Anatomy & Pathophysiology:
The palatine tonsils, lingual tonsils, and adenoid (also known as the pharyngeal tonsils) form a collection of lymphoid tissue known as Waldeyer's ring. This lymphoid tissue consists of B- and T-cells in a 60:40 ratio and plays a role in regulating secretory immunoglobulins. Because of the location of Waldeyer's ring, it has been postulated to protect the aerodigestive tract from airborne antigens entering via the nasal and oral cavities.
The palatine tonsils are encapsulated structures located laterally in the oropharynx. They are bounded anteriorly by the palatoglossus muscle (anterior tonsillar pillar) and posteriorly by the palatopharyngeus muscle (posterior tonsillar pillar). The tonsil rests on the superior constrictor muscle of the pharynx, which forms the tonsillar bed. The capsule of the tonsil is loosely connected to the pharyngeal muscles by connective tissue that is easily dissected. The surface of the palatine tonsil is marked by numerous tonsillar crypts, which are invaginations of squamous epithelium. Multiple arteries supply the palatine tonsils, including branches of the dorsal lingual, ascending palatine, and facial arteries inferiorly, and the ascending pharyngeal and lesser palatine arteries superiorly. Venous drainage of the palatine tonsils is via a peritonsillar venous plexus that eventually empties into the internal jugular vein. Branches of the glossopharyngeal nerve and the lesser palatine nerves innervate the palatine tonsils. The glossopharyngeal nerve passes in close proximity to the tonsillar bed and may be injured if the superior constrictor muscle is disrupted during surgery.
The adenoid pad is a triangular structure, which is broad anteroinferiorly and tapers superoposteriorly at the roof of the nasopharynx. The surface of the adenoid pad is covered with pseudostratified ciliated columnar epithelium and is supplied by branches of the ascending pharyngeal, ascending palatine, facial, pterygoid canal, and maxillary arteries. Venous drainage is via the pharyngeal plexus, which drains into the internal jugular and facial veins.
Immunologic activity of the tonsils peaks between the ages of 4 and 10. Although Waldeyer's ring likely has some role in overall mucosal immunity, studies have not demonstrated any significant negative immunologic impact as a result of adenotonsillectomy. Subsequent to puberty, the tonsillar tissues begin to involute and atrophy. Accordingly, adenotonsillar hypertrophy and infectious conditions of the tonsils are more commonly seen in children.
Chronic adenotonsillar hypertrophy may be a result of increased pathogen load due to higher susceptibility to colonization or recurrent infection. Infections of the tonsils may be bacterial or viral in nature. Bacterial infections can be caused by normal oral flora or external pathogens and are typically polymicrobial. Group A streptococcal infections cause acute pharyngitis or tonsillitis and warrant prompt diagnosis and treatment to prevent their potential sequelae (poststreptococcal glomerulonephritis and rheumatic fever). Viral infections of the tonsils may be caused by a variety of viruses responsible for upper respiratory infections (e.g., rhinovirus, adenovirus, influenza virus), as well as Epstein-Barr virus (EBV), which causes mononucleosis syndrome.
Acute tonsillitis is extremely common among children aged 5-15 years, but is rare under the age of 2. Viral tonsillitis is more common in younger children.
Sleep disordered breathing is the most common indication for tonsillectomy in pediatric patients. Obstructive sleep apnea is estimated to affect 1-5% of children; the vast majority of cases are due to adenotonsillar hypertrophy.
In many cases, adenotonsillar hypertrophy improves with age, due to involution of the lymphoid tissue. However, treatment is often pursued prior to that time in order to alleviate symptoms. Occasionally, hypertrophic tonsils may persist into adulthood.
Viral and bacterial tonsillitis also spontaneously resolve in the vast majority of cases. Treatment of Group A streptococcal infections is advised due to the risk of rheumatic fever and poststreptococcal glomerulonephritis, although these conditions are rarely seen. Repeated episodes of acute tonsillitis may result in the development of tonsillar scarring and deepening of the tonsillar crypts. This may predispose to accumulation of tonsilloliths, or concretions of debris and bacteria that can result in halitosis or pain.
Chronic tonsillar hypertrophy may present with symptoms of airway obstruction and sleep disordered breathing (e.g., snoring, apneas) or dysphagia. Adenoid hypertrophy may result in changes to the craniofacial morphology ("adenoid facies"), or an elongation of the face with open mouth posture) and hyponasal voice, as well as symptoms of nasal obstruction and otitis media with effusion.
