Clinical features of pertussis in 248 hospitalized children and risk factors of severe pertussis / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the clinical features of pertussis in children and analyze the risk factors of severe pertussis.Methods:The clinical data of 248 children with pertussis hospitalized in Hunan Children′s Hospital from March 2018 to March 2022 were analyzed retrospectively.According to the age at admission, the patients were divided into two groups ≤3 months and > 3 months.According to the patient′s condition, they were classified into ordinary group and severe group.According to the pathogens detected, the children were divided into single infection group and mixed infection group.The independent sample t-test, chi- square test were used to analyze the clinical indexes of the infants in above groups. Results:(1)Of 248 hospitalized children with pertussis, 204 cases (82.2%) were less than 1 year old, 92 cases (37.0%) had contact with a coughing family member before, and 169 cases (68.1%) were unvaccinated.Among 248 children, 193 cases (77.8%) had an elevated white blood cell count, and 145 cases (58.4%) had mixed infections.The most common pathogen was respiratory syncytial virus [29/248(11.6%)]. About 173 cases (69.7%) had concurrent pneumonia, and 35 cases (14.1%) had pulmonary consolidation.(2)Compared with the group > 3 months of age, more patients in the group ≤3 months of age had contact with a coughing family member before, and suffered from cyanosis, dyspnea, respiratory failure, heart failure and pertussis encephalopathy ( χ2=4.612, 20.810, 7.882, 16.617, 13.740, 7.846, all P<0.05). The proportions of patients in the group ≤3 months of age required intensive care unit(ICU) hospitalization and mechanical ventilation were higher than those in the group > 3 months of age ( χ2=14.810, 21.436, all P<0.05). The mortality of the group ≤3 months of age was higher than that of the group >3 months of age ( χ2=12.016, P<0.05). Children ≤3 months of age had a higher WBC level [(27.83±27.70)×10 9/L vs.(23.34±15.28)×10 9/L, t=22.244, P<0.001], longer duration of spasmodic cough [(16.56±9.33) d vs.(15.06±6.16) d, t=10.145, P=0.002] and longer hospitalization time [(11.47±10.48) d vs.(9.48±4.80) d, t=20.050, P<0.001] than those >3 months of age.(3)Compared with the ordinary group, a higher proportion of children in the severe pertussis group were under 3 months old, and had not been vaccinated against pertussis vaccine ( χ2=14.803, 4.475, all P<0.05). The ratio of patients with dyspnea, an lymphocyte count/neutral cell(LC/NC) ratio <1, mixed infections, lung consolidation and pleural effusion in the severe pertussis group was higher than that in the ordinary group ( χ2=116.940, 43.625, 13.253, 106.370, 11.874, all P<0.05). The patients in the severe pertussis group had a higher WBC [(61.66±29.63)×10 9/L vs.(18.83±10.00)×10 9/L, t=112.580, P<0.001] and a lower LC (0.494±0.186 vs.0.676±0.132, t=13.752, P<0.001) than those in the ordinary group.(4)Compared with the single infection group, the proportions of children with fever, dyspnea, fine moist lung rales, an LC/NC ratio <1, and lung consolidation were higher in the mixed infection group ( χ2=8.909, 6.804, 7.563, 8.420, 12.458, all P<0.05). More children in the mixed infection group required ICU hospitalization and mechanical ventilation than those in the single infection group ( χ2=11.677, 7.397, all P<0.05). The mixed infection group had higher respiratory failure and death rates than the single infection group ( χ2=7.980, 4.267, all P<0.05). Compared with the single infection group, the mixed infection group had a higher WBC level [(27.73±24.13)×10 9/L vs.(21.25±14.65)×10 9/L, t=13.318, P<0.001], longer hospitalization time [(11.593±9.010) d vs.(8.339±4.047) d, t=17.283, P<0.001], and a smaller LC ratio (0.626±0.165 vs.0.684±0.132, t=7.997, P=0.005). (5) Logistic regression analysis showed that age ≤3 months, peak WBC and dyspnea were risk factors of severe pertussis. Conclusions:Hospitalized pertussis children are prone to pneumonia and pulmonary consolidation.Patients aged ≤3 months with a large WBC and dyspnea easily develop into severe pertussis.Monitoring blood routine is helpful for judging the severity of the disease.Mixed infections increase the incidence of complications and can impair the treatment effect.