Colleen B Litof

Although it is one of the most common lower respiratory tract infections of very young children, bronchiolitis can be dangerous and even fatal for some infants. 

There are different, perhaps previously unappreciated, factors that can make otherwise healthy children sick enough to require intensive care. The authors of a recently published study of risk factors that predispose to severe disease found that compared with infants who weather the bronchiolitis storm well, those who become seriously ill share certain distinguishing characteristics:

• They are smaller, younger (<3 months), and more likely to have been delivered by cesarean section. The younger the infant, the more likely he or she is to require admission to the pediatric ICU. 
• Their hemoglobin, sodium, and lymphocyte counts are lower, and gamma-glutamyl transpeptidase (GGT) levels are higher.

• Their chest films show more pulmonary consolidation and/or atelectasis. Infants with the most consolidation/atelectasis have the highest serum levels of C-reactive protein.

 followed 310 infants younger than 12 months of age who were having a first episode of bronchiolitis. Infants were selected over 5 epidemic seasons so that an adequate sample size could be collected while minimizing the effect of changing standards of care. Unlike other studies of bronchiolitis, all infants were otherwise healthy; the investigators excluded those who were premature, extremely young (younger than 37 weeks) or underweight (<2000 g at birth), or compromised by congenital heart disease or immunodeficiency. Infants were sorted into 4 groups based on severity of illness--ranging from needing no oxygen or fluids, to requiring fluids and/or oxygen or mechanical ventilation/noninvasive respiratory support. Epidemiologic, clinical, demographic, radiologic, and laboratory data were evaluated with respect to these groupings.

The investigators found that epidemiologic factors such as maternal smoking, family incidence of atopy, and breastfeeding, had no significant bearing on severity of bronchiolitis. This effect could have been related to the general good health of the children studied.

The investigators also performed viral analysis on nasal washings from each child. There were a variety of causative viruses, but respiratory syncytial virus (RSV) was most common. Children most susceptible to RSV were those with pulmonary consolidation/atelectasis or high levels of C-reactive protein.

Most of the infants in the study were admitted to intensive care right from admission, suggesting that in healthy infants who are carried to term, severe bronchiolitis probably develops too early to be predicted or prevented.

Papoff P, Moretti C, Cangiano G, et al. Incidence and predisposing factors for severe disease in previously healthy term infants experiencing their first episode of bronchiolitis. 

Articles

Although bronchiolitis is commonly seen in very young children, the infection can be dangerous and even fatal for some infants. Here, new thoughts on risk factors that may determine which babies get very sick.  

With Bronchiolitis Season in Full Swing, New Insights into Factors Affecting Severity

Asthma happens. While daytime attacks are obvious, those that occur at night may be more subtle. Patients may notice that they have trouble falling or staying asleep or that they are sleepy during the day. Some patients, however, experience disturbing snoring, choking, coughing, and/or breathlessness during sleep.

Teodorescu and colleagues,

  have published numerous studies on sleep disorders in persons with asthma, finding it to be a common issue. These researchers are not alone: recent data from the Room to Breathe Survey (a global initiative underway in Canada, Greece, Hungary, The Netherlands, the United Kingdom, and South Africa) shows that 59% of 943 children and adolescents who had asthma and were interviewed reported nocturnal awakening.

   

What mechanisms cause sleep disturbance in persons with asthma? In persons who do not have asthma, PEFR and FEV

 are greatest at night and lowest in the morning. In asthmatic persons, this pattern is similar but exaggerated. Flow rates are lower and there is more variation in respiratory function. The amount of nitric oxide exhaled in the morning is lower in persons who do have asthma than in those who do not. The net result of this is increased bronchoconstriction and airway resistance, occurring in airways that are already inflamed. Cortisol and corticotropin levels are peaking simultaneously-a response that is most pronounced in persons with nocturnal asthma (compared with both asthmatics and non-asthmatics).

The other part of the equation is that REM sleep is heaviest during early morning. During REM periods, respiratory function is normally subdued (tidal volume and functional residual capacity both decline).

 For persons with asthma, this period then becomes a sort of “double whammy,” with compounded airflow restriction that can compromise the quality of sleep. 

The consequences of lack of sleep are signficant-especially for children with asthma. Horner and colleagues,

 working at the Washington University School of Medicine in St Louis, Missouri, examined the clinical consequences of nocturnal asthma symptoms requiring albuterol (NASRAs) in children with mild-to-moderate persistent asthma. A total of 285 children aged 6 to 14 years were randomized to receive one of 3 controller regimens and completed daily symptom diaries for 48 weeks.



Results showed that 72.2% of the children experienced at least one NASRA, and 24.3% had 13 or more episodes. Over 80% of nocturnal symptoms occurred when asthma was not exacerbated.

Symptoms were associated with the following next-day events: albuterol use (56.9%), school absence (5.0%), and doctor contact (3.7%). Nocturnal symptoms clearly contributed to school absence, increased medication use, and physician contact, although they did not predict exacerbation of asthma.

In another recent study, Fagnano and team

 studied the impact of nocturnal asthma on the quality of life (QOL) in a group of 287 urban children with persistent asthma who were enrolled in the School-Based Asthma Therapy trial of Rochester, New York. Caregivers reported on nocturnal asthma symptoms (number of nights/2 weeks with wheezing or coughing), parent QOL, and sleep quality by using the validated Children's Sleep Habits Questionnaire.

Forty-one percent of the children had intermittent nocturnal asthma symptoms, which were mild and persistent in 23% and moderate to severe in 36%.

Children's average total sleep quality score was 51 (range, 33-99, with a clincally significant cut-off score of 41), indicating pervasive sleep disturbances. Sleep scores were worse in the children having the worst nocturnal asthma symptoms. Not only were the children affected, but their parents were troubled as well: parental QOL scores decreased with the severity of their child’s illness.


Answers to questions about sleep quality and daytime sleepiness are important, during an initial history and on an ongoing basis. Answers may offer clues regarding inital asthma severity and disease progression, and direct modification of the treatment plan. Controlling noctural asthma is certainly a worthy goal that could have significant impact on overall health, functional ability, and QOL--for adults, children, and their parents.

References1. Teodorescu M, Polomis DA, Hall SV, et al. Association of obstructive sleep apnea risk with asthma control in adults. Chest. 2010;138(3):543-50. Epub 2010 May 21.2. Wildhaber J, Carroll WD, Brand PL. Global impact of asthma on children and adolescents’ daily lives: the Room to Breathe survey. Pediatr Pulmonol. 2011 Oct 25. doi: 10.1002/ppul.21557. Epub ahead of print.

3. Spengler CM, Shea SA. Endogenous circadian rhythm of pulmonary function in healthy humans. Am J Respir Crit Care Med. 2000;162:1038-1046.

4. Sutherland ER, Martin JR, Bowler RP et al. Physiologic correlates of distal lung inflammation in asthma. J Allergy Clin Immunol. 2004;113:1046-1050.

5. Horner CC, Mauger D, Strunk RC et al. Most nocturnal asthma symptoms occur outside of exacerbations and associate with morbidity. J Allergy Clin Immunol. 2011 Nov;128:977-982.e2. Epub ahead of print.

6. Fagnano M, Bayer AL, Isensee CA et al. Nocturnal asthma symptoms and poor sleep quality among urban school children with asthma. Acad Pediatr. 2011;11:493-499.

Author | Colleen B Litof

Articles

With Bronchiolitis Season in Full Swing, New Insights into Factors Affecting Severity

Controlling Nocturnal Asthma: Rx for Quality of Life