urinary Flashcards
cats kidney
-true unipyramidal before and after birth
-can be yellow if cat is obese and is normal
-FIP leads to vasculitis which is white lesions following vasculature. if not following than could be neoplasia
Horse kidney
-left normal, right heart shaped.
-urine has lots of calcium carbonate cloudy pee is normal
major components of the kidney
-if you damage one the others will follow, damaged glomeruli leads to damaged tubules. -vessels, glomeruli, tubules, interstitum.
-kidney looks the same in chronic stages of the disease
vascular supply to the kidney
-20-25% cardiac output
-helps maintain BP
-supplied by end arterioles
-supplied by renal artery
Regulation of renal blood flow
Juxtaglomerular apparatus
1. Juxta glomerular cells (afferent arteriole)
2. Efferent arteriole
3. Macula densa (distal convoluted tubule)
4. Mesangial cells
what and how kidneys respond to changes in BP
Respond to:
1. Depletion of extracellular fluid–> ADH release
2. Decrease in renal blood pressure–> ang-II
3. Decrease in sodium chloride-> Aldosterone
glomerulus
Function: production of the ultrafiltrate
Structure:
- Capillaries
- Mesangial cells
- Podocytes
Glomerular Filtration Barrier
- Composed of
1. Fenestrated endothelium
2. Glomerular basement membrane
3. Podocytes
-selective permeability based on size, charge, and capillary pressure
tubules
_Proximal convoluted tubules:
* Reabsorb water, solutes
(Na, Cl, HCO3), glucose,
amino acids
* Excrete hydrogen.
* PT have large number of mitochondia since they need lots of energy.
-first structure to encounter toxins ect. will get necrosis first. decreased renal BP can cause death of tubule cells.
loop of henle
- Creats a corticopapillary
osmolarity gradient**
-the one structure responsible for water conservation/ reabsorption. - Establishes hypertonicity
within the medullary interstitium - Descending loop is
permeable to water only
(water goes out) - Ascending loop is
permeable to solutes only
(solutes go out)
how is urine concentrated?
- Two requirements for urine concentration:
1. Cortico-papillary osmolarity gradient
(within the interstitium) created by countercurrent multiplier (loop of henle) and urea recycling in the renal medulla.
2. Presence of ADH
Collecting duct
- Permeable to small amount of water but not urea (except at its distal end)
- Susceptible to ADH which causes the collecting tubules to become more permeable to water
- ADH increases water reabsorption from 4%-24%
Interstitium:
- Contain peritubular capillaries and fibroblasts
- Expansion is abnormal and may occur due to
edema, infiltrate or fibrosis
examining capsule of kidney
- should be able to remove easily, if you are unable to it means there is renal fibrosis. Capsule is stuck to the kidney.
-ex. horses can be hard to peel
Functions of the kidney
- Formation of urine elimination of waste and conservation of water
- Acid-base regulation
- Maintenance of electrolyte balance
- Endocrine function:
– Renin-angiotensin system (hypertension with renal failure)
– Erythropoietin (rbc formation) can get anemia with renal failure
– Vitamin D
Kidney function requirements
- Adequate blood flow
- Functioning nephrons
- Excretion of urine
Azotemia
-Increased concentration of non-
protein nitrogenous wastes (urea and creatinine) in the BLOOD
3 causes:
1. Pre-renal azotemia
2. Renal azotemia
3. Post-renal (obstruction)
azotemia and renal failure
-azotemia in blood and low USG in urine means renal failure.
-you can have azotemia and no renal failure.
Renal failure, 3 types and causes
-Impaired renal function associated with azotemia
* 75-80% of the renal function is lost
Pre renal causes: Shock, hemorrhage, heart failure, severe
dehydration, DIC. related to blood.
- Renal causes: damage to tubules or glomeruli by a long list of
industrial or natural (plant) toxins and metals, acute
glomerulonephritis, renal infection. related to renal disease. - Post renal causes: Obstruction within the lower urinary tract.
- Can be acute or chronic
- Can be reversible
uremia
-The syndrome associated with
multisystemic lesions and clinical signs because of renal failure.
-animal with uremia will have azotemia.
