Chronic cough in children: bronchoalveolar lavage findings

Isolated chronic cough in childhood is a common complaint. Although the sym ptom cough is included in the definition of childhood asthma, there is deba te as to whether the majority of these children have asthma. The authors st udied children with isolated chronic cough looking for evidence of airway i nflammation typical of asthma, with increased numbers of airway eosinophils as assessed from bronchoalveolar lavage (BAL). The investigations were carried out an 23 children (median age: 6.7 yrs; ra nge: 1.7-12.75 yrs), attending the Royal Belfast Hospital for Sick Children for elective surgery, who also had a chronic unexplained tough. Written in formed consent was obtained from the parent(s) and a nonbronchoscopic BAL w as performed. BAL samples were analysed for total and differential white ce ll counts and also for the inflammatory mediators, eosinophil cationic prot ein (ECP) and histamine. Results were compared with a group of normal nonat opic children and also a group of atopic asthmatic children, who had been r ecruited for other studies on airway inflammation. There was a small but statistically significant increase in BAL percentage eosinophils in the children with chronic cough compared with nonasthmatic c ontrols (0.28% versus 0.10%, p=0.03). However, the children with cough had lower percentage eosinophils than the atopic asthmatic controls (0.28% vers us 0.66%, p=0.01). Three out of 23 children with chronic cough had BAL eosi nophils greater than the normal upper 95% reference interval in BAL. There was a small but statistically significant increase in percentage neutrophil s in the children with cough compared with the nonasthmatic controls (5.85% versus 3.21%, p=0.03). Four out of the 23 children had BAL neutrophils gre ater than the normal upper 95% reference interval in BAL. The authors conclude that only a minority of children with chronic unexplai ned cough have asthmatic-type airway inflammation. It is speculated that th e increased percentage neutrophils in bronchoalveolar lavage from children with cough could relate to underlying persistent airways infection.