Vocal cord dysfunction in adolescents
Pediatric Pulmonology, 03/30/2012
Schulze J et al. – The combination of methacholine challenge test (MCT) and laryngoscopy may be able to differentiate between Vocal cord dysfunction (VCD) and non–VCD. VCD patients showed a positive reaction at lower methacholine doses and displayed greater airway obstruction after MCT.Methods
- Adolescents with clinical suspicion of VCD were invited to participate. After an initial pulmonary function test (PFT), direct laryngoscopy was performed.
- This was followed by a methacholine challenge test (MCT); the methacholine dose causing a 20% drop in forced expiratory volume after 1sec (FEV1) (PD20FEV1) was calculated.
- Then a second laryngoscopy was conducted.
- PFT changes before and after MCT were compared with the data of 14 healthy controls (HCs).
- Thirty-five patients (8–19 years) were investigated.
- Three showed anatomical alterations.
- Of the remaining 32 patients, 14 had VCD and 18 had bronchial hyperresponsiveness (non-VCD).
- In 29 patients with a positive MCT, PD20FEV1 methacholine was significantly lower in VCD compared with non-VCD (VCD 0.24±0.4mg, non-VCD 0.73±0.73mg, P=0.0006).
- A PD20FEV1<0.24mg methacholine predicted VCD with a sensitivity of 85% and a specificity of 75%.
- VCD patients showed significantly lower PFT parameters after challenge; FEV1: VCD 58.5±20.1%, non-VCD 80.2±18.0%, and HCs 98.7±16.6% (P<0.0001).