADV (2/164, 1.22%), PIV 1 (1/164, 0.61%), and hMPV (1/164, 0.61%).
A positive BALF culture was obtained in all children with airway malacia; 26.83% (44/164) BALF samples had a positive bacterial culture: 10.98% (18/164) Streptococcus pneumoniae (SP), 7.93% (13/164) Haemophilus influenzae (HI), 1.83% (3/164) Escherichia coli, 1.22% (2/164) Staphylococcus aureus, 1.22% (2/164) Enterobacter aerogenes, 1.22% (2/164) Klebsiella pneumoniae, 0.61% (1/164) coagulase-negative staphylococci, 0.61% (1/164) Acinetobacter baumannii, 0.61% (1/164) Moraxella catarrhalis, and 0.61% (1/164) Acinetobacter. Patients with a positive BALF culture had a higher median neutrophil percentage in the BALF (Fig. 2); however, this difference was not statistically significant.
In patients (n=90) aged ≤6 months, 61 pathogens were detected; the most commonly detected viral pathogens were HRV (10/61, 16.39%), RSV (9/61, 14.75%), and PIV3 (7/61, 11.48%). In patients aged 6–12 months (n=42) and ≥12 months (n=32), the most commonly detected viral pathogens were RSV (3/28, 10.71% and 4/30, 13.33%, respectively), HRV (4/28, 14.29% and 2/30, 6.67%, respectively), and HBoV (3/28, 10.71% and 4/30, 13.33%, respectively). The main bacterial pathogens in children of all ages were SP and HI.
In the airway malacia group, the incidence of premature delivery and mechanical ventilation was higher than that in the non-airway malacia group. Children with pneumonia with airway malacia had a longer duration of symptoms before admission (median, 13.5 d) and longer hospital stay (median, 10.0 d) than children with pneumonia without airway malacia. A greater proportion of children with pneumonia with airway malacia required supplemental oxygen than children with pneumonia without airway malacia (11.59% vs. 4.88%. respectively, p<0.05). Children with pneumonia with airway malacia were significantly more likely to have wheezing (67.07%), laryngeal stridor (32.93%), dyspnea (10.98%), cyanosis (11.11%), and intercostal retraction (23.17%); all of these were statistically different between the two groups (all p<0.05). Children with airway malacia had a higher neutrophil count than children without airway malacia, while there was no significant difference between the two groups with respect to the WBC count or CRP level (p>0.05).
Table 3. Clinical features of CAP children hospitalized with or without airway malacia
Clinical features
|
airway malacia
(n=164)
|
Non-airway malacia
(n=164)
|
P
|
|
|
Personal history
|
|
|
|
|
premature delivery n(%)
|
27(16.46)
|
11(6.71)
|
0.006
|
|
mechanical ventilation n(%)
|
10(6.10)
|
2(1.22)
|
0.019
|
|
Length of stay(day)
|
10(7.25~15)
|
7(6~8)
|
<0.001
|
|
Symptom duration prior to admission(day)
|
13.5(4~30)
|
6.5(4~10)
|
<0.001
|
|
requirement for supplemental oxygen(%)
|
19(11.59)
|
8(4.88)
|
0.027
|
|
Clinic presentation
|
|
|
|
|
cough
|
162(98.78)
|
163(99.39)
|
1.000
|
|
wheezing
|
110(67.07)
|
79(48.17)
|
<0.001
|
|
fever
|
58(35.37)
|
63(38.41)
|
0.567
|
|
laryngeal stridor
|
54(32.93)
|
17(10.37)
|
<0.001
|
|
Dyspnea
|
18(10.98)
|
8(4.88)
|
0.041
|
|
Cyanosis
|
11(11.11)
|
2(1.22)
|
0.011
|
|
Retractions
|
38(23.17)
|
6(3.66)
|
<0.001
|
|
Crackles n (%)
|
82(50.00)
|
90(54.88)
|
0.376
|
|
Laboratory findings
|
|
|
|
|
WBC count(× 109/L)
|
10.55(7.61~14.99)
|
10.34(7.56~12.89)
|
0.212
|
|
N count(×10^9/L)
|
3.67(2.32~5.58)
|
3.06(1.86~5.01)
|
0.013
|
|
CRP count >8mg/L[n(%)]
|
24(14.63)
|
31(18.90)
|
0.301
|
|
pathogens
|
|
|
|
|
virus
|
60(36.59)
|
64(39.02)
|
0.649
|
|
bacteria
|
66(40.24)
|
62(37.80)
|
0.651
|
|
MP
|
21(12.80)
|
15(9.15)
|
0.289
|
|
Clinical and laboratory characteristics of different age groups of children hospitalized with airway malacia complicated by pneumonia
To evaluate the difference among different age groups of children with airway malacia complicated by pneumonia, we divided the children into three age groups (Table 3). There was no significant difference in sex between the different age groups. The common characteristics among the 164 confirmed patients were cough (98.78%), wheezing (67.07%), fever (35.37%), retractions (23.17%), dyspnea (10.98%), cyanosis (11.11%), and crackles (50%); fever was more commonly detected in older children and wheezing was more commonly detected in children aged 6–12 months, while younger patients were more likely to have intercostal retractions. Other characteristics showed no significant difference among the three age groups (p>0.05). Older children were more likely to have a higher neutrophil count than younger children (p<0.05). The incidence of MP was higher among children aged >6 months than among younger children and was highest among children aged ≥12 months. The incidence of different viruses and bacteria were similar across age groups.
Table 3. Clinical features of CAP children hospitalized with airway malacia in different age groups
Clinical features
|
≤6 months(n=90)
n(%)
|
6~12 months(n=42)
n(%)
|
≥12 months(n=32)
n(%)
|
P
|
Female sex
|
26(28.89)
|
7(16.67)
|
8(25)
|
0.32
|
Clinic presentation
|
|
|
|
|
cough
|
89(98.89)
|
41(97.62)
|
32(100)
|
0.703
|
wheezing
|
51(56.67)
|
36(85.71)
|
23(71.88)
|
0.003
|
fever
|
19(21.11)
|
19(45.24)
|
20(62.50)
|
<0.01
|
Dyspnea
|
14(15.56)
|
3(7.14)
|
1(3.13)
|
0.075
|
Cyanosis
|
8(8.89)
|
1(2.38)
|
2(6.25)
|
0.320
|
Retractions
|
27(30.00)
|
9(21.43)
|
2(6.25)
|
0.023
|
Crackles
|
47(52.22)
|
19(45.24)
|
17(53.13)
|
0.719
|
Laboratory findings
|
|
|
|
|
WBC count(x10^9/L)
|
9.98(7.23~15.92)
|
10.86(7.89~13.49)
|
12.06(8.36~15.26)
|
0.538
|
Neutrophils count(x10^9/L)
|
3.2(2.25~4.83)
|
4.14(2.15~6.46)
|
4.75(2.99~7.94)
|
0.024
|
CRP count>8mg/L[n(%)]
|
10(11.11)
|
8(19.05)
|
6(18.75)
|
0.371
|
pathogens
|
|
|
|
|
virus
|
29(32.22)
|
10(23.81)
|
11(34.38)
|
0.538
|
bacteria
|
23(25.56)
|
11(26.19)
|
10(31.25)
|
0.818
|
MP
|
9(10.00)
|
6(14.29)
|
10(31.25)
|
0.026
|