Presentation of acute tonsillitis due to Group A streptococcal infection typically involves pharyngeal pain, fever, tonsillar exudate, and cervical lymphadenopathy. Viral infections generally do not result in tonsillar exudate, although the tonsils may be swollen and erythematous. Signs and symptoms of Epstein-Barr virus include fever, general malaise, odynophagia, cervical lymphadenopathy, and hepatosplenomegaly.
Differential Diagnosis of Adenotonsillar Disease:
- Causes of Adenotonsillar Hypertrophy
- Chronic lymphoid tissue hypertrophy
- Acute infection
- Causes of Tonsillar Infection
- Group A streptococcus
- Neisseria gonorrhoeae
- Spirochaeta denticulata, Borrelia vincentii (Vincent's angina)
- Treponema pallidum (syphilis)
- Corynebacterium diphtheriae (rare in vaccinated populations)
- Epstein-Barr virus (mononucleosis)
- Influenza virus
- Parainfluenza virus
- Respiratory syncytial virus
- Candida (oral thrush)
The physical examination in cases of adenotonsillar hypertrophy should involve visualization of the oropharynx and evaluation of palatine tonsil size and symmetry. Tonsillar size is graded on a scale from 0 to 4+, where 0 represents no visible tonsillar tissue protruding medially from the borders of the tonsillar pillars, 1+ represents up to 25% obstruction of the oropharyngeal airway by tonsillar tissue, 2+ represents 25-50% obstruction, 3+ represents 50-75% obstruction, and 4+ represents greater than 75% airway obstruction by tonsillar tissue. The adenoid pad is evaluated either by mirror exam via the oral cavity or by flexible fiberoptic nasoendoscopy. In cases of severe adenoid hypertrophy, the adenoid may even be visualized by anterior rhinoscopy as tissue obstructing the choanae posteriorly. Although the adenoid pad may also be visualized on lateral neck plain films, direct visualization via endoscopy provides a much more accurate representation of adenoid size. Other features to assess include the presence of characteristic adenoid facies (open mouth posture, facial elongation, dental malocclusion), other causes of nasal obstruction (e.g., turbinate hypertrophy, polyps, septal deviation), and voice quality.
Often, the diagnosis of sleep-disordered breathing as a result of adenotonsillar hypertrophy can be made based on clinical evidence alone. However, in cases where the history and physical examination do not correlate as well (e.g., symptoms of sleep disturbance in the absence of significant hypertrophy), a polysomnogram may be useful in confirming a diagnosis of obstructive sleep apnea. Polysomnography is also recommended preoperatively for patients with significant comorbidities or at high risk for surgical complications.
Workup of acute tonsillitis involves identification of risk factors and exposures that may point to a particular pathogen. Group A streptococcal infections may be diagnosed by rapid strep test and/or pharyngeal culture. Generally, pharyngeal cultures are ordered if symptoms persist despite negative rapid strep test. If EBV infection is suspected, serologic studies should be performed.
Chronic adenotonsillar hypertrophy resulting in sleep-disordered breathing or other significant symptoms (e.g., dysphagia or changes in craniofacial morphology) is treated by adenotonsillectomy. See Adenotonsillectomy for details regarding this procedure and its indications. While intranasal steroid therapy may be tried for isolated adenoid hypertrophy resulting in nasal obstruction, there is insufficient data regarding long term efficacy at this time.
The treatment of bacterial tonsillitis is with oral antibiotics. Penicillin or a penicillin plus a β-lactamase inhibitor are first line agents and should provide coverage of group A streptococci. Empiric therapy should be initiated as soon as possible after symptom onset, with subsequent changes to the antibiotic regimen made based on culture results. Prompt treatment with antibiotics lessens symptom severity, decreases communicability, and reduces the risk of complications. A full 10 day course is recommended to reduce recurrence. In cases of frequent recurrent acute tonsillitis, or in patients with or at high risk of complications, adenotonsillectomy should be considered.
Viral tonsillitis is treated with supportive care. Patients with infectious mononucleosis should be cautioned against playing contact sports or engaging in other activities that may result in traumatic impact to the abdomen, as they are at increased risk for splenic rupture.
Complications, Prognosis & Follow-Up:
The complications of chronic adenotonsillar hypertrophy are primarily related to sleep disordered breathing. Obstructive sleep apnea in children may result in behavioral changes (e.g., attention deficit-hyperactivity disorder, aggressiveness, irritability), potentially irreversible deficits in neurocognitive development, enuresis, stunted growth or failure to thrive, and cardiopulmonary dysfunction (e.g., cor pulmonale, pulmonary hypertension).
