This information is condensed from a lecture given by Erica Pan of the San Francisco Public Health Department, at an event designed to teach primary care physicians about H5N1 flu. (note, this was NOT the emergency physician meeting referenced elsewhere) My comments are in square brackets. I found the discussion to be rather obvious and elementary by wiki-an standards, but I think it is ‘good enough’ for introducing it to docs unfamiliar with the topic. There’s good information for identifying cases but little on treating them; nobody yet has enough data and confidence to say to others, ‘do [i]this[/i]’.
Case presentation 1:
20 y. o. previously healthy Indonesian male presents to the emergency department with a 2 day history of fever, productive cough, rhinorrhea, and mild shortness of breath.
physical exam: alert, mild respiratory distress, Temp—39.5C, Respiration Rate 22, inspiratory crackles
labs: lymphopenia [low white cells], thrombocytopenia [low platelets], mild elevation of transaminases [liver enzymes released by damaged liver cells], chest x-ray with diffuse interstitial infiltrates
[y’all have seen chest x-ray’s’ from bird flu patients, this is the ‘medicalese’ used to describe what you’ve seen. ‘interstitial’ means that there is excess fluid in the lung tissue itself and not necessarily in the actual alveolar air sacs. Textbook-wise (meaning never seen as a pure situation in real life) this indicates early inflammatory reaction, where fluid in the alveolar sacs happens later and when there’s more tissue damage already present.]
differential diagnosis [ie: list of suspects}: Community acquired pneumonia —viral—influenza vs. other viruses —bacterial
[This was followed by an explanation of Influenza A B and C, and subtype nomenclature for A. I’ll skip this because everyone here is well versed in it.]
Then—
[b]Labs[/b] that help distinguish H5N1 from H3N2:
Chest x-ray [as described above] (seen in 61–100% of cases)
lymphopenia (seen in 50–80% of cases) —median white blood count: 2.1–4.9 —median absolute lymphocyte count 0.7–1.4 [percent lymphocytes x total white blood cell count] [white cells address bacterial infection and cleaning up tissue damage. lymphocytes are involved in defense against viruses. In many viral infections, the count of lymphocytes *increases*, but in some, the lymphocytes are working so hard they are consumed and the count drops.]
Mild-moderate thrombocytopenia (seen in 33–80% of cases)
Slightly or moderately increased AST/ALT levels (seen in 61–83% of cases)
[b]Outcomes:[/b]
Respiratory failure (seen in 44–100% of cases) —median time from onset of symptoms, Thailand data—6 days.
Renal dysfunction (seen in 10–29% of cases)
Death (seen in 33–100% of cases) —9–10 days post onset —higher in infants and young children —higher death rate in those observed to have lower white blood cell, platelet, and absolute lymphocyte counts. [this is important in ‘prognosis’--if you were to have two patients and one had lower values on these parameters, they would be more likely to die, given equal care. Depending how resources go this may become a basis for triage.]
[b]Distinguishing clinical features[/b]
conjunctivitis is rare compared to H7 bird flu
Diarrhea, vomiting, abdomenal pain, pleuritic pain [pain on taking a breath], epistaxis [nosebleed], and bleeding gums may occur early in illness. [no news to us, but news to them…]
Watery non-bloody diarrhea is more common than in H3N2 and may precede respiratory symptoms.
Better viral replication in the pharynx than nasal samples means that pharyngeal, rather than nasal, samples should be used for viral testing. Viral loads are typically >10x those found in H3N2 samples.
2 patients have been identified with encephalitis and diarrhea and NO respiratory symptoms [ie: these should be considered rare presentations but should not rule out the diagnosis. Again I suspect this is old news to most fluwikians.]
[b]Epidemiological Exposure Criteria[/b]
A) history of travel to a country with influenza H5N1 documented in poultry, wild birds, and/or humans AND at least one of the following potential exposures during travel:
—direct contact/touching of ---sick or dead domestic poultry ---survaces contaminated with poultry feces ---sick or dead wild birds suspected or confirmed to have H5N1
—consumption of raw or incompletely cooked poultry or poultry products—well cooked is not a risk factor.
