12 - Urinalysis

Question 1

Main tests of urinalysis

Answer 1

1️⃣ Gross appearance
2️⃣ Specific gravity
3️⃣ biochem: test strip, urinometer, refractometer (ph, protein, glucose, ketones, nitrites, br/ubg)
4️⃣ water deprevation test (desmopressin test)
5️⃣ sulphosalisylic acid test, gmelin test, ultrasensitive method, prot:creatinine , bence-jones proteins, microalbuminuria (proteins)
6️⃣ donne test(pus)
7️⃣ benzidine test(blood, hgb, myoglobin)
8️⃣ urine sediment analysis (microscopid

Question 2

Storage of sample

Answer 2

Should be processed as soon as possible!! If not:
1️⃣ refridgerated up to 12h, then warmed and mixed
2️⃣ ligth sensitive (bilirubin -> biliverdin)
3️⃣ never freeze! Cellular components - we need for microscopic examination

Routine analysis:
🔺 fresh sample, roomtemperature (4-6h)
🔺for biochem: strip, SG, gross evaluation and native stain

Not routine:
🔺 culture, put in fridge immediately!

Question 3

How to de obtain a sample

Answer 3

1️⃣ free catch (no sedation, equptment, at home, but contamination!! Cant be used for microbiological culturing) difficult in cat(special litter box). We want middle stream, first in the morning, fresh
2️⃣ catheterisation - direct from bladder
3️⃣ cystocentesis - needle into bladder through abdomen: palpation or ultrasound when animal resting lat/dors, standing too in cats

Question 4

Pros and cons with cathetarisation

Answer 4

GOOD
1️⃣less contamination, 2️⃣V measurement, 3️⃣diagnose urethra obstruction,
4️⃣good even if little urine

BAD - worst method! Never use
1️⃣cant be used for microbiological culturing,
2️⃣good catheter is needed,
3️⃣difficult in small females, but easy in large females, not male.
4️⃣Bacteria into bladder - 1/4 get uti!
5️⃣injury causing false positive for blood in urine.
6️⃣Anasthesia may be needed.

Use: measure urinary output, treat/diagnose urinaty retention, tetanus

Question 5

Cystocentesis pros and cons

Answer 5

1️⃣ only method which provides sterile samples, which can be used for bacterial culture
2️⃣ no urethrsl, genital contamination,
3️⃣ safe, usually no anasthesia

1️⃣ rare: bruising, haemorrhage, urine leakage, bladder rupture (especially in case of urethra blockage and very extended bladder) and peritonitis
2️⃣ false pos blood
3️⃣ in cats vagal stimulation can cause transient side-effects (retching, panting, collapse), from which recovery is spontaneous within a few minutes.

Question 6

Urine samples in horses

Answer 6

Urine samples of horses should always be filtered before analysis because they contain mucous and crystals which can disturb the analysis.

Question 7

Urine color description normal

Answer 7

Urobilins - yellow clear (horse may be turbid)

Question 8

Urine color description abnormal

Answer 8

1️⃣ Very light yellow or very pale: polyuria, polydipsia in diabetes mellitus or chronic kidney failure
2️⃣ Deep yellow or orange: severe dehydration or acute kidney failure, jaundice, carotenoids, B vitamins, drugs e.g. sulphasalazine
3️⃣ Dark yellow-greenish - biliverdin long term stasis of urine in the bladder e.g. urinary tract blockage; (2) long storage of sample, especially if not protected from light
4️⃣ Red, yellow-reddish: trauma or haemostasis disorders, BEETROOT or red food dyes (brown if older blood)
5️⃣ Dark red-brown, chocolate: oxidized haemoglobin, methaemoglobin present (e.g. babesiosis(old tea), paracetamol poisoning), myoglobinuria e.g. burns, myositis
6️⃣ Blue: methylene blue, multivitamins, B vitamins, food dyes and any drugs that contain blue dye, Pseudomonas spp. infection, familial hypercalcaemia, indicanuria
7️⃣ Green: asparagus and food dyes, propofol, indocyanine green administered intravenously (iv). Storage - biliverdin!
8️⃣ Cloudy or opaque: mucus – physiological in the horse, proteinuria e.g. kidney failure, strenuous exercise lipiduria, pyuria, (pus in the urine) – cellular elements mostly include white blood cells, some red blood cells, epithelial cells, casts and bacteria; (5) crystals or amorphous materials e.g. crystalluria in hyperparathyroidism.

