The palatine tonsils are two masses of lymph tissue located on either side of the back of the throat. They function as a component of the immune system, specifically as part of Waldeyer’s ring, a collection of lymphatic tissue that guards the entrance to the respiratory and digestive tracts. Tonsils capture pathogens, such as viruses and bacteria, that enter the body through the mouth or nose. This exposure helps the body develop immunity, but it can also cause the tonsils to become enlarged. Tonsil size is variable and often changes in response to infection, which is why healthcare providers measure and grade their size to assess potential health risks.
How Tonsil Size is Graded
Healthcare professionals use a standardized method, often referred to as the Brodsky scale, to visually grade tonsil size based on how much they obstruct the oropharyngeal airway. This grading system classifies tonsil size from Grade 0 to Grade 4. Grade 0 typically means the tonsils have been removed or are entirely buried within the tonsillar pillar.
A Grade 1 tonsil is visible but occupies less than 25% of the space between the tonsillar pillars. Grade 2 indicates a mild enlargement, where the tonsil takes up between 26% and 50% of the lateral dimension of the oropharynx. Tonsils graded at Level 3 are moderately enlarged, occupying 51% to 75% of the airway space.
The highest level, Grade 4, signifies severe tonsillar enlargement, meaning the tonsils fill more than 75% of the oropharyngeal width. These Grade 4 tonsils may appear to be nearly touching one another at the midline, a condition sometimes called “kissing tonsils”.
Common Causes of Tonsil Enlargement
The most frequent reason tonsils increase in size is in response to an infection, which triggers an immune reaction within the lymph tissue. Acute tonsillitis can be caused by various viruses, including adenovirus and influenza virus, or by bacteria like Streptococcus pyogenes (strep throat). In these acute cases, the tonsils swell rapidly as they fight off the invading organism, but they usually return to their normal size once the infection is resolved.
When tonsil enlargement is chronic, it is referred to as tonsillar hypertrophy. This persistent enlargement is often seen in children between the ages of three and seven, a period when they frequently encounter childhood illnesses. Chronic hypertrophy can also be linked to repeated upper respiratory infections, long-term inflammation from irritants like secondhand smoke or air pollution, or chronic acid reflux.
Health Implications of High Tonsil Levels
High tonsil levels, specifically Grades 3 and 4, have significant health implications primarily due to physical obstruction of the airway. Severely enlarged tonsils interfere with normal breathing, especially during sleep. This obstruction leads to loud, persistent snoring and is a major contributing factor to Obstructive Sleep Apnea (OSA).
In OSA, the airway periodically collapses during sleep, causing pauses in breathing and fragmenting the sleep cycle. This chronic sleep disturbance can lead to daytime sleepiness, behavioral problems, and difficulty concentrating. For children, chronic OSA can affect physical growth and increase the risk of cardiovascular issues over time.
Beyond breathing issues, high tonsil levels can also cause mechanical problems, such as difficulty swallowing, medically known as dysphagia. Large tonsils may make it hard to eat certain foods, particularly drier items. Furthermore, chronic inflammation can lead to the formation of deep crevices, called crypts, which can trap debris and bacteria, sometimes resulting in tonsil stones or persistent bad breath.
When Medical Intervention is Required
The decision to pursue medical intervention, typically tonsillectomy (surgical removal of the tonsils), is not based on tonsil size alone. A high tonsil grade is considered only one part of the overall clinical picture. Intervention is usually warranted when the size causes significant functional impairment or when chronic infection meets specific frequency criteria.
For recurrent tonsillitis, surgical guidelines often recommend tonsillectomy if a patient has experienced at least seven documented infections in the past year. Alternatively, the criteria are met if the patient has had at least five infections per year for two consecutive years, or three infections per year for three consecutive years. These episodes must be properly documented in the medical record to qualify for intervention.
The most common indication for tonsillectomy now relates to airway obstruction, specifically documented Obstructive Sleep Apnea. If a sleep study confirms a diagnosis of OSA caused by enlarged tonsils, surgery is often recommended. Watchful waiting may be appropriate for milder symptoms, but surgery is typically considered when the high tonsil levels directly cause documented breathing difficulties or frequent, debilitating infections.