Polydipsia refers to excessive thirst, a common symptom often associated with endocrine disorders, renal disorders, psychogenic causes, or certain medications. It may reflect decreased fluid intake, increased urine output, or excessive loss of water and electrolytes.

History and Physical Examination

History

• Determine daily fluid intake and frequency/volume of urination.

• Ask if nocturia (urination at night) occurs.

• Assess for family history of diabetes or kidney disease.

• Review medications and recent lifestyle changes.

Physical Examination

• Measure blood pressure and pulse in supine and standing positions.

  • A systolic drop ≥10 mmHg and pulse increase ≥10 bpm may indicate hypovolemia.

• Inspect for dehydration: dry mucous membranes, decreased skin turgor.

• Monitor weight changes and provide IV fluid replacement if necessary.

Medical Causes of Polydipsia

Other Causes

Drugs: diuretics, demeclocycline, phenothiazines, anticholinergics (cause dry mouth → excessive drinking).

Special considerations

• Monitor fluid balance by recording intake and output.

• Weigh the patient daily using the same scale and clothing.

• Check blood pressure and pulse in supine and standing positions to detect orthostatic hypotension.

• Ensure the patient has ample fluids, as thirst is often compensatory for water loss.

Patient counseling

• Explain the underlying disorder and treatment plan.

• Educate on diet, exercise, and home blood glucose monitoring.

• Emphasize reporting unexplained weight gain or loss.

Pediatric pointers

• Most commonly caused by diabetes insipidus or diabetes mellitus.

• Rare causes: pheochromocytoma, neuroblastoma, Prader-Willi syndrome.

• Habitual polydipsia can occur without underlying disease.

References

1. Berkowitz, C. D. (2012). Berkowitz’s Pediatrics: A Primary Care Approach (4th ed.). USA: American Academy of Pediatrics.

2. Buttaro, T. M., Tybulski, J., Bailey, P. P., & Sandberg-Cook, J. (2008). Primary Care: A Collaborative Practice (pp. 444–447). St. Louis, MO: Mosby Elsevier.

3. Colyar, M. R. (2003). Well-Child Assessment for Primary Care Providers. Philadelphia, PA: F.A. Davis.

4. Lehne, R. A. (2010). Pharmacology for Nursing Care (7th ed.). St. Louis, MO: Saunders Elsevier.

5. McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N. S. (2010). Pathophysiology: The Biologic Basis for Disease in Adults and Children. Maryland Heights, MO: Mosby Elsevier.

6. Sommers, M. S., & Brunner, L. S. (2012). Pocket Diseases. Philadelphia, PA: F.A. Davis.