2Urinary SystemDesigned to maintain a balance between fluid, electrolytes, and acid-base homeostasis by selectively eliminating waste products from the body.Urine is formed through glomerular filtration, tubular reabsorption, and tubular secretion (remember everything you were taught in A&P).These are influenced by hormones
4Medical Terminology Pollakiuria Polyuria Oliguria Anuria Dysuria Frequent urinationPolyuriaIncreased urine output or productionOliguriaDecrease in the formation or elimination of urineAnuriaComplete absence of urine formation or eliminationDysuriaDifficult urination
5UrinalysisUrine collection can be accomplished through mid-stream free catch, manual expression, catheterization, and cystocentesis.
6Advantages to Urinalysis FastSimpleInexpensiveProvides useful information (urinary tract and/or other body systems)
7Voided Urine Sample Easiest to obtain May be contaminated from distal genital tractNot satisfactory if examining for bacteria.
8Voided Urine Sample Collection Use a clean containerWash prepuce or vulva (when possible)Try to collect mid-stream urine
9Disadvantages to Voided Sample ContaminationDifficult in catsMay be difficult in easily scared dogs and short breeds
10Expressing the Bladder Use steady gentle pressureWill feel like a balloon or ball under your hands.Make sure you are expressing in a squeezing motion where you are forcing urine down urethra.Wash external genitaliaContamination from lower urinary tract/genital tract is a concern.DO NOT DO MANUAL EXPRESSION WHEN THERE IS AN URETHRAL OBSTRUCTION!!!
11Urinary Catheterization Act of placing a catheter through urethra into bladderAdvantages:Less possibility of contamination from lower genital tract.Helpful in obese animals when bladder is difficult to palpateDisadvantagesTrauma to sensitive urethral mucosaPossible contamination
13CystocentesisAct of obtaining a urine sample via a needle and syringe directly from the bladderAdvantagesSterile sampleDisadvantagesDifficult to obtain in obese animalsTrauma to organs if not done correctly
16Urine Sample Preservation Analyze all urine within 30 minutes if possibleMay refrigerate for 6-12 hours if neededBring to room temperature before anlaysisMorning samples are more concentratedIf allowed to stand at room temperature, may get false results.
17Physical Characteristics of Urine ColorTransparencyOdorSpecific gravityVolume
18Urine Color Normal color is due to pigments called urochromes Normal: light yellow to amber colorAbnormals:Red: blood (hematuria)Reddish-brown: Hemoglobin or MyoglobinDark yellow-brown: Bilirubin (bilirubinuria)Orange-Reddish brown: Normal in rabbits
20Urine Transparency Clear vs. Cloudy Cloudy could indicate increase cells, mucus, casts, crystals and bacteria.Horses and some rabbits have cloudy urine due to high content of mucus and calcium carbonate crystals.
21Urine Odor Not Very diagnostic Strong odor may suggest bacterial productionMale cats, goats, and pigs have a very strong urine odor
22Urine Specific Gravity Measure urine concentration which is dependent on the number, molecular size, and weight of urine solutesMeasures the density of urine as it compares to waterSpecific gravity of water is always 1.000
23“Normal” Urine Specific Gravities Man:Dog:Cat:Horse:
24Methods of collecting a urine specific gravity RefractometerReagent stripUrinometer
25Causes of Altered Specific gravity Increased specific gravityDehydrationIncrease fluid lossDecreased water intakeDecreased specific gravityKidney diseaseExcessive waterPyometraSome drugs
26Urine Volume Influenced by several factors Water intake Size of animal Species of animal
27Crystals The presence of crystals in the urine is called crystalluria. There are many types of crystals that can form in urine, we are going to cover just a few. (More to come in Clinical Pathology!)Crystalluria may or may not be of clinical significance.Certain crystals form as a result of elements being secreted into the urine by normal renal activity.
28Crystal formationCrystal formation depends on the pH of the patients urine.Some crystals form in acidic urine, while others form in basic or neutral urine.If a urine sample is allowed to stand and cool to room temperature, the number of crystals in the urine will increase because the material that forms the crystals is less likely to dissolve at cooler temperatures.
29Types of crystals Triple phosphate Includes Struvite, and Ammonium Magnesium Phosphate.While their name may be interchanged, these crystals have slightly different composition.Generally appear as “coffin lids” or roof-topsForm in alkaline to slightly acidic urine.May take a fern-leaf shape if urine has high concentration of ammonia
31Calcium Oxalate Dihydrate Generally appear as small squares with a visible “X” across the top of the crystal.Most often form in acidic and neutral urine.Are commonly seen in small numbers in dogs and horses.If seen in large numbers, can indicate calculi formation.
33Calcium Oxalate Monohydrate May be small and “dumbbell” shaped, can also appear as a slat from a picket fence.Generally form in any pH urine, but are a key indicator if an animal is experiencing ethylene glycol toxicity!
35Uric Acid/Ammonium Urate Crystals Uric Acid crystals often appear as yellow-brown “rosettes” or as diamond-shaped “plates”.Can form in any pH urine!Ammonium Urates often appear as “thorn-apples”Generally form in neutral to alkaline urine.Are very rarely seen in dogs and cats. (Except Dalmatians!!)