Poor Urinary Output Flashcards
What is important to ask if you find a patient with poor urinary output?
- trend in urine output: suddenly stopped or gradually decreased? checked catheter not blocked by flushing it
- obs of patient: HR, BP, Resp rate, O2 sats, and temp to see how unewell
What is the urine output of a healthy adult roughly?
1mL/kg/hour
What is oliguria?
reduced urine output
How is oliguria defined?
<400mL/day
<0.5mL/kg/hr
<30ml/hr
What does anuria refer to?
complete absence of urine output
Why does decreased urine output need to be taken seriously?
could be first and only sign of impending acute renal failure
What can happen to untreated patients of poor urinary output?
die due to
- hyperkalaemia
- profound acidosis,
- pulmonary oedema as kidneys not doing usual role
What does normal urine output require?
- Adequate blood supply to kidney
- Functioning kidneys and
- Flow of urine from kidneys, down ureter, into the bladder and out via urethra
What are the pre-renal (i.e. inadequate blood supply to kidney) causes for poor urinary output?
- Hypovoleamia
- Hypotension
- Hear failure
- Reduced local perfusion of kidneys
What can cause hypovolaemia?
decreased circulating volume due to e.g. dehydration, haemorrhage
What can cause hypotension?
decreased vascular resistance due to e.g. sepsis, pancreatitis
What can cause reduce local perfusion of kidneys?
e.g. dissecting aneurysm, renal emboli
What are the renal (i.e. damage resulting in impaired kidney function) causes of poor urinary output?
1, Tubular causes
- Glomerular causes
- Interstitial causes
- Vascular causes
- Infectious causes
- Complex mechanism
What are the tubular causes of poor urinary output?
acute tubular necrosis
What are the glomerular causes of poor urinary output?
glomerulonephritis
What are the interstitial causes of poor urinary output?
interstitial nephritis (caused by drugs e.g. NSAIDs and antibiotics)
What are the vascular causes of poor urinary output?
- Vasculitides
- Haemolytic uraemic syndrome
- Thrombocytic thrombocytopenic purpura
- Disseminated intravascular coagulation
- Malignant hypertension
- Scleroderm
What are the infectious causes of poor urinary output?
- Malaria
- Legionnaires’ disease
- Leptosipirosis
What are the complex mechanism causes of poor urinary output?
multiple myeloma
What are the post-renal (i.e. obtstruction to urinary flow) causes for poor urinary output?
- ureter
- bladder
- urethra
What are the ureter causes of poor urinary output?
- Abdominal/pelvic mass (e.g. tumour) compressing ureters
- Complication of pelvic surgery
- Bilateral calculi
- Retroperitoneal fibrosis
What are the bladder causes of poor urinary output?
- Neuropathic bladder
- Anticholinergic or sympathomimetic drugs
- Bladder stones or tumour
- Uterovaginal prolapse (women)
What are the urethra causes of poor urinary output?
- BPH
- Blocked catheter
- Prostate cancer
- Urethral stricture
- Posterior urethral valve
- Trauma
- Infection (e.g. herpes simplex making it painful to pass urine)
What 5 things must you check to establish cause of poor urinary output?
- fluid balance chart
- surgical opt notes
- drug chart
- blood test results
- PMHx
What do you check on the fluid balance chart?
- Adequate intake
2. Positive balance