- Clinical syndrome of renal failure
- Can be seen with acute and chronic renal failure (more in chronic).
- Results in gross lesions within other organs via one of two mechanisms: ***
1. Vascular endothelial injury
2. Alteration in Ca/P balance
End Stage Renal Disease or Kidney disease
- Renal function is less than 5% of normal
- Animal is in the terminal stages of uremia
acute renal failure
- Acute and sudden reduction in renal function that result in
azotemia - Cause is severe damage to kidney components from pre-renal,
renal or post renal causes - BUN and creatinine are both high and urine specific gravity is low
- Reduced blood pH (metabolic acidosis)
- Alterations in plasma ion concentrations, particularly hyperkalemia, calcium, and phosphate
-hyperkalemia effects heart and can kill animal - Can be reversible
Chronic Renal Failure
- Similar to acute BUT longer duration and irreversible
- Most common renal disorder in dogs and cats
- Usually progressive loss of renal function
- Usually high blood phosphate and low calcium and normal to low potassium
-diffusly fibrotic kidneys, white, shrunken. could have areas of uremia.
How uremia produces gross lesions following vascular injury
-Vascular injury causes one or more of the following:
1 . Thrombosis, ischemia, necrosis and hemorrhage
2. Increased vascular permeability (edema)
3. leakage of urea and its conversion to caustic ammonia by bacteria leading to ulceration
How uremia produce gross lesions
Alteration in Ca/P balance.
Low Ca and high P
- Chronic renal failure causes low Ca and high P due to decreased GFR
- Chronic renal failure causes decreased Vit. D production leading to decreased gut absorption of Ca.
Consequences of low Ca and high P:
- Parathyroid hyperplasia and increased parathyroid hormone. bilateral usually renal failure, one usually thyroid.
- Fibrous osteodystrophy (release of Ca from bone and with time Ca is
replaced by fibrous tissue)
- Widespread mineralisation***
where to exam gross if you have renal failure
-bilateral parathyroid hyperplasia
-oral cavity (tongue tip necrsis or ulcerative glossitis)
-stomach: uremic glossitis, in small animals, uremic colitis in large animals.
-bones (grab rib bone is it bends there is fibrous osteodystrophy)
Renal Dysplasia
- Renal dysplasia is disorganized development of renal parenchyma due to anomalous differentiation
- Congenital
- Young animals present with renal failure
- Cause:
Unknown (viral, random hereditary abnormality)
Progressive Juvenile Nephropathy
- A form of renal dysplasia?
- Also known as familial (hereditary) renal disease
- Young dog disease
- Runs in families of dogs and in specific dog breeds
- Hereditary
-white fibrotic misshaped kidney
renal cysts
- Dilated nephron structure filled
with water fluid - Acquired: secondary to fibrosis squeezing tubules.
- Congenital
Polycystic Kidney Disease
- Inherited as an autosomal
dominant trait in families of Persian
cats and bull terriers and
others….. - Can lead to renal failure
Renal congestion
-Difficult to recognize grossly because of the
color of the kidney
Example: Right sided heart failure will lead to
renal congestion
Renal hemorrhage
-Examples DIC, bacterial
septicemia , viral disease
-canine herpes virus 1 ***infection causes echmotic hemmorages on surface of kidney of puppies/ dogs 90% time
Renal infarction
-Cause: obstruction to renal vasculature.
-Appearance depends on type of obstructing material and size of affected vessel and duration
-Often wedge shaped
-chronic will have area of depression
-if obstructing material is infected you will see pus in kidney, valvular endocarditis or bacteria give you septic emboli which is an infected infarct.
-wedge shaped area red and buldging (necrosis and hemmorage)= acute, significant for the case (not the kidney) look at AV valve.
-wedge shaped, pale from fibrosis (acute to subacute)
-wedge shaped, bulging with hyperemia (subacute)
-wedge shaped, depressed =chronic infarcts are insignificant unless abscessed
which vessel is blocked during renal infarction
-Arcuate artery: wedge of both cortex and
medulla, straight line infarction.
