A 72-year-old man with gram-negative sepsis presents with hypotension (BP 78/52 mmHg), tachycardia (HR 118/min), tachypnea (RR 22/min), and fever (38.9°C). Laboratory findings reveal elevated D-dimer (8.2 mg/L) and prolonged PT/INR consistent with disseminated intravascular coagulation. He develops refractory septic shock unresponsive to fluid resuscitation. Platelet count remains above 100,000/μL. The bacterial product most directly triggers macrophage activation through which of the following lipid components?
- A)Flagellin hook protein
- B)Teichoic acid
- C)Lipid A of lipopolysaccharideGABARITO
- D)Peptidoglycan tetrapeptide cross links
- E)Protein A
Explicação
Endotoxin activity in gram negative bacteria resides in lipid A, the toxic portion of lipopolysaccharide. Lipid A activates innate immune pathways through TLR4 and CD14, promoting cytokine release, tissue factor activation, and shock. Ver explicação completa e trilha adaptativa →