The Case of Diabetes Insipidus

The Case of Diabetes Insipidus

Directions: Go to this website: http://www.sciencecases.org/diabetes_insipidus/diabetes_insipidus.asp

Complete these questions:

1. Describe the mechanism by which normal fluid regulation in the body occurs.

Fluids are stored in the bladder. If the fluid regulation system is working properly, the kidneys will make less urine to conserve fluid when water intake is decreased.

2. What is considered to be excessive thirst and urination in an adult?

• Urination- more than 50 ml/kg every two hours

• Thirst- drinks more than 1 gallon or about 12 glasses of beverages per day

3. List and briefly describe the four types of diabetes insipidus.

• Pituitary Diabetes Insipidus- the most common type of diabetes insipidus; lack of ADH due to destruction of the posterior pituitary gland

• Nephrogenic Diabetes Insipidus- results from a type of ADH resistance; kidneys don’t respond to ADH by producing a more concentrated urine

• Gestational Diabetes Insipidus- occurs during pregnancy and is due to destruction of ADH by the placenta; treatable

• Dipsogenic Diabetes Insipidus- happens as a result of ADH suppression secondary to the excessive ingestion of fluids

4. How is pituitary diabetes insipidus diagnosed?

It is diagnosed by a collection of blood for genetic testing, an MRI of the brain, a therapeutic trial of DDAVP, and a water deprivation test.

5. In what ways is diabetes insipidus similar to diabetes mellitus? In what ways do they differ?

Both diseases result in increased frequency of urination and thirst. However, they both have different treatments and causes.

6. How does the mechanism by which diuresis occurs with diabetes insipidus differ from that which occurs in diabetes mellitus?

Diuresis occurs in diabetes mellitus because the high sugar/low water concentration inside the kidney tubules creates a concentration...