September 2019 HSC Section 1 Congenital and Pediatric Problems

issues, 26% were reported to have aspiration, and 94% of these patients displayed silent aspiration. 8 In addi- tion, a separate study reported that children with silent aspiration were 3.37 times more likely to have neuro- logic impairment than children with overt aspiration. 3 These studies further emphasize the interdependent relationship between neurologic function and swallowing mechanisms. 3 Our results are limited by the retrospective nature of the study. All MBS studies were conducted in 2015, with some serving as a patient’s first evaluation and some serving as a follow-up study. It is likely that a number of patients in our sample had a previous MBS and were in the process of being treated for swallowing issues. For this reason, our results may be a conserva- tive estimate of the actual prevalence of dysphagia in this patient population. An additional limitation was that patients were tested only on the consistencies that were suspected to elicit aspiration in order to prevent unnecessary radiation exposure to the patient. We did not collect data on follow-up clinic visits or swallow stud- ies to evaluate the long-term effects or resolution of aspi- ration. Patients may also have been in the process of treatment for overlapping diagnoses, which could have confounded silent aspiration prevalence for each diagno- sis group. In addition, all patients were seen at a single tertiary care children’s hospital, which may involve referral bias. However, this institution caters to a large and diverse patient population, providing heterogeneity in our cohort with regard to age and comorbidities. CONCLUSION This study highlights the prevalence of silent aspi- ration in a cohort of pediatric patients who underwent MBS for suspicion of aspiration. Children with laryngeal cleft, laryngomalacia, unilateral vocal fold paralysis, developmental delay, epilepsy/seizures, a syndrome, or congenital heart disease may be at increased risk. Young age may also be a risk factor. Caregivers and clinicians should be aware that the absence of cough does not elim- inate the possibility of aspiration, and suspicions should be raised for children with recurring pulmonary issues. Evaluation should consist of a thorough medical history and MBS on all food textures deemed necessary by the speech-language pathologist. Coordinated multidisciplin- ary management strategies are important to ensure comprehensive and optimum care. The management team may consist of a nutritionist, speech-language pathologist, general pediatrician, pediatric gastroenterol- ogist, otolaryngologist, radiologist, pulmonologist, and neurologist, depending on the severity and etiology of silent aspiration.

a specific texture of food and not all consistencies in their diet, 8 and 2) silent aspiration is more prevalent than overt aspiration, regardless of consistency. When patients with silent aspiration and patients with no aspiration were compared, the most significant predictors of silent aspiration were age, laryngeal cleft, laryngomalacia, unilateral VFP, developmental delay, epilepsy/seizures, syndrome, and cardiac disease. Other pediatric studies have found that age is not significantly related to aspiration or silent aspiration. 3,8,16 However, our results show that children who silently aspirate (median 1.1 years old) were significantly younger than children who demonstrated overt aspiration (median 1.3 years) and those who did not aspirate at all (1.7 years old). A previous study also found that children with car- diac disease were significantly less likely to demonstrate aspiration or silent aspiration, 3 whereas our study found that cardiac disease was significantly associated with silent aspiration ( P < 0.001). It is important to note that patients with cardiac disease tend to have multiple impaired body systems and underlying diagnoses that may contribute to dysphagia. The airway disorders that were evaluated in this study may put patients at higher risk for silent aspira- tion. A substantial portion of included children with laryngeal cleft (41%) and laryngomalacia (41%) demon- strated silent aspiration, whereas rates of overt aspira- tion were much lower in these cohorts (6% for laryngeal cleft, 2% for laryngomalacia). Please note, however, that the equal prevalence of laryngeal cleft and laryngomala- cia in this cohort is not reflective of the actual compara- tive incidences of these conditions. All patients with laryngeal cleft were referred for MBS testing due to aspiration, whereas only a portion of laryngomalacia patients—those presenting with feeding difficulty and choking—were referred for MBS testing. Additionally, over half of patients with unilateral VFP and a quarter of patients with bilateral VFP demonstrated silent aspi- ration. This was the only form of aspiration demon- strated in these patients because overt aspiration was not documented in any patients with unilateral or bilat- eral VFP. These findings further highlight the impor- tance of testing for silent aspiration in this patient population. Based on the present study and prior literature, there is a relationship between neurologic impairment and silent aspiration that deserves further investigation. In our patient cohort, neurologic disease was the most common diagnosis among patients with silent aspiration, and more than a third of patients with neurologic issues showed silent aspiration. Children with developmental delay and epilepsy/seizures were significantly more likely to silently aspirate than those without these diag- noses. Among patients with silent aspiration, the most common neurologic diagnoses were developmental delay, hypotonia, and epilepsy/seizures. Each of these diagno- ses was significantly more prevalent in the silent aspira- tion group than the overt aspiration group. These findings have been supported by similar studies in the literature. For example, in a study of 186 pediatric patients with significant dysphagia and developmental

BIBLIOGRAPHY

1. Leith DE. The development of cough. Am Rev Respir Dis 1985;131:S39– S42. 2. Ramsey D, Smithard D, Kalra L. Silent aspiration: what do we know? Dys- phagia 2005;20:218–225. 3. Weir KA, McMahon S, Taylor S, Chang AB. Oropharyngeal aspiration and silent aspiration in children. Chest 2011;140:589–597.

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