Oliguria is defined as urine output of less than 0.5 mL/kg/hour. It can be caused by pre-renal, renal, or post-renal acute kidney injury. Pre-renal causes include decreased blood flow from conditions like dehydration, heart failure, or blood loss. Renal causes involve direct kidney damage from acute tubular necrosis, glomerulonephritis, or infections. Post-renal causes result from urinary outflow obstruction. Evaluation of oliguria includes history, physical exam focusing on fluid status and signs of obstruction, urine and blood tests to identify the specific cause, and imaging tests. Treatment depends on the underlying etiology but initially involves fluid resuscitation

1. OLIGURIA

2. AIMS
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Definition of oliguria
Aetiology
History
Assessment
Management
Case
Past paper question

3. WHAT IS OLIGURIA?

4. DEFINITIONS
Oliguria
 <0.5 mL/kg/hour of urine produced
Acute Renal Failure
 Rapid loss of renal function
Acute Kidney Injury
 The new name for ARF

5. AETIOLOGY
 Classification
 Pre-renal
 Renal
 Post-renal

6. AETIOLOGY
 The acute renal failure “clown face”
ATN
Pre
RPGN
Tubulo-interstitial
nephritis
Infections
Other
Post

7. AETIOLOGY
Rapidly Progressive Glomerulonephritis:
1.
SLE
2.
Goodpasture’s
3.
Infective Endocarditis
4.
Post-streptococcal
5.
ANCA +ve vasculitides
6.
Henoch-Schonlein Purpura
 The acute renal failure “clown face”
Pre-renal: “hypoperfusion”
1.
Cardiogenic
2.
Hypovolaemic
3.
Haemorrhagic
4.
Septic
5.
Anaphylactic
6.
Neurogenic
7.
Hepatorenal syndrome
Infections:
1.
Malaria
2.
Typhoid
3.
HUS (E.Coli) and TTP
4.
Leptospirosis
5.
HIV
6.
Hanta virus
ATN
Pre
RPGN
Tubulointerstitial
nephritis
Post
Tubulointerstitial: “drugs”
1.
NSAIDs
2.
ACEi
3.
PPIs
4.
Cisplatin + other chemo.
5.
Gentamicin
6.
Vancomycin
Infections
Other:
1.
Myeloma
2.
Rhabdomyolysis
Other
Post-renal: “back pressure”
1.
BPH
2.
Prostate cancer
3.
Urinary retention
4.
Stones
5.
Retroperitoneal fibrosis
6.
Urethral strictures

8. HISTORY
B a s ic s
 A g e , G e n de r, Oc c upa t i o n ( rubbe r m a n ufa c t urin g?)
Pc
 Ol i guria o r a n uri a ( e m e rgenc y !)
HPc
 ? D + V, LUT S, ra s h e s, bl e e di ng, feve r, c o r y z a
PMH
 B P H , pro s t a te c a n c e r, s to n es, STIs , UTIs
DH
 di uret i c s, a n t i bi ot ic s, N SAID s
FH
 re n a l fa i l ure
SH
 s m o king a n d a l c o h ol

9. EXAMINATION
 ABC
 Two most common causes:
 Pre-renal: examine fluid status (extravascular vs. Intravascular)
 Post-renal: check and flush catheter
 Examine with “the face” in mind
 Left ear – pre-renal: ?dehydrated/septic/cardiac failure/ anaphylatic/blood
loss/neurogenic/liver disease (HRF)
 CRT/HR/BP/RR/JVP/Temperature
 Right ear – post-renal: ?retention/LUTS/back pain
 Percuss out bladder/PR
 Right eye – RPGN: ?butterfly rash/haemoptysis/ coryza/epistaxis/murmurs
 Nose – drugs: look at the drug chart
 Lip – infections: ?diarrhoea/fever/lymph nodes
 Chin – other: ?back pain/anaemic/cachectic
 Nephrotic syndrome?
 oedema (esp. eyes), proteinuria and hypoalbuminaemia
 Nephritic syndrome?
 Hypertension, haematuria (and proteinuria), reduced GFR (uraemia)