Interlobular artery: wedge limited to the
cortex
Renal Papillary/Medullary Crest
Necrosis
-white/yellow/green dull lesion at renal papillae, could have hyperemia.
Causes:
1. NSAIDs by inhibiting PGE-2 which is a vasodilator, while the horse is dehydrated.
2. Space occupying mass: If severe leads to loss if urine concentrating ability and renal failure. (amyloidosis can aslo cause renal pap necrosis)
-esp cats renal vasculature is very thin walled (and other animals mass pushes on vasculature leading to renal papillary necrosis.
Glomerulonephritis (GN)
-disease within the glomerulus with extension to tubules and interstitium.
-type of glomerular disease–> cause of renal failure
-gross: will have thickened glomeruli, cortex will have bumpy appearance
path:
-immune complexes are deposited in the kidney->Immune complex glomerulonephritis
* Most common and most important form of GN in
domestic animals
- Non-glomerular antigen-antibody complexes
localize in glomeruli and cause damage - Most cases are related to prolonged antigenemia
secondary to viral infection
Hydronephrosis
-Hydronephrosis is dilation of the renal pelvis*** and calyces associated with progressive atrophy and cystic enlargement of the kidney.
* Cause is Urinary Obstruction:
* Ureteral obstruction leads to severe unilateral hydronphrosis. unilateral = incidental finding.
* Lower obstruction leads to bilateral hydronephrosis with less severe kidney lesions
- The kidney lesions are always more severe with Unilateral hydrophrosis.
-if bilateral animal dies from uremia –> hyperkalemia which leads to heart arrythmias before it progresses.
glomerular diseases
*can lead to Nephrotic syndrome you will see hypoalbuminemia, edema and hyperphosphatemia.
* Animals with GD can be hypercoagulable** due to loosing antithrombin 3 in kidneys.
-glomerular disease = very high proteinuria with no inflammation. (no inflammatory cells in urine) also high prot could be from amyloidosis.
Types of glomerulonphrotis
- Membraneous (cats)
- Proliferative (horses)
- Membranoproliferative (dogs)
You will read these terms in histology reports, immuno florescent, PAS stains
amyloidosis
-orange organ
-can also react with iodine and give us black dots
* Reactive amyloidosis is the most common type
* Dogs: Glomerular deposition & marked
protein urea (EXEPTION SHARPIE DOGS ARE IN MEDULLA)
* Cats: Medullary deposition is more common (low protein urea)
-usually associated with chronic conditions
Suppurative Glomerulitis
- Results form septicemia
- Example:
- Actinobacillus equuli infection in
young foals, foal that died, look at kidney see yellow dots in cortex in kidney = pus.
Diseases of Tubules
- Fanconi-like syndrome (inherited syndrome, high glycose urea but normal in blood, in basenhi dogs)
- Acute tubular necrosis due to
- Ischemia
- Nephrotoxins
acute tubular necrosis (neprhosis)
- Common cause of acute renal failure
- Clinical presentation: Oliguria or anuria (not peeing)
- Why?
- Leakage of urine outside the tubules
- Blockage of tubules and backflow of urine
- Vasoconstriction and decreased GFR at the glomerulus
-gross: Cortex may buldge towards you, paler in color
acute tubular necrosis causes
- Two general causes of ATN
1. Low renal perfusion (not enough BF to kidneys)
2. Toxins (antifreeze/ ethylene glycol-> you will see crystals in urine) - Dogs & cats: cardiac failure, deep anaesthesia, severe blood loss, profound dehydration
- Cattle: endotoxemic conditions, such as mastitis or metritis, and in gastrointestinal diseases, such as severe enteritis and grain overload
- Pigmentary nephrosis: leads to low perfusion and necrosis
pigmentary nephrosis causes and types which can to acute tubular necrosis
-Pigmentary nephrosis: dark red almost black, either hemoglobin or myoglobin deposited.
-If hemoglobin causes of intravascular hemolysis (Cu poisoning, blood parasites, ruminants bacilaryhemoglobinurea) you will have dark urine.
-If myoglobin: severe muscle damage, tieng up could lead to.
acute tubular necrosis caused by toxins, toxin types
-Ethylene Glycol (antifreeze) leads to crystals on urinalysis, high metabolic acidosis and high anion gap on blood.
