Upper respiratory tract infection (URTI) refers to a wide range of acute illnesses that affect the upper respiratory tract. URTIs are the most common reason for general practice consultations.¹ On average adults suffer two to three such infections per year.²

The upper respiratory tract includes the external nose, nasal cavity, pharynx, larynx and sinuses. During an infection, all these areas may be affected either simultaneously or at different times. Terms such as rhinitis, rhinosinusitis, nasopharyngitis, pharyngitis, laryngitis and epiglottitis denote the specific sites of inflammation. The common cold is probably best defined as a viral infection that primarily affects the nasal mucosa.

Clinical syndromes

The diagnosis of a URTI is fairly straightforward and is usually a self-diagnosis. However, when assessing a patient with a URTI in general practice it is important to recognise which patients may require antibiotics, further investigations and/or hospital referral.

The common cold is typically characterised by nasal discharge and congestion, sneezing, sore throat and cough. Symptoms may last up to 14 days with an average of 7 to 11 days' duration.^{3, 4} Viruses causing the common cold include rhinoviruses, adenoviruses, coronaviruses, parainfluenza viruses, respiratory syncytial viruses and enteroviruses.⁵

Fever, fatigue, myalgia and headache are more common but not specific symptoms of an influenza infection.⁶

Most URTIs occur during autumn and winter but they can occur all year round (see table 1, above).⁷

Group A streptococcus is the most common bacterial cause of acute pharyngitis accounting for approximately 5-10% of cases in adults.^{8, 9} Several studies have attempted to differentiate between group A streptococcal and viral causes based on the clinical features.

A systematic review has shown that the Centor scoring system (see box 1, below) may help categorise the patient's risk for group A streptococcal infection.¹⁰

Other organisms that may cause acute pharyngitis include:¹¹

• Coxsackie virus A
• Epstein-Barr virus - infectious mononucleosis
• Cytomegalovirus
• Human immunodeficiency virus - as part of the primary infection
• Non-group A streptococci
• Corynebacterium diphtheriae - rare in the developed world
• Neisseria gonorrhoeae
• Arcanobacterium haemolyticum
• Mycoplasma pneumoniae - isolated from patients with symptomatic pharyngitis and controls, significance unclear
• Chlamydia pneumoniae - may occur as an isolated URTI or with pneumonia

Acute rhinosinusitis is an infection of the nasal cavity and paranasal sinuses. Patients with acute sinusitis have pain over the affected sinus, maxillary toothache, nasal discharge and congestion. It is difficult to distinguish viral from bacterial infections. Persistent (longer than 10 days) or worsening symptoms (after five to seven days) usually suggest a bacterial infection.^{4, 12} However, treatment with antibiotics cannot be justified even if symptoms persist.¹³ Common bacterial pathogens in adults include Streptococcus pneumoniae and Haemophilus influenzae.¹⁴

Epiglottitis is an acute inflammation of the supraglottic region with inflammation of the epiglottis, vallecula, arytenoids and aryepiglottic folds. Since the introduction of Haemophilus influenzae type b (Hib) vaccine, the occurrence in children has decreased dramatically. The ratio of incidence in children to adults has also dropped. The incidence rates in adults remain constant, with a mean value of 1.9 cases/100,000/year.¹⁵ Adults with acute epiglottitis may present with symptoms such as sore throat, fever, odynophagia/dysphagia and muffled voice and have features suggestive of upper airway obstruction such as drooling and stridor.

Potential complications

URTIs although annoying to the patient are usually benign and self-limiting. However, URTI may cause infections of adjacent structures such as the middle ear, lower respiratory tract and central nervous system. Potential complications of certain URTIs are listed in table 2, above left. Complications of influenza infection will be discussed later.

The NICE guideline on antibiotic prescribing for self-limiting respiratory tract infections in primary care, recommends immediate antibiotics or further investigation and/or management in the following patients who are at risk of complications: 16

• Systemically very unwell
• Features suggestive of serious illness and complications (particularly pneumonia, mastoiditis, peritonsillar abscess, peritonsillar cellulitis, intraorbital or intracranial complications)
• Pre-existing comorbidities - patients with significant heart, lung, renal, liver or neuromuscular disease, immunosuppression, cystic fibrosis, and young children who were born prematurely
• Older than 65 years with acute cough and two or more of the following, or older than 80 years with acute cough and one or more of the following:

- Hospitalisation in the previous year

- Type 1 or type 2 diabetes

- History of congestive heart failure

- Current use of oral glucocorticoids

The British Thoracic Society has published specific guidelines for

the management of patients with

an influenza-like illness during

an influenza pandemic.6

Pneumonia, either primary viral (rare) or secondary bacterial (common), is the most common complication of influenza in adults. Patients complaining of new or worsening dyspnoea should be carefully assessed for signs of pneumonia. If pneumonia is diagnosed, severity should be assessed using an assessment tool such as the CRB-65 score and appropriate treatment and/or referral carried out (see table 3, above).17, 18

Other influenza-related complications are uncommon and there are no specific criteria to assess severity or recommend admission.

Community management

Self-management

Most URTIs are self-managed. A UK study of 516 women aged 20-44 years found that only one in 18 episodes of sore throat led to a general practice consultation.19 Patients who do seek consultations often benefit from reassurance, education and instructions for symptomatic home treatment. The evidence for benefits of home treatment/interventions is shown in table 4, above.

Antibiotics

A large proportion of antibiotic prescribing in primary care is for respiratory tract infections.28 There was a 44% reduction in antibiotic prescribing for respiratory tract infections between 1994 and 2000. The larger part of this reduction was due to lower consultation rates rather than a decrease in prescribing by GPs.29 Antibiotics are frequently prescribed for resolving symptoms and to prevent complications. Patients' expectations have a significant influence on prescribing, even when their doctor judges that antibiotics are not indicated.30

There are certain at-risk groups who require immediate antibiotics or further evaluation (see section above on assessing severity and potential complications).16 Antibiotics should also be considered for patients with three or more Centor criteria. In other cases (acute otitis media, acute sore throat/pharyngitis/acute tonsillitis, common cold, acute rhinosinusitis or acute cough/acute bronchitis), NICE advocates a no prescribing or delayed prescribing strategy. Patients' or carers' concerns and expectations should always be addressed first. It is important to explain the natural history of the illness and duration.16

When a no prescribing or delayed prescribing strategy is employed. NICE recommends the following approach:16

• Reassure the patient that antibiotics are not needed straightaway. Explain that antibiotics will make little difference to the symptoms and may cause side effects such as diarrhoea, vomiting and rash
• Offer a clinical review if the condition worsens or persists
• Give advice about using the delayed prescription if symptoms do not improve or get worse
• Advise the patient to come back if symptoms worsen despite the use of the delayed prescription