What causes dysphagia

What is Dysphagia?

Dysphagia is the medical term for difficulty in swallowing. It's not a disease itself, but rather a symptom of an underlying condition. This difficulty can occur at any stage of the swallowing process, from the mouth to the esophagus and down to the stomach. Swallowing is a complex process involving numerous muscles and nerves, and any disruption to this intricate system can result in dysphagia.

Types of Dysphagia

Dysphagia can generally be categorized into two main types:

• Oropharyngeal dysphagia: This occurs when there's a problem initiating the swallow in the mouth or moving food/liquid from the mouth down into the throat (pharynx). This often involves issues with the cranial nerves or the muscles of the tongue, pharynx, and larynx.
• Esophageal dysphagia: This occurs when food gets stuck in the base of the throat or chest after swallowing has been initiated. It's typically caused by problems with the esophagus, the muscular tube connecting the throat to the stomach.

Common Causes of Dysphagia

The causes of dysphagia are diverse and can range from temporary irritations to serious chronic conditions. Understanding these causes is crucial for proper diagnosis and treatment.

Neurological Conditions

Many neurological disorders can impair the nerve signals required for swallowing. These conditions can affect the brain, brainstem, or the nerves that control the muscles of the mouth, throat, and esophagus.

• Stroke: This is one of the most common causes of oropharyngeal dysphagia. A stroke can damage the parts of the brain that control swallowing, leading to immediate or delayed difficulties.
• Parkinson's disease: This progressive neurodegenerative disorder affects muscle control, including those involved in swallowing.
• Amyotrophic Lateral Sclerosis (ALS) / Motor Neuron Disease: ALS progressively damages nerve cells in the brain and spinal cord, leading to muscle weakness and atrophy, which severely impacts swallowing.
• Multiple Sclerosis (MS): MS is an autoimmune disease that damages the myelin sheath covering nerve fibers, disrupting nerve signals. This can affect the coordination of swallowing muscles.
• Myasthenia Gravis: This autoimmune disorder causes muscle weakness that worsens with activity and improves with rest. It can affect the muscles of the face, throat, and esophagus.
• Brain Injury: Traumatic brain injuries (TBIs) can disrupt the neurological pathways responsible for swallowing.
• Cerebral Palsy: This group of disorders affects a person's ability to control their muscles, often impacting swallowing from a young age.

Esophageal Issues

Problems within the esophagus itself can also lead to dysphagia, particularly the sensation of food getting stuck.

• Gastroesophageal Reflux Disease (GERD): Chronic acid reflux can irritate and inflame the esophagus (esophagitis). Over time, this inflammation can lead to scarring and narrowing of the esophagus (strictures), making it difficult for food to pass.
• Esophageal Strictures: These are narrowings in the esophagus caused by scar tissue, often from GERD, radiation therapy, or surgery.
• Achalasia: This rare disorder affects the lower esophageal sphincter (LES), the muscular ring that opens to allow food into the stomach. In achalasia, the LES fails to relax properly, and the muscles of the esophagus don't contract normally, leading to food backing up.
• Esophageal Spasms: These are uncoordinated contractions of the esophageal muscles that can cause chest pain and difficulty swallowing.
• Diverticula: These are small pouches that can form in the esophageal wall, where food can get trapped, leading to difficulty swallowing and sometimes regurgitation.
• Eosinophilic Esophagitis (EoE): This is an allergic inflammatory condition of the esophagus that can cause narrowing and difficulty swallowing.

Physical Obstructions and Other Causes

External factors or structural abnormalities can also cause dysphagia.

• Cancer: Tumors in the mouth, throat, or esophagus can physically block the passage of food. Radiation therapy and chemotherapy used to treat these cancers can also damage swallowing structures and nerves.
• Foreign Bodies: An object lodged in the throat or esophagus can cause immediate dysphagia.
• Zenker's Diverticulum: A pouch that forms in the upper esophagus can trap food.
• Cervical Osteophytes: Bone spurs on the vertebrae in the neck can press on the esophagus and cause difficulty swallowing.
• Medications: Some medications, particularly those taken in pill form, can cause esophageal irritation or narrowing if they get stuck, or as a side effect affecting muscle function.
• Age-Related Changes: As people age, the muscles and nerves involved in swallowing may weaken or become less coordinated, leading to a higher risk of dysphagia. This is sometimes referred to as presbyphagia.

When to See a Doctor

If you experience persistent difficulty swallowing, pain when swallowing, the sensation of food getting stuck, unintended weight loss, or frequent choking or coughing during meals, it's important to consult a healthcare professional. Early diagnosis and management of dysphagia can prevent complications such as malnutrition, dehydration, and aspiration pneumonia (when food or liquid enters the lungs).