-Melamine Toxicity
-raisins or grapes (dogs only) can give you renal failure ATN
-lilly toxicity (cats): ATN
Pyelonephritis
-(pylo = renal pelvis)
-Inflammation of the RENAL PELVIS with extension into tubules and
interstitium. (A form of suppurative tubulointerstitial nephritis)
-puss in renal pelvis when chronic, when acute there are lines from the pelvis to cortex, may have white spots on surface of kidney
causes:
* Bacterial Ascending infection (from the lower urinary tract)
Pyelonephritis causes
- Bacteria
- Ruminants (Corynebacterium renale & E.coli, Trueperella pyogenes)
- Pigs (Actinobaculum suis)
other species e.coli
Diseases of the Renal Interstitium
- Interstitial nephritis or tubulointerstitial nephritis (TIN)
- Infectious: leptospirosis,
- Two types:
1. Non suppurative (Lymphoplasmacytic) TIN
2. Granulomatous
- Interstitial nephritis or tubulointerstitial nephritis (TIN) causes
-Leptospirosis (LIN)
* Porcine Postweaning Multisystemic Wasting
Syndrome (PMWS) (LIN)
* White spotted kidney (LIN)
* Feline infectious peritonints (GIN): nodules on kidney of cat either FIP or lymphosarcoma. nodules of FIP that track along vessels. causing granulomatous nephritis
Leptospirosis
- Rare, loves the kidneys
- Cause is Leptospira interrogans
-gross: white spots on outside of kidney - Three forms of the disease:
- Acute = liver damage + RBC hemolysis > icterus, hemoglobinurea (not a renal Dz)
-can cause hemoglobinuric nephrosis - Subacute = Renal disease (lymphoplasmacytic
interstitial nephritis) > renal failure (dogs only), other spps usually don’t progress to renal failure. - Chronic = Abortion, stillbirth (most important form in livestock) not kidney lesions.
Porcine Postweaning Multisystemic
Wasting Syndrome (PMWS)
Cause: Porcine circovirus-2
-Can cause lymphoplasmacytic
interstitial nephritis
-white spots on surface of kidney
White spotted kidney
- Young calves
- Old E.coli septiceia
- Incidental finding, lymphoplasmacytic
interstitial nephritis.
-if spots are not raised its insignificant
Hypercalcemic Nephropathy
- Definition: Renal Dz secondary to hypercalcemia.
- Can lead to renal failure
- Causes of hypercalcemia
– Primary hyperparathyroidism
– Nutritional secondary hyperparathyroidism
– Granulomatous inflammation
– Hypoadrenocorticism
– Neoplasia
– Vitamin D toxicity
renal adenocarcinoma
- Rare
-most kidney tumors are metastisis - Most common primary renal tumor in the dog
- Tubular epithelial origin
nephroblastoma
- Embryonic tumor
- Young animals***
- In swine it is an incidental
finding and most animals
-not incidental in dogs MALIGNANT since metastasizes
-lumpy, white, invasive tumor, unilateral
Lymphosarcoma (LSA)
- Metastasis to the kidney
- Most common tumor type found in the
kidney of cats - Differential FIP
urethra in males vs females
- Urethra:
- Females :short and close to skin, GI and genital tract (predisposed to ascending infections)
- Males: long narrow (prone to obstruction)
-all urinary tract is transitional epithelium
urinary tract gross examination
- Urinary bladder often contracts at the time of death and appears thick (not pathology)
- Mucosal surface should be smooth and urine should be clear
Defense mechanism of the Lower urinary tract
- Urine flow, Urine is not favorable for bacterial growth, urine flushes bacteria and dirt away
1. Acidic PH, especially in carnivores (too acidic for bacteria)
2. High urine osmolality is considered bacteriostatic.
3. Protective mucous coating (slippery i.e., reduce bacterial attachment and also reduces damage when crystals form)
4. Urothelium routinely slough and will void attached bacteria.
ectopic ureter
-developmental abnormality
-Ureter open in abnormal location
-Most common in dogs (females > males)
-Usually leads to incontinence (urine dribbling) at birth.
