Chapter 038. Dysphagia (Part 2)

Pathophysiology of DysphagiaBased on anatomic site of involvement, dysphagia may be divided into oral, pharyngeal, and esophageal dysphagia. Normal transport of an ingested bolus through the swallowing passage depends on the size of the ingested bolus and size of the lumen, the force of peristaltic contraction, and deglutitive inhibition, including normal relaxation of UES and LES during swallowing. Dysphagia caused by a large bolus or a narrow lumen is called mechanical dysphagia, whereas dysphagia due to weakness of peristaltic contractions or to impaired deglutitive inhibition causing nonperistaltic contractions and impaired sphincter relaxation is called motor dysphagia. ...
Nội dung trích xuất từ tài liệu:
Chapter 038. Dysphagia (Part 2) Chapter 038. Dysphagia (Part 2) Pathophysiology of Dysphagia Based on anatomic site of involvement, dysphagia may be divided intooral, pharyngeal, and esophageal dysphagia. Normal transport of an ingested bolusthrough the swallowing passage depends on the size of the ingested bolus and sizeof the lumen, the force of peristaltic contraction, and deglutitive inhibition,including normal relaxation of UES and LES during swallowing. Dysphagiacaused by a large bolus or a narrow lumen is called mechanical dysphagia,whereas dysphagia due to weakness of peristaltic contractions or to impaireddeglutitive inhibition causing nonperistaltic contractions and impaired sphincterrelaxation is called motor dysphagia. ORAL AND PHARYNGEAL (OROPHARYNGEAL) DYSPHAGIA Oral-phase dysphagia is associated with poor bolus formation and control,so that food may either drool out of the mouth or overstay in the mouth or thepatient may experience difficulty in initiating the swallowing reflex. Poor boluscontrol may also lead to premature spillage of food into the pharynx and aspirationinto the unguarded larynx and/or nasal cavity. Pharyngeal-phase dysphagia isassociated with stasis of food in the pharynx due to poor pharyngeal propulsionand obstruction at the UES. Pharyngeal stasis leads to nasal regurgitation andlaryngeal aspiration during or after a swallow. Nasal regurgitation and laryngealaspiration during the process of swallowing are hallmarks of oropharyngealdysphagia. Oropharyngeal dysphagia may be due to mechanical causes, including avariety of developmental abnormalities, head and neck tumors, radiation therapy,and inflammatory processes (Table 38-1). Table 38-1 Oropharyngeal Dysphagia Oropharyngeal Mechanical Dysphagia I. Wall defects A. Congenital 1. Cleft lip, cleft palate 2. Laryngeal clefts B. Post surgicalII. Intrinsic narrowing A. Inflammatory 1. Viral (herpes simplex, varicella-zoster, cytomegalovirus) 2. Bacterial (peritonsillar abscess) 3. Fungal (Candida) 4. Mucocutaneous bullous diseases 5. Caustic, chemical, thermal injury B. Web 1. Plummer-Vinson syndrome C. Strictures 1. Congenital microganthia 2. Caustic ingestion 3. Post-radiation D. Tumors 1. Benign 2. MalignantIII. Extrinsic compression A. Retropharyngeal abscess, mass B. Zenkers diverticulum C. Thyroid disorders D. Vertebral osteophytes Oropharyngeal Motor Dysphagia I. Diseases of cerebral cortex and brainstem A. With altered consciousness or dementia 1. Dementias including Alzheimers disease 2. Altered consciousness, metabolic encephalopathy, encephalitis,meningitis, cerebrovascular accident, brain injury B. With normal cognitive functions 1. Brain injury 2. Cerebral palsy 3. Rabies, tetanus, neurosyphilis 4. Cerebrovascular disease 5. Parkinsons disease and other extrapyramidal lesions 6. Multiple sclerosis (bulbar and pseudobulbar palsy) 7. Amyotrophic lateral sclerosis (motor neuron disease) 8. Poliomyelitis and post-poliomyelitis syndromeII. Diseases of cranial nerves (V, VII, IX, X, XII) A. Basilar meningitis (chronic inflammatory, neoplastic) B. Nerve injury C. Neuropathy (Guillain-Barré syndrome, familial dysautonomia, sarcoid,diabetic and other causes) III. Neuromuscular A. Myasthenia gravis B. Eaton-Lambert syndrome C. Botulinum toxin D. Aminoglycoside and other drugs IV. Muscle disorders A. Myositis (polymyositis, dermatomyositis, sarcoidosis) B. Metabolic myopathy (mitochondrial myopathy, thyroid myopathy)C. Primary myopathies (myotonic dystrophy, oculopharyngeal myopathy)