Clinical Skills Flashcards
What could be abnormal on observation of urine?
Colour - Turbidity - Odour
What are causes of abnormal colour of urine?
Brown = bile pigments, myoglobin - brown/black = bile pigments, melanin, methaemaglobin - green/blue = pseudomonas UTI, biliverdin - orange = bile pigments - red = haematuria, haemoglobinuria, myoglobinuria, porphyria - yellow = dehydration
Name some causes of cloudy urine
Contamination with vaginal mucus or epithelial cells
Excess phosphate crystals in alkaline urine
Pyuria - infection
Lipiduria
What are causes of abnormal odour?
Pungent = concentrated Ammonia = alkaline fermentation Fruity = diabetic ketoacidosis Faecal = GI fistulae
What is specific gravity?
Says how much more dense urine is than water
What are causes of increased specific gravity?
Dehydration - glycosuria - renal artery stenosis - heart failure - inappropriate ADH secretion - proteinuria
What are causes of decreased specific gravity?
Excessive fluid intake - renal failure - pyelonephritis - central and nephrogenic diabetes insipidus
What is the normal pH of urine?
4.5 - 8
Is urine normally acid or alkaline?
Acidic (5.5-6.5) - due to metabolic activity
What are causes of acidic urine?
Dietary intake and uric acid calculi
Define haematuria
Presence of blood in the urine
Why may you get a false positive reading for haematuria?
Contamination with menstrual blood, dehydration and exercise
Define proteinuria
Presence of protein in the urine - albumin:creatinine ratio >30mg/mmol
How much protein is normally excreted per day?
80-150mg
What does the presence of proteinuria indicate?
Renovascular disease - glomerular interstitial disease - tubulointerstitial disease - multiple myeloma
What is the normal concentration of glucose in urine?
10mmol/L
What does increased glucose in urine indicate?
Diabetes mellitus
Are ketones normally found in the urine?
No
What does a positive dip for ketones indicate?
Uncontrolled diabetes, pregnancy without diabetes, carbohydrate free diets and starvation
Does bilirubin normally appear in urine?
Unconjugated bilirubin is not water soluble so doesnt appear in urine
Conjugated bilirubin appears in liver disease or obstruction of bile ducts
Insignificant amount of urobilinogen found in urine
In what situation would urobilinogen be increased?
Conditions associated with increased nitrate levels - eg. UTI
Why would nitrites be found in the urine?
Gram -ve and +ve bacteria breakdown urinary nitrates to nitrites
Why would leukocyte esterase be found in the urine?
It is produced by neutrophils - pyuria associated with UTI
How do pulse oximeters work?
Relative absorption of red by deoxygenated haemoglobin and infrared by oxygenated haemoglobin light of systolic wave form correlates to blood saturations. Two light emitting diodes are positioned opposite their detectors through tissue