Overview

Croup, a respiratory condition, leads to inflammation of the upper airway that includes the larynx (voice box), trachea (windpipe), and bronchi tubes and consequents obstruction that manifests as breathing difficulties.¹ Croup mostly affects young children that are less than six years. The airway obstruction reduces the space available for air to enter the lungs and produces the characteristic symptoms such as barking cough that develops suddenly at night, inhalatory stridor (a high-pitched noisy breathing), hoarseness, mild/severe respiratory difficulties, with or without low grade fever (99 to 101⁰ F [ 37.3 to 38.3⁰]).¹³ 

Croup is experienced by approximately 3% of children per year, typically between the ages of 6 months and three years. The frequency in boys is higher than in girls with a 5:1 ratio. Approximately 85% of cases are defined as mild croup, and less than 1% are considered severe croup.

The breathing difficulties may worsen at night. Retractions (sucking in of the skin around the ribs and the sternum) have also been reported.^1,13

The timing of croup development often coincides with the presence of viral infections, most commonly the parainfluenza virus. Other causes of viral croup include respiratory syncytial virus, influenza A and B, rhinovirus (common cold virus), enterovirus, and adenovirus.¹ 

Most recently, croup-like symptoms have been observed with COVID-19 infection due to SARS-CoV-2.³ Patients may express other signs of viral illness depending on the viral aetiology. Dehydration can also be present if a child is not able to drink enough fluids.¹³

Spasmodic croup on the other hand, develops suddenly due to allergy or reflux from the stomach without a viral illness.² Croup is usually self-limited, resolving within three days but cough may continue up to one week. There are more cases of croup during the fall and early winter months.

Croup in healthcare settings

Croup patients are often seen by the general practitioner, paediatrician, nurse practitioner, or in the emergency departments hence, there exists close interaction of health care workers (HCWs) and affected individuals. When an infected individual coughs or sneezes, the virus-rich respiratory droplets are expelled into the air and consequently inhaled by others nearby, including HCWs and patients.^3,4 Croup is transmissible for three days during which the symptoms peak. 

Additionally, by touching contaminated fomite surfaces patients and healthcare workers can introduce the virus into their respiratory tracts when they touch their faces with infected hands.⁵ In the context of the COVID-19 pandemic, the emergence of SARS-CoV-2 as a causative agent of croup has further complicated transmission dynamics. Hospitalisation may be required in the 5 to 10% of croup cases seen in the emergency department. The purpose of hospitalisation may be for observation for only a few hours to half a day. 

Control measures to prevent croup transmission in healthcare settings

Implementing effective infection control measures is crucial to stall transmission and protect individuals in healthcare settings. Healthcare facilities management should develop, maintain, and enforce strict adherence to standard infection control precautions such as good hand hygiene, the use of personal protective equipment (PPE), and rigorous environmental cleaning. Standard infection control measures are:

Good hand hygiene 

Frequent hand washing with soap and water or alcohol-based hand sanitisers, and careful handwashing requires rubbing hands with antimicrobial soap for about 30 seconds, while also paying attention to the fingernails and wrists. Hands should then be rinsed and dried with a single-use paper towel. Also, thorough handwashing before and after patient contact has been shown to reduce the risk of pathogen transmission significantly.^6,7

Health education

Patients and healthcare workers should be instructed about covering coughs and sneezes, proper disposal of tissues and medical waste. Continuous education and training for healthcare workers regarding the transmission dynamics of respiratory viruses and the importance of infection control measures are vital. This includes training on recognising symptoms of croup and other respiratory infections, as well as understanding the protocols for managing these patients.^6,7

Use of personal protective equipment (PPE)

The appropriate use of PPE, such as gloves, scrubs, hospital gowns, N95 respirator masks and eye protection, is crucial in preventing the spread of respiratory viruses. Masks can help block respiratory droplets that may carry the virus, while eye protection can prevent ocular transmission.⁸ In particular, during outbreaks or when caring for patients with suspected or confirmed respiratory infections, the use of surgical masks by healthcare workers can reduce the risk of transmission.^6,9 

Isolation of infected patients

Patients diagnosed with croup or exhibiting symptoms of upper respiratory infections should be isolated from other patients, especially in pediatric wards. This can help prevent the spread of the virus to other vulnerable patients. Patient management and isolation practices include:^6,7

