IDBR - Respiratory Viral infections Flashcards
Describe the types of Influenza virus?
Flu A, B, C. Flu A: 16 HA types, 9N types, responsible for seasonal drift. Huge reservoir in fowl Causes disease in poultry Point Mutations in neuraminidase lead to resistance to NAIs
Minor complications of Influenza?
- Croup
- Bronchiolitis
- Asthma exacerbation
- OM
- Sinusitis/parotitis
Groups at risk for complications of Influenza?
45 y/o with CC: fever, diarrhea, myalgia, sore throat, and dyspnea. Hypotensive and hypoxemic. CBC shows mild leukopenia, everything else normal. 3 days prior he was inspecting poultry operations in Jiangsu, China.
- H1N1?
- H3N2
- H5N1
- H7N9?
- Influenza B?
H7N9
Name the influenza A viruses that infects human
Basics of H7N9?
- Avian to human transmission
- some intrinsic and some emergent oseltamivir resistance
- 22% case fatality
basics of seasonal influenza transmission?
5 days ago (january), healthy 25 year old female developed fever, myalgia, sore throat, and malaise, dx with influenza with slow improvement. 16 hours ago, she becomes hypotensive, diarrhea, abdominal pain, with a diffuse erythematous rash.
On exam, slow to respond, diffuse, rales, mild non-focal abdominal tenderness. CXR diffuse infiltrates, WBC 5500 (60% poly,30% bands). Platelets 40K, creatinine 1.9, AST and ALT 2x normal, with normal ammonia level. Erythoderma on exam.
What is the most likely cause of this influenza complication?
- Reyes syndrome
- Staph aureus pneumonia with TSS
- GN sepsis with ARDS
- Pneumococcal meningitis
- Viral encephalitis
Staph Aureus with Toxic Shock Syndrome
what are the severe complications of influenza?
18 yo HS student with F/C/cough, myalgia in January. Given azithromycin, rest, NSAIDs, but fever, cough, continue becomes progressively dyspneic and weak. T39, P150, RR24-30, BP 120/50. Crackles throughout base and an S3 gallop. Influenza PCR positive. WBC 9K, creatinine 1.9, BNP high, CXR shows diffuse b/l infiltrates and cardiomegaly. Requires V-A ECMO.
What is the most likely cause of this influenza complication?
- pneumococcal PNA
- Staph aureus pneumonia w/purulent pericarditis
- Influenza cardiomyopathy
- MIS-C due to recent COVID infection
- Viral pericarditis with effusion
- PE due to hypercoaguable state
influenza cardiomyopathy
what are the non-respiratory complications of influenza?
20 year old woman s/p 18 days from HSCT in january, engrafted 3 days ago. Develops fever, hypoxemia, b/l lung infiltrates, and requires intubation. Nasal swab is negative by rapid test for influenza. Which of the following is the next best action?
- Do not initiate anti-influenza therapy due to rapid test. The timing suggests idiopathic pulmonary syndrome (engraftment)
- Initiate anti-influenza therapy empirically and send tracheal aspirate/BAL for influenza PCR?
- Send IgG and IgM for influenza
- Send RSV EIA and initiate empiric IV ribavirin
initiate anti-influenza therapy empirically and send tracheal aspirate or BAL for influenza PCR
how do you make the diagnosis of influenza? serology?
clinical dx as good as rapid PCR in high peak seasons!
influenza in transplant patients pearls?
32 y/o nurse, 34 weeks pregnant, during influenza season. Gets symptoms, seen at urgent care where rapid test positive, and given Azithromycin. 72 hours later, gets fever, tachypnea, decreased UO with CXR showing bl hazy infiltrates. She’s hospitalized.
what is the correct statement?
- she should get supportive care only since >48 hours
- Oseltamivir is relatively CI in pregnancy
- Zanamaivr is clearly preferred b/c of low systemic absorption
- Oseltamivir should be started ASAP
Oseltamavir should be started ASAP
what are the recommended medications for influenza treatment? prophylaxis?
- oseltamivir, zanamivir, baloxavir
- Empiric treatment for pregnant women and up to 2 weeks postpartum
- duration 5 days
- initiating tx within 2 days of symptoms results in M&M reduction
- Pregnancy should not be CI to oral oseltamivir or zanamivir use