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]
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 [2] [3]
- 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
Management
Shown below is an algorithm summarizing the approach to polyuria.
| Suspected hypotonic polyuria[4] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Confirm presence of polyuria >50ml/kg/24hrs or >3-4L/day | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Polyuria confirmed | No polyuria/ or >800 mOsm/kg | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Measure urine osmolality | 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 | Normal serum Sodium/plasma osmolality | High serum Sodium >146 mmol/L, plasma osmolality >300 mOsm/kg | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Primary polydipsia | Indeterminate diagnosis | 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 | Nephrogenic DI(partial or complete) | Complete Central DI | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Therapeutic trial with desmopressin | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Primary polydipsia | Partial Nephrogenic DI | Partial Central DI | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Initial urine osmolality: 30 mOsm/kg and >50% increase after desmopressin: | Urine osmolality <300 mOsm/kg or <50% increase | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Complete Central DI | Complete Nephrogenic DI | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Shown below algorithm for the diagnostic approach to polyuria based on American Journal of Kidney Diseases.
| Polyuria (Urine Output > 3L/d)[5] | |||||||||||||||||||||||||||||||||||||||||
| Urine Osmolality | |||||||||||||||||||||||||||||||||||||||||
| Uosm <100mOsm/kg (Water Diuresis) *Psychogenic Polydipsia *DI (central and nephrogenic) | Uosm =100-300mOsm (Mixed Polyuria) *Partial DI(central and Nephrogenic) *Simultaneous water and solute intake *CKD | Uosm >300mOsm/kg (Solute Diuresis) *Hyperglycemia *Azotemia *High solute intake intravenous fluids enteral and parenteral nutrition Exogenous supplements | |||||||||||||||||||||||||||||||||||||||
| Water Deprivation Test | 24-Hour Urine Collection (estimation of osmoles) *Urine sodium *Urine potassium *Urine glucose *Urine urea nitrogen *Other osmoles | ||||||||||||||||||||||||||||||||||||||||
Do's
- Recommend diet modification, like avoiding any food that irritates bladder including caffeine, alcohol, carbonated drinks, tomato-based products, chocolate, artificial sweeteners, and spicy foods.
- Monitor fluid food intake, drink enough to prevent constipation and over concentration of urine and avoid drinking just before the bedtime.
- Recommend Kegel exercises to strengthen the muscles around the bladder and urethra.
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.
- ↑ Wieliczko M, Matuszkiewicz-Rowińska J (2013). "[Polyuria]". Wiad Lek. 66 (4): 324–8. PMID 24490488.
- ↑ 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.
- ↑ Feingold KR, Anawalt B, Boyce A, Chrousos G, de Herder WW, Dungan K; et al. (2000). "Endotext". PMID 30779536.
- ↑ Bhasin B, Velez JC (2016). "Evaluation of Polyuria: The Roles of Solute Loading and Water Diuresis". Am J Kidney Dis. 67 (3): 507–11. doi:10.1053/j.ajkd.2015.10.021. PMID 26687922.