Frequency of nocturnal symptoms in asthmatic children attending a hospital out-patient clinic.

Since nocturnal symptoms indicate more severe asthma, we investigated their frequency in a hospital-based population of asthmatic children. Recognition of these symptoms offers the possibility to introduce appropriate treatment. We studied 796 consecutive children with asthma (mean (SD) age 9 (4) yrs) attending a hospital clinic, to determine whether these nocturnal symptoms predicted that daytime activities would be affected, and also the patients' perception of disease severity. At the end of a regular out-patient clinic visit, the answers to seven different questions concerning nocturnal symptoms in the previous 3 weeks were recorded. The forced expiratory volume in one second (FEV1) was > or = 90% predicted in 98% of the population that was able to perform lung function measurements (72% of the total population). In 38% of the patients with nocturnal symptoms, these symptoms were reported spontaneously. When asked for, nocturnal symptoms were reported by 47% of the children; 6% every night and 34% at least once a week. Cough was the most frequently reported symptom (31%). Children with nocturnal symptoms had a lower FEV1, scored their perception of asthma as more severe, and had their daytime activities affected more than those without nocturnal symptoms. Doctors should specifically ask about nocturnal symptoms, as not all patients with nocturnal symptoms report them spontaneously and they predict more severe disease.