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INFLUENZA A (H1N1)
LIZA D. MARIPOSQUE, M.D.2nd Year Family Med Resident
Perpetual Succour HospitalSeptember 2009
OBJECTIVES:
To present a case of H1N1 in a 28 years old pregnant patient.
To discuss Influenza A H1N1 Epidemiology Signs & symptoms Risk factors Diagnosis Treatment and Prevention
J. L., 28 years old, pregnantG4P1-1-1-2, 13 wks 6/7 days AOG by LMPMarriedFilipinoRoman CatholicSambag I, Cebu City admitted for the 4th times at PSH
CC: fever, cough & shortness of breath
PAST MEDICAL HISTORY
Non-diabetic, non-hypertensive,
non-asthmatic.
Non-smoker, non-alcohol beverage drinker Allergy: shrimp
HFD: HPN, DM 2, Bronchial Asthma
PAST MEDICAL HISTORY
2004 – PSH : NSVD (PT) 2005 – PSH : Ectopic pregnancy,
S/P Salpingectomy R 2008 – PSH : NSVD (FT)
2 wks PTA : Herpes Zoster infection
OBSTETRICAL HISTORY
Menarche - 10 y.o x 28 days cycle 7 days duration
LMP: April 1, 2009 AOG: 13 wks & 6 days EDC: January 8, 2010
HISTORY OF PRESENT ILLNESS
3 days PTA, sudden onset of fever with cough, coryza, headache & poor appetite.
Night PTA, had shortness of breath and spontaneously resolved, but recurred in the morning PTA thus prompted admission.
PHYSICAL EXAMINATIONS
Examined conscious, coherent & slightly respiratory distress.
BP: 110/80 mmHg HR: 86 bpm
RR: 29 cpm T: 36.8 0C
Wt: 59.8 kg
PHYSICAL EXAMINATION
SKIN: Fair, warm, no rashes, no cyanosis
HEENT: Anecteric sclerae, pinkish palpebral conjunctivae, nasal congestion, non-hyperemic tonsils.
NECK: No lymphadenopathy
C/L: Equal chest expansion, clear breath sounds, no rales, no wheeze.
PHYSICAL EXAMINATION
ABDOMEN: Flabby, normoactive bowel sound, soft, nontender,
no hepatomegaly, no palpable mass.
GUT: fundus 4 fingerbreaths below umbilicus, FHT: 139 bpm, (-) KPS
EXT. : No edema, strong pulses, CRT <2 sec.CNS: WNL
ADMITTING IMPRESSION
Upper Respiratory Tract Infection
PU 13 wks 6/7 AOG, Not in labor
COURSE IN THE WARD
1ST HOSPITAL DAY
P: Cough, fever, coryza, shortness of breathS: w/ cough, w/ coryza O: conscious, coherent & not in respiratory
distress.BP: 100/70-110/80 mmHg PR: 76-85 bpm RR: 19-29 cpm T: 36.9-37.5 0C
COURSE IN THE WARD
1ST HOSPITAL DAY
SKIN: Fair, warm, no rashes.HEENT: Anecteric sclerae, pinkish palpebral conjunctivae,
with both nasal congestionnasal congestion, non-hyperemic tonsils.NECK: No lymphadenopathyC/L: Equal chest expansion, clear breath sound, no rales,
no wheeze.ABDOMEN: Flabby, normoactive bowel sounds, soft,
nontender, no hepatomegaly, no mass.GUT: fundus 4 fingerbreaths below umbilicus
FHT: 139-160 bpm, (-) KPSEXT. : No edema, strong pulses, CRT <2 sec.CNS: WNL
COURSE IN THE WARD
1ST HOSPITAL DAY
A: Influenza A
R/O Influenza H1N1
Pregnancy Uterine 13 wks 6/7 AOG, not in labor
COURSE IN THE WARD1ST HOSPITAL DAY
P: > Oxygen inhalation.
> IVF started.
> Hypoallergenic diet.
