Prevalence of symptoms associated with respiratory illness in children and young people with cerebral palsy.

Abstract

SIR–Population registry studies in Sweden and Australia have shown that survival for young people with cerebral palsy (CP) in developed countries has not improved during the past 40 years, and certainly not for individuals with severe motor impairments.1, 2 These studies also indicate that premature death in individuals with CP is most often due to respiratory causes, resulting from aspiration and/or pneumonia. The development of serious respiratory illness in young people with CP probably results from a number of contributing factors.3 Impaired swallowing, poor coordination of breathing with swallowing during meals, gastro-oesophageal reflux, and seizures may all lead to pulmonary aspiration. Aspiration may be recognized by signs such as choking, coughing, and changes to breathing and voice; but it can also be silent.4 Chronic coughing, chestiness, or wheeziness may indicate the presence of recurrent aspiration. Individuals with more severe gross motor function impairment would be expected to have a higher risk of respiratory illness, partly because of their reduced physical activity (associated with reduced chest expansion and respiratory muscle strength), and partly because they have more comorbidities. Scoliosis may also be a risk factor because it reduces lung capacity and because of its association with severe gross motor impairment and other comorbidities. Although many clinicians and researchers would agree that these factors probably contribute to the development of severe respiratory illness in children and young people with CP, this is based more on clinical reasoning than on research evidence. There is surprisingly little empirical literature describing the development of respiratory illness in this population. We have recently described associations between respiratory symptoms and oromotor dysfunction in CP,5 but neither we nor other researchers have published findings on the prevalence of respiratory symptoms in this cohort. In this letter, we wish to do this, and to make a few comments on the interpretation and implications of these data. We had two outcome measures of respiratory illness: (1) at least two courses of antibiotics and (2) at least one hospitalization during the previous year. Table 1 shows the factors that we found to be statistically significantly associated with one or both of these measures in 551 individuals, aged 1 to 26 years, with CP. It indicates the prevalence of these factors in the entire sample and at each Gross Motor Impairment Function Classification System (GMFCS) level. The lower part of the table shows the percentages of individuals at each GMFCS level who took nutrition by the following methods: without modifications, orally but with food texture modifications, orally and by tube, and by tube only (nil by mouth). Table 1 indicates that individuals at GMFCS level V have much higher rates of most of these symptoms than individuals at the other GMFCS levels. Our research suggests that this is not due to their gross motor function per se, but to their difficulties eating and drinking. The few individuals at GMFCS levels IV and V who had neither food modifications nor a tube had no higher risk of respiratory illness than individuals at GMFCS levels I to III with no food modifications. This suggests oropharyngeal motor or sensory dysfunction, and perhaps a reduced ability to coordinate breathing and swallowing in the group with higher rates of respiratory symptoms. The presence of at least one respiratory symptom during or directly after meals was reported by nearly half of the respondents (46.4%). Mealtime symptoms were reported by some respondents in each category of method of nutritional intake: those with no food modifications (36.4%), those with oral intake and food texture modifications (87.5%), those with oral intake plus tube (82.1%), and those who took all nutrition by tube and nil by mouth (71.4%). Non-oral intake (tube only) does not entirely prevent symptoms suggestive of aspiration, possibly because of ongoing gastro-oesophageal reflux and salivary aspiration, and possibly also because respiratory disease is sometimes already established by the time that mealtime interventions are introduced. These results also raise a question about whether the one-third of respondents with no food modifications who nevertheless report mealtime symptoms would benefit from food texture modifications to reduce aspiration. For any child, the decision to modify diet and/or use non-oral methods of intake is an individual one, and will depend on a diverse range of factors, including safety, maintenance of a healthy body weight, and quality of life. To enable informed decision-making, aspiration and risk of later respiratory disease should be discussed among these other factors. In conclusion, respiratory symptoms are common in children with CP, especially those at GMFCS level V. Respiratory symptoms at meals are also very prevalent. It is important to consider the risk of respiratory illness associated with pulmonary aspiration in these individuals. The study was funded by Health Networks Funding from the Western Australian Health Department.