Oliguria

<Presentations>

<Index>

 

 

Definition

-  Oliguria = urine output < 500mls in 24hrs

-  Anuria =

 

Features

-  Minimum urine output 0.5ml/kg/hr

-  Typically 30mls/hr minimum (ie: 60kg adult)

-  Urine output is indicator of systemic perfusion

 

Causes

-  Dehydration

-  Renal disorders or obstruction

-  Prerenal

-  Hypovolaemia

-   Septic shock

-   Vomiting, diarrhoea, fever

-  Renal

-  ATN: rhabdomyolysis

-  Postrenal

-  Urinary tract obstruction: BPH

-  Catheter occlusion

-  Medications

-  Anticholinergics

-  Diuretics

-  Nephrotoxic drugs

-   Methotrexate

-   Cyclosporin

-   Gentamicin

 

Associated S/S

- Palpable bladder & urge to void: obstruction

- Thirst wo urge to void: volume depletion

- Dark brown urine: myoglobinuria: rhabdomyolysis

 

Ix

- U&E

-  Urea:Cr > 20mEq/L: prerenal

- +/- CMP

- Urine Na

-  Decreased: prerenal

-  Increased: renal: ATN

- Fractional excretion of Na

-  <1: prerenal

-  >3: renal

 

Mx

- As per cause

- If IDC flush to ensure patency & not blocked

-  50mls NS flush, withdraw, flush

- If no IDC consider insertion to monitor output

- Test bolus of 250-500ml NS IV fluid

-  250mls if frail, CCF..

-  Increased urine output suggests prerenal oliguria

- Volume repletion: IV fluids