> Labs: CBC, U/A, CXR w/ abdominal shield,
Screening test for Influenza A & B
LABORATORY RESULTS
CBC N.V. RESULTS
WBC 4-11.30 6.42
Neutrophils 47-80% 72
Lymphocytes 13-40% 16
Monocytes 2-11% 10
Eosinophil 0-5% 1
Basophil 2-4% 1
Hb 12-16 13.2
Hct 36-46% 38.7
plt 140-440 235
URINALYSIS RESULTS
Color & transparency Yellow, clear
Glucose NEG
Protein +
pH 6
Urine Ketone +
RBC/hpf 5-10 / hpf
WBC/hpf 0-2 / hpf
Epithelial cells rare
Mucus Threads abundant
Amorphous material rare
Bacteria rare
(Rapid Qualitative Test)
Sample Type: Nasopharyngeal Swab
Results: (+) Influenza A
(-) Influenza B
SCREENING TEST FOR INFLUENZA A & B
COURSE IN THE WARD1ST HOSPITAL DAY
P: >FHT monitoring BID.> Paracetamol 500 mg 4H prn for T≥38 0C & headache.> Sinupret 1 tab TID then revise to BID.> Salbutamol 1 neb q 6H.> Vit. C (Benutrex) 1 amp infused to present IVF ANST and in succeeding IVF to follow.> Prenatal Vit. (Beniforte) 1 cap OD is continued.> co-managed with OB.
COURSE IN THE WARD
2nd Hospital Day
S: no complaints
O: BP: 100/70-120/80 mmHg
PR: 77-91 bpm
RR: 18-20 cpm
T: 36.7-37 0C
COURSE IN THE WARD2nd Hospital Day
SKIN: Fair, warm, no rashes.HEENT: Anecteric sclerae, pinkish palpebral conjunctivae,
no nasal congestionno nasal congestion, non-hyperemic tonsils.NECK: No lymphadenopathyC/L: Equal chest expansion, clear breath sounds, no rales,
no wheeze.ABDOMEN: Flabby, normoactive bowel sound, soft,
nontender, no hepatomegaly, no mass.
GUT: fundus 4 fingerbreaths below umbilicus, FHT: 150-159 bpm , (-) KPSEXT. : No edema, strong pulses, CRT <2 sec.CNS: WNL
COURSE IN THE WARD
2nd Hospital Day
P: > Confirmatory throat swab test for Influenza A H1N1 c/o DOH.
> IVF terminated.
> meds given.
COURSE IN THE WARD3rd Hospital Day
S: No complaints
O: BP: 100/70-120/70 mmHg PR: 74-75 bpm RR: 18-19 cpm T: 36.4-36.7 0C
COURSE IN THE WARD3rd Hospital Day
SKIN: Fair, warm, no rashes.HEENT: Anecteric sclerae, pinkish palpebral conjunctivae,
no nasal congestionno nasal congestion, non-hyperemic tonsils.
NECK: No lymphadenopathyC/L: Equal chest expansion, clear breath soundsclear breath sounds, no rales,
no wheeze.ABDOMEN: Flabby, normoactive bowel sound, soft,
nontender, no hepatomegaly, no mass.GUT: fundus 4 fingerbreaths below umbilicus
FHT: 149-150 bpm, (-) KPSEXT. : No edema, strong pulses, CRT <2 sec.CNS: WNL
COURSE IN THE WARD3rd Hospital Day
A: > condition improved
> Patient discharge.
> Take home meds:
1. Bisolvon syr. 1 tbsp TID x 1 wk
2. Multivit. (Centrum) 1 cap OD
3. Beniforte 1 cap OD.
> Encourage oral fluid intake.
> ff-up with AP 1 wk after discharge.
COURSE IN THE WARD3rd Hospital Day
Final Diagnoses:
Influenza A H1N1 Pregnancy Uterine 14 wks 1/7 AOG,
not in labor.
Real-Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR)
(+) NOVEL INFLUENZA A (H1) VIRAL RNA
INFLUENZA Acute respiratory illness caused by infection with
influenza viruses.
