Osmolalitätsspiegel

Osmolalitätsspiegel refers to the concentration of osmotically active particles in a solution, typically blood plasma or urine. Osmolality is measured in milliosmoles per kilogram of solvent (mOsm/kg). The osmolalitätsspiegel is a crucial indicator of the body's water balance and kidney function.

In blood plasma, the normal osmolalitätsspiegel ranges from 275 to 295 mOsm/kg. Deviations from this range can signal various physiological conditions. An elevated osmolalitätsspiegel, or hyperosmolality, indicates a higher concentration of solutes, often due to dehydration, increased intake of salt or sugar, or certain medical conditions like diabetes insipidus or diabetic ketoacidosis. Symptoms can include thirst, dry mouth, and reduced urine output.

A decreased osmolalitätsspiegel, or hypoosmolality, suggests a lower concentration of solutes, typically caused by excessive water intake (polydipsia), or conditions like syndrome of inappropriate antidiuretic hormone (SIADH) secretion, where the body retains too much water. This can lead to water intoxication, confusion, and seizures.

Urine osmolality varies much more widely, reflecting the kidney's ability to concentrate or dilute urine to maintain homeostasis. Normal urine osmolality can range from 50 to 1200 mOsm/kg. A high urine osmolalitätsspiegel indicates that the kidneys are conserving water, while a low osmolalitätsspiegel suggests the kidneys are excreting excess water. Measuring both plasma and urine osmolality helps clinicians assess hydration status and diagnose kidney disorders.