—close contact (approach within 3 feet) of a person who was hospitalized or died due to a severe unexplained respiratory illness
B) close contact with an ill patient confirmed or suspected to have H5N1
C) worked with live H5N1 virus in a laboratory.
[listing of human cases by country, online references—CDC, WHO, OIE]
[b]Transmission[/b]
evidence supports
—bird to human —possible environment to human [bird poop] —limited non-sustained human to human
examples of direct poultry contact
—plucking and preparing birds —handling fighting cocks —playing with poultry —consumption of duck’s blood —eating undercooked poultry.
[more when I feel like typing again]
We also have some case information here… http://www.fluwikie.com/pmwiki.php?n=Resources.H5N1
Good approach to collaborative problem solving. Doctors teaching doctors, and nurses, dentists, medical therapists, home healthcare workers,…we need all the cross training we can get.
Anon22 and rrteacher worked on this treatment page http://www.fluwikie.com/pmwiki.php?n=Main.Treatment
I started this treatment brainstorming page based on symptoms seen on the cases cited in Chest and NEJM. I framed the page…
Thanks for the cross links, Fred.
I don’t think there’s anything in this presentation by SF PHD that isn’t already known to the frequent visitors to the wiki, but I do think there is some value in seeing how it is being presented to physicians who are not familiar with the information. So when I’ve got more time I’ll put up more of the salient points from this presentation.
This also lets folk know what elements are ‘official party line’ type stuff and what elements are not (yet?) accepted by mainstream medicine.
obviously I had some problems with uploading the information, sorry for the duplicates. Pogge or other mods, if you could delete the excess copies? I think the last is the one that should be kept, though they differ only by a couple of introductory remarks by me.
Back to the lecture—
Case presentation part 2
travel history—
patient returned 4 days ago from a month long visit to grandparents in rural indonesia
grandparents kept chickens and a fighting cock. patient assisted chicken care
at the end of his visit, some of the chickens became ill and died.
Lab testing for AI
Indicated (recommended by CDC) when—
a patient has an illness that requires hospitalization or is fatal AND
has or had a documented tempreature of > 38C (100.4F) AND
has radiographically confirmed pneumonia, acute respiratory distress syndrome (ARDS) or other severe respiratory illness for which an alternate diagnosis has not been established AND
Meets epidemiological exposure criteria within 10 days of symptom onset.
Consider in consult with public health in cases where
a patient with mild or atypical disease (hospitalized or ambulatory who has one of the exposures listed above OR
a patient with sever or fatal respiratory disease whose epidemiological information is uncertain, unavailable, or otherwise suspicious but does not meet the criteria above.
Influenza Testing
Rapid Antigen Test (EIA) for Flu A & B
—preferred specimens oropharyngeal swab or lower respiratoray tract. Nasopharyngeal also okay.
—specimen collected in sterile cup or onto NP swab; most sites will need to put the swab into viral transport media.
—swabs should have a dacron tip and plastic or aluminum shaft (no wood, no cotton).
PCR is available at many local public health labs for A H1, H3, and H5, or B.
[reports on sensitivity and specificity at the local lab]
Case presentation part 3
Rapid test is negative for influenza A and B
Specimen is sent for pcr to hospital lab thence to public health.
Patient admitted for antibiotics and antiviral treatment [shotgun approach, treat everything until you know what you have]
Infection control —identify and treat patients —use PPEs —identify and treat other cases, potential contacts, if relevent.
Influenza A characteristics —latent period 1–3 days—no symptoms, no shedding, viral shedding may begin 1 day prior to sx. —incubation period—2–4 days (H3N2), up to 8 days (H5N1) from exposure to symptoms —Infectious period—1 day prior to symptoms, in general, but depends on patient age and immune status
Transmission routes—direct, respiratory droplet, airborne
Survival outside host—
[tired of typing again. more later. learning to format, hope this is more readable apologies if not]