Affects the upper and/or lower respiratory tract and is often accompanied by systemic signs and symptoms: fever - headache myalgia - weakness
What is the Novel Influenza A (H1N1)?
Quadruple Reassortment 2 swine strains, 1 human strain, 1 avian strain of influenza
6 of 8 gene segments were similar to triple reassortant swine influenza viruses in pigs
1. Emergence of a Novel Swine-Origin Influenza A (H1N1)Virus in Humans. N Engl J Med 2009;3612. Epidemiology, clinical manifestations, and diagnosis of swine H1N1 influenza A. Uptodate, May 15, 2009
Antigenic Variation
Influenza A virus Subtypes
16 different HA antigens (H1 to H16) 9 different NA antigens (N1 to N9) 3 subtypes of HA (H1, H2, and H3) &
2 subtypes of NA (N1 and N2) – caused human disease.
found in birds & pigs
Immune responses to the H antigen are the major determinants of protection against infection with influenza virus.
N antigen limit viral spread and contribute to reduction of the infection.
Emergence of Antigenic Subtypes of Influenza A Virus Associated with Pandemic or Epidemic Disease
Years Subtype Extent of Outbreak
1889–90 H2N8a Severe pandemic
1900–03 H3N8a ?Moderate epidemic
1918–19 H1N1b (formerly HswN1) Severe pandemic
1933–35 H1N1b (formerly H0N1) Mild epidemic
1946–47 H1N1 Mild epidemic
1957–58 H2N2 Severe pandemic
1968–69 H3N2 Moderate pandemic
1977–78c H1N1 Mild pandemic
Late March and early April 2009 outbreak of H1N1 influenza A virus infection detected in Mexico several other countries
including the United States.
April 17, 2009 – CDC reported a novel H1N1 virus
The Western Pacific Region has reported a total 609 laboratory-confirmed cases of influenza A(H1N1): (WHO 5/29)
Japan 367 Australia 147 China 41 Republic of Korea 33 Zealand 9 Philippines 6 Singapore 4 Malaysia 2
Cumulative total as of 13 Aug 2009
Cases* Deaths
WHO Regional Office for the Americas (AMRO) 105,882 1579
WHO Regional Office for the Western Pacific (WPRO) 27,111 50
WHO Regional Office for South-East Asia (SEARO) 13,172 106
WHO Regional Office for the Eastern Mediterranean (EMRO) 2532 8
WHO Regional Office for Africa (AFRO) 1469 3
Total 182,166 182,166 1,7461,746
Interspecies Transmission
Person-to-person Transmission
Droplets spray.
No risk from eating pork
Transmissibility - higher compared with seasonal influenza
Incubation period
for most cases ranges from 1 to 4 days
Infectious - from 1 day prior to the development of signs and symptoms until resolution of fever
Contagious - until seven days after the onset of illness
Longer - in children (especially young infants), elderly adults, patients with chronic illnesses, and immunocompromised hosts.
Most common clinical findings (642 confirmed cases):1
Fever (94%) Cough (92%) Soar throat (66%) Diarrhea (25%) Vomiting (25%)
Influenza-Like Illness (ILI)2
fever plus cough and/or sore throat
1. Emergence of a Novel Swine-Origin Influenza A (H1N1)Virus in Humans. N Engl J Med 2009;3612. Epidemiology, clinical manifestations, and diagnosis of swine H1N1 influenza A. Uptodate, May 15, 20093 CIDRAP
Danger signs in all patients
shortness of breath dyspnea cyanosis bloody or coloured sputum chest pain altered mental status high fever that persists beyond 3 days hypotension
Complications
Progressive Pneumonia Respiratory Failure – cause of most deaths Acute Respiratory Distress Syndrome
* In the U.S., most described cases have been mild
Anna R Thorner, MD. Treatment and prevention of swine H1N1 influenza. Uptodate, May 14, 2009.
