Upper Respiratory Tract Infection

An upper respiratory tract infection (URTI) is an illness caused by an acute infection involving the upper respiratory tract, including the nose, sinuses, pharynx, larynx, or trachea. Common conditions under URTI include nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold.

Most infections are viral, though bacterial, fungal, and helminthic origins are also possible but less common. In 2015, an estimated 17.2 billion cases of URTIs occurred globally, leading to approximately 3,000 deaths in 2016.

Signs & Symptoms

Symptoms of URTIs often include cough, sore throat, runny nose, nasal congestion, headache, low-grade fever, facial pressure, and sneezing. In uncomplicated cases, coughing and nasal discharge can persist for 14 days or more after other symptoms have resolved. Acute URTIs include rhinitis, pharyngitis/tonsillitis, and laryngitis, commonly referred to as the common cold. Complications can involve sinusitis, ear infections, and sometimes bronchitis. Rhinovirus symptoms in children typically begin 1–3 days after exposure, with the illness lasting 7–10 days. Notably, changes in mucous discharge colour or consistency are part of the natural viral course and do not warrant antibiotics.

Cause

URTIs are primarily caused by viruses that do not damage the cells of the upper respiratory tract but cause changes in the tight junctions of epithelial cells, allowing access to tissues underneath and triggering immune responses. Up to 15% of acute pharyngitis cases may be bacterial, most commonly caused by Streptococcus pyogenes (group A streptococcus). Other bacterial causes include Streptococcus pneumoniae, Haemophilus influenzae, and Bordetella pertussis. Sexually transmitted infections can also cause oral and pharyngeal infections.

Diagnosis

Differentiating URTI from allergies and influenza involves comparing symptoms such as itchiness, nasal discharge, sneezing, sore throat, cough, headache, fever, malaise, fatigue, and muscle pain. URTIs may be classified by the area of inflammation, affecting the nasal mucosa (rhinitis), paranasal sinuses (sinusitis), or the pharynx, hypopharynx, uvula, and tonsils (pharyngitis).

Prevention

Vaccination against influenza viruses, adenoviruses, measles, rubella, Streptococcus pneumoniae, Haemophilus influenzae, diphtheria, Bacillus anthracis, and Bordetella pertussis can prevent or reduce the severity of URTIs.

Treatment

Treatment generally involves symptomatic support, such as analgesics for headaches, sore throats, and muscle aches. Moderate exercise in sedentary individuals with URTI does not significantly alter the illness's severity or duration. No randomised trials have confirmed the benefits of increasing fluid intake.

Antibiotics

Antibiotics are not typically recommended for URTIs, particularly for laryngitis, as they do not significantly reduce recovery time for viral illnesses. Health authorities encourage reducing antibiotic prescriptions to prevent resistance. C-reactive protein testing, procalcitonin-guided management, and shared decision-making have shown promise in reducing antibiotic use. Narrow-spectrum antibiotics are effective and have fewer side effects for children with bacterial URTIs. Delayed antibiotic approaches may maintain patient satisfaction while reducing antibiotic usage.

Cough Medicine

There is insufficient evidence for the effectiveness of over-the-counter cough medicines in adults and children. Children under 2 years should not be given cough or cold medicine due to potential life-threatening side effects, and caution is advised for children under 6 years.

Decongestants

A single oral dose of nasal decongestant can provide short-term relief for adults, but data for children are insufficient, and decongestants are not recommended for children under 12. They are contraindicated in patients with hypertension, coronary artery disease, and history of bleeding strokes.

Mucolytics

Mucolytics like acetylcysteine and carbocysteine are prescribed but show limited efficacy. Acetylcysteine is considered safe for children older than 2 years.

Alternative Medicine

Routine vitamin C supplementation is not justified for the general population but may be beneficial for those exposed to severe physical exercise or cold environments. Nasal irrigation with saline solution may alleviate symptoms.

Epidemiology

Children typically experience two to nine viral respiratory illnesses annually. In 2013, 18.8 billion cases were reported, causing about 3,000 deaths by 2014. In the United States, URTIs are the most common infectious illness, leading to significant absenteeism from work and school.

Dietary Research

Weak evidence suggests probiotics may help prevent URTIs compared to placebo or no treatment.

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Self-assessment MCQs (single best answer)

What is the primary cause of upper respiratory tract infections (URTIs)?

Which of the following symptoms is NOT commonly associated with URTIs?

How long can coughing and nasal discharge persist in uncomplicated cases of URTI?

Which bacterial species is most commonly associated with acute pharyngitis?

Which preventive measure is recommended to reduce the severity of URTIs?

Why are antibiotics generally not recommended for treating URTIs?

At what age should children NOT be given over-the-counter cough or cold medicine due to potential life-threatening side effects?

Which of the following is contraindicated for patients with hypertension and coronary artery disease?

What alternative treatment may alleviate symptoms of URTIs?

How many viral respiratory illnesses do children typically experience annually?