Download Influenza Physician Update 10/9/09

INFLUENZA UPDATE
For Physicians
October 9, 2009
The purpose of this communication is to clarify current issues regarding influenza testing,
treatment, and infection control. Vaccine-related questions are addressed in other
communications.
Influenza is currently circulating widely, both nationally and locally. At the present time,
essentially all disease is due to novel influenza A (H1N1) or “swine flu” virus. This organism
tends to infect younger and healthier patients than does usual seasonal influenza. Fortunately,
this strain has so far been no more virulent than usual seasonal influenza but is being watched
closely for any evidence of increasing pathogenicity. The groups at increased risk for influenza
A H1N1 complications are similar to those for seasonal influenza:
1) Children under 2,
2) Adults 65 or older,
3) Pregnant women,
4) Persons less than 19 on chronic aspirin,
5) Patients with chronic lung disease (including asthma),
6) Patients with chronic cardiovascular disease (excluding hypertension),
7) Patients with chronic renal or hepatic conditions,
8) Patients with chronic hematologic conditions (including sickle cell disease)
9) Patients with neurologic neuromuscular conditions that compromise
respiratory function or increase risk of aspiration,
10) Patients with chronic metabolic disorders (including diabetes mellitus),
11) Patients with immunosuppression (due to medications or HIV).
Management of influenza is more complicated this year due to the new strain, evolving drug
resistance issues in both novel and seasonal influenza, and increased public fear of influenza.
Recommendations will therefore evolve over time as the influenza season unfolds and
epidemiologic and resistance trends evolve. The CDC and local and state health
departments will be critical sources of information during this time. Both the CDC
(www.cdc.gov/H1N1 or www.flu.gov ) and PA Department of Health (www.H1N1INPA.com)
maintain web sites with updated information and recommendations.
Diagnostic testing for influenza is less than ideal. Viral culture and PCR are the most accurate
tests but are time-consuming, expensive, and/or not widely available. Rapid influenza diagnostic
tests (RIDTs) are antigen detection tests that can be used on nasal or nasopharyngeal specimens
and provide results promptly (30-60 minutes). These tests are widely used in many laboratories
including our own, but are of limited use because of only moderate sensitivity. The test is
specific and is useful to decide if a specimen should be sent to the state laboratory for
confirmation, but its’ sensitivity is 70% at best (and sometimes much lower). In a patient with a
clinical syndrome consistent with influenza in an area with known widespread influenza (i.e.,
here), a negative RIDT is not sufficient to exclude influenza or make decisions regarding
treatment or infection control questions. It is quite possible that the RIDT kits could be in
short supply over this coming season so indiscriminate testing should be avoided. There is no
role for RIDT in surveillance or “screening”.
CDC recently issued updated recommendations for the use of antiviral medications for influenza
treatment and prophylaxis, a copy of which is included. This is a concise document that should
be required reading for all health care professionals involved in management of influenza and is
readily available on the CDC website. A few points deserve comment:
1) Clinical judgment is important in making decisions regarding treatment and
prophylaxis.
2) Oseltamivir and zanamavir are the presently recommended agents.
3) Treatment is indicated for persons with suspected or confirmed influenza who
are sicker or are at increased risk of complications. Most patients will not
require therapy.
4) Treatment should be initiated early in disease for those at increased risk of
complications.
5) The decision to treat is a clinical decision and should not await influenza
studies.
6) Post-exposure prophylaxis should only be considered when there is significant
exposure (defined in the guidelines) and the exposed person is at increased
risk for influenza complications.
7) In health care settings, the emphasis is on prompt identification of
symptomatic patients and implementation of infection control measures. Postexposure prophylaxis is generally not recommended for health care workers
unless they have risk factors for complications.
8) Historically, antiviral prophylaxis has been overused and likely contributes to
development of resistance. Therefore, counseling, close observation, and
prompt initiation of treatment if symptoms occur is a reasonable alternative to
post-exposure prophylaxis, especially if antiviral shortages occur.
It is anticipated that H1N1 will remain the prominent circulating strain this year, but time will
tell. The antiviral recommendations could well change depending on trends in epidemiology,
resistance, and virulence, so updates will likely follow.
Guidelines for influenza-like illness (ILI) inpatient infection control are as follows:

Every patient being admitted to SH will be screened with the ILI screening tool
immediately upon entering the facility (refer to the attached form) to determine if they fit
the criteria for an ILI.
 If the patient fits the criteria for an ILI the patient will be placed in Special
Droplet Precautions by the nursing staff.


Special Droplet Precautions are the same as Droplet Precautions except that,
during aerosol-generating procedures (bronchoscopy, elective intubation,
suctioning, or administration of medications by nebulizer) the staff must wear an
N-95 respirator or PAPR rather than a surgical mask.
Physicians Responsibility
o Patients are not to be taken out of Special Droplet Precaution based on a negative
rapid influenza test.
o Physicians will be expected to follow the hospital’s Special Droplet Precautions.
ILI-related Susquehanna Health employee work restrictions will be determined by the
employee’s manager as per established guidelines.
Thank you for your cooperation in trying to limit the spread of infection in the hospital and
community.
Sincerely,
Stephen Weber, MD