Urinalysis part 2 Flashcards
what does hemoglobin bound to haptoglobulin cause?
hemolyzed plasma
where does excess unbound hemoglobin go?
urine
+/- hemoglobin casts
+/- damage to proximal tubular cells
what happens with acute syndrome of copper toxicity in sheep?
bolus of excessive amounts: feed/pastures
severe gastroenteritis and then hemolysis
what happens in chronic syndrome of copper toxicity in sheep?
days to weeks: low molybdenum/sulfur intake and/or hepatotoxic plants
precipitating stressors lead to disease
what do horses and camelids need to ingest to get red maple toxicosis?
wilted leaves of Acer rubrum
what does copper and red maple leaves cause to red blood cells?
oxidative injury
methemogloninemia
intravascular hemolysis due to oxidation
Heinz bodies due to denaturation of oxidized hemoglobin: extravascular hemolysis
what is a common cause of hemolysis in dogs?
zinc toxicity
what does zinc cause in dogs?
oxidation through inhibition of protective enzymes
possible multi-organ damage
what are some causes of intravascular hemolysis other than heavy metals and red maple?
infectious disease
immune mediated
red blood cell metabolic defects
envenomation
what is rhabdomyolysis?
muscle necrosis
what can be seen with rhabdomyolysis?
muscle enzymes elevated in serum: creatine kinase and AST
is anemia and hemolytic serum present with rhabdomyolysis?
not usually
in whom is pigment nephropathy common in?
large animals
what causes pigment nephropathy?
hemoglobin and myoglobin being broken down
nephrotoxic heme protein
what are the mechanisms of pigment nephropathy?
tubular obstruction by casts
tubular cells ingest hemoglobin
increased synthesis of vasoconstrictive molecules
_____________ can be toxic to renal tubules- cause of AKI
especially in humans and large animals
myoglobin
your patient has a positive heme (blood) reaction and red blood cells in the sediment. what is the best interpretation for these findings?
hemorrhage in the urinary tract
artifact if did cystocentesis (hit capillary)
your patient has a positive heme (blood) reaction, but there are no red blood cells in the sediment. what is the best interpretation for these findings?
skeletal muscle necrosis and myoglobinuria
intravascular hemolysis (red blood cells breaking down within blood vessels) and hemoglobinuria
where does bilirubin originate from?
destruction of old worn-out red blood cells by macrophages in the spleen
only _____________ bilirubin can cross the glomerular wall
conjugated
why can unconjugated bilirubin not cross the glomerular wall?
bound to albumin: too large
albumin already too large to cross
is bilirubin normal to have in the urine of most species?
no
in what species is some bilirubin normal in the urine? what amount?
dogs and ferrets with highly concentrated urine
trace to 1+
renal epithelium in ____________ can conjugate bilirubin
male dogs
what are some causes of bilirubinuria?
hemolysis
hepatic disease
bile duct obstruction
what does extravascular hemolysis (increased rate) lead to?
anemia
bilirubinuria
jaundice
icteric serum
what is the rate-limiting step of elimination of bilirubin?
gall bladder excreting conjugated bilirubin
what does increased intravascular hemolysis lead to?
anemia
bilirubinuria
jaundice
increased bilirubin
hemoglobinuria
hemolyzed serum
what does hepatic disease lead to?
bilirubinuria
jaundice
icteric serum
increased liver enzymes
what does biliary obstruction lead to?
bilirubinuria
jaundice
icteric serum
increased liver enzymes
what in hepatic disease actually leads to accumulation of bilirubin?
excretion: conjugated (by liver) bilirubin accumulates
most glucose is absorbed in _______________
proximal tubules
when will you see glucosuria?
serum glucose exceeds renal threshold
what is the renal threshold for serum glucose for most species?
180 mg/dl
what are some things that can cause hyperglycemia that leads to glucosuria?
diabetes mellitus
hyperadrenocorticism
epinephrine secretion
what are some things that can cause the proximal tubule to be unable to handle the normal load of glucose?
acute renal failure
congenital proximal tubular disorders
what breeds are predisposed to hereditary renal glucosuria?
norwegian elkhounds
scottish terriers
what does hereditary renal glucosuria cause?
defective proximal tubular transport of glucose
what is fanconi syndrome caused by?
defect in multiple proximal tubule transporters
is GFR normal in fanconi syndrome?
yes: not usually azotemic
in fanconi syndrome, animals have high excretion of:
glucose
amino acids
bicarbonate
electrolytes (Na, Cl, K, Phos)
who is hereditary fanconi syndrome common in?
basenjis
what is the urine like with fanconi syndrome?
glucosuria with normoglyemia, +/- proteinuria, ketonuria
isosthenuric to minimally concentrated
what can cause acquired fanconi syndrome?
chicken jerky treats
heavy metals
copper storage
chemicals
what leads to cystinuria?
sex-linked or autosomal recessive defect in cysteine transport
what causes hyperuricosuria?
missing transporter for uric acid uptake: liver, kidney
what does hyperuricosuria lead to?
urate crystals in urine
what is ketonuria caused by?
negative energy balance
what are some conditions that can lead to negative energy balance?
bovine ketosis and hypoglycemia
pregnancy toxemia
diabetes mellitus
starvation
what do the urine tests for ketonuria detect?
acetoacetic acid
also some for beta-hydroxybutyric acid
what does the proximal tubule of the kidney do for acid/base regulation?
NaBicarbonate absorbed in proximal tubule:
carbonic anhydrase needed
what do alpha intercalated cells in the collecting duct and distal convoluted tubule do to the blood and urine (overall)?
alkalinize blood
acidify urine
what are some causes of aciduria?
diet: normal in carnivores
acidosis
hypokalemia (associated with alkalosis)
hypochloremic metabolic alkalosis can be associated with ________________________
paradoxic aciduria
hypochloremic metabolic alkalosis starts with loss/sequesteration of gastric fluid, which leads to:
dehydration
alkalosis
hypochloremia
hyponatremia
hypokalemia
what are some causes of alkalinuria?
diet: normal in herbivores
urease producing bacteria
post-prandial
alkalosis
storage at room temperature
what are the clinically important urease-producing pathogens?
Staphylococcus
Klebsiella
Pseudomonas
Proteus
how do the kidney proximal tubules respond to dehydration?
increases absorption of Na and water
Na co-transported with HCO3-
worsens alkalemia, acidifies urine
what makes up distal renal tubular acidosis- type I?
selective impairment of H+ secretion in collecting ducts
why is it a problem that tubular cells ingest hemoglobin?
free heme creates oxygen radicals
membrane, mitochondria, DNA damage
methemoglobin more toxic than hemoglobin
when can glucosuria occur secondary to renal disease?
acute renal failure
congenital proximal tubular disorders
what is normal carnivore urine pH?
5.5-7.5
what is normal herbivore urine pH?
7.0-8.5