Question 9

Describe the odour of urine

Answer 9

normally is specific, varies among species and is usually stronger in male animals than in females
1️⃣ lower urinary tract infections or bladder retention urine has ammoniacal odour
2️⃣ ketoacidosis e.g. diabetes mellitus or starvation, smell maybe sweet, fruity or acetone-like
3️⃣ Faecal contamination or E. coli infection may cause faecal odour
4️⃣ drugs e.g. penicillin or foods e.g. asparagus, B vitamins excreted through the kidneys can cause special odour (and/or colour) change.

Question 10

Describe the Transparency of urine

Answer 10

1️⃣ stored for too long, cell destruction occurs and dissolved salts in the urine become precipitated which decrease transparency
2️⃣ Opacity of the urine can also be caused by lower urinary tract infection, lipiduria and contamination with preputial or vaginal discharge

Question 11

What is the Specific gravity of urine, measure

Answer 11

an indicator of concentrating ability (tubular function) of the kidneys: ratio of the weight of the liquid to an equal volume of distilled water.
Measured by urinometer💙, refractometer, or test strip

Question 12

💙Urinometer measurement

Answer 12

Urinometers are calibrated to normal room temperature 21˚C, so results are less reliable when measurement is done in lower or higher temperature. this is the most accurate method for urine SG measurement ecause it is not influenced by opacity of urine! Easy, cheap.
👎 need a lot! Can dilute 1:1, but then
the last two digits of the result should be doubled

Urine is poured into a glass cylinder then the urinometer is placed into the urine. It should be spinned slightly so that it does not get attached to the side of the cylinder. The result is read from the scale on top of the urinometer.

Question 13

Refractometers

Answer 13

calibrated with distilled water before measurement

🔺veterinary use: contain a separate scale for cat urine as the SG is otherwise overestimated.
🔺Advantages: easy to perform, one droplet of urine sample is enough
🔺disant: not reliable if urine isnt transparent!

Question 14

Test strip measurement

Answer 14

are not very useful for urine SG measurements in animals, because the results are frequently unreliable. The SG region on the test strip contains precipitated polyelectrolyte reacts with the ions in urine, results in local pH change which gives the colour change. In animals however, other osmotically active substances influence SG e.g. glucose, proteins, urea.

Question 15

Normal range SG

Answer 15

Dep on hydration status, variable always compaire SG to hydration status!

Non persistant change: physiological
Persistant change: pathological

dogs 1015-1040g/cm3
cats 1.35-1060 g/cm3

Question 16

Hyposthenuria in SG

Answer 16

SG < 1.008
1️⃣ incr water intake (temporary)
Persistant - pathological
2️⃣ hyperadrenocorticism(⬆️Na)
2️⃣ decreased ADH-production (central diabetes insipidus - CDI)
3️⃣ resistance to ADH (peripheral or nephrogenic diabetes insipidus - NDI)
4️⃣ renal tubular damage and psychogenic polydipsia (PP)
5️⃣ hypoadrenocorticism(⬇️Na), liver disease (⬇️ urea synth), prolonged fluid therapy ➡️ medullary washout - tubular concentration ability is decreased

Question 17

Isosthenuria in SG

Answer 17

SG 1.008-1.012 (ish same as protein free plasma) most worrysome bc. No change from plasma - tubules have serious disfunction)
1️⃣tubules are not able to concentrate (or dilute) primary glomerular filtrate. This finding is an indicator of severe tubular damage.
2️⃣medullary washout
3️⃣ central diabetes insipidus - CDI
4️⃣ peripheral or nephrogenic diabetes insipidus - NDI
5️⃣ psychogenic polydipsia (PP)

