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An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the
nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passe ...
, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis,
pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice ...
,
laryngitis Laryngitis is inflammation of the larynx (voice box). Symptoms often include a hoarse voice and may include fever, cough, pain in the front of the neck, and trouble swallowing. Typically, these last under two weeks. Laryngitis is categorised ...
,
sinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, hea ...
,
otitis media Otitis media is a group of inflammatory diseases of the middle ear. One of the two main types is acute otitis media (AOM), an infection of rapid onset that usually presents with ear pain. In young children this may result in pulling at the ear, ...
, and the
common cold The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear fewer than two days after exposur ...
. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common. In 2015, 17.2 billion cases of URTIs are estimated to have occurred. As of 2014, they caused about 3,000 deaths, down from 4,000 in 1990.


Signs and symptoms

In uncomplicated colds, coughing and nasal discharge may persist for 14 days or more even after other symptoms have resolved. Acute URTIs include
rhinitis Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip. The inflammation is caused by viruses, bacteria, irritant ...
, pharyngitis/tonsillitis, and laryngitis often referred to as a common cold, and their complications:
sinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, hea ...
, ear infection, and sometimes
bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. S ...
(though bronchi are generally classified as part of the lower respiratory tract.) Symptoms of URTIs commonly include
cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phas ...
, sore throat,
runny nose Rhinorrhea, rhinorrhoea, or informally runny nose is the free discharge of a thin mucus fluid from the nose; it is a common condition. It is a common symptom of allergies ( hay fever) or certain viral infections, such as the common cold or COV ...
, nasal congestion, headache, low-grade fever, facial pressure, and
sneezing A sneeze (also known as sternutation) is a semi-autonomous, convulsive expulsion of air from the lungs through the nose and mouth, usually caused by foreign particles irritating the nasal mucosa. A sneeze expels air forcibly from the mouth and ...
. Symptoms of rhinovirus in children usually begin 1–3 days after exposure. The illness usually lasts 7–10 more days. Color or consistency changes in mucous discharge to yellow, thick, or green are the natural course of viral URTI and not an indication for antibiotics. Group A beta-hemolytic streptococcal pharyngitis/tonsillitis (strep throat) typically presents with a sudden onset of sore throat, pain with swallowing, and fever. Strep throat does not usually cause a runny nose, voice changes, or cough. Pain and pressure of the ear caused by a middle-ear infection (otitis media) and the reddening of the eye caused by viral
conjunctivitis Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The ...
are often associated with URTIs.


Cause

In terms of pathophysiology, rhinovirus infection resembles the immune response. The viruses do not cause damage to the cells of the upper respiratory tract, but rather cause changes in the tight junctions of epithelial cells. This allows the virus to gain access to tissues under the epithelial cells and initiate the innate and adaptive immune responses. Up to 15% of acute pharyngitis cases may be caused by bacteria, most commonly '' Streptococcus pyogenes'', a group A streptococcus in streptococcal pharyngitis ("strep throat"). Other bacterial causes are '' Streptococcus pneumoniae'', '' Haemophilus influenzae'', ''
Corynebacterium diphtheriae ''Corynebacterium diphtheriae'' is the pathogenic bacterium that causes diphtheria. It is also known as the Klebs–Löffler bacillus, because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834–1912) and Friedrich Löffl ...
'', ''
Bordetella pertussis ''Bordetella pertussis'' is a Gram-negative, aerobic, pathogenic, encapsulated coccobacillus of the genus ''Bordetella'', and the causative agent of pertussis or whooping cough. Like '' B. bronchiseptica'', ''B. pertussis'' is motile and exp ...
'', and ''
Bacillus anthracis ''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus ''Bacillus''. Its infection is a t ...
''. Sexually transmitted infections have emerged as causes of oral and pharyngeal infections.


Diagnosis


Classification

A URTI may be classified by the area inflamed.
Rhinitis Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip. The inflammation is caused by viruses, bacteria, irritant ...
affects the nasal mucosa, while rhinosinusitis or
sinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, hea ...
affects the nose and
paranasal sinuses Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the spheno ...
, including frontal, ethmoid, maxillary, and sphenoid sinuses. Nasopharyngitis (rhinopharyngitis or the common cold) affects the nares, pharynx, hypopharynx,
uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers. It also conta ...
, and tonsils generally. Without involving the nose, pharyngitis inflames the pharynx, hypopharynx, uvula, and tonsils. Similarly, epiglottitis (supraglottitis) inflames the superior portion of the larynx and supraglottic area; laryngitis is in the larynx; laryngotracheitis is in the larynx, trachea, and subglottic area; and tracheitis is in the trachea and subglottic area.


Prevention

Vaccination against influenza viruses,
adenoviruses Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from thei ...
, measles, rubella, '' Streptococcus pneumoniae'', '' Haemophilus influenzae'', diphtheria, ''
Bacillus anthracis ''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent (obligate) pathogen within the genus ''Bacillus''. Its infection is a t ...
'', and ''
Bordetella pertussis ''Bordetella pertussis'' is a Gram-negative, aerobic, pathogenic, encapsulated coccobacillus of the genus ''Bordetella'', and the causative agent of pertussis or whooping cough. Like '' B. bronchiseptica'', ''B. pertussis'' is motile and exp ...
'' may prevent them from infecting the URT or reduce the severity of the infection.


Treatment

Treatment comprises symptomatic support usually via
analgesics An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It i ...
for headache, sore throat, and muscle aches. Moderate exercise in sedentary subjects with a naturally acquired URTI probably does not alter the overall severity and duration of the illness. No randomized trials have been conducted to ascertain benefits of increasing fluid intake.


