Polydipsia
Polydipsia refers to excessive thirst, a common symptom associated with endocrine disorders and certain drugs. It may reflect decreased fluid intake, increased urine output, or excessive loss of water and salt.
History and physical examination
Obtain a history. Find out how much fluid the patient drinks each day. How often and how much does he typically urinate? Does the need to urinate awaken him at night? Determine if he or anyone in his family has diabetes or kidney disease. What medications does he use? Has his lifestyle changed recently? If so, have these changes upset him?
If the patient has polydipsia, take his blood pressure and pulse when he’s in supine and standing positions. A decrease of 10 mm Hg in systolic pressure and a pulse rate increase of 10 beats/
minute from the supine to the sitting or standing position may indicate hypovolemia. If you detect these changes, ask the patient about recent weight loss. Check for signs of dehydration, such as dry mucous membranes and decreased skin turgor. Infuse I.V. replacement fluids, as needed.
Medical causes
Diabetes insipidus
Diabetes insipidus characteristically produces polydipsia and may also cause excessive voiding of dilute urine and mild to moderate nocturia. Fatigue and signs of dehydration occur in severe cases.
Diabetes mellitus
Polydipsia is a classic finding with diabetes mellitus — a consequence of the hyperosmolar state. Other characteristic findings include polyuria, polyphagia, nocturia, weakness, fatigue, and weight loss. Signs of dehydration may occur.
Hypercalcemia
As hypercalcemia progresses, the patient develops polydipsia, polyuria, nocturia, constipation, paresthesia and, occasionally, hematuria and pyuria. Severe hypercalcemia can progress quickly to vomiting, a decreased level of consciousness, and renal failure. Depression, mental lassitude, and increased sleep requirements are common.
Hypokalemia
Hypokalemia is an electrolyte imbalance that can cause nephropathy, resulting in polydipsia, polyuria, and nocturia. Related hypokalemic signs and symptoms include muscle weakness or paralysis, fatigue, decreased bowel sounds, hypoactive deep tendon reflexes, and arrhythmias.
Psychogenic polydipsia
Psychogenic polydipsia is an uncommon disorder that causes polydipsia and polyuria. It may occur with any psychiatric disorder, but is more common with schizophrenia. Signs of psychiatric disturbances, such as anxiety or depression, are typical. Other findings include a headache, blurred vision, weight gain, edema, elevated blood pressure and, occasionally, stupor and coma. Signs of heart failure may develop with overhydration.
Renal disorders (chronic)
Chronic renal disorders, such as glomerulonephritis and pyelonephritis, damage the kidneys, causing polydipsia and polyuria. Associated signs and symptoms include nocturia, weakness, elevated blood pressure, pallor and, in later stages, oliguria.
Sheehan’s syndrome
Polydipsia, polyuria, and nocturia occur with Sheehan’s syndrome, a disorder of postpartum pituitary necrosis. Other features include fatigue, failure to lactate, amenorrhea, decreased pubic and axillary hair growth, and a reduced libido.
Sickle cell anemia
As nephropathy develops, polydipsia and polyuria occur. They may be accompanied by abdominal pain and cramps, arthralgia and, occasionally, lower extremity skin ulcers and bone deformities, such as kyphosis and scoliosis.
Other causes
Drugs
Diuretics and demeclocycline may produce polydipsia. Phenothiazines and anticholinergics can cause dry mouth, making the patient so thirsty that he drinks compulsively.
Special considerations
Carefully monitor the patient’s fluid balance by recording his total intake and output. Weigh the patient at the same time each day, in the same clothing, and using the same scale. Regularly check blood pressure and pulse in the supine and standing positions to detect orthostatic hypotension, which may indicate hypovolemia. Because thirst is usually the body’s way of compensating for water loss, give the patient ample liquids.
Pediatric pointers
In children, polydipsia usually stems from diabetes insipidus or diabetes mellitus. Rare causes include pheochromocytoma, neuroblastoma, and Prader-Willi syndrome. However, some children develop habitual polydipsia that’s unrelated to any disease.
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
Other Book Chapters Related to Diabetes insipidus
Read excerpts from these other book chapters related to Diabetes insipidus:
Medical Books Excerpts
- POLYDIPSIA
- "Algorithmic Diagnosis of Symptoms and Signs" (2003)
- [ read ]
- Polydipsia
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
- [ read ]
- Polydipsia
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
- [ read ]
- Polydipsia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Polydipsia
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2008 Williams & Wilkins.
More About Causes of Diabetes insipidus
» Next page: Diabetes Insipidus (A Pocket Manual of Differential Diagnosis)
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