小中中的異想世界

Case I
A 34 year-old man visited our emergency department due to left lower leg rapidly swollen in 2 days.

He was quite well before and has no underlying major systemic disease.

Three days ago, he got his left toe injured by an oyster shell in the beach.(initially a 0.5x0.5 cm wound)

On the next day, his left foot got swollen, pain, and tense sensation.

He visited local clinic and received some local treatment and medications but in vain.

Then left lower leg swelling rapidly progression associated with hypotension was found.

He was sent to our emergency department immediately.

 His left leg showed swollen, erythematous change and some hemorrhagic bullae.

(Figure 1.) His initial lab tests showed leukopenia, thrombocytopenia and renal failure.

: 

Figure 1

Question 1. What is the diagnosis?

Question 2. What are the likely pathogens?

Question 3. What are your initial managements? (including empirical antibiotics regimen)