UPPER RESPIRATORY TRACT INFECTIONS

Sore throat is one of the most common complaints in the general population, especially in autumn and winter. Sore throat can occur in the context of the most common upper respiratory tract infections such as colds and flu. 

In children under four years of age, the diagnosis of acute pharyngitis or tonsillitis can be made difficult by certain presenting symptoms, such as vomiting, abdominal pain, fever, and difficult swallowing, that not typical of sore throat. Depending on the site of inflammation causing the symptoms, the following can be distinguished: 
• Pharyngitis (inflammation of the pharynx only),
• Tonsillitis (inflammation of the tonsils only),
• Pharyngotonsillitis (inflammation of both the tonsils and the pharynx),
• Infection of the soft tissue surrounding the pharynx and the tonsils (peritonsillar abscess).

The most common cause of sore throat is viral infection, which is self-limiting and generally requires only symptomatic treatment. In other cases, this condition is caused by bacterial infection; tipically, group A β-hemolytic Streptococcus pyogenes is the causative organism, and it affects mainly children and adolescents aged 4 to 15 years, but can also affect adults. It is often difficult to distinguish, based on clinical findings alone, between viral and bacterial forms of acute upper respiratory tract infections. Signs may be minimal in viral pharyngitis, but swollen lymph node in the oropharynx and mild redness of the pharynx are typical; in most cases streptococcal pharyngotonsillitis is characterized by severe inflammation affecting both the tonsils and pharynx, with intense redness, difficulty in swallowing, and exudate. Throat swab has proven effective in the diagnosis of streptococcal infection, but its routine implementation is controversial; typically, the swab is required only to verify the presence of Streptococcus pyogenes, especially in facilities such as canteens, or in every case where diphtheria is suspected in a not immunised patient. The infections of presumed or proven bacterial aetiology should be treated with antibiotics active against streptococci.
Antibiotic efficacy against specific bacterial strains can be quantified by determining the minimum inhibitory concentration (MIC), which represents the lowest concentration of antibiotic capable of inhibiting the in vitro growth of a given microorganism. In particular, low MIC values against a wide range of bacterial pathogens indicate high antibiotic efficacy.