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The adenoid is a part of the Waldeyer’s ring of lymphoid tissue, which consists of palatine tonsil, adenoid or pharyngeal tonsil, tubal (eustachian) tonsil, and lateral pharyngeal band. The adenoid is a single, lobulated lymphoid tissue located on the roof of the nasopharynx. The entire nasopharynx is lined by respiratory epithelium, which covers the adenoid and the eustachian tube to the tympanic cavity. There are variations in shape and size of the adenoid, which can occupy some part of the nasopharynx or fill the entire nasopharyngeal cavity and obstruct the view of the choanae. The adenoid is the lymphatic tissue without the afferent lymphatic channel. The efferent drainage is to the retropharyngeal lymph nodes to the upper deep cervical lymph nodes and posterior triangular lymph nodes.
Adenoid tissue consists mainly of lymphocytes. The percentage of adenoid lymphocytes is highest in children age 0 to 5 years (about 75%), and it decreases with time, with significant decrease in children after 10 years of age. The subpopulations of lymphocytes are approximately 50% B cells and 30% T cells. The adenoid is considered to be the gatekeeper of the upper respiratory tract, performing both protective and immunologic function. The microorganisms entering the airway are presented as antigens to the adenoid. The lymphoid cells in the adenoid are then stimulated, resulting in continuous immunologic reactions. B cells are transformed into plasma cells that produce antibodies. T-helper cells stimulate B cells in the transforming process and cytotoxic T cells (CD8) kill antigen by releasing cytokines. The adenoid and the tonsils are involved in both local and systemic immunity. In addition, the adenoid is different from the tonsils in that it produces local mucosal antibody, secretory IgA, with the secretory component that does not exist in the tonsil. Adenoid surface secretion contains antibody-secreting cells, which produce IgG and IgA against pathogenic bacteria. The function of the adenoid is active in children, but its role decreases in adolescence.
The adenoid is the reservoir of bacteria in the nasopharyngeal area, including Streptococcus pneumoniae , nontypable Haemophilus influenzae , and Moraxella catarrhalis , which are common pathogenic bacteria for otitis media and sinusitis. The location of the adenoid is in the vicinity of the Eustachian tube and the ostiomeatal complex so that the bacteria in the adenoid is the contributing factor for infections of the middle ear and sinuses. The bacterial load in the adenoid, particularly H. influenzae , stimulates the lymphoid cells, causing increased activity of the antigen-stimulated B lymphocyte and polyclonal B-cell proliferative response. Adenoid hypertrophy causes nasal obstruction and obstructive sleep disorders in children, when accompanied by tonsillar hypertrophy. Adenoidectomy is recommended in the guidelines for the treatment of pediatric otitis media with effusion (OME) and sinusitis, to eliminate the source of infection. Adenoidectomy or adenotonsillectomy is recommended in hypertrophic adenoid for chronic infection, nasal obstruction, or obstructive sleep apnea (OSA) in children.
The adenoid is located on the roof of the nasopharynx, which is attached to the base of the skull under the sphenoid bone. The floor of the nasopharynx is the upper surface of the soft palate.
The anterior boundary of the nasopharynx is the choanae, which is a continuation from the nasal cavity. The posterior boundary of the nasopharynx is the pharyngeal wall, which consists of the mucosa, the pharyngobasilar fascia, and the superior constrictor muscle.
The torus tubarius is the nasopharyngeal end of the Eustachian tube, which opens into the lateral wall of the nasopharynx on both sides of the adenoid. The slit-like recess formed by the Eustachian tube and the concave upper border of the superior constrictor muscle is called the pharyngeal recess or the fossa of Rosenmȕller. Hypertrophic adenoid can extend laterally, encroaching upon the torus tubarius, which is the nasopharyngeal prominence overlying the cartilage of the Eustachian tube, and care must be taken to avoid injury to the Eustachian tube while removing the adenoid.
Bleeding from adenoidectomy is mostly raw surface bleeding. Hemostasis is achieved by electrocautery and nasopharyngeal packing with vasoconstrictors. The blood supply of the adenoid is from the ascending palatine branch of the facial artery, ascending pharyngeal artery, pharyngeal branch of the internal maxillary artery, and ascending cervical branch of the thyrocervical trunk. Venous drainage is through the pharyngeal plexus to the pterygoid plexus, facial vein, and internal jugular vein.
