INTRODUCTION
‘Dysphagia’ is the sensation of difficult passage of food from the mouth into the stomach. (Greek—Dys: difficulty, Phagia: eat). This common clinical problem almost always denotes malfunction of the esophagus.
MECHANISMS
Functionally, the esophagus has been divided into upper esophageal sphincter (UES), body and lower esophageal sphincter (LES). The UES, upper esophagus and the muscles involved in oropharyngeal phase of swallowing are striated. Lower 2/3 of esophagus and LES are smooth muscles. Swallowing is facilitated by voluntary and involuntary control mechanisms located in the CNS, the peripheral nerves and muscles of the esophagus.
The act of deglutition initiates integrated esophageal motor activity leading to aboral peristaltic waves. Exaggeration of normal physiologic activity or its abnormalities can result in motor disorders. The accumulated food bolus distends the esophageal lumen, producing discomfort, which is perceived as dysphagia. It can also occur with luminal obstruction.
CLASSIFICATION
- Oropharyngeal dysphagia: Caused by abnormalities of pharynx and the neuromuscular mechanisms of UES.
- Esophageal dysphagia: Due to disorders that affect the esophageal body.
COMMON CAUSES OF DYSPHAGIA
Oropharyngeal | Esophageal |
1. Neuromuscular | 1. Mechanical obstruction |
Cerebrovascular accident | Benign strictures |
Parkinson's disease | Webs and rings |
Brainstem rumors | Diverticuli |
Multiple sclerosis | |
Amyotrophic lateral sclerosis | |
2. Mechanical obstruction | 2. Motility disorders |
Retrophaivngeal abscess | Achalasia |
Zenker's diverticulum | Spastic motility disorders |
Thvromegaly | Scleroderma |
Cervical osteophyte | Chaga's disease |
3. Skeletal muscle disorders | 3. Miscellaneous |
Polymyositis | Diabetes mellitus |
Muscular dystrophies | Chronic alcoholism |
Myasthenia gravis | Gastroesophageal reflux disease |
Metabolic myopathies | (GERD) |
4. Miscellaneous | |
Decreased saliva (medication, Sjogren's syndrome) | |
Alzheimer's disease | |
Depression |
OROPHARYNGEAL DYSPHAGIA (TRANSFER DYSPHAGIA)
Patients are unable to initiate swallowing and have difficulty in propelling food from mouth into esophagus. This is perceived as food not having left the oropharynx, and discomfort is felt at the cervical esophagus. Food impaction and regurgitation of liquids into trachea can occur, leading to recurrent pulmonary infection. Hoarseness of voice occurs due to recurrent laryngeal nerve dysfunction or intrinsic muscular disease. Weakness of soft palate and pharyngeal constrictors produces dysarthria and pharyngonasal regurgitation. These can lead to reluctance to eat and weight loss. Myasthenia gravis, polymyositis, Alzheimer's disease and depressive illness can also be associated with oropharyngeal dysphagia.
ESOPHAGEAL DYSPHAGIA (TRANSIT DYSPHAGIA)
Mechanical obstructions and motility disorders produce difficulty in transporting food bolus down the esophagus after initiation of swallowing. Symptoms are often localised to restrosternal area. Dysphagia for solids as well as liquids, waxing and waning severity over long periods of time and episodic chest pain are characteristic of motility disorders. Provocation of symptoms by liquids at extremes of temperature, relief by physical maneuvres like elevation of arms, systemic symptoms like chronic cough, recurrent aspiration pneumonia are often associated.
Dysphagia only to solids and never with liquids alone is indicative of mechanical obstruction, unless the obstruction is high grade. Progressive symptoms indicate peptic stricture or carcinoma. Nonprogressive dysphagia without weight loss can occur with esophageal webs and rings. Esophagitis due to corrosives, drugs or viruses have dysphagia along with odynophagia.
INVESTIGATIONS
Radiology
Esophagogram and video fluroscopy can detect many of UES lesions. Double contrast mucosal detail techniques are useful to study diseases of esophageal body. Special techniques like iced barium suspension and solid bolus methods can detect motility disorders.
