Question

Amanda Richards is a 20-year-old junior in college. She is majoring in biology and hopes someday to be a pediatrician. About three months ago was diagnosed with a bipolar disorder and has been taking lithium.  Amanda noticed that she was waking up once, sometimes twice a night, with the need to go to the bathroom. More recently, she has noticed that she needs to go to the bathroom during her school day much more frequently than before, sometimes as often as once every hour.

At first Amanda thought that her increased frequency of urination was due to the coffee she drank, but when she reduced her coffee consumption to one cup in the morning, she still needed to go to the bathroom just as often. In addition, Amanda was buying bottled water by the case, and she found herself never without a beverage in her hand or nearby because she was always thirsty. She also noticed that her urine seemed pale and colorless.

When Amanda told her mother of her problem, her mother became very concerned and arranged for Amanda to see the family physician. Amanda did mention to the doctor that she has missed the last week of taking lithium because she forgot to fill her prescription. Her physician found no abnormalities on physical examination. However, a blood chemistry profile revealed Amanda’s serum sodium level was 174 mEq/L, plasma (serum) osmolality was 376 mOsm/L, urine osmolality was 200 mOsm/L and fasting glucose was 85 mg/dl. Her urine was negative for the presence of glucose.

An extensive history revealed that no other member of the family had ever displayed Amanda’s symptoms. Amanda had no history of traumatic head injury and an MRI of her brain was normal.

Normal Lab Values:

Sodium 135 – 145 mEq/L, fasting glucose levels should be less than 100 mg/dL, serum osmolality should be 275 – 295 mOsm/L, urine osmolality should range from 500 to 800 mOsm/L.

Also, refer to page 811 for clinical manifestations of diabetes.

1. If Amanda’s condition goes untreated which of the following conditions would she most likely have:  hypervolemia, hypovolemia, dehydration, water intoxication.  Explain your answer. Also explain why she would not have the other conditions.
2. If she leaves her condition untreated how could this potentially affect her blood volume and blood pressure?
3. Why is Amanda always thirsty? Explain
4. Why did her doctor measure her glucose levels?

Answer 1

She will have water intoxication, hypervolemia, and dehydration.
Water intoxication leads to increased thirsty due to the withdrawal of lithium that leads to the intoxication of water. water intoxication makes compulsive water drinking.
Increased sodium level leads to hypervolemia that involves in dehydration.
Hypovolemia can result in low sodium concentration in the blood, causing water retention in the kidney that makes the hyponatremia worsen.
When there is a high level of sodium in the blood that makes the person get thirst that leads to again mental dysfunction, muscle twitching, and seizure.
when hypernatremia worsens that leads people to get more thirsty.
Glucose test must when there is electrolyte imbalance, there is a chance of high glucose level in the blood. hypernatremia caused by insufficient water replacement due to hypotonic renal loss due to diabetes.