Influenza Flashcards
What is the most dangerous Influenza Virus?
Type A
What are the Type A subtypes?
Hemagglutinins H1, H2, H3 Neuraminidases N1, N2
How is influenza transmitted?
Air Droplets
When are the seasonal outbreaks of Influenza?
Winter time: Jan-Feb
What are the symptoms of Influenza that separate it from the common cold?
- Abrupt onset - Fever - Myalgias - Severe Cough - Photophobia
Influenza Physical Exam Findings
Relatively Benign ( does not seem like a big deal) - Flushing due to fever - Hot & dry skin - Red mucus membranes
How to decide between a FLU vs COLD pt: “FACTS”
Fever Aches Chills Tiredness Sudden Onset
How do we diagnose Influenza?
Rapid Influenza Diagnostic Tests aka Rapid Antigen Test.
Rapid Influenza Diagnostic Test aka Rapid Antigen Tests (RAT) has a low ______________
sensitivity low sensitivity = a negative test does not rule influenza out
Rapid Molecular Assay is used in the __________ setting
Hospital setting: can identify the H and M proteins of the influenza. They are more accurate but take too long and too expensive.
What kind of swab do patients need for the RAT?
nasopharyngeal swab
When would you do diagnostic tests for the patient?
- If you can’t identify what the patient has from the history and physical exam. - If you can’t decide whether you want to treat the patient with antivirals or not - Institutionalized patients in nursing homes who may spread it and cause harm to other patients
Additional Diagnostics
- CBC - BMP: dehydration and electrolytes - Pulse Oximetry: difficulty breathing - CXR: flu vs. pneumonia (rule out pneumonia)
Populations you want to treat with antivirals
- illness requiring hospitalization
- not hospitalized but very severe and complicated illness
- high risk for complications
High Risk Groups that require antiviral treatment
- Extremes of age: under 2 years old and over 65 years old
- Chronic illnesses: cardiac and pulmonary dz or diabetes
- Immunosuppression
- Pregnancy or post-partum (2 wks)
- Children <19 y/o on chronic Aspirin therapy: @ risk of Reyers Syndrome (affects liver + brain) because they have high fever + aspirin
- American Indians and Alaskan Natives
- Morbidly obese BMI greater than or equal to 40
- Residents of nursing homes, chronic care facilities
Antiviral Medication you would prescribe
Neuraminidase Inhibitors for Influenza A/B Oseltamivir (most common) Zanamivir Peramivir (IV only- seen in hospital settings)
How do Neuraminidases work?
Decreases and inhibits further spread to the additional cells in the body. Does not kill the virus.
When do you need to give Neuraminidase for it to have its greatest benefit?
Within the first 24-48 hours
What are the benefits of Neuraminidase?
Decreases the course and severity a bit
Adverse effects of Oseltamivir (Tamiflu)
- Nausea and Vomiting - Reports of neuropsych symptoms in peds (fever causes hallucinations, agitation)
Adverse effects of Zanamivir (Relenza)
- bronchospasm - decreased respiratory function
Most common complication of Influenza
Pneumonia
Who should get vaccinated and when?
Everyone over the age of 6 months in October
How is the live virus vaccine administered?
nasal spray
Which populations should we be cautious with in regards to giving the live vaccine?
- Pregnant women - Immunocompromised - Eldery - The very young
How many doses do the pediatric population (6mo- 8yrs) need to get of the Flu Vaccine?
2 doses that must be 4 weeks apart 1st time: primes immune system 2nd time: immunity develops
Can patients with a regular egg allergies receive the influenza vaccine? Do they need to be monitored afterwards?
The advisory committee on Immunization Practices says they can receive the vaccine and DO NOT need 30 mins of monitoring after the vaccine.
Can patients with a severe egg allergy receive the influenza vaccine?
Yes. They must be vaccinated in a medical setting and be supervised by a health care provider who is able to recognize and manage severe allergic conditions.
Contraindications to Influenza Vaccine?
Hx of severe allergic reaction to any component of the vaccine or after previous dose of any influenza vaccine.
What are some precautions for the Influenza Vaccine?
- Pt has Moderate-severe acute illness with or without fever - Hx of Guillain-Barre syndrome within 6 weeks of receipt of influenza vaccine
How does the dosage of the Influenza Vaccine differ for adults 65+?
- Give a higher dose vaccine since it is harder for older pts to mount an immune response - Adjuvanted seasonal vaccine for adults 65+
Influenza - Prevention (only do to high risk pts)
Neuraminidase Inhibitors 1. Pre-exposure chemoprophylaxis: Flu is circulating and you have not been exposed but you want to prevent yourself from getting sick. 2. Post-exposure chemoprophylaxis (rare): you do this to patients who don’t have access to the vaccine or there is a shortage of the flu vaccine. You need to vaccinate the patient at the same time of the treatment.
