Children who have difficulty feeding or swallowing may be at risk for dehydration, malnutrition, aspiration, infection, and social ostracization. As a result, medical attention is necessary immediately. Symptoms of a feeding or swallowing disorder may include frequent spitting or throwing up, recurring upper respiratory infections, non-optimal weight gain, coughing or gagging when trying to swallow, and completely refusing food and liquid. Swallowing disorders (also known as dysphagia) can occur in any of the three stages of swallowing: the oral phase, the pharyngeal phase, and the esophageal phase. To diagnose a feeding or swallowing disorder, a physician may observe the child eating or drinking or perform a special test, such as a modified barium swallow, in which the child eats or drinks something with liquid barium in it, so its progression can be tracked in an X-ray, or an endoscopic assessment, in which a scope is inserted through the nose into the throat so the swallowing mechanisms can be observed on a screen. Often a team of medical professionals will collaborate in order to provide the most effective treatment for a child with difficulty feeding or swallowing. This team may include a speech-language pathologist, an occupational therapist, a pediatrician, a nutritionist, and a developmental specialist.