-May cause skin irritation and hyperemia
Patent Urachus
-Urachus: Tube connecting the urinary bladder and the allantois
-congenital abnormality
-Should close at birth
-Most common in foals.
-Urine dripping form the umbilicus.
-Secondary infection:
Rupture uroperitonium and chemical peritoinits
Hydroureter
- Dilation of the bladder
– Urethral obstruction (main
cause)
– Neuroparalytic (less common) brain doesn’t tell bladder to contract, examine spinal cord
-can lead to rupture of the bladder (cystorrhexis) from
– Urethral obstruction
– Pelvic trauma
– Result in chemical peritonitis and
uroabdomen
-usually dorsal surface of the bladder esp horses.
Urolithiasis
- Urolithiasis (stones) is the presence of calculi in the urinary passages
- Can be found any where, but most commonly found in the ureter and least in the renal pelvis.
- Common in dogs, cats and ruminants(important)
Urolithiasis predisposing factors
- Sufficient amounts of calculogenic material in urine to be precipitated
– Abnormal metabolism (uric acid in Dalmatians** they get uric acid calculi)
– Abnormal processing in kidney (cystine calculi)
– High levels in diet (silica) - Urinary pH (optimum for solute precipitation)
- Reduced water consumption DEHYDRATION most important
- Bacterial infection
Calculi
-bladder stones
* Highly variable in appearance (due to variable amounts of protein and minerals)
* Can’t tell the composition on gross
examination of the calculus.
* Stone analysis
- Struvite calculi (Magnesium Ammonium Phosphate)
-bacterial infections** like alkaline conditions high pH
- Most common type in dogs (Females > males)
- Dogs: Bacterial ureases->Ammonia (increase pH)->decreased struvite
solubility->calculus formation
- Important in cats and cattle as well
- Cats: Important manifestation is Feline Urologic Syndrome (“Blocked” cat)
- Oxalate crystals
– Dogs
* Second most common type of calculi
-likes acid conditions
– Cats
* Incidence increasing dramatically
* Cause unknown but likely related to diet- acidifying
diets
sabulous urolithiasis
-Horses get sabulous urothiasis: where bladder is filled with sludgy white material
Consequences of urolithiasis
- Pressure necrosis at point of impaction
- Obstructive disease:
* Ureter- painful, hydronephrosis; fatal if bilateral
* Urethra- fatal if complete and unresolved
cystitis, predisposing factors
-inflammation of the bladder
-usually bacterial cause
- Predisposing factors
– Female
– Urine stasis-obstruction, incomplete voiding
– Trauma-catheterization
– Glucosuria-emphysematous cystitis
– Compromise of immune system-Cushing’s
– Prolonged antibiotic therapy
cystitis causes
- The bacteria associated with cystitis are the same as those that cause
pyelonephritis - Rectal, dermal or genital flora
- Specific pathogens
– Virulence factors-fimbriae or pili to enhance adhesion
– Uropathogenic E. coli
– C. renale group in cattle
– A. suis in swine
cystitis gross
-acute: hyperemia, hemmorage, necrosis, fibrin
-chronic: polyps or follicles, bumpy bladder with nodules on mucosal surface. called follicular cystitis which is chronic. can also have polypoid cystits irregular surface due to chronic irritation and hemmorage.
Toxic Cystitis cattle
- Enzootic Hematuria of Cattle
- Chronic bracken fern ingestion
- Several toxic components
– Thiaminase
– Numerous carcinogens
– “Bleeding factor” - Chronic hematuria and anemia can lead to Bladder tumors-> Benign and malignant
– Epithelial and mesenchymal
Feline Lower Urinary Tract Disease
- Idiopathic
- Chronic condition
- No bacteria isolated
- Calculi are sometimes found
-blocked cats, not passing urine, usually males.
bladder neoplasia
Rare <1%
* Most commonly found in urinary bladder Transitional Cell Carcinoma**
* Most important in dogs, cats and cattle
(enzootic hematuria)
* Most are epithelial and malignant
-Botryoid rhabdomyosarcoma is a rare tumor of very young, large breed dogs
