Urinalysis & Renal Flashcards
ADH
Hypthalamus –> posterior pituitary –> AHD release –> DCT and collecting duct –> increased urine concentration
release triggered by-
increased plasma sodium
hypovolemia
hypotension
Diabetes Insipidus
low ADH
Too much water released
polyuria and polydipsia
Addisons
high potassium –> aldosterone release
low aldosterone
Diabetes Mellitus
increased blood glucose
glucose in urine
increased volume
increased USG and osmolality
signs - weight loss, polyphagia, lehtargy, cataracts
mix up with stress hyperglycemia in cats
stranguria
straining to pass urine
lower urinary or genital tract
obstructive or non-obstructive
bladder inflammation
bladder atony
urinary tract obstruction
caliculi or mineralised masses
hematuria
blood in urine
macro or micros
iatrogenic
pathological
genital source
coagulopathies - look for hemorrhage at other sites
pigmenturia - hemoglobinuria or myoglobinuria
gross - >150 RBCs/hpf
occult - >5 RBCs/hpf
dysuria
difficult/painful urination
pollakiruria
frequent urination insmall amounts
periuria
urination at inappropriate sites
anuria
failure of urine production at kidneys
oliguria
reduction of urine production by kidneys
polyuria
increased urine production
polydipsia
increased thirst
2x normal maintenance drinking - around 100ml/kg/day
Free catch
ideally mid flow
pros - easy, owner can do, non-invasive, non-traumatic, modified cat litter
cons - manual expression can rupture bladder, contamination
Cystocentesis
pros - don’t have to wait or force, easy in cats, aseptic - culture, better tolerated than catheter, easy, low risk of iatrogenic hematuria and infection
cons - some experience needed, needs enough urine in bladder, may cause rupture if severe disease or clotting problems, risk of hitting other organs - sample contamination
Catheterisation
pros - low contamination risk, don’t have to wait
cons - needs experience, easier in males, infection, hematurria, mucosal damage, contamination from lower urinary tract
USG
Normal ranges
dogs - 1.015-1.045
cats 1.035-1.060
hypostheniuria - <1.008 - actively diluting
isosthenuria - 1.008-1.012 - neither diluting or concentrating
hypersthenuria - >1.012 - actively concentrating
dehydration - >1.030
pH
high - UTI - urease producing bacteria
low - UTI - acid-producing bacteria
dipstick - bilirubin
RBC breakdown
dipstick - haem/blood
presence of hemoglobin - or alkaline urine can lyse RBCs (false positive)
dipstick - glucose
diabetes mellitus or stress induced hyperglycemia
dipstick - ketones
diabetes mellitus
dipstick - protein
kidney damage
Crystals
struvite - most common
cystine - hexagonal
calcium oxalate dihydrate - envelope
calcium oxalate monohydrate - picket fence
bilirubin - orange-brown spikes
ammonium biurate - round
amorphous - random shape - urates in acidic urine, phosphates in alkaline
Nephrolith
kidney calculus
often asymptomatic, pain, pyuria, pyrexia, PUPD
Ureterolith
ureter calculus
renomegaly, renal failure, PUPD
Cystolith
bladder calculus
lower urinary tract signs, sometimes palpable, PUPD
Urethroliths
urethra calculus
lower urinary tract signs, abdominal discomfort, licking at penis/vagina
most likely to be emergency
Urolithiasis - imaging
radiograph -
radiopaque - struvite, calcium oxalate, calcium phosphate
radiolucent - ammonium urate, cystine
Ultrasound - hard to spot
PUPD - signs (6)
needing to go out more frequently
having accidents
long stream of urine
filling bowl more frequently
at bowl more often
puddle drinking
primary polyuria with secondary polydipsia
more common
primary central diabetes insipidus - hypothalamus dysfunction, lack of ADH
primary nephrogenic diabetes insipidus - inability of DCT to respond to ADH - due to mutation
secondry nephrogenic diabetes insipidus - inability of DCT to respond to ADH - reduced sensitivity - ecoli toxins or Addisons
osmotic diuresis - diabetes mellitus, CKD, liver disease, medications
reduced medullary concentration gradient - fluid therapy, corticosteroids, addisons, liver failure
Primary polydipsia with secondary polyuria
cerebrocortical disorders - lesion affecting thirst centre
psychogenic
endocrine disorders
CKD
signs - hallitosis, decreased BCS, inappetance, oral ulcers
lost nephrons –> reduced water reabsorption
diagnosis - renal azotemia, non-regen anemia, hypokalemia, hyperphosphatemia, USG low, proteinuria
pyelonephritis
inflammation of renal pelvis
loss of nephrons –> eventual CKD
signs - lower UT signs, hematuria, pollakiuria, stranguria, spine pain, renomegaly, pyrexia, lethargy
diagnostics - US, left shift in inflammatory leukogram, urine culture and sensitivity
Pyometra
infection in progesterone primed uterus - usually ecoli
open and closed type - purulent discharge or lethargy, pyrexia, inappetence, vomiting, diarrhoea
diagnostics - left shift leukogram, azotemia, ultrasound
hyperthyroidism
over production of thyroid hormones
signs - poor condition, weigh loss, v++, d++, hyperactivity and weirdness, tachycardia, heart murmur, gallop rhythm, thyroid goitre
diagnostic - ALT and T4 increase
hyperadrenocortisim (cushings)
signs - polyphagia, pot belly, tinning skin, coat changes
diagnostics - high ALP, low USG, ACTH stimulation, low dose dexmethadone suppresion test, urine cortisol:creatinine ratio (rule out not confirm)
hypoadrenocorticism (addisons)
loss of adrenal cortical cells
signs - vague, GI signs, collapse, shock
diagnostics - Na:K under 23, ACTH stim
hypercalcemia
range of conditions but usually result of neoplasia
increase total calcium in blood
hepatic disease
increased liver enzymes (ALP, ALT, GGT), decreased urea, cholesterol albumin and glucose, bile acid stim test, imaging
Azotemia
accumulation of non-protein nitrogenous compounds in blood - urea and cretinine
uremia
azotemia that is causing clinical signs of renal failure
renal disease - pre-renal
reduced renal blood flow
expected USG >1.030
increased urine volume
resolves with fluid therapy
dehydration, hypovolemia, hypotension, shock
renal disease - renal
reduced GFR
expected USG - 1.007-1.013
azotemia sustains after fluid therapy
dehydration
renal disease - post renal
defective excretion distal to nephron
obstruction or rupture of urinary tract
dysuria
usually reversible unless renal component with nephron damage
Causes of renal disease (3)
glomerular (excretory) dysfunction - BUN, creatinine
metabolism failure - insulin, glucagon, GH
failure to synthesise - erythropoieitin, calcitrol
acid-base homeostasis
kidneys reabsorb bicarb in PCT
excrete metabolic acid load at DCT
dysfunction –> lost bicarb in urine –> reduced acid secretion –> metabolic acidosis