Radionuclide Studies
Scintigraphy is used to study bolus transit through the esophagus and can be quantified.
Video Endoscopy
Primarily used to diagnose structural lesions of esophagus, endoscopy can detect tracheobronchial aspiration and secondary changes in neurogenic dysphagia (Fig. 1.1)
Manometry
Muscle contraction patterns of body and LES are measured indirectly, by placing recording probes comprising of fused small calibre catheters in the lumen, that are sensitive to pressures generated by circular muscle layer.
Fig. 1.1: Upper GI endoscopy showing proliferative mass in the lower esophagus suggested esophageal counter
Based on peristaltic wave patterns, contraction wave configuration, LES basal pressure and LES relaxation, various motor disorders can be identified.
Classification of Esophageal Motility Disorders
- Inadequate LES relaxationAchalasiaAtypical disorders of LES relaxation
- Uncoordinated contractionsDiffuse esophageal spasm
- Hyper contractionNut cracker esophagusIsolated hypertensive LES
- HypocontractionIneffective esophageal motility.
Disorders of UES and Cervical Esophagus
Primary CNS disease like cerebrovascular accidents (damage to swallowing centre or the motor nuclei controlling striated muscles of swallowing), Parkinsonism, multiple sclerosis, focal cranial neuropathies, diabetic autonomic neuropathy or diffuse skeletal muscle disorders result in dysphagia. These should be differentiated from ‘globus sensation’ where there is a sensation of cervical fullness (but no true dysphagia), and a visceral sensory abnormality has been postulated.
Treatment
The diseases producing motor dysfunction of UES and upper esophagus are progressive and supportive measures alone are feasible.
- Maintenance of nutrition
- Prevention of tracheobronchial aspiration by improving swallowing function (adjustments of head and body posture; modifying consistency, volume and rate of delivery of food)
- Indirect therapy to improve neuromuscular controls
- Medical therapy of primary disorder, cricopharnygeal myotomy, maxillofacial prostheses.
Specific Motor Disorders
Achalasia (failure to relax)
Pathophysiology: There is increased resting basal pressure of LES due to reduction in number of inhibitory ganglion cells in the intramural plexus, degeneration in vagal motor nucleus, and denervation of smooth muscle segment.
Clinical features: Onset is in 3rd to 5th decades, with equal gender distribution. Slowly progressive dysphagia with fluctuating severity is typical. Chest pain, bronchopulmonary aspiration and weight loss can occur.
Diagnosis
- Compatible clinical history.
- Barium swallow: Failure of peristalsis to clear barium from esophagus, dilatation of distal body, air fluid level and bird's beak appearance are characteristic.
- Endoscopy is done to evaluate the mucosa and to exclude other causes.
- Manometry: Incomplete relaxation of LES along with aperistalsis in body is confirmatory. LES pressure is elevated.
Differential Diagnosis (pseudo achalasia)
Carcinoma of lower esophagus or cardia, sarcoidosis, amylodosis, post vagotomy states.
Treatment
- Pharmacotherapy: Nitrites and calcium channel blockers relax LES. Long-term efficacy is poor.
- Botulinum toxin: When injected circumferentially at the level of LES, toxin binds to cholinergic receptors irreversibly inhibiting acetyl choline release. This decreases LES tone. Recurrence rate is high.
- Dilatation: Forceful dilation of LES, producing tearing of circular muscles leads to long lasting reduction in LES tone. Pneumatic dilators are commonly used with 60–80% response. Complication—perforation in 5%.
- Myotomy: Modified Heller's anterior myotomy or minimally invasive surgery, (transthoracic or laparoscopic) has 80–90% response. Complication: Gastroesophageal reflux.Complications of achalasia include esophagitis, aspiration and 20% incidence of carcinoma.
