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rsv

January 23 2022

Respiratory Syncytial Virus

PME-Admin article, medical children, infants, pediatrics, respiratory, respiratory syncytial virus, rsv, single-strand RNA virus, virus

Respiratory Syncytial Virus — Santa J. Bartholomew M.D.

Respiratory Syncytial Virus (RSV) is a single stranded RNA virus that attacks the respiratory system in people of all ages but is particularly dangerous in the very old and very young. It typically causes seasonal outbreaks of disease from October to April. In the past year with COVID precautions (mask wearing, school closures and physical distancing) there were marked reductions in other respiratory viruses including RSV. RSV is the most common virus causing lower respiratory tract disease (pneumonia) in children under 12 months of age.

Hospitalization rates are 4.4/1000 children and are highest in the under 6-month-old population (20/1000 children). Although severe RSV disease is seen mostly in younger infants it can also be seen in the neurologically debilitated and in immunocompromised children in its severest forms.

RSV is an important cause of death in infants and young children estimated at 2.3% mortality in neonates, 6.7% in infants up to a year old. It has been estimated to have caused more deaths in infants and children worldwide than any other infectious agent except for malaria. In the USA mortality rates are estimated at 3.1/100,000 person years in children under a year of age.

RSV has been estimated to have caused more deaths in infants and children worldwide than any other infectious agent except for malaria.

RISK FACTORS FOR GETTING RSV

Infant less than 6 months old born in RSV season
Infants attending daycare or who have older siblings attending daycare
Infants with lung disease like BPD (bronchopulmonary dysplasia)or cystic fibrosis.
Infants born < 35 weeks gestation
Infants and children with congenital heart disease
Infants exposed to secondhand smoke.
HIV exposed, uninfected infants
Children with trisomy 21 (Down’s syndrome)
Children that are immunocompromised (SCID, cancers, transplant patients)
Children with persistent asthma
Children under 5 years old who are socially vulnerable (young maternal age, no heat or running water in home, no electric in home, parents with psychiatric disease)

TRANSMISSION + INCUBATION

RSV is typically transmitted by direct contact. It can survive for several hours on hands, toys and other surfaces. So if those become the repository for mucous infected with RSV it is easy to pass to another child via sharing of utensils, bottles, pacifiers, toys or simply touching these infected items.
Most infected people shed virus for 11 days however young infants can she for up to 4-6 weeks.
The virus incubates in its new host for 4-6 days before causing signs or symptoms of disease.
By 2 years of age virtually all individuals have been infected with RSV but unfortunately that does not prevent reinfections or provide substantial immunity.

PATHOGENESIS

After exposure the virus reproduces (replicates) in the nose and throat in the small bronchiolar epithelial cells.
It spreads via secretions to the lower lung and by 1-3 days after exposure can begin to cause lower lung symptoms: cough, increased breathing rate, struggling with breathing.
It causes a vigorous immune response which can cause further debris in the airways along with bronchoconstriction and this can lead to wheezing that is typically unresponsive to therapy with beta-agonists like Albuterol.
RSV is highly restricted to the lung. It only very rarely causes disease outside the lung. These extrapulmonary places are typically: liver, spinal fluid and pericardial fluid.

CLINICAL FEATURES

Fast breathing
Bronchospasm
Poor feeding
Fever
Runny nose, congestion and cough
Some children with severe disease present with abnormal electrolytes specifically sodium.
APNEA in infants is not uncommon

DIAGNOSIS + TREATMENT

CLINICAL SUSPICION

There are now PCR based tests for RSV as well as many other viruses that cause disease in children. These are most helpful in advising families about the course of disease as to date there are no treatments for RSV or most other winter viruses.

DIFFERENTIAL DIAGNOSIS

Other winter viruses: human metapneumovirus, adenovirus, rhino/enterovirus
Bacterial pneumonia
Wheezing without infection

TREATMENT

Supportive (Suctioning, IVF if child cannot eat, Oxygen)

PROGNOSIS

Disease if often self-limited and mortality in USA is low (0.1% in infants), mortality is higher in low-birth-weight premature infants and those with underlying heart disease or pre-existing pulmonary disease. Deaths in these circumstances are often caused by complications of disease such as bacterial superinfections with respiratory failure and not the primary viral disease.

