The ultra-frequent pit stops will drive you nuts (even if he's your beloved grandpa). Buy grandpa a plane ticket!
Excessive thirst and urination signals uncontrolled diabetes mellitus, diabetic ketoacidosis or diabetes insipidus.(1) Urinalysis and blood testing are meant to detect the first two conditions.(2&3) When blood testing shows normal glucose levels and there is no presence of ketones in the urine, then diabetes insipidus is diagnosed.(1&2)
Diabetes insipidus is a condition that occurs when the kidneys cannot conserve water properly.(3) The cause is a defect in antidiuretec hormone receptors or an inability to secrete antidiuretic hormone.(4p659) The hormone, produced by the hypothalamus and stored and released by the pituitary gland, cause the kidneys to return more water to the blood.(4p631-3) Without the hormone working properly, urination increases substantially.(4p633)
References
1. MedlinePlus. Urination - excessive volume. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/003146.htm. Accessed on Nov. 1, 2008.
2. MedlinePlus. Ketones - urine. Available at: http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/003585.htm. Accessed on Nov. 1, 2008.
3. MedlinePlus. Diabetes insipidus. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000377.htm. Accessed on Nov. 1, 2008.
4. Tortora, GJ & Derrickson, B. Principles of Anatomy and Physiology, 11th ed; 2006. New York: John Wiley & Sons, p.659.
