Treatment of Community-acquired pneumonia

Mr. ABC is hospitalized and decompensated For Treatment initiated for community-acquired pneumonia.

Mr. ABC is a 50 years old man admitted to the hospital with 7 days history of worsening cough, high fever, and dyspnea. Upon admission, he was noted to be tachypneic (RR 30 breaths/min), hypoxia with oxygen saturation of 89%, and febrile (39 degrees celsius). Chest X-ray: Infiltrates in both lower lobes.

CBC : WBC of 20,000. Treatment initiated for community-acquired pneumonia. Despite treatment, he has worsening hypoxia which requires intubation and ventilatory support. Despite mechanical ventilation using high oxygen concentration, his arterial blood oxygen remains low. Chest X-ray from today shows the progression of infiltrates throughout both lung fields. His WBC count is 35,000, he has a fever of 40 degrees celsius, HR 120, bp 70/30, not responding to fluids, Levophed has just been started.

What additional diagnosis does Mr. ABC has?

What is the most likely cause of Mr. ABC’s diagnosis?

Why is Mr. ABC Hypoxic?

What is an A-a gradient, what does it tell you and what do you expect Mr. ABC A-a gradient to be?

What is Mr ABC at an increased risk of developing?