Paired structures located in the back of the throat that are composed primarily of lymph tissue and are strategically placed to serve as a defence against infection. Unfortunately, they themselves can become acutely or chronically infected, a condition called tonsillitis. While any number of viruses or bacteria can cause tonsillitis, two of the most important types of infections are streptococcal tonsillitis and acute infectious mononucleosis (see sore throat and mononucleosis). In previous generations, tonsillectomy (removal of the tonsils) was an extremely common surgical procedure, but it is done much less frequently today. Reasons for tonsillectomy that are widely accepted at this time include:

  • Severe, persistent enlargement of tonsils causing repeated difficulty with swallowing, sometimes accompanied by drooling. (The tonsils may appear to touch each other in the back of the mouth).
  • Recurrent peritonsillar abscess – a severe infection involving the soft tissue adjacent to one of the tonsils. This infection not only causes serious illness but also indicates that the tonsil is no longer preventing the spread of infection.
  • Recurrent cervical adenitis – a significant bacterial infection of lymph nodes in the neck (also indicating that the tonsil is not inhibiting the spread of infection).
  • Suspected tumor of a tonsil – an extremely rare situation.
  • Severe snoring accompanied by multiple episodes of apnea (a few seconds of interrupted breathing) during the night. This condition disrupts sleep and is associated with both daytime drowsiness and worsening school performance.