Effect of lowering Methacholine Challenge Test cutoff in children

Airway hyperreactivity is frequent in non-asthmatic children with sickle cell disease

“…For the MCT, the tidal volume breathing method was used in accordance with the American Thoracic Society (ATS) Guidelines . Methacholine was administered via nebulization (AirLife™ Misty Max 10 Nebulizer) starting with 0.25 mg/ml and doubling the dose up to a maximum of 4 mg/ml . A positive MCT was defined as a fall of FEV 1 by 20% from baseline.…”

“…29 Methacholine was administered via nebulization (AirLife TM Misty Max 10 Nebulizer) starting with 0.25 mg/ml and doubling the dose up to a maximum of 4 mg/ml. 30 A positive MCT was defined as a fall of FEV 1 by 20% from baseline. The precise dose of methacholine at which the FEV 1 decreased by 20% was calculated by linear interpolation of the logarithmic doseresponse curve expressed as the provocation concentration (PC 20 ).…”

Special considerations—asthma in children

“…The limited MCT studies conducted in children indicate the cutoff value for a provocative concentration of inhaled methacholine that causes a decrease in FEV1 of 20% is 4.0 mg/mL; therefore, similar to the adult population. 40,41 However, positive MCT results may be found in pediatric pathologies other than asthma (eg, allergic rhinitis, cystic fibrosis), though negative testing is helpful to rule out a diagnosis of asthma. 42 Allergy testing may be undertaken to determine potential environmental triggers.…”

Predictive factors for a shortened methacholine challenge protocol in children

“…Several studies have proposed methods to shorten this test in children, including reducing the threshold to affirm the presence of airway hyperreactivity from 8 mg/ml to 4 mg/mL [6] and using more rapid nebulizers [7]. Few studies that included mostly adults demonstrated the possibility to shorten the provocation procedure by starting at a higher concentration or omitting some concentrations based on baseline lung function measurement, symptom control, and use of medication [8,9].…”