Additionally, adenotonsillar hypertrophy may effect changes in craniofacial morphology. Chronic mouth breathing has been shown to be associated with retrognathia, dental malocclusion, and elongation of the face.
As mentioned previously, the most concerning complications associated with group A streptococcal tonsillitis are the postinfectious conditions of acute rheumatic fever and poststreptococcal glomerulonephritis. Rheumatic fever is thought to be mediated by endotoxins produced by the streptococci and presents with fever, lymphadenopathy, rash, tachycardia, strawberry tongue, and exudate of the tonsils and pharynx. This condition is now infrequently seen; it is treated with intravenous penicillin G. Poststreptococcal glomerulonephritis is a result of infection with nephritogenic streptococci strains that produce antigens with affinity for the glomerulus. The condition is more common in males and presents with edema, hematuria, proteinuria, and hypertension 1-2 weeks following primary infection. Treatment is supportive in nature.
Suppurative complications of acute tonsillitis include peritonsillar abscess (PTA), parapharyngeal space abscess, and retropharyngeal abscess. Peritonsillar abscess is more common in adolescents and young adults, although they may occur in younger children as well. It results from superior spread of the tonsillar infection and is usually unilateral. Patients may present with severe pain, odynophagia, difficulty managing oral secretions, trismus, and referred otalgia. On examination, there is uvular deviation away from the side of infection and medial and inferior displacement of the affected tonsil. Treatment of peritonsillar abscess involves drainage of the pus collection, either via needle aspiration or by incision. Although ongoing acute infection is generally a contraindication to tonsillectomy, in some cases the tonsils are removed in the acute setting of peritonsillar abscess. It may be considered in patients who are at risk of being lost to follow-up or in young children who are unlikely to tolerate incision and drainage under local anesthesia.
Further spread of infection beyond the peritonsillar region may result in a parapharyngeal space abscess. This occurs when pus collects lateral to the superior constrictor muscle. The surrounding musculature, including the pterygoid and paraspinal muscles, is typically inflamed, causing the patient to present with trismus and neck stiffness in addition to fever and pain. Because of the location of the abscess beneath the sternocleidomastoid, it may be difficult to palpate an area of fluctuance on examination; computed tomography (CT) is a useful aid to diagnosis in these situations and can differentiate parapharyngeal abscess from PTA. Parapharyngeal abscesses have the potential to spread via the carotid sheath into the mediastinum and should be closely monitored in an inpatient setting. Treatment is with incision and drainage of the abscess and intravenous antibiotics.
Unlike PTA and parapharyngeal abscesses, which are more commonly seen in older children, retropharyngeal space abscesses are most common in children younger than 2 years. These abscesses arise from the spread of infection from the retropharyngeal lymph nodes. The retropharyngeal space is located posterior to the pharynx and is bounded anteriorly by the buccopharyngeal fascia, posteriorly by the alar fascia, and laterally by the carotid sheath. It extends from the skull base superiorly to the mediastinum at the level of the tracheal bifurcation inferiorly. Children with retropharyngeal abscess present with fever, irritability, dysphagia, stridor, neck stiffness, and cervical lymphadenopathy. Diagnosis is clinical, particularly in the setting of airway obstruction, where the priority is to secure the airway prior to drainage of the abscess. If the airway is stable, the diagnosis can be confirmed using computed tomography. Retropharyngeal abscesses are treated by transoral incision and drainage and intravenous antibiotics, although an external surgical approach may be necessary if the abscess also involves the adjacent parapharyngeal space and extends low into the neck.
- Waldeyer's ring consists of the palatine tonsils, lingual tonsils, and adenoid and plays a role in protecting the aerodigestive tract from airborne pathogens.
- The most common indication for tonsillectomy in the pediatric population is obstructive sleep apnea, which is estimated to affect 1-5% of all children.
- Oral antibiotic therapy with coverage of group A streptococci should be initiated in patients suspected of having acute bacterial tonsillitis; prompt treatment reduces the risk of rheumatic fever and poststreptococcal glomerulonephritis.
- Complications of chronic adenotonsillar hypertrophy include the sequelae of obstructive sleep apnea (behavioral changes, neurocognitive deficits, enuresis, cardiopulmonary dysfunction, failure to thrive) and changes in craniofacial morphology.
- Suppurative complications of acute tonsillitis include peritonsillar abscess, parapharyngeal abscess, and retropharyngeal abscess.
- Rare nonsuppurative complications of acute tonsillitis include rheumatic fever (treated with intravenous penicillin G) and poststreptococcal glomerulonephritis (treated with supportive care).