Elevated Osmolality

An increase in osmolality, representing an elevated concentration of osmotically active particles per kilogram of solvent in body fluids (serum: approximately 275-295 mOsm/kg; urine: approximately 50-1,200 mOsm/kg), reflecting a disturbance in water balance or accumulation of osmotically active solutes.

Causes

• Water deficit states

  • Dehydration

  • Excessive fluid loss (vomiting, diarrhea, sweating)

  • Diabetes insipidus

• Hypernatremia

• Hyperglycemia

• Kidney failure --> increased urea concentration

• Toxic substances

  • Ethanol

  • Methanol

  • Ethylene glycol

• Medications and treatments

  • Diuretics

  • Mannitol therapy