The pharyngeal tonsils (adenoids) are a lobulated mass of lymphoid tissue located on the upper and posterior walls of the nasopharynx. This lymphoid structure is capable of considerable hypertrophy under adverse conditions such as chronic and recurrent infection of the upper respiratory tract, and/or allergies (Brodsky 1993; Javadyan 2003; Raphael 1987). There are few prevalence and incidence data available, but adenoidal hypertrophy is generally considered a common condition of childhood, and represents one of the most frequent indications for surgery in children (Rutkow 1986).

The enlarged adenoids can obstruct the nasopharyngeal airway, particularly at night when the patient is supine. Classically, the symptoms and physical signs considered indicative of adenoidal nasal airway obstruction in children are mouth breathing, hyponasal voice and nocturnal snoring (Kenna 2000; Paradise 1998). In more severe cases, obstructive sleep apnoea may occur potentially causing neurocognitive disturbance, growth failure and cor pulmonale (Guilleminault 1981; Breuillette 1982; Menashe 1965; Gozal 1998). Enlarged adenoids could also obstruct the Eustachian tube orifice resulting in a conductive hearing loss. The presence of fluid in the middle ear (otitis media with effusion) is frequently associated with adenoidal hypertrophy and suggests Eustachian tube dysfunction or chronic adenoidal infection (Kenna 2000; Grimmer 2005).

The diagnosis of adenoidal hypertrophy should be considered when the child presents with signs or symptoms of nasal airway obstruction. The validity of standardised clinical assessment of adenoidal obstruction of the nasopharynx has recently been confirmed by a well‐designed prospective study (Paradise 1998). The degree of a patient's mouth breathing and speech hyponasality were rated by one of eight study‐team nurse practitioners on a 4‐point scale (none = 1; mild = 2; moderate = 3; marked = 4). The two ratings were averaged to obtain a Nasal Obstruction Index (NOI) from 1 to 4. This study demonstrated a high inter‐observer agreement for mouth breathing and speech hyponasality (weighted k 0.84 to 0.91). The overall correlation between NOI and radiological assessment ratings was moderate, however a high correlation was found in children with NOI values at the lower and upper extremes (i.e. 1.0 and 3.5 respectively). Another instrument for the clinical measurement of nasal obstructive symptoms associated with adenoidal hypertrophy was a parent‐administered symptom questionnaire (Demain 1995). This encompassed assessment of a child's nasal congestion, nasal voice, snoring, daytime drowsiness, sleep quality, nasal discharge, ear popping or pain, and bad breath. The degree of each symptom was scored from 0 (never) to 10 (constant) using a visual analogue scale.

As nasal obstruction may be caused by other conditions such as rhinitis, nasal polyps or septal deviation, complementary examinations are needed for a definitive diagnosis of adenoidal hypertrophy. The lateral neck radiograph remains a widely employed investigation, in some countries, for children with suspected adenoidal hypertrophy. The low cost, widespread availability, non‐invasive nature and good correlation with symptoms and rhinoscopy findings are the main advantages of this diagnostic test (Mary 2005; Modrzynski 2005). The following radiological assessment methods have been reported to measure the adenoidal size in children: 1) Cohen and Konak's method (Cohen 1985): the ratio between the soft plate thickness (1 cm below the hard palate or 1/2 cm in children under three years old) and the air column width between the palate and the highest point of convexity of the adenoidal shadow; 2) Fujioka's method (Fujioka 1979): the ratio between the maximal thickness of the adenoidal shadow and the distance measured along a line from the superior/posterior edge of the hard palate to spheno‐occipital synchondrosis on the skull base; 3) Johanneson's method (Johanneson 1968): the distance between the perpendicular line from the pharyngeal tubercle on the skull base and the adenoidal shadow convexity. Of these methods, Cohen and Konak's shows the best correlation with endoscopic findings and clinical symptoms (Wormald 1992; Modrzynski 2005). This method accounts for the relationship between nasopharyngeal and adenoidal size and it is known that it is not the absolute adenoidal size but its ratio to the dimensions of the whole nasopharyngeal cavity which seems crucial in the clinical manifestation of adenoidal hypertrophy (Wang 1994).

Another method for the assessment of adenoidal size is trans‐oral mirror visualisation. A high correlation between mirror examination and fibreoptic nasopharyngeal endoscopy has been demonstrated by a recent prospective and blinded study, however the degree of choanal obstruction may be underestimated by this diagnostic test (Chisholm 2005). Fibreoptic nasopharyngeal endoscopy is considered the gold standard for the diagnosis and evaluation of adenoidal hypertrophy. This diagnostic method allows direct visualisation of the nasal cavity and the nasopharynx providing a dynamic evaluation of the magnitude of nasal airway obstruction (Wang 1992). The diagnostic accuracy of fibreoptic nasopharyngeal endoscopy may be of fundamental importance in establishing suitable indications for adenoidectomy (Wang 1992; Neri 2004), however the requirement of costly equipment and the need for child co‐operation limit this diagnostic approach.

The management of adenoidal hypertrophy in children is dependent on the degree of nasal airway obstruction and any associated morbidity. When obstructive sleep apnoea (OSA) or cardio‐respiratory syndrome occurs, adenoidal and tonsillar hypertrophy are usually implicated and adenoidectomy is generally indicated. However, the effects of surgical intervention in children with OSA attributable to adenoidal hypertrophy have not yet been investigated by randomised controlled trials (Lim 2006). Other potential indications for adenoidectomy include chronic sinusitis and otitis media with effusion (Gates 1992; Paradise 1995). The risk‐benefit ratio of surgical intervention for the individual child needs to be carefully assessed in light of potential anaesthetic complications (cardiac arrhythmia, malignant hyperthermia, vocal cord trauma and aspiration) and postoperative complications (haemorrhage, airway obstruction secondary to oedema, prolonged muscular paralysis and palato‐pharyngeal insufficiency). In less severe cases, non‐surgical interventions may be considered, however few medical alternatives are currently available. Commonly, medical management is limited to the treatment of concurrent infections and the complications of adenoidal enlargement (Sclafani 1998). Recently, the effects of intranasal corticosteroids in children with adenoidal hypertrophy have been assessed by randomised trials (Demain 1995; Criscuoli 2003).

The mechanism by which intranasal corticosteroids would reduce nasal airway obstructive symptoms is unclear, however the following mechanisms have been suggested (Demain 1995): 1) direct reduction of adenoidal size by lympholytic action of corticosteroids on adenoidal tissues; 2) reduction in adenoidal and nasopharyngeal inflammation by anti‐inflammatory effects of corticosteroids; and 3) a reduction in the significance of the adenoids as a reservoir for infection.

Despite the uncertainty of the precise mechanism, establishment of a therapeutic role for intranasal corticosteroids in children with adenoidal hypertrophy may have significant clinical implications. This modality may provide an effective non‐surgical alternative treatment for children with adenoidal hypertrophy. The use of intranasal corticosteroids has been generally considered safe in the paediatric population, despite uncommon reports of some local and systemic adverse events, including epistaxis, nasal mucosal irritation, moderate adrenal suppression and growth retardation (Adamopoulos 1995; Gazis 1999; Skoner 2000). There is a need for a comprehensive systematic review and meta‐analysis of the evidence for the effects of intranasal corticosteroids on reducing nasal airway obstruction associated with adenoidal hypertrophy in children.