Antibiotics

Prescribing antibiotics for laryngitis is not a suggested practice. The antibiotics penicillin V and erythromycin are not effective for treating acute laryngitis. Erythromycin may improve voice disturbances after a week and cough after 2 weeks, but any modest subjective benefit is not greater than the adverse effects, cost, and the risk of bacteria developing resistance to the antibiotics. Health authorities have been strongly encouraging physicians to decrease the prescribing of antibiotics to treat common URTIs because antibiotic usage does not significantly reduce recovery time for these viral illnesses. A 2017 systematic review found three interventions which were probably effective in reducing antibiotic use for acute respiratory infections:
C-reactive protein C-reactive protein (CRP) is an annular (ring-shaped) pentameric protein found in blood plasma, whose circulating concentrations rise in response to inflammation. It is an acute-phase protein of hepatic origin that increases following interleukin-6 ...
testing, procalcitonin-guided management, and shared decision-making between physicians and patients. The use of narrow-spectrum antibiotics has been shown to be just as effective as broad-spectrum alternatives for children with acute bacterial URTIs, and has a lower risk of side effects in children. Decreased antibiotic usage could also have prevented drug-resistant bacteria. Some have advocated a delayed antibiotic approach to treating URTIs, which seeks to reduce the consumption of antibiotics while attempting to maintain patient satisfaction. A Cochrane review (updated 2017) of 11 studies and 3,555 participants explored antibiotics for respiratory tract infections. It compared delaying antibiotic treatment to either starting them immediately or to no antibiotics. Outcomes were mixed depending on the respiratory tract infection; symptoms of acute otitis media and sore throat were modestly improved with immediate antibiotics with minimal difference in complication rate. Antibiotic usage was reduced when antibiotics were only used for ongoing symptoms and maintained patient satisfaction at 86%. For sinusitis while at the same time discouraging overuse of antibiotics the CDC recommends: * Target likely organisms with first-line medications:
amoxicillin Amoxicillin is an antibiotic medication used to treat a number of bacterial infections. These include middle ear infection, strep throat, pneumonia, skin infections, and urinary tract infections among others. It is taken by mouth, or less ...
, amoxicillin/clavulanate * Use the shortest effective course; should see improvement in 2–3 days. Continue treatment for 7 days after symptoms improve or resolve (usually a 10–14 day course). * Consider imaging studies in recurrent or unclear cases; some sinus involvement is frequent early in the course of uncomplicated viral URI


Cough medicine

No good evidence exists for or against the effectiveness of over-the-counter cough medications for reducing coughing in adults or children. Children under 2 years old should not be given any type of cough or cold medicine due to the potential for life-threatening side effects. In addition, according to the
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C. Background The Academy was founde ...
, the use of cough medicine to relieve cough symptoms should be avoided in children under 4 years old, and the safety is questioned for children under 6 years old.


Decongestants

According to a Cochrane review, a single oral dose of nasal decongestant in the common cold is modestly effective for the short-term relief of congestion in adults; however, data on the use of decongestants in children are insufficient. Therefore, decongestants are not recommended for use in children under 12 years of age with the common cold. Oral decongestants are also contraindicated in patients with hypertension, coronary artery disease, and history of bleeding strokes.


Mucolytics

Mucolytics such as
acetylcysteine Acetylcysteine, also known as ''N''-acetylcysteine (NAC), is a medication that is used to treat paracetamol overdose and to loosen thick mucus in individuals with chronic bronchopulmonary disorders like pneumonia and bronchitis. It has been used ...
and carbocystine are widely prescribed for upper and lower respiratory tract infection without chronic broncho-pulmonary disease. However, in 2013 a Cochrane review reported their efficacy to be limited. Acetylcystine is considered to be safe for the children older than 2 years.


Alternative medicine

Routine supplementation with vitamin C is not justified, as it does not appear to be effective in reducing the incidence of common colds in the general population. The use of vitamin C in the inhibition and treatment of upper respiratory infections has been suggested since the initial isolation of vitamin C in the 1930s. Some evidence exists to indicate that it could be justified in persons exposed to brief periods of severe physical exercise and/or cold environments. Given that vitamin C supplements are inexpensive and safe, people with common colds may consider trying vitamin C supplements to assess whether they are therapeutically beneficial in their case. Some low-quality evidence indicates the use of nasal irrigation with saline solution may alleviate symptoms in some people. Also, saline
nasal spray Nasal sprays are used to deliver medications locally in the nasal cavities or systemically. They are used locally for conditions such as nasal congestion and allergic rhinitis. In some situations, the nasal delivery route is preferred for syst ...
s can be of benefit.


Epidemiology

Children typically have two to nine viral respiratory illnesses per year. In 2013, 18.8 billion cases of URTIs were reported. As of 2014, they caused about 3,000 deaths, down from 4,000 in 1990. In the United States, URTIs are the most common infectious illness in the general population, and are the leading reasons for people missing work and school.


Dietary research

Preliminary research indicates that consumption of
probiotic Probiotics are live microorganisms promoted with claims that they provide health benefits when consumed, generally by improving or restoring the gut microbiota. Probiotics are considered generally safe to consume, but may cause bacteria-host i ...
s may reduce the incidence of acute URTIs.


See also

* Lower respiratory tract infection


References


Further reading

* *


External links


Upper Respiratory Tract Infection
from Cleveland Clinic Online Medical Reference {{Common cold Infectious diseases Inflammations Upper respiratory tract diseases