URTI

Upper respiratory tract infections (URTIs) are common self-limiting illnesses that present with coryzal symptoms.

An upper respiratory tract infection (URTI) refers to inflammation of the mucosa of the nostrils, nasal cavity, mouth, throat (i.e. pharynx), and larynx that all constitute the upper respiratory tract. URTIs are very common and lead to symptoms of nasal stuffiness, runny nose, sneezing, sore throat, and cough. This collection of symptoms is often referred to as ‘coryza’.

URTI is caused by a viral infection and there are numerous causative viruses including rhinovirus, adenovirus, and many others. URTI is colloquially known as the ‘common cold’ or more simply a ‘cold’. It usually leads to a mild, self-limiting illness.

It is estimated that adults will have on average 2-3 URTIs each year.

URTIs are very common in the population across all age groups. They are most commonly observed in children who will get an estimated 5-8 URTIs per year. Adults are expected to have 2-3 URTIs per year. URTIs are more common in the winter months in Northern hemisphere countries.

The most common cause of URTIs are viruses.

URTIs are caused by a variety of viruses. The most common of these is Rhinovirus, which accounts for up to 50% of cases. There are >100 different subtypes of rhinovirus. Other viruses include:

• Coronavirus (excluding COVID-19)
• Influenza
• Respiratory syncytial virus
• Adenoviruses
• Enteroviruses
• Metapneumovirus
• Unknown: up to 25% will have no identifiable cause

Transmission

The main routes of transmission for an URTI include:

• Direct contact: contact with an infected person or contaminated surface
• Small or large particle droplets: viral particles that become airborne through coughing, sneezing, or talking. Divided into small and large based on the size of the droplets. This is a classic route of transmission for respiratory diseases

Pathology

The symptoms of the common cold seem to develop due to the inflammatory response to the infective viral particles within the upper airway mucosa. There is an influx of polymorphonuclear cells (i.e. neutrophils, eosinophils) and the subsequent release of inflammatory mediators such as interleukins. This immune response coincides with the development of symptoms.

Coryzal symptoms are the hallmark of URTIs that include nasal stuffiness, runny nose, sneezing, sore throat, and cough.

The clinical features of URTIs are very typical and the majority of adults are able to diagnose the symptoms within a day of development. The onset of symptoms of URTIs is usually rapid, occurring over 1-2 days.

Symptoms

• Nasal stuffiness
• Runny nose (rhinorrhoea)
• Sneezing
• Sore throat
• Cough
• Hoarse voice
• Malaise/fatigue
• Fever (usually low grade)
• Other symptoms: headache, myalgia, pressure in sinuses

Signs

The clinical signs of an URTI may be minimal but can include:

• Conjunctival injection
• Nasal mucosal swelling
• Nasal congestion and runny nose
• Pharyngeal erythema (when assessing the back of the throat)

In young children, there may be features of irritability, poor feeding, and restlessness.

URTI is a clinical diagnosis based on characteristic symptoms and signs.

The majority of adults are able to recognise the features of an URTI or ‘common cold’ leading to self-diagnosis. Investigations are not required to make the diagnosis. However, in light of the COVID-19 pandemic, testing for COVID-19 is commonly recommended in patients with symptoms of an URTI to avoid transmitting it to other people. For more information always check the latest government advice on coronavirus.

Viral assays or polymerase chain reaction (PCR) tests on nasal and/or throat swabs are available for many common viruses if required. These are typically reserved for patients admitted to the hospital to try and identify the cause and inform the appropriate isolation protocols. PCR tests can be commonly performed for COVID-19, influenza, rhinovirus, and RSV amongst many others.

The majority of cases of URTI are self-limiting and do not require any specific medical treatment.

URTIs are most commonly mild, self-limiting viral infections that do not require any specific treatment. Symptoms typically peak over 2-3 days and resolve over 7 days in adults and 14 days in children. Certain symptoms such as cough may linger for a few weeks. Most importantly, antibiotics and antihistamines are not effective in the treatment of URTIs.

Basic advice should be given to all patients with URTI, which includes:

• Rest
• Stay adequately hydration
• Antipyretics (e.g. paracetamol): to treat fever, aches, pains
• Maintain nutrition as tolerated: loss of appetite common with any infection (should return as improve)
• Maintain good hygiene (e.g. hand washing, avoid sharing towels)
• Consider other self-care remedies (e.g. steam inhalation, decongestants): note that many of the over-the-counter products have limited benefits and potential adverse effects

In patients at risk of deterioration (e.g. elderly and frail, immunosuppressed), those with persistent symptoms (e.g. fever > 3 days, symptoms worsen after 5 days), or those with a possible secondary complication (e.g. lower respiratory tract infection), closer monitoring should be arranged (e.g. follow-up review). If there is a major concern, or any significant deterioration (e.g. hypoxia), hospital admission may be required.

Patients with URTIs can develop complications due to viral spread or a secondary bacterial infection.

Complications are uncommon in patients with URTIs. If they do develop, they usually occur due to the virus spreading to adjacent organs or from a secondary bacterial infection (i.e. a bacterial infection developing during or after the treatment of another infection). Examples include:

• Rhinosinusitis: typical clinical features include sinus pain and congestion, excessive rhinorrhoea, and nasal stuffiness (may be difficult to differentiate from URTI)
• Lower respiratory tract infection (includes acute bronchitis): usually results in worsening cough and shortness of breath. In some patients, there may be an exacerbation of their asthma or chronic obstructive pulmonary disease symptoms leading to wheeze
• Otitis media: commonly associated with severe earache