What Is RSV Bronchitis

If you have come across this article, chances are that your infant or young child has fallen ill with a moderate-to-severe respiratory infection. They may have a fever, wheezing, trouble breathing, and other cold symptoms. You may have looked around the internet and found a scary-sounding condition called bronchiolitis, and you might have also seen that it’s usually caused by something called the respiratory syncytial virus (RSV). You have likely read that RSV infection usually resolves on its own, but also that severe RSV infections also occur and can become life-threatening, especially in infants at risk.

But what should be your takeaway from all this information? Should you be worried about your sick child? How can you know that they have severe RSV disease, and if you should contact doctors or even rush to the hospital? We will take a detailed yet easily accessible look into this viral infection and help you to organise the scattered information you have gathered on the internet into a comprehensive framework

What RSV bronchiolitis means is an inflammation of your bronchioles caused by the respiratory syncytial virus (RSV). Bronchioles are part of your smallest airways. Your windpipe branches off into two bronchi which then subsequently branch off into these smaller bronchioles, and these bronchioles connect to the alveoli of your lungs, where your blood gets rid of its carbon dioxide and gets filled with oxygen.

With the definition settled, let’s take a more practical approach into what all of this should mean for you or your child. Children with RSV bronchiolitis often appear very sick, and although this illness frequently resolves on its own despite the dramatic symptoms , a visit to the hospital will often be indicated in most situations because of the slight albeit all too real risk of mortality. We will discuss these cases in greater detail now, and help you get a better understanding of which course to follow when your child presents with lower respiratory tract infection symptoms. 

What is RSV bronchitis?

Signs and symptoms

As discussed, bronchiolitis is the inflammation of the bronchioles, which are narrow tubes. When these structures get inflamed, edema develops in the walls of the bronchioles, narrowing the tube-like structures. This can cause several symptoms. Just as you get a blowing sound as you blow air through a narrow tube (like a flute), air passing through edematous, narrowed bronchioles will produce a characteristic sound. This sound is what’s called wheezing (this narrowing of tubes is the same reason why recurrent wheezing is seen in asthma). Furthermore, since the bronchioles connect to your alveoli, some of the air you inhale won’t be able to reach the alveoli to oxygenate your blood and some of the air you should exhale won’t leave your lungs, leaving your body with an excess of carbon dioxide. As a result, your body tries to increase the total circulation of air to compensate, resulting in rapid breathing and a subjective feeling of trouble breathing. This symptom is called dyspnea.  

As your blood contains excess carbon dioxide and not enough oxygen (called hypoxia), blue-tinged skin, especially on the fingertips and around the mouth can develop, which is called cyanosis. In small infants and premature babies, bronchiolitis can also cause apnea, which is a temporary pause in breathing for several seconds. This, in combination with the often high-grade fever observed in bronchiolitis, could even lead to convulsions. 

But even though RSV infection predominantly affects the bronchioles, it is also a viral upper respiratory infection, which causes signs typical for these illnesses - cold symptoms, a runny nose, persistent coughing, a sore throat, and nasal congestion 

Severe bronchiolitis is usually seen in small infants and children with underlying asthma or immunosuppression. Signs of severe RSV infection include chest retractions (where the skin between the ribs appears to get sucked in with each breath), nasal flaring (where the nostrils appear to dilate with each breath), and most importantly, a child who gets increasingly tired, lethargic and sleepy. The effort required to sustain the deep and rapid breathing that becomes necessary in severe bronchiolitis can be very tiring and exhausting. As a result, the muscles that make you breath can get exhausted and this breathing effort may start to falter. When this happens, the individual will quickly start building up excess carbon dioxide, becoming less alert, tired, lethargic, sleepy, and difficult to arouse, leading to a vicious cycle culminating in the child stopping breathing altogether. This is why the respiratory syncytial virus is the most important identified global cause of infectious death among infants between one month and one year of age, second only to malaria.⁴. Fortunately, even in these cases hospital or intensive care treatment offers excellent results, and the mortality of this disease in developed countries is mostly limited to extremely premature babies with severe chronic illnesses.⁵ 

Causes and risk factors

Respiratory syncytial virus spreads just like the flu and COVID-19 in coughed or sneezed droplets carrying viruses and demonstrates seasonal clumping where RSV activity is at its peaks. If virus particles reach the skin of the hands, an infection can easily occur when the child places their hands into their mouth, nose, or eyes. Adults are commonly asymptomatic if they get the virus, but will easily transmit it to young children. This is why both children and adults who have been near sick children should practice regular hand washing and sick children should be kept away from school or nurseries.⁶ 

