II. Definitions
- Nocturia
- Frequent Urination at night (more than once)
III. Mechanism
- Urine Volumes are typically reduced at night via diurnal rhythm
- Nocturia occurs when urine formed exceeds Bladder capacity
IV. Causes
- All causes of Polyuria also cause Nocturia
- Diabetes Mellitus
- Diabetes Insipidus
- Primary Polydipsia (e.g. Water Intoxication)
- Decreased Bladder capacity (may be due to inflammation or irritability)
- Urinary Tract Infection
- Bladder Tumor
- Urinary tract stone
- Edematous State fluid redistributes at night into dependent positions and then intravascularly mobilized
-
Bladder outflow obstruction
- Benign Prostatic Hyperplasia
- Urethral Stricture
- Urinary tract stone
- Pelvic tumor
- Other causes
V. Management
- Identify and treat underlying causes
- Employ simple strategies
- Dose Loop Diuretics earlier in the day
- Redistribute edema during the daytime (e.g. Compression Socks, leg elevation)
- Medications (not recommended)
- Low dose Desmopressin (Noctiva)
- Expensive, marginal efficacy, risk of Hyponatremia (requires Sodium monitoring)
- Low dose Desmopressin (Noctiva)
VI. References
- (2018) Presc Lett 25(5): 27
- Coe in Wilson (1991) Harrison's Internal Medicine, 12th ed, McGraw Hill, p. 275