Question 18

Hypersthenuria in SG

Answer 18

SG > 1.012. NORMAL! Since concentration is goal. Pathological if:
1️⃣ decreased water intake
2️⃣ substantial water loss (vomiting, diarrhoea, excessive exercise: panting – dog, sweating - horse
3️⃣ acute kidney failure (oliguria)
4️⃣ diabetes mellitus because of increased glucose concentration

Rarely exceed normal range bc polydipsia, polyuria!

Question 19

When do we measure specific gravity

Answer 19

polyuria and polydipsia, a lot of variatoon of water intake so repeat!! One measurement is no measurement!

persistent hyposthenuria, eventually isosthenuria it is necessary to perform water deprivation test.

Question 20

Water deprivation test (WDT) - goal, principle, indication

Answer 20

🔺Goal: assess concentrating ability of tubules, to differentiate between CDI, NDI and PP
🔺by checking if ADH is released(PP) or if added ADH works at 5% dehydration. C vs. N
🔺 Indications: persistent PU/PD, more than one urine SG measurement result in the range of hyposthenuria

Question 21

Water deprivation test (WDT) - Contraindications

Answer 21

1️⃣severe endocrine disturbance (diabetes mellitus,
2️⃣Cushing’s disease, Addison’s disease),
3️⃣dehydration,
4️⃣azotaemia,
5️⃣uraemia,
6️⃣liver dysfunction,
7️⃣pregnancy,
8️⃣lactation,
9️⃣growth and inflammatory disease (e.g. urinary tract infection).

Before WDT basic haematology and blood biochemistry (endocrine tests or abdominal USG) are required to rule out the above contraindications!

Question 22

Water deprivation test (WDT) - Procedure

Answer 22

1️⃣ Partial water restriction is recommended for 2-3 days prior to the test.
2️⃣ bladder is emptied by catheterisation, urine SG and body weight (BW) is recorded
3️⃣ Water and food is withheld and in 1-2 hourly intervals BW is monitored and bladder is emptied (urine SG measured!) by catheterisation
4️⃣ continued until BW reaches 5% decrease from the starting BW or urine SG >1.025 or the animal becomes depressed and/or azotaemic.

Question 23

Water deprivation test (WDT) - Interpretation

Answer 23

🔺in case of PP urine SG will become >1.025.
🔺In case of CDI or NDI urine SG will be ≤1.010 even with 5% loss of BW.
🔺Values between 1.010-1.020 are equivocal and may suggest suboptimal concentration ability in the tubules (e.g. partial CDI).

Question 24

differentiate between CDI and NDI

Answer 24

desmopressin response test can be performed: after emptying the bladder and measuring urine SG, desmopressin is administered.

Question 25

desmopressin response test in hospital

Answer 25

1️⃣admin desmopressin im, iv
2️⃣Then urine SG is measured every 2 hours (for 12 hours) and after 24 hours.
3️⃣Restrict slightly water intake (3 ml/kg/hour) to prevent cerebral oedema!

Interpretation:
🔺urine SG >1.015 indicate CDI as substitution therapy restored concentration ability of renal tubules, 🔺≤1.010 indicate NDI as ADH could not bind to receptors of damaged tubular cells.
🔺 1.010- 1.015 are equivocal and may indicate medullary washout (see Hyposthenuria).

Question 26

desmopressin response test At home

Answer 26

1️⃣admin desmopressin Po or in conjunctival sac every 12h for 5-7days
2️⃣ In the first 2-3 days limit water intake 90-110 ml/kg to prevent cerebral oedema

🔺 If CDI, owners should notice a decrease in PU/PD by the end of treatment period.
🔺Increase in urine specific gravity by 50% or more, compared with pre-treatment values, also support diagnosis of central DI (Nelson 2002).