10. INVESTIGATIONS (“BUMERS”)
Bedside:
 M i d - s t r e a m u r i n e d i p s t i c k ( h a e m a t u r i a , p r ot e i n u r i a )
B l o o d te s t s :
 Re n a l f u n c t i o n ( U + E , C r e a t . , C a 2 + , P O , e G F R , % N a . e x c r e t i o n )
 F B C ( w h i te c e l l s , H b ) a n d C R P
 ABG (pH and PaO2)
 PSA
U r i n e te s t s
 M i c r o s c o p y ( r e d c e l l c a s t s , hya l i n e c a s t s )
M i c r o s c o py
 Blood cultures
Electro.
 ECG
Radiology
 Re n a l U S S / B l a d d e r U S S
S p e c i a l te s t s
 Re n a l b i o p s y
 C o m p l e m e n t l e v e l s a n d Au to - a n t i b o d y s c r e e n

11. MANAGEMENT
ABC
Pre-renal
 5 0 0 m L 0 . 9 % s a l i n e f l u i d c h a l l e n g e – m o n i to r u r i n e o u t p ut a n d B P – r e p e a t
 D i ur et i c s ? I f c a r d i ac f a i l ur e – a l w ay s a d e l i c a te b a l a n c e b et w e e n H F a n d r e n a l
f a i l ur e . G et ex p e r t h e l p .
Post-renal
 F l u s h c a t h ete r i f p r e s e n t , c a t h ete r i s e i f n o t
 S u p r a p ub i c c a t h ete r i s t h e n ex t o p t i o n
G e n e r a l m e a s ur e s :
 S t r i c t f l u i d b a l a n c e a n d c o r r e c t i o n o f e l e c t ro l y te a b n o r m a l i t y.
 D a i l y w e i g h t s to d ete r m i n e o n g o i n g t h e r a py.
Dialysis:
 D i a l ys i s m ay b e r e q u i r e d u n t i l t h e k i d n ey s r e c o ve r
 Indications (AEIOU): acidaemia, edema, ingestion, overload (fluid), uraemia
S u r g ic a l
 Po s t - r e n a l o b s t r uc t io n m ay n e e d d e c o m p r e s s i v e n e p h r o s to my.

12. CASE
 6 7 - ye a r - o ld m a l e
 Pc - generalized weakness
 T h e p a t i e n t h a s s ev e r e o s te o a r t h r it i s a n d t a ke s h i g h - d o s e N S A I D s . I n t h e r e c e n t
h e a t w av e , h e n o t i c e d t h a t h e d i d n o t g o to b a t h r o o m a s o f te n a s h e u s e d to f o r t h e
l a s t 2 - 3 d ay s .
 P a s t m e d ic a l h i s to r y ( P M H )
O b e s i t y, o b s t r uc t iv e s l e e p a p n e a ( O S A ) , hy p e r te n s i o n ( H T N ) , o s te o a r t h r i t i s ( OA ) .
 M e d ic a t io n s
I b u p ro fe n ) , l i s i n o p r il , s i m v a s t a t i n
 P hy s ic a l e x a m i n a t i o n
Dr y mucosal membranes
 L a b o r a to r y r e s ul t s
B l o o d s – p o t a s s i um 6 . 5 m M
C r e a t i n i n e 2 8 0 uM ( 7 0 u M 2 m o n t h s a g o )
Fr a c t i o n a l ex c r et i o n o f N a i n u r i n e < 1 %

13. CASE
What is the most likely diagnosis?
 Prerenal ARF due to volume depletion.
How to confirm the diagnosis?
 Urinary sodium and creatinine to calculate the fractional excretion of sodium (FENA).
What other tests would you order?
 Renal ultrasound to rule out urinary obstruction and nephrolithiasis.
What treatment would you start for this patient?
 Fluid resuscitation
 Calcium gluconate 10mL, 10%
 Insulin 10 units IV with dextrose
 Foley catheter.
 Strict fluid balance
 Avoid fluid overload and hold ACEi and NSAIDs
Final diagnosis
 Prerenal Acute Renal Failure due to Volume Depletion.
What did we learn from this case?
 ARF is frequently defined as an acute increase of the serum creatinine level by 25 % from baseline.
 The fractional excretion of sodium ( FENa) is useful in diagnosing pre -renal ARF. FENa is less than 1
% in many patients with prerenal ARF.
 Intravenous hydration is the mainstay of treatment.

14. PAST PAPER QUESTION

15. ANY QUESTIONS??