The Esophagus. Группа авторов

3 Disorders Causing Oropharyngeal Dysphagia

       Patrick Sanvanson and Reza Shaker

       Department of Medicine, Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Introduction

      Swallowing requires the voluntary and involuntary coordination of numerous structures of the oral cavity, pharynx, larynx, and esophagus. The major function of swallowing is successful bolus transit to the esophagus while preventing aspiration. The term oropharyngeal dysphagia (OPD) refers to difficulty in swallowing because of abnormalities in either the delivery of oral contents to the proximal esophagus or misdirection of the bolus to the airway or nasopharynx.

      OPD is not rare and has significant morbidity and mortality, including decreased rehabilitation potential, decreased quality of life, increased hospital length of stay, and increased healthcare costs [1–5]. An estimated >16 million American, 30 million European, and 10 million Japanese elderly citizens have oropharyngeal dysphagia [6, 7]. The prevalence in a population survey is 6.9%; 30–40% of the population ≥65 years old; 30% in acute care, post‐traumatic, and single hemispheric cardiovascular accident (CVA); and 59–66% in a chronic care setting [8]. In one study in an acute and community mental health setting, the prevalence of OPD of 32% [9]. OPD is seen in 50% of patients after surgery and chemotherapy for head and neck cancer [10], 6.6–29.8% after anterior cervical decompression and fusion [11], and 7% of patients with inflammatory myopathies [12]. A growing population of patients with OPD have Parkinson’s disease (60%), Alzheimer’s disease (80%), and multiple sclerosis (30–40%) [13–19]. Oropharyngeal dysphagia is the first symptom for 60% of patients with amyotrophic lateral sclerosis [20].

      Despite the myriad causes of OPD, the pathophysiologic end result falls into one of two inter‐related categories: (i) abnormalities of bolus transfer and (ii) abnormalities of airway protection. Abnormalities of bolus transfer can be further grouped into those caused by (i) oropharyngeal pump failure; (ii) oral/pharyngeal and pharyngo‐upper esophageal sphincter (UES) discoordination; or (iii) pharyngeal outflow obstruction. Abnormalities of airway protection may manifest themselves as pre‐, intra‐, and post‐deglutitive aspiration. Whereas intra‐deglutitive aspiration is usually caused by a defective deglutitive laryngeal closure mechanism, the pre‐deglutitive aspiration is mainly caused by disorders affecting oral pharyngeal transit and its coordination with deglutitive airway closure. Post‐deglutitive aspiration for the most part results from pharyngeal outflow compromise and incomplete clearance. These distinctions carry with them important therapeutic implications. For instance, in a patient diagnosed with post‐deglutitive aspiration, therapy will be directed to enhance UES deglutitive opening and improve pharyngeal clearance. In a patient diagnosed with intra‐deglutitive aspiration, however, therapy will be directed at repairing/improving the closure mechanism of the larynx. In a patient with pre‐deglutitive aspiration, postural techniques, bolus modification, and swallow maneuvers will need to be instituted.

Considering the wide array of clinical presentations and large number of patients with swallow‐induced silent aspiration, the diagnosis of OPD requires a high index of suspicion. Some patients may be completely asymptomatic and present with pneumonia, whereas others may complain of difficulty swallowing, or demonstrate frequent throat clearing, repetitive swallowing, and hoarseness (Table 3.1). The investigating physician should seek out a history of recurrent pneumonia, weight loss, and regurgitation, as well as a garbled voice after meals, nasal regurgitation with meals, hoarseness, nasal speech, swallow‐related coughing, and avoidance of social dining.

Table 3.1 Symptoms/signs of oropharyngeal dysphagia.

OPD develops as a result of a large number of local and system causes leading to abnormal oropharyngeal bolus transit, compromise of airway protection, and compromise of volition and cognition. OPD must be distinguished from globus sensation and esophageal dysphagia as the causes of oropharyngeal pathology are often significantly different from those of esophageal dysphagia. OPD frequently requires a multidisciplinary approach as the etiology is often diverse and requires multiple expertise for management (Table 3.2). Therefore, it is imperative that the physiology be properly defined to address all modifiable aspects of the swallow to improve quality of life. Potential key participants in the care of the patient include gastroenterologists, radiologists, speech pathologists, neurologists, dietitians, otolaryngologists, geriatricians, rehabilitation medicine providers, palliative care physicians, and home caregivers who provide assistance with meals and medications. A managing physician needs to coordinate the care of dysphagic patients.

Swallowing

      Mechanisms

Swallowing occurs under three distinct conditions: volitional, subconscious, and reflexive pharyngeal. Volitional is mostly for nutritional purposes and is so effortless that it is often taken for granted. Subconscious occurs at a rate of one per minute on average and is considered airway housekeeping and reflux clearing. Reflexive pharyngeal is an airway protective mechanism against aspiration of food inadvertently falling into the pharynx during chewing or materials refluxed into the pharynx from the stomach.

Table 3.2 Causes of oropharyngeal dysphagia.

      Source: Modified from Cook [21]; and Feldman, Friedman, Brandt [22].