Differential Diagnosis

The patient's symptoms of difficulty swallowing on the left side of the neck and a feeling of fullness on the left side when lying down flat can be approached by considering various potential causes. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Gastroesophageal Reflux Disease (GERD): This condition is characterized by the backflow of stomach acid into the esophagus, which can cause discomfort, difficulty swallowing, and a feeling of fullness, especially when lying down. The symptoms can be more pronounced on one side due to the esophageal anatomy and the position of the lower esophageal sphincter.

• Other Likely Diagnoses

  • Esophageal Dysmotility: Disorders affecting the movement of food through the esophagus can cause difficulty swallowing (dysphagia) and may lead to a sensation of fullness, particularly if food accumulates in the esophagus.
  • Left-sided Thyroid Enlargement or Nodule: An enlarged thyroid gland or a nodule on the left side can compress the esophagus, leading to difficulty swallowing and a sensation of fullness on that side, especially when lying down.
  • Torticollis or Cervical Spine Issues: Abnormal posturing of the neck or cervical spine problems can lead to referred pain and discomfort that might be interpreted as difficulty swallowing or a feeling of fullness on one side of the neck.

• Do Not Miss Diagnoses

  • Esophageal Cancer: Although less common, esophageal cancer can present with progressive dysphagia and should be considered, especially in older adults or those with risk factors such as smoking or alcohol use.
  • Aortic Dissection: This is a medical emergency where the inner layer of the aorta tears. It can cause severe, tearing chest pain that may radiate to the neck and can lead to swallowing difficulties if the esophagus is compressed by the expanding aortic dissection.
  • Pulmonary Embolism: While less directly related to swallowing, a pulmonary embolism can cause sudden onset of chest pain and shortness of breath, which might be confused with or contribute to the sensation of fullness or discomfort when lying down.

• Rare Diagnoses

  • Eosinophilic Esophagitis: An inflammatory condition of the esophagus that can cause dysphagia and food impaction, more commonly seen in patients with atopic diseases.
  • Cervical Osteophyte: Bony spurs in the cervical spine can rarely compress the esophagus, leading to dysphagia.
  • Zenker's Diverticulum: A condition where a pouch forms in the pharynx, which can lead to difficulty swallowing and regurgitation of food, though it typically presents more with symptoms of food getting stuck rather than a feeling of fullness on one side.