RSV is an extremely common virus and almost every person will have been infected with it by three years of age. However, only some children will develop bronchiolitis and some won’t. The reason for this is complex, but the bottom line is that the younger the child is, the more marked the symptoms become. Children older than two years of age almost never develop bronchiolitis, but are nonetheless very commonly infected with RSV. These children will usually present with bronchitis, and as they get older the common cold will be the most common presentation. As adults get old and become frailer, RSV becomes an increasingly important cause of viral pneumonia, especially in individuals with asthma, chronic lung disease, or heart failure. RSV infection importantly does not confer any significant immunity, so children will almost certainly get reinfection, though reinfections almost never present as bronchiolitis.⁷

Diagnosis

Bronchiolitis is a clinical diagnosis. This means that a diagnosis is made based on symptoms and signs. A detailed history and physical examination are usually adequate for a correct diagnosis and an x-ray or blood test will not be necessary unless a severe disease is suspected.

Although there are specialized tests that can determine which type of virus is the culprit (such as swabs taken from the nose or blood tests sent for PCR), these are not necessary and are very rarely performed. One reason to do these tests is if a bacterial infection is strongly suspected and antibiotics are considered. Another reason is determining if bronchiolitis is a symptom of COVID-19.

Who is at risk

Every infant, child and adult is at risk of RSV infection. However, only small children (and rarely immunosuppressed adults) are at risk of RSV bronchiolitis. Older children may develop bronchitis and adults usually only develop common colds. It’s important to note, however, that older adults with underlying heart or lung diseases (such as COPD or heart failure) may develop RSV pneumonia and RSV can be an important trigger for asthma attacks in any age group with asthma. 

Treatment and prevention

Treatment of RSV infection is dependent on age, health status, and disease severity. The treatment of bronchiolitis will be discussed in more detail here. Treatment for bronchiolitis is supportive, which means treating the symptoms until the body fights off the infection itself since there is no specific cure. This doesn’t mean that the child should not be evaluated. Contrary to upper respiratory infections, bronchiolitis symptoms are commonly severe and bronchiolitis can even prove deadly. This is why any infant or child with new onset dyspnea, chest retractions, or even mild wheezing, especially if they become tired or lethargic, should be reviewed and you should promptly seek care. Around 3% of children (and even more among infants) will require hospital admission with monitoring, IV fluids, and sometimes feeding tubes if the child refuses to eat or can’t eat due to rapid and labored breathing. Oxygen supplementation may be necessary if the bronchioles are severely inflamed, and if breathing effort becomes too exhausted and the child is deteriorating, intubation and mechanical ventilation in an intensive care setting might be necessary.⁸

Preventive measures against RSV infection include regular disease control. This means isolating sick children, practicing hand-washing, and wearing masks where necessary.⁹ Despite all these measures, RSV infection is very difficult to fully prevent. This is where the medicine Palivizumab (Trademark Synagis in the UK) comes into play. Palivizumab is a medicine administered to very high-risk children (premature babies with severe heart, lung, or immunological disorders or those with chronic respiratory disease) that does not prevent RSV infection, but very effectively prevents severe disease and hospitalizations. It is not a vaccine, but can be thought of as working like one. If your baby is at very high risk for RSV infections, your doctor will discuss palivizumab administration before discharge.¹⁰ 

When to seek medical attention

It is impossible to tell whether an episode of common cold, bronchitis, or bronchiolitis may be caused by RSV, but any infant or child sick with the telltale signs of lower respiratory tract infection such as wheezing, chest retractions, deep and rapid breathing should be urgently reviewed by a professional. In most cases, supportive treatment at home such as nasal saline irrigation and proper care advice will be adequate and antibiotics or decongestants are usually not necessary, but a medical review is essential. If the infant or child starts to get tired, exhausted, or excessively sleepy, a visit to the accidents and emergency is imperative. 

Summary

RSV illness can take many forms, but bronchiolitis is the most significant type of respiratory illness that you should be aware of when considering RSV. It should not be forgotten that respiratory syncytial virus infection is a significant cause of mortality in young infants, but it is much more often a mild and self-resolving disease despite the presence of dramatic symptoms. Whether your child needs supportive treatment at home or monitoring in a hospital is a decision only your healthcare provider can take.