Other Hypermotility Disorders
Spectrum of diseases exemplified by diffuse esophageal spasm and nutcracker esophagus present usually in 4th decade, commoner in females. Up to 60% have intermittent nonprogressive dysphagia of varying severity [with no weight loss], often associated with chest pain, heartburn and psychological dysfunction.
Diagnosis
Barium swallow: Shows non-propulsive contractions and indentation of barium column—‘cork screw’ appearance.
Manometry: Diffuse esophageal spasm shows repetitive, nonperistaltic, simultaneous contractions of long duration after initiation of swallow. Nutcracker esophagus is characterized by high amplitude peristaltic waves in distal esophagus.
Treatment: Essentially symptomatic. Exclude coronary artery disease, GERD by appropriate investigations. Low dose anti depressants, nitrites, calcium channel blockers are useful.
Esophageal Hypomotility
Connective tissue disorders, scleroderma, CREST syndrome and polymyositis show muscle atrophy and fibrosis. Heartburn, dysphagia due to associated esophagitis, and strictures are common. Manometry shows aperistalsis in body and hypotensive LES. Treatment involves antireflux therapy.
Diabetes mellitus, hypothyroidism and ageing also show failed contractions in the body leading to hypomotility symptoms.
Obstructive Lesions
Tumors
Both squamous cell carcinoma and adenocarcinoma produce significant rapidly progressive dysphagia, associated with weight loss.
Diagnosis is made by barium studies and endoscopy and histological examination, which is confirmatory. CT and endoscopic ultrasonography help in evaluating operability.
Treatment: Primary modes of treatment are surgery, radiotherapy and chemotherapy. Since most patients present with advanced stages of tumor, endoscopic palliation is the commonly used option to either displace (dilatation, 8stenting) or ablate tumor tissue (thermal methods, lasers, debulking agents and photodynamic therapy).
Dilatation: Lateral shearing force is used to stretch and tear stenotic tissue using polyvinyl dilators (Savary Guilliard) or hydrostatic ‘through the scope’ (TTS) balloons.
Debulking agents injection therapy: Alcohol, polidocanol, etc. can be injected for debulking.
Fig. 1.3: Self-expanding metallic stents used for dysphagia palliation in patients with inoperable esophageal cancer.
Contact-thermal methods: Application of electrosurgical BICAP probe to ablate tissue.
Endoscopic laser therapy: Delivery of Nd-YAG, Argon laser energy burns tumor tissue to produce adequate lumen. Argon plasma coagulation is less useful, since only superficial necrosis occurs. 10
Esophageal stents: Self-expandable metallic stents (SEMS) offer excellent relief of dysphagia and have replaced the older plastic rigid ones. Newer innovations include Ultraflex stent, Z stent (expensive). Tumor ingrowth, stent migration and chest pain are complications.
Photodynamic therapy: Photosensitizing agents, when administered, are retained in tumor cells. These are activated by delivering low dose laser energy, resulting in local cytotoxicity and tissue necrosis (Figs 1.3 and 1.4)
Benign tumors such as leiomyoma, hemangioma, hamartoma and lipoma produce luminal obstruction, which are all amenable to surgery. Lymphoma and metastases from melanoma and breast cancers can also produce dysphagia.
SUGGESTED READING
- Castell DO, Kartz PO. Approach to the patient with dysphagia. Yamada T, Text-book of Gastroenterology. 3rd Edn, 1999.
- AGA medical position statement on management of Oropharyngeal dysphagia. Gastroenterology 1999;116.
- Spechler SJ. American gastroenterological association medical position statement on treatment of patients with dysphagia caused by benign disorders of the distal esophagus. Gastroenterology 1999; 117:229–33.
- Lind CD. Dysphagia evaluation and treatment—Gastroenterol Clin North Am 2003; 32: 553–75.
- Saud B. A diagnostic approach to dysphagia—Clin Fam Pract—2004; 6: 525.
- Cook IJ, Kahrilas PJ. AGA technical review on the management of oropharyngeal dysphagia. Gastroenterology 1999; 116:455–78.