Question 27

desmopressin response test in cats

Answer 27

1️⃣drop into the conjunctival sac twice daily for 2–3 days; a dramatic reduction in water intake or a 50% or greater increase in urine concentration gives strong evidence for a deficit in ADH production. (Bruyette 1991)

Question 28

Urine pH measurement by…

Answer 28

1️⃣pH meter (ion specific electrode - most precise method),
2️⃣urinary test strips - most used
3️⃣ indicator papers

Question 29

Test strip - how to do it

Answer 29

Dip or pipette on the urine, get rid of excess straight away with filter paper. Read after 1min.

Question 30

Test strip - interpretation

Answer 30

• only use the numbers for pH, otherwise use + on top
• We use human ones, there will be “good” and “bad” squares:

GOOD
• pH, glucose, blood
MODERATE
• nitrite, protein, ketone, br (pos protein - check with sulphosalisylic acid tes, opaque -> positive)
BAD
• SG, leukocytes, UBG

“Compensation area” on bottom is white and can help in compairing to original color - the white square shouldn`t change - mistake!

Question 31

pH normal range urine, false high low

Answer 31

herbivores is 7.0-8.5 (neutral to alkaline)

carnivores 5.5-7.5 (mostly acidic to neutral)

In case of acid- base balance alterations in the body urine pH can be 4-8.5 due to renal compensation!!

🔺False low pH can occur due to contamination by acid from the protein region of the test-strip
🔺false high pH can occur due to contamination with detergents, bleach, disinfectants and false colour can appear due to presence of blood substitute (Oxyglobin).

Question 32

Causes of pH change in urine:

Decrease

Answer 32

1️⃣ metabolic and respiratory acidosis
2️⃣ in vomiting (paradoxical aciduria) Na+ is reabsorbed with HCO3-, due to decreased HCO3- excretion urine pH becomes more acidic
3️⃣ hypokalaemia
4️⃣. treatment with acidifying drugs (e.g. ammonium chloride).
5️⃣. distalis renalis tubularis acidosis (decreased HCO3- excretion)
6️⃣. abomasal displacement
7️⃣. toxicosis with acidifying substances (ethylene glycol, methaldehyde)

Question 33

Causes of pH change in urine:

Increase

Answer 33

2️⃣. feeding in carnivores results in metabolic alkalosis bc the stomach acid is used
2️⃣. urinary tract infection (UTI) caused by urease-producing bacteria like Proteus spp., Staphylococcus spp. Urease enzyme breaks down urea to ammonia, which causes increase in urine pH to 7-7.5 - use early mor ing urine bc then ph is 6.3-6.8 (culture!)
3️⃣. metabolic and respiratory alkalosis (for causes see Acid-base balance!) results in decreased H+ excretion
4️⃣. proximal renal tubular acidosis (e.g. in Fanconi syndrome) is caused by increased HCO3- excretion to urine
5️⃣. alkalizing substances, overload of bicarbonate- or lactate containing infusion
6️⃣ long storage time causes urea decomposition to ammonia (pH increase), this can also occur in the bladder in case of urinary tract obstruction etc.

Question 34

Proteinuria

Answer 34

Very low, almost completely reabsorbed. Should always be compaired to the SG as it may Show the significance of proteinuria. Must check:
1️⃣ is it prerenal or renal?
2️⃣ then if its selective or not(alb:glob ratio, urine electrophoresis)

Question 35

Protein content of urine can be determined by which methods.

