Adenoiditis overview

# Overview
Adenoid is a lymphoid tissue that forms the Waldeyer ring. Adenoiditis is the inflammation of adenoid tissue. Adenoid infection is mostly due to viral infections. Some bacterial pathogens including H. influenzae, group A -hemolytic streptococcus, and S. aureus can cause the disease as well. Adenoids can cause recurrent sinusitis and chronic persistent or recurrent otitis if left untreated and can lead to chronic adenoiditis. Medications (antibiotics or steroids) or surgical approach may be required for the management of adenoiditis, depending on the causative agent.

# Historical perspective
Adenoid was thought to be a part of tonsils and responsible for the symptoms of nasal congestion and obstruction. As a result adenotonsilectomy was performed for at least 2000 years. In the early beginning of 19th century, adenoid and tonsil tissue were known as remnants of an unknown infectious disease, and so they were removed with adenotonsilectomy. Willhelm Meyer of Copenhagen, Denmark in 1800 firstly describe adenoiditis due to adenoid vegetations responsible for nasal symptoms and impaired hearing. He probably was the first one who performed an adenoidectomy separately.

# Classification
Adenoiditis can be classified into the following types including acute adenoiditis, recurrent acute adenoiditis, and chronic/persistant adenoiditis.

# Pathophysiology
Adenoids are involved in the production of mostly secretory IgA. IgA is transported to the surface providing local immune protection. Studies suggest that a reduction in IgA will occur after an adenoidectomy. bacteria in the normal flora of the oral cavity, are found in adenoid tissue as well. These include alpha-hemolytic streptococci, enterococci, Corynebacterium species, Coagulase-negative staphylococci, Neisseria species, haemophilus species, micrococcus species, stomatococcus species. Adenoiditis can occur as a result of infection. They can harbor pathogenic bacteria, which may lead to the development of disease of the ears, nose, and sinuses. Adenoiditis can progress to chronic disease if it remains untreated for a long period of time.

# Causes
Acute adenoiditis is mainly due to viral infection but bacterial infections can cause the disease as well. Bacterial infections have a more important role in recurrent and chronic adenoiditis. The most important viral causes of adenoiditis include EBV, CMV and RSV. The most important bacterial causes adenoiditis include Haemophilus influenzae, group A -hemolytic streptococcus,  and staphylococcus aureus.

# Differentiating tonsillitis from other diseases
Diagnosis of adenoiditis can be challenging as majority of upper respiratory tract infections present in the same pattern. The most important differential diagnosis of adenoiditis includes tonsilitis, viral upper respiratory tract infection, sinusitis and pharyngitis.

# Epidemiology and Demographics
The prevalence of adenoiditis is not completely known. Research indicates that 15-30% of sore throats in children and 5-10% sore throats in adults are due to bacterial adenotonsillitis. The prevalence of adenoiditis decreases with age. Adenoid tissue undergoes atrophy after 10 years of age, so adenoiditis is rarely seen after 15 years.

# Risk Factors
The most potent risk factor in the development of adenoiditis is being a young child. Other risk factors include immunodeficiencies, living in an urban environment with more exposure to viruses or bacteria and usage of immunosuppressant drugs.

# Screening
There is insufficient evidence to recommend routine screening for adenoiditis.

# Natural history, complications and prognosis

## Natural History
Acute adenoiditis will usually present with erythema and edema of the adenoids. This occurs rapidly upon infiltration of the adenoids by the pathogen. Symptoms including fever and sore throat will usually manifest within 24 hours of infection. Adenoiditis is usually combined with tonsillitis due to close anatomical location.

## Complications
Complications of adenoiditis are caused by persistence and/or spread of the responsible pathogen - usually bacterial. The complications of adenoiditis include speech abnormalities, otitis media, acute sinusitis, pneumonia, adenoid hyperplasia, peritonsillar abscess, and sleep apnea.

## Prognosis
The prognosis for acute adenoiditis without treatment is usually good. Adenoiditis is usually a self-limiting disease and resolves by itself within 3-4 days.

# Diagnosis

## Diagnostic criteria
There is no criteria for the diagnosis of adenoiditis. However, seeing inflamed and hypertrophied adenoid tissue with flexible or rigid nasopharyngoscopy can be used as a criteria for adenoidectomy in patients suspected of chronic adenoiditis.

## History and Symptoms
A positive history of fever, nasal obstruction, and snoring is suggestive of adenoiditis. The most common symptoms of adenoiditis include purulent nasal discharge, mouth breathing, nasal pain and sore throat.

## Physical Examination
Patients with adenoiditis are usually well-appearing. Physical examination of patients with adenoiditis is usually remarkable for fever, and purulent nasal discharge.

## Laboratory Findings
Laboratory findings consistent with the diagnosis of adenoiditis include neutrophilia, positive culture for organism from throat exam sampling, and positive blood culture for the organism in severe cases.

## Imaging Findings
On lateral neck x-ray, adenoiditis is characterized by enlargement of adenoids and narrowing of airways. Adenoiditis diagnosis can be confirmed if during flexible or rigid nasopharyngoscopy inflamed adenoid tissue is seen. Flexible or rigid nasopharyngoscopy can provide a direct visualization of nasopharynx and Waldeyer ring so that the inflamed adenoid tissue can be seen too.

# Treatment

## Medical Therapy
The mainstay of therapy for adenoiditis is symptomatic therapy. Medical therapy is recommended among patients with recurrent and chronic adenoiditis. The best antibiotic therapy regimen include amoxicillin - clavulanic acid or cephalosporin.

## Surgery
Surgery is not the first-line treatment option for patients with adenoiditis. Adenoidectomy is usually reserved for patients with chronic persistent adenoiditis who developed adenoid hypertrophy. Adenoidectomy has shown to be effective independent of the size of the adenoids.

# Prevention

## Primary Prevention
Primary prevention strategies to prevent adenoiditis include hygienic practices.

## Secondary Prevention
Secondary prevention involves usage of antibiotics to prevent recurrence of adenoiditis. It can be helpful in certain circumstances like history of rheumatic fever, to prevent pharyngitis cause by group A beta-hemolytic streptococci.

# Related Chapters
- Tonsilitis