SELECTED ARTICLES FROM THE RECENT LITERATURE 2003

12/4/03

Corticotrophin levels and nocturnal asthma

Summary
There has been considerable investigation of the nocturnal worsening of asthma (NA) seen in some asthmatics. However, the possible role of the hypothalamic-pituitary-adrenal (HPA) axis in such NA episodes is still not well defined. Sutherland et al of the National Jewish Medical and Research Center in Denver, CO found that plasma levels of corticotrophin but not cortisol were elevated in those with NA, when compared to levels in asthmatics without NA (1). Another study also found that a single dose of inhaled corticosteroids (ICS) given late in the afternoon was enough to prevent NA episodes (2). This preventive effect was due to a direct effect of the ICS on the lungs rather than a systemic effect of any ICS, which had been absorbed systemically.

Reference
1. J Allergy Clin Immunol 2003; 112:52-57
2. Thorax 2003; 58:632-33

Editor's Comments
The elevated plasma levels of corticotrophin seen around 3-4 AM in those with NA episodes appears to be due to an attempt to stimulate endogenous corticosteroid secretion without a suitable corticosteroid response. It should be noted that the preventive effect of a single dose of ICS on the occurrence of NA episodes requires a sizable dose of ICS (around 1000 mcg) given in the late afternoon, the timing of this treatment is very important.

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