REN and inappropriate ADH syndrome: Babayev and colleagues (2013)[9] describe a 28-year-old gentleman with human immunodeficiency virus (HIV) who developed P jiroveci pneumonia and a precipitous decrease in serum sodium from 135 mEq/L to 117 mEq/L following treatment with TMP/SMX, initially attributed to SIADH, though clinical evidence of hypovolemia, along with high renin and aldosterone levels, implicated renal salt wasting to represent the chief intermediary mechanism.