Respiratory tract infections (RTIs) are extremely prevalent, accounting for 20% of medical consultations and 30% of lost work days. Not at all trivial, RTIs contribute to 20% of mortality in children under five in developing countries (WHO, cited in Reed 2015).
The following article aims to help re-familiarise you with the different symptoms and presentations of the most commonly seen respiratory illnesses so that you can be confident in the care you provide.
What is a Respiratory Tract Infection?
Respiratory tract infections (RTIs) are various infections affecting parts of the respiratory system, such as the sinuses, throat, airway or lungs (NHS 2021a).
RTIs are separated into two categories depending on the area of the respiratory system they affect:
Upper respiratory tract infections affect the sinuses and throat.
Lower respiratory tract infections affect the airways and lungs.
(NHS 2021a)
Lower RTIs are generally longer-lasting and more serious (NHS 2021a).
RTIs are generally spread through direct contact, airborne particles or droplets (coughs and sneezes) from an infected person (Harvard Health Publishing 2017).
Below is an overview of some common RTIs. Please note this is not an exhaustive list.
Common cold
Type: Upper RTI
Cause: Viruses
Common symptoms:
Sore throat
Runny nose
Sneezing
Cough
Headache.
Treatment: No specific treatment.
The common cold is the most prevalent contagious disease in Australia and can be caused by over 200 different viruses. Most of these viruses belong to the rhinovirus or coronavirus families.
Colds can affect the ears, nose and throat. They are generally not considered serious and will usually resolve on their own. However, they may lead to secondary infections in some cases, particularly in children.
(Lung Foundation Australia 2016; Healthdirect 2022a; Healthy WA 2018)
Influenza
Type: Upper or lower RTI
Cause: Viruses
Common symptoms:
Sore throat
Fever
Cough
Body aches
Fatigue
Gastrointestinal symptoms (more common in children).
Treatment: Preventative vaccination.
Influenza (the flu) is similar to the common cold but is generally more severe with a very sudden onset. In some cases, it can lead to life-threatening complications.
Those who are at an increased risk of serious complications include older adults over 65, children under 2, pregnant women and people who are immunocompromised.
Treatment: Usually treated with antibiotics. Severe cases may require hospitalisation.
Pneumonia is an infection causing inflammation of the alveoli (air sacs) in one or both lungs. The alveoli fill with secretions and fluid, decreasing the ability for oxygen to be transported across the tissue to adequately oxygenate vital organs. Patients may experience shortness of breath, hypoxia and may often need oxygen therapy and ventilatory support.
Pneumonia can be a serious and potentially fatal infection, with young children, older adults and those with pre-existing health conditions most at risk of complications such as pleurisy, lung abscess or sepsis.
According to WHO (2019), pneumonia accounts for 14% of deaths of children aged under five years of age. In 2019, it contributed to the deaths of 740,180 children in total.
As the immune system naturally weakens over time, older adults become more at risk of developing pneumonia as they age.
Pneumonia may present as a relapse after a cold or flu.
(WHO 2022; NHS 2023; Lung Foundation Australia 2023; Gamache 2020)
Sinusitis
Type: Upper RTI
Cause: Bacteria or viruses
Common symptoms:
Pain, swelling and tenderness around cheeks, eyes and forehead
Blocked nose
Loss of smell or taste
Thick, green or yellow mucus
Headache
Fever
Bad breath.
Treatment: Decongestant nasal spray or drops, and salt water sprays or solutions.
Sinusitis is an inflammation of the nasal sinuses. It generally presents as a secondary infection after a cold or untreated allergies.
Sinusitis generally resolves on its own after a few weeks.
(ASCIA 2019; NHS 2021b)
Bronchitis
Type: Lower RTI
Cause: Viruses or bacteria
Common symptoms:
Cough (dry or productive)
Sore throat
Headache
Runny or blocked nose
Aches and pains
Fatigue.
Treatment: No specific treatment.
Bronchitis is an infection of the bronchi (the main airways of the lungs that branch off the trachea), which causes them to become inflamed and create more copious amounts of secretions than usual. This results in a productive cough, which is an attempt to excrete sputum.
Bronchitis is usually caused by the same viruses that cause colds and influenza.
(Healthdirect 2022b; NHS 2022b)
Bronchiolitis
Type: Lower RTI
Cause: Virus
Common symptoms:
Dry cough
Slight fever
Runny nose
Difficulty breathing
Noisy breathing (e.g. wheezing).
Treatment: No specific treatment.
Bronchiolitis causes inflammation and congestion in the smallest airways (bronchioles). It is usually caused by the respiratory syncytial virus (RSV) and almost exclusively affects infants under the age of two.
The symptoms are initially similar to those of a cold, but will then develop into coughing and in some cases, difficulty breathing.
Bronchitis is generally mild, clearing within two to three weeks.
Tonsillitis is an inflammation of the tonsils, most commonly affecting children (though anyone can contract it). Sometimes it will cause small, white patches of pus on the tonsils or back of the throat.
Tonsillitis generally resolves on its own after a few days. Those who experience frequent bouts of tonsillitis may choose to undergo tonsillectomy surgery to remove their tonsils permanently.
(Healthdirect 2021; NHS 2021c)
Laryngitis
Type: Upper RTI
Cause: Viruses, bacteria (rarely) or non-infection-related vocal strain
Common symptoms:
Hoarse voice or voice loss
Sore throat
Dry cough.
Treatment: No specific treatment.
Laryngitis is the inflammation and irritation of the larynx (voice box), causing swelling of the vocal cords and a consequent distortion of the voice.
It is usually caused by a virus, but in some cases can be acquired through vocal strain without any infectious agent involved.
Acute laryngitis should resolve on its own in up to two weeks.
Bhuyan, G et al. 2017, ‘Bacterial and Viral Pathogen Spectra of Acute Respiratory Infections in Under-5 Children in Hospital Settings in Dhaka City’, PLoS One, vol. 12 no. 3, viewed 6 April 2023, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367831/
Centers for Disease Control and Prevention 2022, People at High Risk For Flu Complications, U.S. Department of Health & Human Services, viewed 6 April 2023, https://www.cdc.gov/flu/highrisk/index.htm