The New England Journal of Medicine has just published its first report on a series of COVID19 patients in ICU care, treated in Seattle. Although it was a small series of 24 patients, there are some instructive & sobering facts.
Firstly, cough and SOB are the danger signs, being the presenting features in almost 90% each. Fever was present in only 50%. Could it be that these slightly elderly (mean age 64) with underlying co-morbidities (58% had diabetes, 21% had CKD), are unable to mount a pyrogenic response?
Secondly, the outcome was dire. Fifty percent died, 3 (12.5%) are still ventilated and may well die, only 5/24 were discharged home and 4/24 are in hospital, but off ventilation.
What's killing them? All patients had hypoxaemic respiratory failure, but 17/24 had shock. There was no evidence of cardiac failure on Echo, so this is septic shock, requiring vasopressors.
Hypoxia and shock are a deadly combination and mostly seen in bacterial infections such as Pneumococcus, Staph or with Gram negatives, but microbiological studies showed no superinfection in these patients, either with bacteria or common respiratory viruses. it's fair to assume therefore that the cause of shock was COVID 19 itself.
You'd think this is unusual for a viral infection and you'd be right. However, it is well documented with 3 viruses. The first is a strain of Influenza A- H3N2, which is in fact a component of the trivalent or quadrivalent Influenza vaccine. In years when H3N2 circulates, the mortality rate is 2.7 times the other strains included in the vaccine.
The second is avian influenza A- H5N1, which has a case fatality rate of 60%. The third is another avian Influenza A strain- H7N9- which has a fatality rate of 27%.
The reason these other viruses haven't run amok is because they cause mainly sporadic infections, presumably due to low infectivity, and are therefore easily isolated. Unfortunately COVID19 appears to share their capacity to cause hypoxaemia and shock, while spreading much more rapidly.
Firstly, cough and SOB are the danger signs, being the presenting features in almost 90% each. Fever was present in only 50%. Could it be that these slightly elderly (mean age 64) with underlying co-morbidities (58% had diabetes, 21% had CKD), are unable to mount a pyrogenic response?
Secondly, the outcome was dire. Fifty percent died, 3 (12.5%) are still ventilated and may well die, only 5/24 were discharged home and 4/24 are in hospital, but off ventilation.
What's killing them? All patients had hypoxaemic respiratory failure, but 17/24 had shock. There was no evidence of cardiac failure on Echo, so this is septic shock, requiring vasopressors.
Hypoxia and shock are a deadly combination and mostly seen in bacterial infections such as Pneumococcus, Staph or with Gram negatives, but microbiological studies showed no superinfection in these patients, either with bacteria or common respiratory viruses. it's fair to assume therefore that the cause of shock was COVID 19 itself.
You'd think this is unusual for a viral infection and you'd be right. However, it is well documented with 3 viruses. The first is a strain of Influenza A- H3N2, which is in fact a component of the trivalent or quadrivalent Influenza vaccine. In years when H3N2 circulates, the mortality rate is 2.7 times the other strains included in the vaccine.
The second is avian influenza A- H5N1, which has a case fatality rate of 60%. The third is another avian Influenza A strain- H7N9- which has a fatality rate of 27%.
The reason these other viruses haven't run amok is because they cause mainly sporadic infections, presumably due to low infectivity, and are therefore easily isolated. Unfortunately COVID19 appears to share their capacity to cause hypoxaemia and shock, while spreading much more rapidly.
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