The tonsils and adenoids are a type of soft tissue called lymphoid tissue that is located in the upper throat.  The tonsils are usually distinct structures with visible borders that can be seen when looking in the mouth.  There is one on each side and size varies greatly between people.  Adenoids are the same type of tissue but the term is misleading because it implies that there are distinct number of "adenoids".  In fact, adenoid tissue is usually a lump of lymphoid tissue located on the back wall of the upper throat behind the nose and palate.  This tissue is usually not visible when looking through the mouth. 

Tonsillitis describes inflammation of the tonsils which is usually due to a viral or bacterial infection.  Symptoms include fever and throat pain. Like other infections, treatment is with antibiotics. However, some children have difficulty with multiple recurrent infections requiring multiple courses of antibiotics throughout the year. If this is the case, surgery to remove the tonsils and adenoids may be helpful.  In rare situations, a tonsil infection may become so severe that a collection of pus forms behind the tonsil.  This is called a peritonsillar abscess and usually requires drainage of the pus to help cure the infection.  Repeat infections that lead to a peritonsillar abscess are another reason to consider tonsillectomy.

Tonsil and adenoid hypertrophy describes an abnormal enlargement of the tonsils, adenoids, or both.  This can lead to many problems such as nasal congestion, snoring, and sinus and ear infections.  More importantly, hypertrophy of the adenoids and tonsils is a major cause of obstructive sleep apnea in children.  If this is the case, tonsillectomy and adenoidectomy (surgery to remove the tonsils and adenoids) should be seriously considered.  Obstructive sleep apnea is not normal (at any degree) in children and can lead to many problems including difficulty learning and poor school performance.