Thread by @tarunds

Lets try and learn some basics of the COVID-19 illness
So to understand what’s happening you need to understand the story behind it.

(A Thread)

80% people will have flu like sickness
Mild/Initial phase: presenting with anosmia (lack of smell), fever, cough, diarrhoea. This is something most people understand and is treated with Paracetamol and lots of water.
But beyond the is what we need to learn a bit more about

Basically in the illness people are fine mostly till d4 - d6,
but once the downhill journey begins you r counting each hour
Its a sudden steep downhill slope
Now why is that?

3 things happen
1. a pneumonia like illness that is water filling up in lungs ks Pulmonary Edema;
2. microthrombi in lungs ie millions of tiny clots formed in air sacs of lungs where usually oxygen is filtered in
3. ramping up of immune cells like cytokines and Interleukins

These cytokines further fill up the lungs leading to a condition called cytokine storm syndrome basically a hyperimmune response where the whole lung is filled up with these immune cells

Now lungs are basically a sponge with countless thin films to exchange oxygen with blood but if instead of air there is all fluids and clots filled up how will the oxygen get in?
So oxygen levels start to fall

Now its easy to understand why people deteriorate so soon as lungs are filling up immune cells, water and clots and this progressing exponentially

So what do we do
1. Decrease water and inflammation in lungs: Steroids do that
2. If thrombi formation is there (eg test d-dimer levels) if yes then give anticoagulants to prevent clotting in lungs

3. Prevent replication of chain of virus: this is where remidesvir comes into picture but the caveat is that the virus is mostly replicating till D8-10 so beyond which it is of limited use as per latest studies.

4. If cytokine storm occurs it is usually stimulated exponentially by immune cells one of the potent ones is called IL-6 so we need to stop IL-6 hence Tocilizumab an IL-6 inhibitor finds its role.

5. Another interesting treatment is Cytosorb which basically is a filter membrane to flush out excess immune cells works like a dialysis.

So few FAQ's
So q1: does remdesivir work?
yes it stops viral chain replication (replication usually stops by D8-10) but timing is critical (hence useful in earlier course of illness) but once the pt is in a hyperimmune state the role is limited.

Q2: till when are you infective
You are most infective around the days you turn out to be positive

q3: RAT vs RT-PCR: Rapid Antigen Test is equally good and if positive you don’t need any further testing.
There is no such thing that RAT is cheaper so less accurate.
Just that RT-PCR may pick up the illness some time prior.

q4: Y so many deaths if its a pneumonia like condition.
Actually "severe COVID-19" is much more than a simple pneumonia as it is combined with millions of tiny clots in lungs + an uncontrolled hyperimmune response.

q5: can we know which pt will move to the hyperimmune state?
There is no single marker or test as of now, if there would have been this would have been in much better control.

Summary:
Now if people start being careful in initial days and if see oxygen starting to fall (SPO2 <94) or getting breathless and go to hospital and start early treatment to decrease chances of moving to the severe course of illness.
and for goodness gracious get vaccinated.

How do you define moderate and severe illness

Moderate phase: Rbr 24/94
Look for Respiratory rate (breaths per minute) >24 or
SPO2 <94%
Or shortness of breath/unable to complete sentences.

Severe phase: Rbr 30/90
Ie a respiratory rate >30 or a SPO2<90%
#COVIDSecondWaveInIndia

An opinion: Last year this gave alternative med people a huge opportunity for promotion hence immunity booster / health juice / coronil et al market sprung up as 80-90% pts were getting fine after a week or so

This is leading a lot of people to self / google medicate yourself till late in the disease and I get daily calls when 55 year old people are in their home with SPO2 of 88 asking if we shud go to a hospital!
prompt intervention is critical.

Finally these are my learnings as being a student of medicine and not a medical consultation.
also this illness and the management options are developing rapidly and even better things and research is going to reach us soon. Be hopeful but watchful.
This too shall pass.