Question

Patient behaving strangely, & CNS features were described. Urine osm=1000 & plasma osmolality= 250

• A. Hyponatremia
• B. Hypernatremia
• C. Hypokalemia
• D. Hyperkalemia

Answer 1

The Correct Option is A

The case revolves around interpreting laboratory data related to osmolality in conjunction with clinical symptoms. To understand this, let's dissect the given information.

Urine Osmolality = 1000 mOsm/kg: This indicates concentrated urine, as normal urine osmolality typically ranges from 300 to 900 mOsm/kg, depending on fluid intake and other factors.

Plasma Osmolality = 250 mOsm/kg: Normal plasma osmolality is approximately 275 to 295 mOsm/kg. This value suggests a lower-than-normal plasma osmolality, indicating a possible dilutional state in the body.

Given the combination of low plasma osmolality and concentrated urine, the body is retaining water relative to solutes. This condition often results in hyponatremia, where sodium levels in the blood are lower than normal due to excess water retention.

Considering the CNS symptoms described in the patient, hyponatremia is known to affect neurological function, leading to the "strange behavior" observed. The body responds to low plasma osmolality by retaining water, often through mechanisms such as inappropriate secretion of antidiuretic hormone (SIADH), which can lead to concentrated urine even when plasma osmolality is low.

The correct answer, considering the described scenario and given options:

Hyponatremia