Respiratory Syncytial Virus - How to prevent my severity?

How can I help prevent the spread of RSV?

RSV is spread by coming in close contact with an infected person and the droplets produced when the person coughs or sneezes.  Careful hand washing with soap and warm water is the best way to prevent the spread of RSV. 

Palivizumab (brand name Synagis) is a monoclonal antibody produced by recombinant DNA technology. It is used in the prevention of respiratory syncytial virus (RSV) infections. It is recommended for infants that are high-risk because of prematurity or other medical problems such as congenital heart disease.

Palivizumab is a humanized monoclonal antibody (IgG) directed against an epitope in the A antigenic site of the F protein of RSV. Palivizumab reduced the risk of hospitalization due to RSV infection by 55%. Palivizumab is dosed once a month via intramuscular (IM) injection, to be administered throughout the duration of the RSV season.

Palivizumab targets the fusion protein of RSV, inhibiting its entry into the cell and thereby preventing infection.

The American Academy of Pediatrics (AAP) has published recommendations for the use of palivizumab. Updated AAP recommendations were published in 2009. Palivizumab  is used only for prevention, not for treatment, and once initiated for a given RSV season (usually November–March), it should be continued for the full duration of that season.

Reasons to consider palivizumab prophylaxis include:

Prematurity

• ≤ 28 weeks gestation and < 12 months of age at the start of RSV season
• 29-32 weeks gestation and < 6 months of age at the start of RSV season
• 32-35 weeks gestation and < 3 months of age at the start of RSV season, if there is a risk factor (child care attendance or sibling younger than 5 years old)

Chronic lung disease of prematurity

• Chronic lung disease still requiring oxygen/medication, for the first and second RSV seasons
• Chronic lung disease that required oxygen/medication within the 6 months preceding RSV season, for the first RSV season

Congenital heart disease

• Cyanotic heart disease, for the first 24 months of life
• Moderate to severe pulmonary hypertension, for the first 24 months of life
• Congestive heart failure requiring medication, for the first 24 months of life
• Children who have undergone open heart surgery during RSV season, for one additional dose after cardiopulmonary bypass (only if they still meet one of the other criteria)

Other conditions where prophylaxis might be considered but inadequate data is available:

• Immunocompromise
• Cystic fibrosis

Of note, a course of palivizumab is quite expensive, and the above recommendations were written based on estimates of its overall cost-effectiveness for preventing severe RSV disease.

Who am I and why should you be scared of me now?

I am a very common virus that leads to mild, cold-like symptoms in adults and older healthy children. But I am bad with young babies. Most infants have been infected by me before their second birthday.
I love the season from October to Spring (my season!)

More severe  disease with me may occur in the following infants:

• Premature infants
• Infants with chronic lung disease
• Immunodeficient infants
• Infants with heart disease

The following increase the risk for being affected by me:

• Day care
• Tobacco smoke
• Having school-aged brothers or sisters
• Crowded conditions
  
  
  You get to know about me 4 - 6 days after coming in contact with me.
  Antibiotics cannot make me go away
  If am nice (mild) I go away without treatment.
  Infants and children with a severe infection with me will be in the intensive care unit. Treatment will include:
  • Oxygen ( may need a ventilator)
  • humidified air
  • IV fluids
  
  I AM Respiratory Syncytial Virus
  Belonging to the Paramyxoviridae, I am virus in an enveloped, spherical, negative-strand RNA virus measuring 120-300 nm
  
  
  Diagnosis: You can find me by a direct immunofluorescence test for RSV antigen , and is reported to be 90% sensitive as compared to culture. RSV antigen may appear in the cytoplasm of cells within 8 hours of infection. Viral culture is performed in conjunction with the antigen test. The only acceptable specimen to detect me is a nasopharyngeal aspirate collected in viral transport media.
  Tomorrow I will tell you how to avoid me!!
  Source of picture and some text: http://pathology5.pathology.jhmi.edu/micro/v20n47.htm
  
  

Silly Broncodilators - can they cause hypoxia?

Fall in Arterial Oxygen Pressure

A fall in arterial oxygen pressure (PaO2) has been noted with isoproterenol administration during asthmatic bronchospasm, as ventilation improves and the exacerbation is relieved. 

The same effect has subsequently been noted with newer beta agonists such as albuterol and salmeterol. The mechanism for this seems to be an increase in perfusion of poorly ventilated portions of the lung. 

It is known that regional alveolar hypoxia produces regional pulmonary vasoconstriction in an effort to shunt perfusion to lung areas of higher oxygen tension. 

Administration of inhaled beta agonists may reverse hypoxic pulmonary vasoconstriction by beta 2 stimulation, increasing perfusion to underventilated lung regions. 

Preferential delivery of the inhaled aerosol to better ventilated lung regions increases the ventilation-perfusion mismatch. Oxygen tension falls most in subjects with the highest initial PaO2. Decreases in PaO2 rarely exceed 10 mmHg, and the PaO2 values tend to be on the flat portion of the oxyhemoglobin curve, so that drops in arterial oxygen saturation (SaO2) are minimized. Oxygen tensions usually return to baseline within 30 minutes.

Source: http://www.allbusiness.com/pharmaceuticals-biotechnology/pharmaceutical/14173501-1.html#ixzz1njbKDcNh

 Courtesy Source: http://www.ed4nurses.com/breathsnds.aspx?print=Y :