Answer 35

1️⃣ Test strips (aa from blue to green - albumin mostly) semi-quantitative
2️⃣ Sulphosalicylic-acid test(acidity coagulates protein to opaque urine, +++…) semi-quantitative
3️⃣ Heller test aka gmelin test: bile pigments and protein(layers) layer Bicarbonate under urine. Protein is under urine, semi-quantitative
4️⃣ Spectrophotometric method (ultrasensitive, quantitative) then interpret with ratio👇
5️⃣ Urine protein : creatinine ratio (UPC) - severity of proteinuria
🔺Specific methods:
6️⃣ Determination of Bence-Jones proteins: synthesized in neoplastic plasma cells due to plasma cell myeloma
7️⃣ Microalbumiuria (MA) early glomerular disease albumin in urine - test strips (screening test only)

Question 36

Pre-renal (non-renal) causes of proteinuria

Answer 36

1️⃣physiologic proteinuria by increased tubular permeability occurs in:
🔺neonates below 40 hours of age - colostral proteins are filtered;
🔺 strenuous exercise,
🔺 exposure to extreme heat or cold stress.
2️⃣ increased protein catabolism in fever and seizures, Increased blood pressure, dysproteinaemias, Haemoglobinuria during hemolysis, myoglobin durin mm injury

Question 37

Real proteinuria i.e. nephrogenic (proteinuria vera) causes

Answer 37

1️⃣ selective proteinuria: milder glomerular damage, specific tubulointerstitial lesions or infectious diseases
🔺babesiosis, leishmaniosis, ehrlichiosis
2️⃣ non-selective proteinuria: glomerular dysfunction (more severe, often irreversible glomerular damage) and in some cases severe tubular damage.
🔺 acute renal failure
🔺chronic kidney failure
🔺 nephrosis syndrome
🔺 kidney amyloidosis

(Check bp - hypothermia, temperature - exercise, stress) kodney list(urea renal factors)

Question 38

The urine protein content is usually different in case of acute and chronic renal failure

Answer 38

🔺acute renal failure urine samples have high protein concentration (inflammatory process is frequent, increased tissue damage together with oliguria – very concentrated urine).
🔺In case of chronic renal failure urine samples contain less protein (smaller tissue damage, polyuria - diluted urine). In cats and dogs severe glomerular dysfunction occurs in nephrosis syndrome and kidney amyloidosis. These are chronic diseases, however significant proteinuria (albuminuria) occurs.

Question 39

Pseudo-proteinuria (proteinuria spuria) causes

Answer 39

Unreal bc proteins originate from the cells of lower urinary or genital tract
1️⃣ It is physiological after parturition in female animals, or in males due to high amount of sperm cells or mucous from the praeputium. It is normal in horses as their urine contains highly viscous mucous.
2️⃣ It is pathological in the following cases:
🔺lower urinary tract infection, 🔺urolithiasis,
🔺prostatic or testicular inflammation, 🔺hypertrophy or tumour of the prostate gland,
🔺vaginal tumour (transmissible venereal tumour, TVT) etc.

Question 40

We can differentiate between proteinuria vera and spuria by

Answer 40

centrifuging the sample (5 min approx. 2000-3000 rpm), and repeating protein detection from the upper layer. 🔺 true proteinuria: proteins are mainly small molecules dissolved in the urine, and they do not sediment, thus proteins can be detected in the supernatant.
🔺 pseudo-proteinuria large portion of the proteins are related to cellular elements which sediment during centrifugation, thus we can not detect proteins from the supernatant.
🔺 microscopic examination: cellular elements in sediment indicate pseudo-proteinuria.

Question 41

Pus (pyuria) definition, evaluation

Answer 41

Pus is the accumulation of neutrophil granulocytes, some tissue cells, and microbes. If pus appears in urine sample it is called pyuria.
1️⃣ Donne-test
2️⃣microscopic evaluation of the sediment
3️⃣using urine test-strip(not really used)

Question 42

!Donne test

Answer 42

in-house evaluation: We drip 4-5 drops of 10% NaOH into 2-3 ml urine sample, then shake the mixture and check the speed of the elevation of air bubbles in the sample. If there is pus in sample, the components are colliquated and the sample becomes gel-like (and so air bubbles elevate slower).

