Urinalysis Flashcards
What is dysuria?
Burning pain when urinating
What is nocturia?
Need to constantly urinate throughout night
What are the 3 most common key signs of UTIs in women?
Dysuria
Nocturia
Cloudy urine
When you skip urinalysis and instead obtain an urine culture for a female patient?
They have at least 2 out of 3 of the most common UTI key signs
When a female patient has 2 out of 3 of the most common UTI key signs, what 2 actions must you take?
Skin urinalysis, instead send urine culture to lab
Start patient on antibiotics
What are the 2 first-line antibiotics used to treat UTIs in men and women?
Oral trimethoprim
Oral nitrofurantoin
If a patient with a UTI has pain, what 2 analgesics can be recommended?
Ibuprofen
Paracetamol
Give 3 examples of non-pharmacological treatment recommendations for UTIs?
Drink plenty of fluids to avoid dehydration
Wipe front to back after defecation
Don’t delay urination
If a female patient has 1 out of 3 of the most common UTI key signs, what test do you perform?
Urine dipstick
Apart from the 3 most common UTI key signs, list 4 other symptoms of a UTI in women?
Suprapubic tenderness/lower abdominal pain
Increased urgency and frequency of urination
Haematuria (blood in urine)
Urine has strong unpleasant smell
Is urinalysis or urine dipstick necessary to confirm an UTI diagnosis?
No, but can provide additional info about underlying conditions
Is urine dipstick equally reliable in men and women?
Much more reliable in women than men
What is the precursor of urobilinogen?
Bilirubin
Where does bilirubin originate from, and how is it converted into urobilinogen?
Bilirubin is a byproduct of RBC death
Bilirubin is transported to liver and becomes bile, bile transported to intestines and changed into urobilinogen by gut bacteria
Is the total amount of urobilinogen produced excreted?
Some is stored in liver and rest is excreted in stool and urine
How does presence of urobilinogen change the visible features of stool and urine?
Urine looks yellow
Stool looks more brown
What proportion of urobilinogen in urine is considered normal?
Normal to have small amount of urobilinogen in urine
Large amount suggests that urobilinogen production has significantly increased
Give 2 examples of underlying conditions that are indicated when there is a large amount of urobilinogen in urine?
Haemolytic disease such as anaemia which is causing more RBCs to die
Hepatitis or cirrhosis, which damages liver so that less urobilinogen is reabsorbed
Give 2 examples of underlying conditions that are indicated where there is very little/no urobilinogen in urine?
Blockage in bile ducts between liver and gallbladder
Blockage between gallbladder and intestines
When are ketones produced in the body?
Produced when fat is used as energy source instead of carbohydrates
What is ketoacidosis?
Metabolic state of excessive ketone levels in blood, which makes it more acidic
How does starvation ketoacidosis occur, and why does this lead to ketonuria?
Body hasn’t received glucose as its primary source of energy for a prolonged period, so uses fat instead
Excess ketones are excreted in urine
How does diabetes ketoacidosis cause ketonuria?
Body doesn’t produce enough insulin to break down glucose, so hormones are released to break down fats instead for energy
Excess ketones excreted in urine
Does diabetic ketoacidosis tend to affect type 1 or type 2 diabetes more?
Type 1, as pancreas makes no insulin but in type 2 the pancreas still makes little insulin until resistance develops
How does ketoacidosis occur in pregnancy, and cause ketonuria?
Increased insulin resistance and lipolysis, so overall more fats are broken down which causes excessive ketone levels
What is the glucose level in normal urine?
Little to no (undetectable) glucose in urine
Give 3 possible causes of glucosuria?
Kidney damage
Pregnancy
Diabetes
Why does diabetes cause glucosuria?
Not enough insulin to convert glucose into glycogen, so blood glucose levels become too high and kidney filters excess out into urine
Why does pregnancy cause glucosuria?
Increased insulin resistance causes blood glucose levels to become too high, so excess is excreted in urine
Why does kidney damage cause renal glucosuria?
Often when proximal tubule dysfunction occurs, causes impaired reabsorption of glucose, so it is excreted in urine when it shouldn’t be
How can high vitamin C/ascorbic acid levels in urine produce false negative results of urinalysis, and in particular what 4 substances are affected?
Ascorbic acid interferes with redox reactions of dye indicators for haemoglobin in blood cells, glucose, nitrite, bilirubin presence
Produces false negative results and these 4 clinical findings are overlooked
Give one common reason for high ascorbic level in urine, and does this cause a visible change to urine?
High vitamin C level in urine due to consuming high amount of food containing vitamin C
Urine is dark orange
What substance is the precursor of nitrites, and how are nitrites formed?
Nitrates are converted to nitrites by certain nitrate-reducing bacteria such as gram-negative bacteria
If there is a high nitrite level in urine, can you confirm that there is an UTI?
Nitrituria is usually a sign of UTI presence, but can also cause false negative test
How can urinalysis produce a false negative result for nitrituria?
Some bacteria cause UTI but don’t convert nitrate into nitrite, so this will have negative result
Even if there isn’t nitrituria the patient can still have an UTI
What substance is detected in urine that are produced by white blood cells?
Leukocyte esterase
Is high leukocyte esterase level in urine always caused by an UTI?
No, elevated leukocyte esterase can also be due to kidney stones, inflammatory conditions such as SLE, tumour
Do all UTIs cause elevated leukocyte esterase in urine?
No, 20% of UTI cases have negative result for leukocyte esterase
Give 4 examples of medications that can cause high leukocyte esterase level in urine, even if there is no UTI?
PPIs
NSAIDs
Some antibiotics
Steroids
What is specific gravity of urine?
Measure of urine concentration and density compared to water
What is the correlation between urine concentration and specific gravity?
The higher the urine (solute) concentration, the higher the specific gravity
Explain 3 causes of high specific gravity?
Diabetes, due to glucosuria which increases urine concentration
Dehydration, as lower water concentration causes higher urine concentration
Heart failure, increased urine albumin excretion (UAE) caused by cardiovascular events increases urine concentration
What is diabetes insipidus?
Rare condition that causes fluid imbalance, causes frequent urination and constant thirst
Not related to type 1 and 2 diabetes
Explain 3 causes of low urine specific gravity?
Diabetes insipidus, absence/decrease of anti-diuretic hormone causes water to not be reabsorbed and it is excreted in urine, producing low urine concentration
Excessive fluid intake causes dilute urine due to high water concentration
Acute tubular necrosis
What is the complete pH range of urine, and what is the normal pH found in most individuals?
Urine pH range 4.5-8
normal urine is slightly acidic (5.5-6.5)
What substance does urine pH tend to reflect the pH of?
Blood pH
Give 2 underlying conditions that can cause acidic urine?
Septic acidosis
Diabetes acidosis
What common underlying condition can cause alkaline urine?
Systemic alkalosis
What is the proportion of protein in normal urine?
Very little/trace amount of protein
Give 4 examples of underlying conditions that can cause proteinuria?
CKD
SLE
Hypertension
RA
What is microscopic haematuria?
Blood is not visible in urine but is detected by urine dipstick
Give 4 examples of causes that can cause haematuria?
UTI
Kidney stones
Clotting disorders
Tumours
What is a visible change in urine that indicates proteinuria?
Frothy urine
Is you suspect that a patient has sepsis, should you still do a urine dipstick?
No, take urine cultures and immediately start patient on antibiotics then send patient to hospital
What is the age cutoff for doing an urine dipstick, and why is it at this age?
Aged 65, as half of patients 65 or over/with catheter have asymptomatic bacteriuria (bacteria in stomach that doesn’t cause infection)
