subject: UPPER RESPIRATORY TRACT INFECTIONS [print this page] Most upper respiratory tract infections (URTIs) are viraland the majority of these are the results of infectionwith rhinoviruses of the picornavirus family. However,adenoviruses, coronaviruses, coxsackie viruses, echoviruses,influenza viruses, parainfluenza viruses and therespiratory syncytial virus (RSV) can all cause upper respiratorytract infections.
URTIs represent the mostcommon of all illnesses and are responsible for approximatelyhalf of all time lost from work.In addition to URTI the influenza viruses, parainfluenzaviruses 1 and 2, adenoviruses and RSV can cause acuteinfection of the larynx, trachea and major bronchi, and arecauses of croup.
URTIs are most common in the latewinter months and early spring. The most frequent manifestationof these viral infections is the common cold(acute coryza), which may be complicated by secondarybacterial infection and subsequently by sinusitis, otitismedia, obstruction to the eustachian tubes and infection ofthe lower respiratory tract.
Viral laryngotracheobronchitis,particularly in children, may be complicated by severelaryngeal oedema and life-threatening croup. Croup is alsoa feature of acute epiglottitis in children, and occasionallyin adults, and is most commonly due to Haemophilusinfluenzae type B infection.
The swelling of the epiglottisand surrounding soft tissues can rapidly produce respiratorydistress. Unlike in laryngitis, the voice is not hoarse.The epiglottis is hugely swollen and attempts to examinethe throat can precipitate total upper airway obstruction.
In most patients with URTI the illness is self-limitingand symptoms subside after a few days. Antibiotics are notgenerally required unless there is acute epiglottitis due toH. influenzae, in which case intravenous chloramphenicol,or a cephalosporin such as cefotaxime or ceftriaxone, isindicated.
However, in patients in whom secondary bacterialinfection is both likely and potentially serious (e.g. inchronic bronchitis and emphysema) immediate treatmentwith antibiotics is justified. Oral amoxycillin, co-amoxiclavor tetracycline in standard doses are suitable. The developmentof stridor requires careful observation in hospital,with anaesthetic support for possible emergency intubation.Patients with stridor, particularly children with croup,adopt the posture that facilitates adequate ventilation andthey should be allowed to do so. Inhalation of warm,humidified air is helpful. Given early, high-dose corticosteroidsreduce the need for intubation, and in those whoare intubated they shorten the time for which a tube isnecessary. Nebulized corticsteroid therapy is helpful.
Sinusitis
Sinusitis (infection of the paranasal sinuses) is a commoncomplication of URTI and the bacteria most frequentlyinvolved are H. influenzae and Streptococcus pneumoniae.Amoxycillin, trimethoprim or an oral cephalosporin instandard doses may be given. Facial pain and tenderness,headache, nasal discharge and a postnasal drip are theusual features.
Radiology may demonstrate fluid levelswithin the maxillary sinuses or show sinus mucosal thickening.Sinusitis may complicate the nasal obstruction ofallergic rhinitis, in which case topical steroid therapy isuseful, in addition to oral antibiotics. Topical steroid can beadministered by nasal spray (e.g. beclometasone or fluticasone)but if the nose is obstructed steroid nasal drops,incorporating an antibiotic, are usually more effective (e.g.betamethasone plus neomycin).
Nasal drops are bestinstilled with the head held forward (between the knees)so that the fluid is retained within the nostril and the drugsable to be absorbed into the oedematous nasal mucosa.Persistent or recurrent sinusitis may require surgicaldrainage. Sinusitis is a common feature of patients withbronchiectasis (occasionally, both are manifestations of theimmotile cilia syndromes) and it is equally important tocontrol infection at both sites.