(-, +, ++, +++)
Positive result may occur in males if sperm or seminal fluid is present and in horse-urine because of high mucin content.

Question 43

!!Microscopic evaluation of urine sediment

Answer 43

1️⃣ Urine samples are centrifuged upper layer is removed by one quick movement (and is used for analysis of biochemistry parameters) and the sediment is re- homogenised in the remaining droplet of urine
A🔺 One droplet of re-suspended sediment is poured out to a glass slide and covered with a cover-glass
B🔺 smears from the sediment, cytologic examination - diagnosis of urinary tract tumors!!

Question 44

Causes of pyuria:

Answer 44

1️⃣Physiological in horses
2️⃣Kidney pelvis inflammation (i.e. cattle Corinebacterium pyogenes infection)
3️⃣Cystitis (inflammation in the urine bladder)
4️⃣ inflammation in the genital tract e.g. balanitis (inflammation of the glans penis) or prostatitis in males or vaginitis, endometritis in females

Question 45

Tests used for Haematuria, haemoglobinuria and myoglobinuria

Answer 45

1️⃣benzidine test
2️⃣urinary test-strip
3️⃣ microscopic evaluation(Urine sediment analysis) 🔺major method to differentiate haematuria from haemoglobin- and myoglobinuria.
🔺 centrifuge - clears ut: haematuria, sediment: hgb, myoglobin(check ezymes to defferentiate! muscle damage indicator enzyme activities are elevated (CK, LDH))

Can see color - macrohaematuria
Cannot - microhaematuria (microscope)

Question 46

Benzidine test

Answer 46

Detection of blood, haemoglobin or myoglobin - micro-haemoglobinuria
🔺 qualitative
🔺 sensitive, not specific(show all three not which)
🔺 enzyme will cause color change

Question 47

Causes of haematuria:

Answer 47

1️⃣Lower urinary tract infection
2️⃣ Trauma bladder rupture, car crash
3️⃣ Genital tract injury, tumor or inflammation e.g. endometritis, prostatitis, hypertrophy of
the prostate gland
4️⃣ Infectious or non-infectious inflammatory process in the lower or higher urinary tract
5️⃣ Renal infarction
6️⃣ Thrombocytopenia, coagulopathy (see Haemostasis!)

Question 48

Causes of haemoglobinuria:

Answer 48

􏰄 Intravascular haemolysis (IHA, babesiosis)

􏰄 Long term stasis of blood in he urine bladder

Question 49

Causes of myoglobinuria:

Answer 49

􏰄 excessive muscle trauma or exercise, ischaemia (aortic thromboembolism in the cat),
myositis, burns

Question 50

Glucosuria causes

Answer 50

1️⃣Hyperglycemia - diabetes mellitus, stress in cats
2️⃣ renal tubular defects resulting in decreased reabsorption capacity e.g. Fanconi syndrome, primary renal glucosuria etc.

(If high blood glucose there can be many causes, if very high, DM)

Question 51

Glucosuria tests

Answer 51

🔺most frequently tested using urine test-strips. The glucose oxidase/peroxidise (GOD/POD) reagents are precipitated on the test strip (see Metabolic parameters).

Question 52

Ketonuria

Answer 52

Physiologically ketone bodies are not present in the urine

usually tested using urine test-strips, where ross reagent is precipitated. Not very sensitive. Not B hydroxybutyrate)

Question 53

Nitrite

Answer 53

🔺Nitrates (-NO3) are reduced to nitrites (-NO2) by bacteria (e.g. E. coli, Klebsiella, Salmonella spp. etc, but not Pseudomonas!)
🔺 urine test-strips, pos: UTI

In carnivores this test is unreliable

Question 54

Bilirubin, urobilinogen

Answer 54

Dont use in cat, dog, in general not very reliable!

