A 32-year-old woman was admitted to the hospital following 2½ days of severe vom

ID: 237688 • Letter: A

Question

A 32-year-old woman was admitted to the hospital following 2½ days of severe vomiting. Before this episode, she was reportedly well. Physical findings revealed decreased skin turgor and dry mucous membranes. Admission study results were as follows: 6, Serum Results Urine Results K+ HCO3 Osmolality Na* Ketones 129 mmol/L 5.0 mmal/L 77 mmol/L 9 mmel/L 265 mQsm/kg8 mmol/d trace Circle any results that are not in the normal range for a healthy individual. What is the significance of the urine sodium and serum osmolality results? a. b.

Explanation / Answer

Electrolyte level

Normal range

Patient levels

Significance

Serum Sodium (Na)

136-145 mmol/L

129 mmol/L

Hyponatremia

Potassium (K)

3.5-5.0 mmol/L

5 mmol/L

Normal

Chloride (Cl)

95-105 mmol/L

77 mmol/L

hypochloremia

Bi carbonate

22-30 mmol/L

9 mmol/L

Low

Osmolality

275–295 mosm/kg

265 mosm/kg

Low

Urine Sodium

20 mmol/L

8 mmol/L

Extra renal sodium losses.

Urine ketones

Nil

Traces

Risk for Diabetes Miletus

Significance of serum Osmolality and urine sodium :

Often, the assessment of any disorder involving antidiuretic hormone (ADH) will require both serum and urine osmolality to assess concentrating ability of the kidney. The normal 24-hour urine osmolality is, on average, 500-800 mOsm/kg of water. Random urine osmolality should average 300-900 mOsm/kg of water.