From the Guidelines
The workup for nocturnal urinary frequency (nocturia) should begin with a thorough history and physical examination, focusing on fluid intake patterns, medication review, and symptom characterization, as recommended by the PLanning Appropriate Nocturia Evaluation and Treatment (PLANET) study 1. The initial evaluation should include establishing the impact of nocturia, assessing nocturia severity and overnight volume of urine, and reviewing the patient's past medical history and medications 1. Key areas to consider in the initial evaluation include:
- Sleep medicine: obstructive sleep apnea, insomnia, restless legs syndrome, and parasomnias
- Cardiovascular: hypertension and congestive heart failure
- Renal: chronic kidney disease
- Endocrine: diabetes mellitus, thyroid disease, and diabetes insipidus
- Neurology: conditions that may affect bladder control or increase the likelihood of nocturia Patients should also be screened for medical causes of xerostomia, such as autoimmune diseases affecting salivary glands, diabetes mellitus, and chronic kidney disease 1. A 72-hour bladder diary is a crucial component of the initial evaluation, as it helps to assess nocturia severity and overnight volume of urine 1. Further testing may include blood tests to assess renal function, thyroid function, and electrolyte levels, as well as urine dipstick testing to evaluate for hematuria and proteinuria 1. The goal of the workup is to identify underlying medical conditions that may be contributing to nocturia and to develop a treatment plan that addresses these conditions, while also considering the patient's quality of life and potential impact on morbidity and mortality 1.
From the Research
Nocturia Workup
The workup for nocturia involves a detailed history and physical examination, as well as the completion of a frequency volume chart to help identify underlying causes, such as sleep disorders, bladder storage disorders, and polyuria 2.
Diagnostic Tools
- Bladder diaries for 3 days are an essential part of the assessment 3
- Frequency-volume charts to help identify underlying causes, such as sleep disorders, bladder storage disorders, and polyuria 2, 4
- Sleep-micturition chart to determine the causes of nocturnal urinary frequency 5
Classification of Nocturia
Nocturia can be classified into three types:
- Low voided volume (previously termed low bladder capacity)
- Nocturnal polyuria
- Mixed origin 4 Validated clinical criteria based on frequency-volume data allow the type of nocturia to be specified using two threshold values:
- Largest voided volume/body weight ratio <4 mL/kg for low voided volume
- Nocturnal urinary output/body weight ratio >10 mL/kg for nocturnal polyuria 4
Treatment Goals
Treatment goals include reducing the nocturnal voiding frequency to less than 2 episodes per night, increasing the duration of undisturbed sleep to more than 4 hours, restoring quality of life, and reducing morbidity as well as mortality 3.
Underlying Causes and Treatment
The underlying pathophysiology of nocturia can only be detected by methodical evaluation of the patient, and treatment options may include:
- α-blockers, 5α-reductase inhibitors, phosphodiesterase type-5 inhibitors, plant extracts or prostate operations for patients with reduced functional bladder capacity 3
- Desmopressin to reduce urine production during the night for patients with nocturnal polyuria 3, 2
- Behavioral therapy, timed diuretics, and desmopressin for patients with nocturnal polyuria 2
- Anticholinergic agents for patients with small bladder capacity, sleeping pills for patients with sleep disorders, and restriction of water intake at night for patients with large nocturnal urinary volume 5