Hydration

Hydration items rarely ask for a definition; they hand you a vignette and force a dehydration-versus-fluid-overload call. The tells diverge: dehydration shows tachycardia, orthostatic hypotension, dark/concentrated urine, elevated urine specific gravity (>1.030), and rising hematocrit and BUN from hemoconcentration, while overload shows crackles, JVD, bounding pulses, edema, and weight gain. When a question gives serial weights, trust them — daily weight is the single most reliable indicator of fluid status, more so than the intake-and-output records the exam loves to contrast. The priority answer is almost always assessment before titrating fluids.

Don’t confuse hydration with its neighbors: nutrition concerns nutrient and caloric intake (albumin, prealbumin), not volume; elimination tracks output, where a sudden drop can signal the deficit hydration must correct; and feeding is the delivery route, where free-water flushes double as a hydration intervention. The classic trap is freely pushing fluids in heart failure or renal failure, where restriction is the expected answer (current guidelines individualize it). Hook: wet lungs mean too much water; dry tongue means too little.