Central nervous system disorders
Vascular
Ischemic/hemorrhagic stroke
AV malformations
Temporal arteritis
Infections
Encephalitis
Meningitis
Brain abscess
Neurosyphilis
Subphrenic abscess
Structural
Head trauma
Intracranial neoplasm
Brainstem neoplasms
Multiple sclerosis
Syringomyelia
Hydrocephalus
Vagus and phrenic nerve irritation
Goiter
Pharyngitis
Laryngitis
Hair or foreign body irritation of tympanic membrane
Neck cyst or other tumor
Gastrointestinal disorders
Gastric distention
Gastritis
Peptic ulcer disease
Pancreatitis
Pancreatic cancer
Gastric carcinoma
Abdominal abscesses
Gallbladder disease
Inflammatory bowel disease
Hepatitis
Aerophagia
Esophageal distention
Esophagitis
Bowel obstruction
Thoracic disorders
Enlarged lymph nodes secondary to infection or neoplasm
Pneumonia
Empyema
Bronchitis
Asthma
Pleuritis
Aortic dissection
Mediastinitis
Mediastinal tumors
Chest trauma
Pulmonary embolism 
Cardiovascular disorders
Myocardial infarction
Pericarditis
Toxic-metabolic
Alcohol intoxication
Diabetes mellitus
Herpes zoster
Hypocalcemia
Hypocapnia
Hyponatremia
Influenza
Malaria
Tuberculosis
Uremia
Postoperative
General anesthesia
Intubation (stimulation of glottis)
Neck extension (stretching phrenic nerve roots)
Gastric distention
Traction on viscera
Drugs
Alpha methyldopa
Short-acting barbiturates
Chemotherapeutic agents (eg, carboplatin)
Dexamethasone
Diazepam
Psychogenic
Anorexia nervosa
Conversion reaction
Excitement
Malingering
Schizophrenia
Stress
Vascular
Ischemic/hemorrhagic stroke
AV malformations
Temporal arteritis
Infections
Encephalitis
Meningitis
Brain abscess
Neurosyphilis
Subphrenic abscess
Structural
Head trauma
Intracranial neoplasm
Brainstem neoplasms
Multiple sclerosis
Syringomyelia
Hydrocephalus
Vagus and phrenic nerve irritation
Goiter
Pharyngitis
Laryngitis
Hair or foreign body irritation of tympanic membrane
Neck cyst or other tumor
Ischemic/hemorrhagic stroke
AV malformations
Temporal arteritis
Encephalitis
Meningitis
Brain abscess
Neurosyphilis
Subphrenic abscess
Head trauma
Intracranial neoplasm
Brainstem neoplasms
Multiple sclerosis
Syringomyelia
Hydrocephalus
Goiter
Pharyngitis
Laryngitis
Hair or foreign body irritation of tympanic membrane
Neck cyst or other tumor
Gastric distention
Gastritis
Peptic ulcer disease
Pancreatitis
Pancreatic cancer
Gastric carcinoma
Abdominal abscesses
Gallbladder disease
Inflammatory bowel disease
Hepatitis
Aerophagia
Esophageal distention
Esophagitis
Bowel obstruction
Enlarged lymph nodes secondary to infection or neoplasm
Pneumonia
Empyema
Bronchitis
Asthma
Pleuritis
Aortic dissection
Mediastinitis
Mediastinal tumors
Chest trauma
Pulmonary embolism
Myocardial infarction
Pericarditis
Alcohol intoxication
Diabetes mellitus
Herpes zoster
Hypocalcemia
Hypocapnia
Hyponatremia
Influenza
Malaria
Tuberculosis
Uremia
General anesthesia
Intubation (stimulation of glottis)
Neck extension (stretching phrenic nerve roots)
Gastric distention
Traction on viscera
Alpha methyldopa
Short-acting barbiturates
Chemotherapeutic agents (eg, carboplatin)
Dexamethasone
Diazepam
Anorexia nervosa
Conversion reaction
Excitement
Malingering
Schizophrenia
Stress
Hiccups
Central nervous system disorders
Dysphagia
Vascular
Catatonia
Ischemic/hemorrhagic stroke
Insomnia
AV malformations