Oliguria

Page 1

Defined as urine less than 300mL per day or less than 20mL / hr

Anuria: less than 50mL - 100 mL per day

(bilateral artery occlusion)

Reflects volume filtered and reabsorbed. Not a good indicator of kidney disease

Causes

1. Reduced production e.g. pre-renal injury

Decreased perfusion --> decrease in GFR --> pre-renal azotemia

2. Renal: intrinsic renal injury --> renal infarction, rapidly progressing glomerulonephritis

Decrease in renal perfusion

3. Obstruction of renal tract --> GFR to fall

Assessment:

1. Look for hypotension

a. Hypovolaemia --> haemorrhage, diuretic use, GI fluid losss, pancreatitis, trauma, burns

b. Decreased CO --> CCF, MI, tamponade, PR

c. Vasodilataion --> shock

2. Sx of vascular disease --> bilateral renal vascular obstruction (thrombosis, embolism, renal artery stenosis)

3. Hx consistent with renal parenchymal injury --> (recent contrast agent, nephrotoxin, ethylene glycol, NSAIDS, vasculitis)

4. UTO --> bladder neck obstruction (BPH, prostate cancer, bladder cancer); obstruction of ureters (clots, debris, tumours, fibrosis)

5. Medications

Relevent past medical hx: cancer; surgeyr; kidney stones; neurological disorder; vascualr disease; chronic liver disease; kidney transplant

2. Volume depletion

3. Bladder enlargement

4. Phimosis

5. Meatal stenosis

Pain: --> exercebated by fluid load --> obstruction of renal tract

--> obstruction of bladder neck --> midline abdo discomfort due to bladder dilatation

--> ureteric obstruction --> loin to groin pain

--> obstruction at renal pelvis --> flank pain

Urethral strictures (hx of instrumentation in renal tract)

Bladder enlargement --> benign or malignant enlargement of the prostate

Examination:

1. Vitals

2. Orthostatic BP

3. Signs of hypovolaemia, hypotnesion, dehydration (skin turgor, mucous membranes, CR, warmth of extremeties)

4. Cardiac exam

5. Bruits over kidneys

6. Skin rash

7. Palpate for bladder distension

8. Rectal or pelvic exam

Ix

FBC, EUC

Catherisation

Ultrasound

UA

Page 2

On call - call about decrease urine output

Remember to assess pre-renal, renal and post-renal causes; volume status to identify the cause

On the phone:

1. How much urine has passed in the last 24 hours? (oliguria is < 500ml/day or 20ml/hr and anuria (< 100) --> oliguiria could be a sign of decline in renal function; anuria can be a sign of complete bladder outlet obstruction; blocked IDY or obstructed kidney

2. Are they complaining of any pain? (distended bladder with urinary retentino)

3. Vitals?

4. Do they have a indwelling urinary catheter? --> obstruction is a common cause of post-renal anuria or oliguira

5. Reason for admission

6. MRN

7. Significant medical hx

Instructions for nurse

1. If an IDC is present --> ask nurse to flush it with 20 -30 mL of normal saline

2. Request blood for UEC (check K, serum urea and creatitine)

Priorities

1. If patient is in pain with urine output < 20ml/hr or less than 500 mL ---> sign of AKI --> dangerous hyperkalaemia

Corridor thoughts

1. Pre-renal --> decrease in circulating blood volume ( inadequate fluid intake; haemorrhage; burns; nephrotic syndrome; diuretics; N/V/D; third spacing

--> cardiac failure

--> vasodilation (shock --> sepsis, anaphylactic, neurogenic)

--> pericaditis, PE, tamponade

--> thrombosis; dissection

2. Renal:

--> ATN; medications; poisons

--> glomerulonephritis: CTD; DM; infection; meds;

--> Interstital nephritis (infection; maligiancy; meds)

3. Post-renal:

--> Upper renal tract obstruction

--> lower urinary tract obstruction

--> blocked catheter

Threats to life

1. Hypotension and shock --> K, acidosis, renal failure,

2. Acute hypertension

3. Pulmonary oedema

Examination

1. Quick look test

2. Airway and vital signs (skin temp and colour; BP postural or hypertensive changes, HR i.e. tachy)

any menstal state changes (cerebral perfusion or uraemic encephalopathy

Look at eyes for jaundice (hepatitis, hepato-renal syndrome); slceroderma facies

Dry tongue, mucus membraes

Resp: basal creps, pleural effusions (CCF, tachpnoea, pleuritic chest pain (uraemia, SLE, neoplasm)

CVS: pulse volume, JVP, pericardial friction

GIT: enalrged kidneys; bladder

Rectal: prostate gland

Pelvic: masses

Skin: rash;

3. Review Hx, course notes (looking for pre-renal, renal and post renal)

4. Fluctuations in fluid balance chart; urine output and body weight

5. Medication chart

6. Urea: creatinine if > 10 (then pre-renal cause) if < 10 then renal cause)

Ix

FBC, UEC, BSL (esp K); LFTs

ABG

ECG

Bladder scan

Urine dipstick

Haematuria

Proteinuria

Leucocytes, nitrates

Urine MCS

Mx

1. Oxygen

2. ECG, pulse ox, BP

3. Insert IDC

4. Flush blocked catheter

5. Cease nephrotoxic agents

6. Dialysis (K, acidosis, overload (not responding to diuretics, uraemic encephalopathy)