Acute adenoiditis is characterized by fever, runny nose, nasal airway obstruction resulting in predominantly oral breathing, snoring and sleep apnea, Rhinorrhea with serous secretion in viral forms and mucous-purulent secretion in bacterial forms. In cases due to viral infection symptoms usually recede spontaneously after 48 hours, symptoms of bacterial adenoiditis typically persist up to a week. Adenoiditis is sometimes accompanied by tonsillitis. Repeated adenoiditis may lead to enlarged adenoids.

Adenoiditis is the inflammation of the adenoid tissue, usually caused by an infection. Adenoiditis is treated using medication (antibiotics and/or steroids) or surgical intervention.

Adenoiditis may produce cold-like symptoms. However, adenoiditis symptoms often persist for ten or more days, and often include pus-like discharge from nose.

The infection cause is usually viral. However, if the adenoiditis is caused by a bacterial infection, antibiotics may be prescribed for treatment. A steroidal nasal spray may also be prescribed in order to reduce nasal congestion. Severe or recurring adenoiditis may require surgical removal of the adenoids (adenotonsillectomy).

Catarrh , or catarrhal inflammation, is inflammation of the mucous membranes in one of the airways or cavities of the body, usually with reference to the throat and paranasal sinuses. It can result in a thick exudate of mucus and white blood cells caused by the swelling of the mucous membranes in the head in response to an infection. It is a symptom usually associated with the common cold, pharyngitis, and chesty coughs, but it can also be found in patients with adenoiditis, otitis media, sinusitis or tonsillitis. The phlegm produced by catarrh may either discharge or cause a blockage that may become chronic.

The word "catarrh" was widely used in medicine since before the era of medical science, which explains why it has various senses and in older texts may be synonymous with, or vaguely indistinguishable from, common cold, nasopharyngitis, pharyngitis, rhinitis, or sinusitis. The word is no longer as widely used in American medical practice, mostly because more precise words are available for any particular pathosis. Indeed, to the extent that it is still used, it is no longer viewed nosologically as a disease entity but instead as a symptom, a sign, or a syndrome of both. The term "catarrh" is found in medical sources from the United Kingdom. The word has also been common in the folk medicine of Appalachia, where medicinal plants have been used to treat the inflammation and drainage associated with the condition.

Due to the human ear's function of regulating the pressure within the head region, catarrh blockage may cause discomfort during changes in atmospheric pressure.

Enlarged adenoids can become nearly the size of a ping pong ball and completely block airflow through the nasal passages. Even if enlarged adenoids are not substantial enough to physically block the back of the nose, they can obstruct airflow enough so that breathing through the nose requires an uncomfortable amount of work, and inhalation occurs instead through an open mouth. Adenoids can also obstruct the nasal airway enough to affect the voice without actually stopping nasal airflow altogether.

Nasal blockage is determined by at least two factors: 1) the size of the adenoids, and 2) the size of the nasal pharynx passageway.

The adenoid usually reaches its greatest size by about age 5 years or so, and then fades away ("atrophies") by late childhood - generally by the age of 7 years. The lymphoid tissue remains under the mucosa of the nasopharynx, and could be seen under a microscope if the area was biopsied, but the mass is so reduced in size that the roof of the nasopharynx becomes flat rather than mounded. Just as the size of the adenoids is variable between individuals, so is the age at which adenoids atrophy.

The symptoms caused by enlarged adenoids are mostly due to "where" this lymphoid tissue is located. The adenoids are in the midline of the nasopharynx, and the Eustachian tubes open from either ear to the right and left of them. In children with excessive middle ear infections and chronic middle ear fluid, there is a high bacterial count in the adenoids as compared to children without problematic otitis media, even if the size of the adenoids is small. The adenoids in these cases provides a reservoir of pathogenic bacteria that cause ear infections and subsequent middle ear effusions (fluid).

The nasopharynx lies right above the throat. Splashes of excessive "drip" from infected adenoids may land directly on the vocal cords. Although the larynx and vocal cords do not ordinarily become infected from adenoiditis, their mucosa does become irritated. The vocal cords are extremely sensitive to touch, and any fluid drops falling on them cause an irresistible urge to cough. Adenoiditis therefore is one of the causes of cough.

Adenoid hypertrophy (or enlarged adenoids) is the unusual growth ("hypertrophy") of the adenoid tonsil first described by the Danish physician Wilhelm Meyer (1824-1895) in Copenhagen in 1868. He described that a long term adenoid hypertrophy will cause an obstruction of the nasal airways. These will lead to a dentofacial growth anomaly that was defined as "adenoid facies" (see long face syndrome).

There is very little lymphoid tissue in the nasopharynx of young babies; humans are born without substantial adenoids. The mat of lymphoid tissue called adenoids starts to get sizable during the first year of life. Just how big the adenoids become is quite variable between individual children.

The most common hypopnea symptom is excessive sleepiness, which results from constant sleep interruption. People with hypopnea due to airflow obstruction often have loud, heavy snoring that is interrupted with choking sounds or loud snorts followed by periods of silence, because not enough air can flow into the lungs through the mouth and nose. The periods of silence can last 20 seconds or longer and can happen many times each hour, resulting in poor sleep and reduced levels of oxygen in the blood.

Other symptoms of hypopnea may include depression, forgetfulness, mood or behavior changes, trouble concentrating, loss of energy, nervousness, and morning headaches. Not all people with hypopnea experience all of these symptoms and not everyone who has these symptoms has hypopnea.

Hypopnea is a disorder that may result in excessive daytime sleepiness and compromised quality of life, including traffic accidents, diminished productivity in the workplace, and emotional problems.

Cardiovascular consequences of hypopnea may include myocardial infarction, stroke, psychiatric problems, impotence, cognitive dysfunction, hypertension, coronary heart disease, and memory loss.