Conjugated bilirubin can be present in the urine of healthy dogs. In other species bilirubinuria appears in jaundice (pre-hepatic, hepatic, post-hepatic)

urinary test-strips (diazo-test) or the Gmelin-test (cc. nitric acid)

Question 55

Urine sediment analysis

Answer 55

1️⃣ constant amount(!) of fresh (re-warmed if stored in refrigerator) urine sample should be centrifuged in a conical centrifuge tube gently
2️⃣ The supernatant is decanted (one quick movement) and can be further used for the above biochemistry evaluations. The sediment is rehomogenised by the remaining droplet of urine in the apex of the tube 3️⃣ One droplet of resuspended sediment is poured on a glass slide, a coverslip is placed on the droplet
4️⃣ evaluated firs on low power then high

Question 56

Urine sediment analysis using a smear

Answer 56

1️⃣ droplet of resuspended sediment, dried at room temperature and fixed and stained by routinely used haematological stains.
2️⃣The stained smear allows us to use 1000x (immersion oil) magnification to assess cell quality e.g. neoplastic cells and presence of bacteria –
3️⃣ this is called cytological evaluation of urine sediment and is especially useful for the less experienced evaluator.
4️⃣We classify sediments to organic and inorganic components.

Question 57

Organic sediment

Answer 57

RBC, WBC
- Normal: <5 /hpf (high
power field). Abnormal: haematuria: renal or urinary tract disease, obstruction, trauma, neoplasia, thrombocytopenia and coagulopathies, sometimes cystocentesis. In acute bleeding thrombocytes are frequently seen; 5-6 hours or older bleeding erythro- phagocytosis is seen.

Cells from the lower urogenital tract:
• Normal: 0-2/hpf small cells from the kidney/upper tract or bigger cells from the bladder; sperm cell in males). Abnormal: inflammation or infection of upper and/or lower urinary tract, inflammation of genital tract (e.g. prostatic gland, uterus), neoplasm.
• urothelium cells: large, round to oval shape, central round nucleus, abundant cytoplasm
• renal tubular cells (with smaller more condensed cytoplasm and round nucleus)
• squamous cells from the penis or vagina: big, angular shape, very small nucleus, large light cytoplasm
• sperm cells; tumour cells

• Viral inclusion bodies
• bacteria, parasites, fungi
• Mucin: fat droplets normal in cat
• casts: formed from mucoproteins produced by the renal tubular cells
- Normal: small amount of hyaline or granular casts.
- Abnormal: increased number of casts – acute tubular disease or renal tubule damage (hyaline, granular casts), haemorrhage (RBC cast), inflammation (WBC cast). Casts quickly deteriorate with storage and are flushed from the kidney intermittently, so their absence does not exclude the above pathological conditions!

Question 58

Inorganic compounds in urine

example of why they are in urine

Answer 58

alkaline urine
1️⃣struvite: urease + bacteria - UTI
2️⃣calcium-carbonate and calcium-phosphate: hypercalcuria - hyperparathyroidism
3️⃣amorphous phosphate: meat and grain diet
4️⃣ammonium-ureate/biurate: impaired hepatic function - PSS, dalmatian dog

acidic urine
1️⃣calcium oxalate: cat eating toxic plant
2️⃣uric acid: dalamtian dog
3️⃣cystine, tyrosine, leucine: metabolic disease
4️⃣bilirubin crystals: prehepatic and hepatic jaundice
5️⃣sulphonamides: sulphonamide therapy

Question 59

Struvite

Answer 59

Inorganic sediment Causing stone formation in high amount in alkaline urine mostly

coffin-like) (tripplephosphate, magnesium-ammonium-phosphate): presence of urease positive bacteria in UTI (urinary tract infection).

Question 60

Calcium oxalate:

Answer 60

Inorganic sediment Causing stone formation in high amount in acidic urine mostly:
🔺monohydrate (needle-like) (e.g. ethylene glycol poisoning, consumption of toxic plants in cats e.g. Dieffenbachia, Philodendron), 🔺dihydrate (envelope-like) (e.g. long term feeding of high-oxalate diet: fruits, some vegetables)