Relative imbalance as etiology of laryngomalacia – A new theory

Neuropathological features of pediatric laryngomalacia

OBJECTIVE

Laryngomalacia is the most common pediatric laryngeal anomaly. The pathophysiology of laryngomalacia is not well defined; the leading hypothesis suggests weak laryngeal tone and neuromuscular discoordination. Only a few studies explored the histopathology of the laryngeal submucosal nerves, with reported nerve hypertrophy. Our study aims to describe the histopathology of submucosal nerves in specimens obtained from children with severe laryngomalacia compared to pediatric cadaveric controls.

STUDY DESIGN

Prospective study.

SETTINGS

Tertiary care children's hospital.

METHODS

Histologic and immunohistochemical sections of supraglottic tissue from 26 children with severe laryngomalacia and six pediatric autopsies were digitally scanned and assessed with image analysis software (QuPath), resulting in the identification and measurement of 4561 peripheral nerves and over 100,000 foci of neurofilaments.

RESULTS

Chronic inflammation was noted in all patients. Eosinophils were rare. The mean nerve area and perimeter were significantly smaller for patients with laryngomalacia compared to the control group (1594.0 ± 593.2 μm^2 vs. 2612.1 ± 2824.0 μm^2, p < 0.0001, and 158.8 ± 30.3 μm vs. 217.6 ± 165.0 μm, p < 0.0001). Nerve-per-area unit was significantly greater for patients with laryngomalacia compared to controls (1.39E-05 vs. 6.19 E-06, p = 0.009). The mean area and the number of neurofilaments per total nerve area were similar. Immunohistochemistry for calretinin, a marker for intestinal ganglion cells in Hirschsprung disease, was absent from all specimens.

CONCLUSIONS

This series includes a comparison of all identifiable nerve fibers obtained from children with severe laryngomalacia and shows that the mucosal nerves are smaller on average than controls. These findings fail to provide support for significant morphologic peripheral nerve pathology in laryngomalacia.

Preterm Birth, Low Birth Weight, and Medical Comorbidities Are Risk Factors for Severe Laryngomalacia in Children

Objective: To analyze the clinical characteristics and the risk factors associated with severe laryngomalacia in children. Methods: In this study, the clinical data of children (0-18 years), including gender, age at presentation, preterm delivery, low birth weight, delivery mode, feeding mode, fetal delivery, medical comorbidities, maternal gestational age at presentation, and calcium supplementation during pregnancy, diagnosed with laryngomalacia between January 2013 and January 2023 were retrospectively analyzed. The children were divided into mild-moderate and severe groups. Several risk factors were compared and analyzed between the 2 groups. The statistically significant risk factors were included in the logistic regression analysis. Results: A total of 224 children with severe laryngomalacia were enrolled in this study. The ratio of male to female patients was 1.55:1. All patients had severe laryngomalacia manifested by inspiratory laryngeal stridor. The average age of patients at symptom presentation was 2.7 (1.5-5.2) months. There were significant differences between the 2 groups in the age at presentation, premature delivery, low birth weight, medical comorbidities, and calcium supplementation during pregnancy (P < .05). Multivariate logistic regression analysis showed that premature delivery [odds ratio (OR) = 3.177, 95% confidence interval (CI): 2.329-4.334], low birth weight (OR = 3.188, 95% CI: 2.325-4.370), and medical comorbidities (OR = 1.434, 95% CI: 1.076-1.909) were independent risk factors for severe laryngomalacia (P < .05). Conclusion: Children with severe laryngomalacia exhibited persistent stridor at an earlier age at presentation. Premature delivery, low birth weight, and medical comorbidities were potential risk factors for severe laryngomalacia in children.

Profiling the clinical characteristics and surgical efficacy of laryngomalacia in children

OBJECTIVE

To analyze the clinical characteristics of laryngomalacia in Chinese children and explore the surgical efficacy and factors influencing severe laryngomalacia.

METHODS

Children (0-18 years) diagnosed with laryngomalacia in our hospital from January 2016 to January 2022 were enrolled in this study. Clinical data of patients, including general conditions, clinical symptoms, grading and classification, medical comorbidities, surgical efficacy, and the risk factors influencing severe laryngomalacia were retrospectively analyzed.

RESULTS

A total of 1810 children were enrolled (male:female; 2.02:1), among which most were infants under 1 year (77.18%). Inspiratory laryngeal stridor (69.56%) was the most common symptom. Most patients had mild laryngomalacia (79.28%), with type IV laryngomalacia being the most common classification (52.27%). Congenital heart disease (37.85%) was the most common medical comorbidity. A total of 168 severe laryngomalacia cases were treated via supraglottoplasty with an effective rate of 83.93%. Notably, preterm birth (OR = 3.868, 95% CI 1.340 ~ 11.168), low birth weight (OR = 4.517, 95% CI 1.477 ~ 13.819) and medical comorbidities (OR = 7.219, 95% CI 2.534 ~ 20.564) were independent risk factors for poor prognosis (P < 0.05).

