Explanation
The correct option is a. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score is a crucial diagnostic adjunct for distinguishing early necrotizing fasciitis from severe cellulitis. It utilizes six routine laboratory parameters: C-reactive protein (CRP), total white blood cell count (WBC), hemoglobin, serum sodium, serum creatinine, and serum glucose. A serum sodium level of less than 135 mmol/L scores 2 points. The hyponatremia is pathophysiologically linked to profound systemic inflammation, third-spacing of fluids into necrotic tissue, and potential syndrome of inappropriate antidiuretic hormone secretion (SIADH) triggered by extreme physiological stress. Reference: Wong CH et al., The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med.