Thirty percent of infants previously diagnosed with RSV will have wheezing beyond the course of their disease that can last many months. Some infants have experienced prolonged loss of voice or hoarseness of voice, difficulty feeding.

Overall, most infants and children recover and go on to live healthy normal lives.

Disclaimer: This web site provides general information about pediatric health and related subjects. The information and other content provided on this website or in any linked materials are not intended and should not be considered, or used as a substitute for, medical advice, diagnosis or treatment. Never disregard professional medical advice or delay in seeking it because of something that you have read on this website or in any linked materials.

October 31 2021

RSV and HMPV in Infants and Children

PME-Admin article, medical breathing issues, children, hmpv, infants, pediatrics, rsv

RSV and HMPV in Infants and Children — Santa J. Bartholomew M.D.

Winter is the time for viral season in infants and children. Many of the winter viruses are spread by droplet and secretions making them very transmissible from toddlers to infants and each other as well as their adult caretakers. Since toddlers are at a developmental age of still sharing toys, drinks and germs – diseases such as respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) are very common in hospitals and outpatient offices in the fall through early spring.

These viruses have no primary treatment like a bacterial pneumonia or infection might but can cause severe lung disease none-the-less and make children vulnerable for bacterial disease as the lining of the lung is injured by the inflammatory response that these viruses incite in the body. Many older children and toddlers display these diseases as just a “very bad cold”: fever, runny nose, coughing and sneezing, poor appetite. Slowly in 7-10 days these symptoms abate, and the child begins to feel better and slowly returns to normal the beginning of week two.

ASSESSING RISK

Pediatricians are tasked during the winter months when assessing these children in assessing risk. The natural history of both viruses is the same. Those infected HMPV tend to be slightly more at risk of being super-infected with bacterial disease like Staphylococcus Aureus or Streptococcus pneumoniae pneumonia’s than those primarily infected with RSV but the natural course of disease is essentially the same. So, what makes these diseases deadly?

Newborns and preterm newborns are obligate nose-breathers so if they become congested with mucous and secretions, they can become very distressed.

RISK FACTORS

If the disease infected healthy people age 5 to 30 years old and that was all, everyone would get a cold and then get better in 7-10 days. But 5 years olds live with older siblings who may have asthma or cancer or an immune disease, their families may have a newborn infant, or a preterm infant recently discharged from the NICU. These children have different risk assessments than the initial toddler: the healthy five-year-old. Pediatricians, ED physicians who see children, pediatric hospitalists in caring for patients with RSV and HMPV are not expected to cure a viral disease without as yet a known cure but to assess risk based on the host (or child) that is infected.

Newborns and preterm newborns are obligate nose-breathers so if they become congested with mucous and secretions, they can become very distressed, sometimes turn blue or have great difficulty breathing and eating. They can sometimes have periods of apnea as a response to their disease. These children are often admitted to the hospital for care, they are placed on monitors looking for apnea or for periods of low oxygen levels that may need to be supplemented so as not to injure their developing brain. Because their noses are blocked with secretions they often will not feed and are greater risk for dehydration and the things that may follow this such as hypovolemic shock and kidney failure. The physician in this circumstance is not called upon to cure these children’s virus but to anticipate the child’s response based on age and health and then determine where and how they are best cared for based on available literature and experience.

As newborns are more likely to be admitted to the hospital with RSV and HMPV children 5-10 years old are more likely to be sent home with instructions for supportive care. However, a 5-year-old asthmatic who has a history of being on a mechanical ventilator in the past who now presents, with HMPV who has breathing difficulty to the ED, is at risk of developing a severe asthma attack as the inflammation from the virus progresses. This 5-year-old may be best treated for the peak of his or her disease in the hospital.

A child undergoing chemotherapy who has very few white cells would be a child best cared for by seeing their doctor daily or being in the hospitalized until it is clear they will not be super-infected with a bacterial which could easily lead to their death.

So, winters are difficulty times of doctors who care for infants and children. Viruses and risk abound and they must make savvy, wise decisions often with limited information and quickly as offices and ED’s become overwhelmed with sick infants and children. But good risk assessment is a must!! Careful questioning about other breathing diseases, heart disease, immune diseases, previous hospitalizations, other illnesses. These few extra minutes to gather in the information to make a good risk assessment may save a child’s life.