Influenza: Difference between revisions
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^Shortens symptoms by approximately 1 day if given with symptoms <48 hours<ref>Patel DM, Pitts SR. Should Neuraminidase Inhibitors Be Prescribed for Patients with Influenza? Annals of Emergency Medicine. 63(1) January 2014.</ref> | ^Shortens symptoms by approximately 1 day if given with symptoms <48 hours<ref>Patel DM, Pitts SR. Should Neuraminidase Inhibitors Be Prescribed for Patients with Influenza? Annals of Emergency Medicine. 63(1) January 2014.</ref> | ||
{| class="wikitable" | |||
| align="center" style="background:#f0f0f0;"|'''Antiviral Agent''' | |||
| align="center" style="background:#f0f0f0;"|'''Recommended For''' | |||
| align="center" style="background:#f0f0f0;"|'''Not Recommended With''' | |||
| align="center" style="background:#f0f0f0;"|'''Adverse Events''' | |||
|- | |||
| Oseltamivir (Tamiflu®) | |||
|| | |||
*Treatment: any age | |||
*Prophylaxis: >3 months | |||
||N/A | |||
|| | |||
*Adverse events: nausea, vomiting. Sporadic, transient neuropsychiatric events (self-injury or delirium) mainly reported among Japanese adolescents and adults. | |||
|- | |||
| Zanamivir (Relenza®) | |||
|| | |||
*Treatment: >7 yrs | |||
*Prophylaxis >5 years | |||
||Underlying respiratory disease (e.g., asthma, COPD) | |||
|| | |||
*Allergic reactions: oropharyngeal or facial edema. | |||
*Adverse events: diarrhea, nausea, sinusitis, nasal signs and symptoms, bronchitis, cough, headache, dizziness, and ear, nose and throat infections. | |||
|} | |||
===[[Isolation Precautions]]=== | ===[[Isolation Precautions]]=== |
Revision as of 22:12, 12 December 2014
Background
- Transmission
- Occurs in 6ft radius around infected pt who is sneezing and/or coughing
- Viral shedding lasts ~5d (starts 24-48hr before onset of symptoms)
- Longer duration of shedding occurs in children, elderly, pts w/ chronic illnesses
- Shedding from asymptomatic individuals doesn't contribute significantly to transmission
- Convalescence
- Most pts gradually improve over 2-5d, although may last for one week or more
- Some pts have persistent weakness lasting several weeks (postinfluenza asthenia)
Clinical Features
- Constitutional
- Respiratory
- Non-productive cough
- Sore throat
- Rhinorrhea
Diagnosis
- Influenza PCR preferred for inpatients (sensitivity >95%)
- RSV/Flu/metapneumovirus test low sensitivity for adults (48-60%) and children (62-72%), with turnaround time <24 hours
- The Viral Respiratory Panel (influenza, RSV, adenovirus, parainfluenzavirus) discouraged (sensitive 70-90%) with 3-5 days turnaround
- Rapid tests specific but not sensitive (cannot be used to rule-out)
Treatment
Outpatients
- Risk factors:
- Yes
- Do NOT send Point of Care influenza test
- Do NOT send diagnostic test for influenza
- Empirically treat for influenza using antivirals if symptoms for <48 hours
- No
- Do NOT send Point of Care influenza test.
- Do NOT send diagnostic test for influenza.
- May consider treating with anti-influenza antivirals is symptoms <48 hours
- Yes
Risk Factors
- age <2 years or >65 years
- pregnancy
- chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, hematological (including sickle cell disease), neurologic, neuromuscular, or metabolic disorders (including diabetes mellitus)
- immunosuppression, including that caused by medications or by HIV
- persons younger than 19 years of age who are receiving long-term aspirin therapy
Admitted Patients
- Do not send Point of Care influenza test
- Send diagnostic test for influenza
- Influenza PCR preferred for inpatients (see Diagnosis section)
- Empirically treat for influenza using antivirals
- Most effective when administered when symptoms of influenza have occurred for < 48 hours
- May be benefit when initiated in severely ill inpatients with 48 hours to 5 days of symptoms
- No evidence of benefit after 5 days of symptoms
- Treat empirically promptly with oseltamavir unless there is an alternative diagnosis
- Droplet precautions (see below)
Medications
- Antiviral agents (neuraminidase inhibitors)^
- Oseltamivir 75mg PO BID x5d
- Zanamivir 10mg (2 inhalations) BID x5d
- Relatively contraindicated in pts w/ asthma, COPD, or pregnancy
^Shortens symptoms by approximately 1 day if given with symptoms <48 hours[1]
Antiviral Agent | Recommended For | Not Recommended With | Adverse Events |
Oseltamivir (Tamiflu®) |
|
N/A |
|
Zanamivir (Relenza®) |
|
Underlying respiratory disease (e.g., asthma, COPD) |
|
Isolation Precautions
- Droplet precautions
- If the patient is in an area in which they are in contact with other patients or need to be transported and thus may come in close contact (<3 feet) with staff, visitors, or other patients, the patient needs to wear a surgical mask (or N-95 respirator, if not available).
Complications
- Pneumonia
- Primary influenza PNA
- Most severe and least common type of PNA
- Rare in otherwise healthy adults
- Consider in pts w/ persistent and worsening symptoms (esp high fever, SOB, cyanosis)
- CXR shows b/l opacities w/ or w/o superimposed consolidation
- Secondary bacterial PNA
- Exacerbation of fever and respiratory symptoms after initial improvement
- Higher fever, productive cough, radiographic evidence of infiltrates
- Microbiology
- Pneumococcus, S. aureus (including MRSA), H. flu
- Exacerbation of fever and respiratory symptoms after initial improvement
- Primary influenza PNA
- Otitis Media
- More common in children
- Myositis and rhabdo
- More common in children
- Extreme tenderness of affected muscles (most commonly in the legs)
- Pericarditis/myocarditis
- Rare complication
See Also
Source
UpToDate
- ↑ Patel DM, Pitts SR. Should Neuraminidase Inhibitors Be Prescribed for Patients with Influenza? Annals of Emergency Medicine. 63(1) January 2014.