Adenoidectomy is a surgical procedure that is performed mostly in children. Adenoidectomy is usually done for the relief of nasal obstruction or elimination of the source of infection. According to the guidelines, adenoidectomy is done in pediatric patients with OME, chronic sinusitis, or OSA. Each condition has its own indications for adenoidectomy, but there usually are overlapping conditions in the same patient since the pathogenesis of otitis media, sinusitis, and obstructive adenoid hypertrophy may originate from chronic infection of the adenoid. Sometimes one condition contributes to the timing of surgery for another condition. For example, in a child who reaches the indication for myringotomy for having middle ear fluid for more than 90 days, adenoidectomy should be done in the same setting if the child also has the problem of adenoid obstruction or chronic sinusitis. Performing adenoidectomy with myringotomy and ventilation tube insertion eliminates the source of infection for both conditions and decreases the need for multiple general anesthesias.
History of present illness
Persistent middle ear effusion for more than 90 days
Hearing loss
Speech delay
Chronic rhinorrhea
Chronic cough
Chronic nasal obstruction, snoring
OSA
Behavioral issues that may be the result of OSA: Daytime sleepiness, irritability or hyperactivity, nocturnal enuresis
Past medical history
Allergic rhinitis
Asthma
Cardiac conditions that may be the complications of OSA: Pulmonary hypertension, right ventricular hypertrophy, cor pulmonale
Previous surgery, abnormal bleeding during surgery, or family history of abnormal bleeding
Medications: Anticoagulants, oral or intranasal steroids
Adenoid facies: Patients with long-standing nasal obstruction from adenoid hypertrophy may have the appearance of “adenoid facies,” which is the result of chronic mouth breathing. Malocclusion, excessive showing of the upper gum, and lack of lip seal are characteristics of adenoid faceies.
Hyponasal speech
Presence of middle ear effusion
Abnormality of the tympanic membrane: Retraction, decreased mobility of the tympanic membrane by pneumatic otoscopy
Visible hypertrophic adenoid: The adenoid can be visualized through anterior rhinoscopy or endoscopy if the turbinate is not congested. An obstructing adenoid can sometimes be seen protruding through the choanae ( Fig. 191.1 ).
Postnasal drip and nasopharyngeal discharge are seen in chronic adenoid infection.
Nasal discharge at the middle meatus is suggestive of sinusitis.
Chest radiograph
Lateral nasopharyngeal radiograph
Evaluation of the adenoid size is done by radiographic imaging or imaging obtained from nasal endoscopy. Plain lateral radiograph of the nasopharynx is used for the measurement of the adenoid-nasopharyngeal (A/N) ratio. The most popular method is the measurement by Fujioka et al. used since 1979. A/N ratio is the ratio of the distance from the maximal convexity of the adenoid to the anterior margin of basiocciput (adenoid width) divided by the distance between the posterior edge of the hard palate to the anteroinferior edge of the sphenooccipital synchondrosis (nasopharyngeal width). An average value of normal A/N ratio is 0.63 to 0.73.
The ratio of the adenoid tissue to the choanal opening is measured from the image obtained by the zero degree rigid nasal endoscope. The ratio of the area of the adenoid to the choanal opening is calculated by the Photoshop program. A/N ratio was found to have good correlations with nasal endoscopic examination and intraoperative mirror examination.
Adenoidectomy is done with the first set of tympanostomy tube insertion if the patient has the concurrent problem of the adenoid such as chronic nasal obstruction, OSA, or chronic sinusitis.
For the patients who do not have problems with the adenoid, adenoidectomy is indicated for OME when myringotomy is done for the insertion of the second set of tympanostomy tubes, regardless of the size of the adenoid, provided that the patient does not have any contraindications for adenoidectomy.
Chronic or recurrent sinusitis that fails medical management : Adenoidectomy is the first-line surgical management of chronic sinusitis in children before functional endoscopic sinus surgery, especially in children aged up to 6 years. In children aged 6 to 12 years, adenoidectomy is also considered effective as a first-line treatment according to the clinical consensus statement in pediatric chronic rhinosinusitis.
Adenotonsillar hypertrophy with symptoms and signs of OSA
Cleft palate
Submucous cleft palate and velopharyngeal insufficiency (VPI): Adenoidectomy can cause worsening of VPI and hypernasal speech; therefore it should be avoided. If necessary, superior pole adenoidectomy can be done in some cases.
Hematologic conditions causing coagulopathy: Some of the conditions can be reversed before surgery and therefore are considered as relative contraindications, such as in patients who are using anticoagulants, which should be withdrawn 7 to 14 days before surgery. Consultation with a hematologist should be obtained in patients with von Willebrand disease and other coagulopathy.
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