POLYUREA BASICS

Polyuria defined as urine out put is >3ml/kg/h BASICS Polyuria defined as urine out put is >3ml/kg/h

Acquired dysfunction of salt & water reabsorption Causes Acquired dysfunction of salt & water reabsorption Obstructive uropathy Osmotic diuresis ATN (diuretic phase) Tubulointerstial damage (CKD) Drugs diuretics Corticosteroids caffiene Serious systemic infection Hypercalciemia (↑13mg/dl ) hypokalemia

Herediatry tubulopathies affecting salt reabsorption Causes Herediatry tubulopathies affecting salt reabsorption RTA Proximal (fanconi syndrome) Distal (interstial nephritis) Hyperkalemic, aldosterone defect (obstructive uropathy) Bartter syndrome (AR) ADH abnormalities Centeral DI Nephrogenic DI

Renal tubular acidosis (the essentials ) Failure to thrive Chronic vomiting Episodes of metabolic acidosis Hypercholremic metabolic acidosis with NAG Usually normal renal function It is 4 types (proximal , distal , hyperkalemic & mixed)

Barrter (the essentials ) Failure to thrive Chronic vomiting metabolic alkalosis Hypocholremia Hypokalemia Elevated plasma renin and aldosterone

Diabetes insipidus Sever polyuria Hypernatremia Serum osmolarity >280 Urine osmolarity <280 Response to desmopressin (central type)

ASK FOR Stress to confirm polyurea (Recurrent dehydration with no significant vomiting) CKD Diuretics or corticosteroids Dark urine Is the paient diabetic Head trauma

Examine for Urine volume Hydration state Acidotic breathing Weight centile Blood pressure Racketic manifestations Evidence of CKD Renal mass Cushinoid features

Step 1: confirm polyurea Step 2: review your history and examination Exclude AQUIRED CAUSES at least Step3: initial investigations Urine analysis (SG , glycosuria ) Blood sugar level Serum urea & creatnine Serum electrolytes (calcium , potassium & sodium) ABG Abdominal US Step 4: Classify according ABG No acidosis or alkalosis Metabolic acidosis Metabolic alkalosis

Polyuria with metabolic acidosis Calculate anion gap Normal Wide Consider RTA Serum K Role out renal failure Dehydration Elevated Normal or low Urine PH Consider type IV Investigate for aldosterone defect and obstructive uropathy & drugs <5.5 Consider PRTA Investigate for fanconi syndrome >5.5Consider DRTA Investigate for INTERSTIAL NEPHRITIS

Polyuria with metabolic Alkalosis Role out loop diuretics and chronic vomiting Consider barrter syndrome Confirm Serum potassium (low) Serum renin and aldosterone (low)

Polyuria with no metabolic acidosis or alkalosis Role out acquired causes espically Hypercalcemia Hypokalemia Drugs Do serum & urine osmolarity Plasma osmalrity >280 Or Urine osmalrity <280 NO YES Water deprivation test Diagnostic for DI (no need for WDT