Symptom Scale for Influenza H5N1 (Bird Flu)

This page is part of a set of treatment-related discussions which I am going to upload fairly soon. Some of the information still needs editing but the basics are correct. So check back if you are not sure and hopefully you will see further improvements.

The idea of symptom scale is to help conceptualize all the possibilities when faced with someone with H5N1 infection, to help make some rough judgments as to prognosis in order to help guide treatment choices. I made this up in response to Michael Donnelly’s request and is not referenced to any official guidelines or recommendations. But it is based on current understanding of the clinical course of the disease and general clinical approaches.

0 well

1 symptoms compatible with seasonal flu - fever, cough, sore throat, mild nausea or loose bowels

2 symptoms compatible with severe seasonal flu - tight cough with slight shortness of breath on coughing only, chest pain on coughing, vomiting more than 2x, diarrhea more than 4x in 24 hours, minimal (specks) of blood in sputum, vomitus, or stool, urine output reduced or darkened but still passing urine more than 3x in 24 hours.

3a) symptoms suggestive of onset of ARDS - more or less constant difficulty breathing, inability to lie down, talks only with difficulty, use of accessory respiratory muscles (visible at neck) for beathing, frankly blood-stained sputum

3b) symptoms suggestive of multiple organ involvement - explosive uncontrolled diarrhea, fresh blood in stool or vomit, severe abdominal pain with tenderness or bloating,

3c) symptoms suggestive of early CNS involvement - drowsiness, delirium, restlessness, (in absence of serious breathing difficulty) severe headache unrelieved by non-narcotic analgesics, photophobia, neck stiffness

4a) frank ARDS - severe breathing difficulty with cyanosis, cold clammy skin, unable to talk without severe distress or worsening of cyanosis, respiratory muscle fatigue with visible reduction in ability to expand chest, coughing up massive amounts of fresh blood mixed with minimal or no sputum

4b) signs of systemic failure - drop in blood pressure, weak thready pulse, signs of liver failure eg jaundice, signs of renal failure eg no or almost no urine output, edema, severe abdominal distension

4c) frank CNS involvement - convulsion (in absence of previous history), unconscious, arched rigid back,

5 terminal state - respiratory failure, comatose, persistent low or unreadable blood pressure, signs of disseminated intravascular coagulation (DIC) with bleeding into skin and from multiple sites,

This is the supplementary explanation for the above symptoms scale.

I set out the scale with the following in mind:

1) symptom based : my objective is to make this usable for home folks who mostly will be mostly measuring severity by symptoms and have no access to anything more complicated than a thermometer or a BP monitor, but also to make different grades of symptoms easily recognizable. For example, someone who has difficulty breathing only when coughing is different from one who has difficulty breathing whether he is coughing or not. This is something which is distinctly recognizable by both patient and carer.

2) it is constructed to reflect the possible scenarios of H5N1 infection, which could range from mild flu to death. To make this conceptually simple, basically, I am describing an illness which is similar to seasonal flu, with mild and severe differentiation, stages 1 and 2. The next 2 stages would be stages with complications beyond normal seasonal flu, again with mild and severe, stages 3 and 4. Stage 5 is the almost-end-stage. This broadly reflects a commonly understandable concept that the disease can be ‘like seasonal flu’, ‘have added complications different from normal flu’, and ‘most likely fatal’.

3) Stages 3 and 4 are further subdivided into 3 streams depending on which organ system is involved. This is because even though patient A might have ARDS and patient B might have CNS complications and they look different, in terms of prognosis and treatment approach, they lie on the same scale of severity. That is, the likelihood that you will want to use ‘heroic’ or unconventional methods for stage 4a and 4c would be similar. (more about this later). There is also consistency in progressing from 3a to 4a, these representing early and established ARDS. Notice that one does not progress from 3a to 3b by severity, and one patient might have symptoms that fall within both 3a and 3b, in which case both classification can be quoted eg 3a,b..

4) The scale is also constructed to reflect prognosis and thus treatment considerations. For example, someone who never progressed beyond 1 after 4–5 days is likely to do exceedingly well and therefore will most likely not need steroids or antibiotics. Conversely, the progression from 2 to 3 is where you want to make the biggest attempt to save the patient’s life, because progression to 4 dramatically reduces their survival chances and you would want to avoid that. Here you might try things that you may have been hesitant about before. At stage 3 I would throw everything at the patient except for things that might have immediate life-threatening effects, whereas at stage 4 I would be far more likely to use ‘heroic’ or high risk strategies regardless, since the prognosis is already quite grave. In addition, most people would agree that there comes a point when it might be kinder to let the patient go with dignity, and the situation at stage 5 describes that. Now this is just my own strategy, other people might have different philosophies and want to try something else at stage 5 or give up at stage 4. This is ok and eventually we will be able to compare whether that attempt was worth it, as long as we are comparing a similar level of severity.