Upper respiratory tract infection

An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, or larynx. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. 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 far 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. In uncomplicated, colds, coughing, and nasal discharge may persist for 14 days or more even after other symptoms have resolved.Acute URTIs include rhinitis, pharyngitis/tonsillitis, and laryngitis often referred to as a common cold, and their complications: sinusitis, ear infection, and sometimes bronchitis (though bronchi are generally classified as part of the lower respiratory tract.) Symptoms of URTIs commonly include cough, sore throat, runny nose, nasal congestion, headache, low-grade fever, facial pressure, and sneezing. 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 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 are often associated with URTIs. 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.