• Cohorting patients: grouping confirmed croup patients together to limit the spread to other wards 
• Placing infected individuals in single rooms to prevent cross-contamination

Visitor restrictions and guidelines

Limiting visitors access to patients with croup and ensuring visitors follow proper infection control protocols. Guidelines should be established for visitors, including the use of masks and good hand hygiene practices before and after visiting patients.¹⁰

Patient and family education

Promoting awareness of croup transmission by educating patients and families on croup symptoms and how the virus spreads. Good hand hygiene, disinfection of shared surfaces, and isolation should be practised at home for children with croup.

Environmental control

High-touch surfaces should be prioritized for cleaning, especially in areas where patients with respiratory infections are treated. Protocols must be established like:

• Surface disinfection by using EPA-approved disinfectants against respiratory viruses
• Regular cleaning of doorknobs, medical equipments, and bed rails.
• Proper ventilation systems to reduce viral load in the air
• Using negative pressure rooms for high-risk patients to contain respiratory droplets
• Equipment sterilization : ensuring that all medical equipments, especially respiratory tools (e.g.nebulizers), are properly sterilized between uses

Vaccination and boosting of immunity

Parents should ensure that their children's vaccinations are up to date. Currently, there is no specific vaccine for croup, but innoculation against common respiratory viruses, such as influenza and diphtheria can help to reduce the occurrence of croup infections. Public health campaigns to promote vaccination and awareness of respiratory hygiene can also play a role in preventing outbreaks in healthcare settings.⁶ HCWs are encouraged to get flu vaccine in order to prevent influenza-related croup cases and they should monitor themselves for symptoms. Establishing a healthy diet, getting enough sleep as well as regular exercise also aid in boosting immunity.

Avoid smokinG

Smoking has been shown to irritate the airways and make them more prone to infections. Healthcare settings should ensure a smoke-free environment.

Post-exposure management and surveillance

protocols for managing exposure such as surveillance and reporting systems, to track croup cases and forestall potential outbreaks within the healthcare setting.

Challenges in the prevention of croup transmission 

The delay in diagnosis due to overlapping symptoms with other respiratory illnesses (e.g.,flu and RSV) may weaken the control measures and slow down isolation of infected individuals. In healthcare settings, the resources are limited and compliance with infection control practices is often compromised. Secondary bacterial infections, such as bacterial pneumonia and bacterial tracheitis are significant concerns that can complicate the course of croup prevention and management. Additionally, the seasonal spikes (during fall and winter) in croup cases can overwhelm healthcare systems. The need for rapid testing and effective triage becomes paramount during these peak periods to manage patient flow and minimise the risk of cross-infection .³.

How is croup managed?

Pharmacological and supportive treatment of croup focuses on alleviating the symptoms and preventing complications. Supportive care such as hydration, rest, and the use of humidifiers to ease breathing discomfort play vital roles in managing symptoms for mild croup at home. If symptoms persist, medical treatment may be necessary for moderate to severe croup. The Wesley croup score is used to determine severity. 

Established treatment options for croup primarily involve glucocorticoids, particularly dexamethasone for a Wesley croup score of less than 2 and nebulized epinephrine for more severe cases with scores greater than 3. In life threatening situations, patients may need repeated doses of nebulised epinephrine or even oxygen therapy.^11,12 Moderate to severe cases require up to 4 hours of observation, and if the symptoms do not improve, admission is required. 

Medicines used in treating allergy or reflux conditions are also used in treating spasmodic croup. 

Summary

Croup is a viral infection that can be acquired primarily via respiratory droplets (coughing/ sneezing) of an infected person, and through fomite transmission from contaminated surfaces. Young children are more prone to croup as well as immunocompromised individuals. In healthcare settings, infected patients, HCWs, and contaminated surfaces are potential mechanisms of spread. Hence, preventing the transmission of croup in healthcare settings involves a multifaceted approach that includes strict adherence to standard precautions, hygiene practices, the use of PPE, patient isolation and management using the appropriate standard of care, health education and continual staff training, environmental infection control measures, and commitment to ongoing vigilance to mitigate transmission risks.