Anatomy & Physiology: Current Research
Open Access

Nocturnal Polyuria

Nocturnal polyuria is a syndrome where the usual day to night ratio of urine production is altered.7 In patients with nocturnal polyuria,
33% of the total daily urine output occurs at night, although the daily total urine output remains normal. A careful voiding diary, incorporating measurements of voided volumes, is essential to make the diagnosis. Common causes of nocturnal polyuria are listed in Conditions such as congestive heart failure, nephrotic syndrome, autonomic neuropathy, and venous insufficiency lead to interstitial edema formation during the day. Mobilization of the accumulated interstitial fluid while recumbent results in nocturia. Obstructive sleep apnea is associated with excessive atrial natriuretic peptide production. Neurologic dieases, such as Alzheimer’s disease and Parkinson’s disease, are associated with alterations in the diurnal secretory pattern of neurohormones, such as natriuretic peptides and antidiuretic hormone. Patients with chronic kidney disease are unable to maximally concentrate their urine and often must void at night. In many cases, the cause of nocturnal polyuria is undefined. In idiopathic nocturnal polyuria, Asplund and Aberg8 suggested that anti-diuretic hormone (ADH) levels, which are typically elevated during sleep, are abnormally low in these individuals.