Sepsis Management for the Nephrologist

Antibiotic timing. The timing of antibiotics depends on the presence of shock and the probability of sepsis. Patients with a high probability of sepsis should receive antibiotics within 1 hour. In patients with possible sepsis, antibiotics should be initiated within an hour if shock is present and within 3 hours if they are hemodynamically stable. Reprinted from ref. 4, with permission.

In sepsis, the afferent arteriole undergoes vasoconstriction, whereas the efferent arteriole vasodilates, leading to a reduction in glomerular filtration pressure. The differences in resistance between the two arterioles predispose to glomerular shunting via periglomerular shunting pathways. Both mechanisms lead to a reduction in GFR, despite an increase in renal blood flow early in sepsis.

Sepsis-related kidney injury can be divided into primary and secondary mechanisms. The primary mechanisms include damage-associated molecular patterns (DAMPS) and pathogen-associated molecular patterns (PAMPS), leading to an innate immune response with consequential systemic vasodilation, disseminated intravascular coagulopathy (DIC), and cellular reprogramming of renal tubular epithelial cells. The innate immune response further contributes to microvascular changes and glomerular microthrombi, resulting a net reduction in GFR. Secondary injury occurs due to fluid resuscitation that can lead to venous congestion and intra-abdominal hypertension, which further contributes to AKI.