CONCLUSION

Laryngomalacia is common among infants under the age of one, and it is mostly characterized by inspiratory laryngeal stridor with various medical comorbidity. Supraglottoplasty is the first treatment choice for severe laryngomalacia cases with high success rates. However, premature delivery, low birth weight, and medical comorbidities significantly affect the efficacy of surgery.

Evaluation of vitamin D levels and biochemical markers in infants diagnosed with laryngomalacia

Background/aim

The pathology of laryngomalacia is still not clear. The aim of this study was to investigate the relationship between vitamin D levels and laryngomalacia, and to evaluate vitamin D levels according to the classification of laryngomalacia.

Materials and methods

This retrospective study was conducted in the Kahramanmaraş Sütçü İmam University Medicine Faculty's Otorhinolaryngology Clinic between June 2014 and January 2021. Laryngomalacia was classified. Laboratory tests for all patients included calcium (Ca), phosphorus (P), parathormone (PTH), blood urea nitrogen (BUN), creatinine (Cre), alanine transaminase (ALT), and 25-hydroxy vitamin D (25-OH-D).

Results

Evaluations were performed for 64 infants with laryngomalacia, including 41 male and 23 female infants with a mean age of 4.6 ± 3.0 months, and a control group of 64 healthy infants with a mean age of 4.5 ± 2.8 months. A statistically significant difference was determined between the laryngomalacia group and the control group with respect to 25-OH-D and PTH levels (p < 0.001). When data were examined according to laryngomalacia types, a statistically significant difference was determined between the groups for 25-OH-D, Ca, P, PTH, and ALT values. The 25-OH-D level was statistically significantly lower in the severe laryngomalacia group than in the mild and control groups (p < 0.001). A statistically significant difference was determined between the moderate and severe laryngomalacia groups and the control group regarding PTH levels (p < 0.001).

Conclusion

Vitamin D deficiency may have a role in the etiology of laryngomalacia, and this view is supported by the finding that there was a decrease in vitamin D levels associated with laryngomalacia classification. In addition, the reduction in PTH levels in infants with laryngomalacia may be explained by the change in Ca metabolism. It would be appropriate for further studies to investigate the response to vitamin D replacement therapy in patients with moderate and severe laryngomalacia.

Histopathology of laryngomalacia

BACKGROUND

Laryngomalacia is the commonest laryngeal anomaly and cause of stridor in children. Although most cases are self-limiting, failure to thrive, hypoxaemia or significant apnoeic episodes may warrant surgical intervention in the form of aryepiglottoplasty. Opinion is divided as to the pathophysiological mechanisms involved in the disease process.

AIMS AND OBJECTIVES

This study explores the aetiology of laryngomalacia by reviewing the histology of aryepiglottoplasty resection specimens.

MATERIAL AND METHODS

The histology reports of 61 aryepiglottoplasty specimens resected between 1 October 2014 and 31 October 2018 were reviewed.

RESULTS

Age of patients ranged from 3 weeks to 36 months. 36 patients were male and 25 female. 43 of 61 (70.5%) cases had inflammation, most of which were mild. 3 (4.9%) cases had histological specimens with detectable eosinophils. None of the specimens had signs of granulomatous change, ulceration or calcification. Cartilage was present in the resected specimen in 47 (77%) cases. Over half of these (59.6%) were immature cartilage.

CONCLUSION AND SIGNIFICANCE

The results suggest a mild concurrent laryngitis/supraglottitis in most cases. Eosinophilia is rare and does not support eosinophilic oesophageal reflux as part of the aetiology. The high proportion of immature cartilage in the specimens supports the theory of chondropathic aetiology.

Investigation of the serum vitamin D level in infants followed up with the diagnosis of laryngomalacia: a case-control study

OBJECTIVE

The possible etiological relationship of the vitamin D with laryngomalacia is unclear. The aim of the study was to demonstrate the relationship between laryngomalacia and vitamin D levels.

METHODS

Twenty-three non-syndromic babies under the age of 1 year who were diagnosed with laryngomalacia were included in the study group. Forty healthy babies were included in the control group. The detailed anamnesis was obtained and a complete systemic physical examination, a flexible endoscopic laryngeal examination, and laboratory tests [calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathormone (PTH), alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN), creatinine (Cre), and 25-hydroxy vitamin D (25-OH D)] were performed in all patients. All laboratory tests of the groups were compared.

RESULTS

It was observed that there was no significant difference in the parameters that could affect vitamin D levels, namely type of feeding, vitamin D supplement intake, and the season when the serum sample was taken (p > 0.05). The vitamin D level was significantly lower (p = 0.003, p < 0.05) and the P and ALP levels were significantly higher (p = 0.016 and p = 0.001, respectively; p < 0.05) in the laryngomalacia group. Although the correlation between vitamin D and PTH was not statistically significant according to the Pearson correlation analysis, it was lower in the laryngomalacia group compared to the control group (p = 0.381, p > 0.05).

CONCLUSION

In this study, it was observed that the vitamin D levels were lower in infants with laryngomalacia compared to the control group. We consider that vitamin D deficiency may be a factor in the etiology of laryngomalacia with a yet-to-be-clarified etiology.