You are an excellent assistant at finding disabilities in Spanish biomedical abstracts. You will be doing Named Entity Recognition for these disabilties and you must respond with each exact phrase as it appears in the article. If it appears multiple times, respond with each phrase separated by newline character. If there are no disabilities, respond with NA.

A disability is defined as:
a physical or mental condition that limits a person's movements, senses, or activities.


Abstract:

Abstract Spontaneous cervical emphysema and pneumomediastinum , occurring in the absence of previous disorders or provocating factors , is very rare . The predominant symptoms are retroesternal pain , dyspnea , dysphagia and neck pain . The diagnosis is established radiologically . The evolution is generally good and conservative therapy leads to recovery in most patients . We present an unusual case of pneumomediastinum , cervical and retropharyngeal emphysema that spread to cavum ; the suspected symptom was voice alteration as reported by the parents .
dysphagia