Polyuria resident survival guide
Overview
- Polyuria is defined as urine output more than 2 L/24 hours, or 30 ml/kg/24 hours. There are 3 pathophysiologic causes of polyuria: increased thirst (idiopathic, psychogenic polydepsia, hypothalamic disease, and medications), central diabetes insipidus (DI) (decreased secretion of arginine vasopressin (AVP)), and nephrogenic diabetes insipidus (DI) (renal resistance to AVP).[1]
- Nocturnal polyuria (NP), characterized by overproduction of urine at night (more than 20%-33% of total 24-hour urine volume depending on age). It can be caused by intake, urological, nephrological, hormonal, sleep, and cardiovascular factors. [2]
Causes
Life Threatening Causes
- Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.
- Polyuria does not have life threatening causes.
Common causes [3] [2]
- The most common causes of polyuria are:
- Pregnancy
- Psychogenic polydipsia
- Central diabetes insipidus (CDI)
- Nephrogenic diabetes insipidus (NDI)
- Diabetes mellitus (DM)
- Chronic kidney disease (CKD)
- Urinary tract infection (UTI)
- Interstitial cystitis
- Nephrolithiasis
- Primary hyperparathyroidism
- Familial hypocalciuric hypercalcemia
- Hypercalcemia
- Hypokalemia
- Sickle cell disease (SCD)
- Stroke or neurological diseases
- Benign prostatic hyperplasia (BPH)
- Stress incontinence
- Medications:
- Overactive bladder
- Drinking alcohol or caffeine
Approach to Polyuria
| Suspected hypotonic polyuria[4] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Confirm presence of polyuria: (>50ml/kg/24hrs or >3-4L/day) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| (Polyuria confirmed): Measure urine osmolality | (No polyuria/ or >800 mOsm/kg): Diabetes insipidus(DI)/Primary polydipsia ruled out | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| (<800 mOsm/kg): Hypotonic polyuria confirmed: Measure serum Sodium and plasma osmolality | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Low normal or low serum Sodium (<150 mmol/L), plasma osmolality (<280 mOsm/kg): Primary polydipsia | Normal serum Sodium/plasma osmolality: Indeterminate diagnosis | High serum Sodium (>146 mmol/L), plasma osmolality (>300 mOsm/kg): Central or Nephrogenic DI | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Water deprivation test | Baseline plasma copeptin | Hypertonic saline infusion test | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Urine Osm >800 mOsm/kg | Urine Osm <300 mOsm/kg | Urine Osm 300-800 mOsm/kg | Plasma coprptin >4.9pmol/L | Plasma coprptin <4.9pmol/L | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mild primary polyuria | Desmopressin administration | >21pmol/L | <2.6pmol/L | >2.6pmol/L | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| (Urine Osmolality: 300-800 mOsm/Kg and <50% increase): Therapeutic trial with desmopressin | Nephrogenic DI(partial or complete) | Complete Central DI | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Primary polydipsia | Partial Nephrogenic DI | Partial Central DI | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| (Initial urine osmolality: 30 mOsm/kg and >50% increase after desmopressin): Complete Central DI | (Urine osmolality <300 mOsm/kg or <50% increase): Complete Nephrogenic DI | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Do's
Don'ts
References
- ↑ Moore K, Thompson C, Trainer P (2003). "Disorders of water balance". Clin Med (Lond). 3 (1): 28–33. doi:10.7861/clinmedicine.3-1-28. PMC 4953350. PMID 12617410.
- ↑ 2.0 2.1 Weiss JP, Everaert K (2019). "Management of Nocturia and Nocturnal Polyuria". Urology. 133S: 24–33. doi:10.1016/j.urology.2019.09.022. PMID 31586470.
- ↑ Wieliczko M, Matuszkiewicz-Rowińska J (2013). "[Polyuria]". Wiad Lek. 66 (4): 324–8. PMID 24490488.
- ↑ Feingold KR, Anawalt B, Boyce A, Chrousos G, de Herder WW, Dungan K; et al. (2000). "Endotext". PMID 30779536.