High Risk Groups for Complications
Children < 5 yrs. old > 50 years or older Children and adolescents
(age 6 months to 18 years) Pregnant women
Novel H1N1 Influenza (Swine Flu)http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/biofacts/swinefluoverview.html
High Risk Groups for Complications
Adults & children w/ chronic pulmonary, cardiovascular, hepatic, hematological, neurologic, neuromuscular, or metabolic disorders
Immunocompromised Adults & children Residents of nursing homes and other chronic-
care facilities.
Novel H1N1 Influenza (Swine Flu)http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/biofacts/swinefluoverview.html
DIAGNOSIS
DIAGNOSTIC TEST Real-Time Reverse Transcription-Polymerase
Chain Reaction (rRT-PCR) Detection Qualitative for Influenza A, B, H1, and H3 positive for influenza A and negative for H1 and
H3 If reactivity of real-time RT-PCR for influenza A is
strong (eg, Ct <30), it is more suggestive of a novel influenza A virus.
Novel H1N1 Influenza (Swine Flu)http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/biofacts/swinefluoverview.html
Tests Culture
Isolation of H1N1 influenza A virus - diagnostic too slow negative viral culture does not exclude H1N1
influenza A infection
* Priority for testing should be given to: Those who require hospitalization and Those who are at high risk for severe
complications
Specimen
Upper Respiratory sample Intubated - endotracheal aspirate Placed in viral transport media and placed
on ice (4ºC) or refrigerated or in a -70ºC freezer
CDC Case Definitions for Infection with Novel Influenza A (H1N1) Virus
Suspected case
does not meet the confirmed or probable case definition not novel H1N1 test–negative and is/has one of the following features:
Previously healthy, less than 65 years of age resides in a state without confirmed cases but has
traveled to a state or country where there is/are one or more confirmed or probable cases
has an epidemiologic link in the past 7 days to a confirmed case or probable case
cdc.com
CDC Case Definitions for Infection with Novel Influenza A (H1N1) Virus
Probable case
Influenza-like-illness positive for influenza A, but is unsubtypable by
reagents used to detect seasonal influenza virus infection
cdc.com
CDC Case Definitions for Infection with Novel Influenza A (H1N1) Virus
Confirmed case
Influenza-like-illness laboratory confirmed by one or more of
the following tests:• real-time RT-PCR
• viral culture
cdc.com
Antiviral Treatment and Prophylaxis of Influenza
Age Group (years)
Antiviral Drug Children ( 12)
Oseltamivir
Treatment, influenza A and B Age 1–12, dose varies by weighta
Prophylaxis, influenza A and B Age 1–12, dose varies by weightb
Zanamivir
Treatment, influenza A and B Age 7–12, 10 mg bid by inhalation
Prophylaxis, influenza A and B Age 5–12, 10 mg qd by inhalation
Amantadinec
Treatment, influenza A Age 1–9, 5 mg/kg in 2 divided doses, up to 150 mg/d
Prophylaxis, influenza A Age 1–9, 5 mg/kg in 2 divided doses, up to 150 mg/d
Rimantadinec
Treatment, influenza A Not approved
Prophylaxis, influenza A Age 1–9, 5 mg/kg in 2 divided doses, up to 150 mg/d
Recommended Treatment
supportive intravenous hydrations Antiviral agents
sensitive to oseltamivir and zanamivir resistant to amantadine and rimantadine
Anna R Thorner, MD. Treatment and prevention of swine H1N1 influenza. Uptodate, May 14, 2009.
Oseltamivir (Tamiflu) Adult dose
Rx for acute illness: 75 mg PO bid for 5 d
Prophylaxis: 75 mg PO qd
available as 30-mg, 45-mg, and 75-mg oral capsules and as a powder for suspension that contains 12 mg/mL after reconstitution.
