Understanding Dysphagia: Definition and Causes
Dysphagia, classified under the International Classification of Diseases 10 (ICD-10) as R13, originates from the Ancient Greek words “δυσ” meaning disorder and “φαγεῖν” meaning to eat or swallow. It refers to a disruption in the process of swallowing and the passage of food through the esophagus, ranging from uncomfortable sensations in the throat to difficulty swallowing solid and liquid foods. While dysphagia is primarily an indication of esophageal disorders, it can also result from abnormalities in other organs and systems.
The Swallowing Process:
Swallowing is a complex reflexive process involving the coordinated action of over thirty different muscles. Food enters the esophagus in less than a second, reaching the stomach within fifteen seconds. Normal food passage through the esophagus relies on factors such as food bolus size, esophageal tube diameter, esophageal contractions, and central nervous system function (the swallowing center located in the brainstem).
The swallowing process consists of four stages: the preparatory stage, oral stage, pharyngeal stage, and esophageal stage. The preparatory stage involves transferring food from the plate to the mouth. The oral stage is entirely voluntary and includes food entry into the mouth and preparation for swallowing. The pharyngeal stage begins when the tongue pushes the bolus backward, and the base of the tongue touches the posterior pharyngeal wall, initiating the reflexive response. The soft palate elevates to prevent nasal regurgitation, and the epiglottis flips to cover the larynx, preventing inhalation. The esophageal stage relies entirely on a wave-like contraction system.
Causes of Dysphagia:
Dysphagia can have various causes in adults and children concerning diseases and medical conditions. Dysphagia types are distinguished based on the cause of swallowing disorder: oropharyngeal, esophageal, neurogenic, mechanical, and functional.
Oropharyngeal Dysphagia:
- Structural abnormalities in the mouth, throat, or external structures pressing on the esophagus.
- Xerostomia (dry mouth) due to salivary gland inflammation.
- Inflammatory conditions: pharyngitis, peritonsillar abscess, acute thyroiditis.
- Metabolic and endocrine disorders: submandibular gland inflammation, epiglottitis, diabetes.
- Congenital malformations in upper jaw development: cleft lip, cleft palate.
- Mechanical, chemical, and thermal injuries to the mouth and throat.
Esophageal Dysphagia:
- Esophageal vein dilation or narrowing of the esophageal lumen due to tumor growth in the esophageal tract or compression from adjacent organs with abnormal variations, such as mediastinal tumors, mitral valve stenosis, and hiatal hernia.
- Esophageal muscle contraction due to alkaline base or acid injury.
- Esophagogastroduodenitis.
- Autoimmune diseases: myasthenia gravis, scleroderma.
Neurogenic Dysphagia:
- Myasthenia gravis.
- Infectious diseases: syphilis, rabies, diphtheria, meningitis, encephalitis.
- Neurological disorders: bulbar paralysis or pseudobulbar paralysis, Parkinson’s disease, multiple sclerosis, brain tumors, stroke.
Psychogenic (Functional) Dysphagia:
- Diagnosed in patients after excluding organic disorders. Occurs episodically against a background of psychological and emotional disorders, and in some cases, post-traumatic stress disorder.
Mechanical Dysphagia:
When dysphagia results from a mismatch between food bolus size and esophageal opening, it is termed mechanical dysphagia. Functional dysphagia refers to swallowing difficulties due to esophageal motility disorders or swallowing center suppression.
These are some causes of dysphagia that can affect adults and children, encompassing a diverse range of diseases and medical conditions.
Symptoms of Dysphagia:
The primary symptom of dysphagia is difficulty swallowing, but other symptoms may include:
- Sensation of food sticking in the throat or esophagus (behind the sternum, under the chest).
- Coughing or choking on food or liquids.
- Chest pain or discomfort in the chest area (“below the spoon”) while eating.
- Hoarseness of voice.
- Fear of swallowing – Phagophobia.
- Vomiting that relieves the condition.
- Frequent heartburn.
Dysphagia in Esophageal Cancer:
Dysphagia in esophageal cancer is an early sign of the disease. Tumors growing inside the esophagus obstruct its passage, while tumors growing within the tissues compress the esophagus. Initially, solid food passes with difficulty, and the individual resorts to drinking each bite and transitioning to more liquid foods. Later on, even liquid food passes with difficulty. Swallowing difficulties are accompanied by pain. Initially, this occurs only during eating, but later it becomes continuous.
Dysphagia After Stroke:
Dysphagia occurs after a stroke in patients who suffer from a disorder in blood circulation in the brainstem, resulting from damage to the cranial nerves: glossopharyngeal, vagus, and hypoglossal nerves (nerves IX, X, XII). Patients exhibit paralysis in the muscles of the esophagus, palate, and soft palate. Signs of dysphagia in patients after a stroke include drooling, food falling out of the mouth, and choking. Inhaling food particles or stomach contents into the respiratory pathways can lead to aspiration pneumonia.
Symptoms of Dysphagia in Infants:
Symptoms of dysphagia in infants may include prolonged food retention in the mouth, coughing, choking, facial color change during feeding, regurgitation, hoarseness of voice, refusal to breastfeed, and slight weight gain.
Grades of Dysphagia:
- Difficulty swallowing solid food.
- Solid food does not pass, but the patient can swallow liquid or mashed food.
- Ability to swallow only liquid food and saliva swallowing.
- Complete blockage of the esophagus by food.
Diagnosis of Dysphagia:
Multiple tests are used to confirm the diagnosis, including:
- Videofluoroscopic swallow study – monitoring the passage of barium material from the mouth to the stomach using fluoroscopy.
- Esophageal endoscopy – exploring the lower parts of the throat and esophagus using a flexible optical instrument.
- Esophageal pressure measurement using manometry.
- Measurement of esophageal acidity levels for 24 hours.
- Magnetic resonance imaging of the head in cases of suspected neurological disorders.
Treatment of Dysphagia:
- Treatment depends on the cause and type of dysphagia, aiming to treat the underlying condition and improve the patient’s quality of life.
- Optical balloon dilation is used to dilate any narrow area in the esophagus. Surgical treatment is indicated for patients with esophageal tumors or obstruction.
- In cases of complete esophageal obstruction, surgical placement of a feeding tube into the stomach (gastrostomy surgery) is performed.
- A diet containing essential nutrients is prescribed if there are no contraindications.
- Food should be mechanically soft (mashed, liquid, or semi-liquid) and consumed in small quantities and chewed carefully.
- Sessions with a speech therapist and occupational therapist are conducted to restore or improve swallowing ability using special exercises.
- Swallowing exercises include deep breathing through the mouth and slow exhalation through the nose, shoulder lifting and lowering, circular head movements, head tilts to the left and right, puffing and sucking in the cheeks, tongue protrusion and retraction, slow balloon blowing, and alternating pronunciation.
- Electrical swallowing stimulation with electrodes placed under the skin to strengthen throat muscles is considered appropriate for some patients.