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Laryngeal electromyography findings in idiopathic congenital bilateral vocal cord paralysis
1Department of Otolaryngology, Royal Children's Hospital, Parkville, Victoria, Australia.
Insights
Idiopathic congenital bilateral vocal cord paralysis (BVCP) in children often shows normal electromyography (EMG) findings. However, these results do not predict early recovery, suggesting a complex condition.
Area of Science:
- Pediatric Otolaryngology
- Neuromuscular Disorders
- Laryngeal Electrophysiology
Background:
- Idiopathic congenital bilateral vocal cord paralysis (BVCP) presents a diagnostic challenge in pediatric patients.
- Understanding the underlying pathophysiology is crucial for effective management and prognosis.
Observation:
- Electromyography (EMG) of laryngeal muscles was performed in four children with idiopathic congenital BVCP.
- Patients exhibited varying degrees of paralysis, including abductor and adductor types, with some requiring respiratory or feeding support.
- Laryngeal EMG revealed specific motor unit potential patterns, with some showing improvement upon anesthetic lightening.
Findings:
- All four patients demonstrated phasic bursts with respiration on laryngeal EMG.
- Three patients developed a full interference pattern during the procedure.
- Despite EMG findings, no significant clinical improvement was observed during follow-up (37-52 months).
Implications:
- Normal laryngeal EMG findings can be present in idiopathic congenital BVCP.
- These findings do not guarantee a favorable prognosis for early recovery in affected children.
- Laryngeal EMG may aid in localizing the lesion site in idiopathic congenital BVCP, despite its prognostic limitations.
Abstract:
Children with idiopathic congenital bilateral vocal cord paralysis (BVCP) were investigated by electromyography (EMG) of the posterior cricoarytenoid and thyroarytenoid muscles to determine whether laryngeal EMG findings had diagnostic or prognostic significance. Four children between 3 weeks and 33 months of age were studied. Three had abductor paralysis and were tracheostomy-dependent, while the fourth had adductor paralysis requiring a feeding gastrostomy. Two of these patients also had other anomalies. Motor unit potentials showing phasic bursts with respiration were found in all four cases, while three children developed a full interference pattern on lightening of the anesthetic. Follow-up for between 37 and 52 months showed no significant clinical improvement in any of the patients. While the diagnosis of idiopathic congenital BVCP can represent a heterogeneous group of conditions, the findings suggest that normal laryngeal EMG findings may be a feature of idiopathic congenital BVCP but do not imply a favorable prognosis for early recovery. They may, however, have implications to explain the likely site of lesion in idiopathic congenital BVCP.