Zanamivir (Relenza) Adult dose
Rx for acute illness: 10 mg inhaled orally bid for 5 d
Prophylaxis of household contact: 10 mg inhaled orally qd for 10 d (initiate within 36 h)
Prophylaxis for community outbreak: 10 mg inhaled orally qd for 28 d (initiate within 5 d of outbreak)
powder form for inhalation via the Diskhaler oral inhalation device
Pregnant women
Oseltamivir and zanamivir are "Pregnancy Category C" medications
used only if the potential benefit justifies the potential risk to the embryo or fetus
cdc.com
Post-exposure antiviral prophylaxis
Close contacts who are at high risk for complications individuals with certain chronic medical
conditions ≥ 65 years of age pregnant women
cdc.com
Post-exposure antiviral prophylaxis
Health care workers, public health workers, or first responders who were not using appropriate personal protective equipment during close contact with a confirmed, probable, or suspected patient during that person's infectious period.
Pre-exposure prophylaxis
only be used in limited situations ongoing occupational risk for exposure
healthcare workers public health workers first responders
cdc.com
The single best way to protect against the flu is to get vaccinated each year.
flu shot— an inactivated
vaccine (containing killed virus). - for use in people older than 6 months, including healthy people and people with chronic medical conditions.
The nasal-spray flu vaccine —made with live, weakened flu viruses that do not cause the flu (LAIV or FluMist®). - approved for use in healthy* people, 2-49 y.o. who are not pregnant.
Each vaccine contains three influenza viruses: one A (H3N2) virus one A (H1N1) virus one B virus
2 weeks after vaccination - antibodies that provide protection against influenza virus infection develop in the body.
Influenza A H1N1 Vaccine Not yet available A European prototype of a swine flu vaccine
has been achieved Pandemic specific vaccines will not be
available until 4-6 months after a pandemic virus has emerged
Pandemic influenza vaccine manufacturing process & timeline
When to Get Vaccinated
Yearly flu vaccination should begin in September or as soon as vaccine is available and continue throughout the influenza season, into December, January, and beyond.
Timing & duration of influenza seasons vary.
When H1N1 influenza is confirmed in a community (CDC recommends):
Home isolation School dismissal and childcare facility
closure Social distancing
Preventive measures for health care personnel
single-patient room with the door kept closed An airborne-infection isolation room with
negative-pressure air handling. Suctioning, bronchoscopy, or intubation should
be performed in a procedure room with negative-pressure air handling.
Patients should wear a surgical mask when outside their room.
Preventive measures for health care personnel
Frequently Hand washing & respiratory hygiene practices.
Routine cleaning and disinfection strategies Standard, droplet, and contact precautions
should be used for all patient care activities and maintained for 7 days after illness onset or until symptoms have resolved.
Preventive measures for health care personnel
Personnel providing care to or collecting clinical specimens from patients should wear disposable nonsterile gloves, gowns, and eye protection (eg, goggles) to prevent conjunctival exposure.
Preventive measures for health care personnel
personnel engaged in aerosol-generating activities (eg, collection of clinical specimens, endotracheal intubation, nebulizer treatment, bronchoscopy) and/or resuscitation involving emergency intubation or cardiac pulmonary resuscitation should wear a fit-tested disposable N95 respirator.
Preventions for the Community:
Cover the mouth & nose when coughing and sneezing.
Always wash hands with soap & water. Use alcohol-based hand sanitizers. Avoid close contact with sick people. Increase body resistance.
Travel Advisory
WHO is not recommending travel restrictions related to the outbreak of the influenza A(H1N1) virus
WHO do not believe entry and exit screenings would work to reduce the spread of this disease
May 15, 2009 - CDC Travel Health Warning for Novel H1N1 Flu in Mexico Removed
Department Of Health
Oseltamivir (Tamiflu)
Designated referral centers2
National Referral Center Research Institute of Tropical Medicine (RITM)
Sub-national Referral Center Luzon & Metro Manila = San Lazaro Hospital Visayas = Vicente Sotto Memorial Medical
Center Mindanao = Davao Medical Center
1 Inquirer .net 2 DOH
DOH Lines of Defense
1. Points of Exit and Entry Screening2. Enhanced Diseases Surveillance3. Preventive Measures4. Prescribed Drug of Choice: Oseltamivir5. Infection Control (N95 mask)6. Social Distancing7. Emergency powers: Martial Law
DOH National Epidemiology Center
Thank You