Renal Dysfunction Flashcards
Why is urine normally clear/ amber coloured?
Urobilinogen - breakdown product of haemoglobin
What does SG stand for?
Specific gravity? 1003-1030
pH of urine?
Output?
5-6.5 (due to hydrogen)
0.5ml per kg per hour
What is the composition of urine?
96% water
2% urea
others: creatinine, ammonia, sodium, chlorides, sulphates, potassium
Dip stick?
Lab tests?
Variety of info about urine e.g. SG, nitrates, bilurubin, urobilinogen, proteins etc.
Urine specific gravity test - lab
1.003-1030 is normal range
Above 1030 = dehydration, higher = more dehydration
Why? Sweating,
SG- pneumonia - fast resp rates
What causes high Specific gravity?
Increased concentration of solutes... Anything that makes you dehydrated: - sweating - temperature - fast respiratory rates - UTI - more urination, dehydration - decreased renal blood flow (poor perfusion to kidney) - Excessive ADH secretion (anti-diuretic hormone)
What does HIGH specific gravity indicate?
You have extra substances in your urine e.g. - - - -
What does LOW specific gravity indicate?
Decreased concentration of solutes:
- Renal Failure
- Pylophrenitis
- Diabetus insipidus*
- Acute tubular necrosis*
- Interstitial nephritis
What is diabetes insipidus?
Condition where you produce large amounts of urine, feel thirsty,
AKA POLYURIA
POLYDIPSIA
What is Acute tubular necrosis/
Acute tubular necrosis (ATN) is a medical condition involving the death of tubular epithelial cells that form the renal tubules of the kidneys. ATN presents with acute kidney injury (AKI) and is one of the most common causes of AKI. Common causes of ATN include low blood pressure and use of nephrotoxic drugs.
What does Urine Osmolarity measure?
Number of dissolved particles in urine
It’s more accurate than SG
Useful in diagnosing diabetes insipidus, diagnosing dehydration status
What can high Urine Osmolarity indicate?
- Congestive Heart Failure
- Dehydration
- Acute Kidney Injury
- High glucose
What can LOW Urine Osmolarity indicate?
- Excessive fluid intake
- Kidney failure
- Renal tubular necrosis
What should urine not contain (measured on dipstick)
- Proteins (proteinuria)
- Albumin (albuminuria)
- Red blood cells (haematuria) (small amount = grey /smokey)
- White blood cells
(they’re too large particles)
- glucose (glycosuria)
- keytones - associated with weight loss & diabetes
- nitrites -
Urinary tract infection - what is urine like?
What is the most common cause?
What CAN show on dipstick?
Smelling bad - bacteria acting on urea to increase ammonia levels
Cloudy urine - due to exudate (infection, increased calcium or phosphates)
90% of UTIs are caused by Gram Negative Bacteria which produce nitrate reductase, an enzyme that breaks down nitrate
Dipstick - nitrites CAN show