This summary takes data from 25 April - 5 May 2020 using NodeXL, using methods described previously. There were 17,345 tweets by 5,658 tweeters with 34,819 retweets. Overall 576 (10%) tweeters received 80% of all retweets, from 8,873 tweets (almost half of which were posted by an experimental twitter bot by  MD programmer @_joshcase). In contrast 2,580 (46%) tweeters received no retweets from 3,427 tweets posted. 
The top hashtags were as follows (by number of occurrences in the 17,345 tweets:
#medtwitter 13,520
#meded 4,068
#covid19 2,697
#foamed 1,756   
#coronavirus 892
A sequence of word clouds showing the effect of removing these and other top hashtags from the image are shown below. I have compared these by "intention" - the act of posting a tweet, and "reception" - the number of retweets received. This helps understand the most popular medical topics in medical tweets. There is quite a difference, with cardiology and radiology (including POCUS - point of care ultrasound) coming to the fore when looking at reception. 
The top 20 tweeters are listed below, before listing the top 203 tweets (at least 25 retweets received) chronologically.

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