Otitis media develops when an individual's eustachian tubes become inflamed and swollen due to some mechanism that produces an accumulation of fluid in the middle ear. The flu, a cold, allergies, sinus infection, adenoid infection, and cigarette smoke are the most common causes of trapped fluid in the middle ear. This fluid is a hospitable environment that allows pathogens like bacteria to thrive. The most common types of bacteria to cause otitis media include Streptococcus pneumoniae, Moraxella catarrhalis, and Hemophilus influenzae. Symptoms of bacterial otitis media include ear pain, neck pain, fluid drainage from the ear, fever, diarrhea, vomiting, balance problems, hearing loss, feelings of pressure inside of the ear, headache, sleeplessness, and irritability. Diagnosis of otitis media is made with the use of a physical examination and tests with medical devices that include an otoscope, tympanometry, and reflectometry. A hearing test may also be used in otitis media diagnosis. Bacterial otitis media is treated with the use of antibiotics, pain medication, and in some cases, surgery.