Urinary - Exam 1: Make Like a Kidney and Concentrate!

What can you expect from the specific gravity of a renal azotemic disease (versus a pre-renal azotemia)?

Not concentrated

What electrolyte would be increased in acute renal disease but not chronic?

Potassium

What causes increased protein in a post-renal urinalysis?

Blood, WBC, and bacteria

What test is useful to narrow down tubular versus glomerular proteinuric renal disease?

UPC

If you have a dehydrated cat with isothenuria, is the azotemia pre-renal, renal, or post-renal?

Pre-renal due to dehydration and renal due to isothenuria despite dehydration (can have both)

T/F: Hyperkalemia is life-threatening and should be a priority

True

When is it contraindicated to perform a UPC?

With active sediment

How many urine samples with protein must be taken to confirm persistent proteinuria?

Three samples taken 2 weeks apart

Above what UPC value is considered a proteinuria in dogs?

> 0.5

Above what UPC value is suggestive of glomerular injury in dogs?

> 2.0

What proteins can cause pre-renal (overload) proteinuria?

Hemoglobin, myoglobin, and Bence Jones

A diffuse glomerular lesion would involve more than what percent of glomeruli?

50%

If the whole glomerulus is damaged (versus just one part), we would describe the lesion as what?

Global

T/F: Immune complex glomerulonephritis is most commonly from antibodies directly targeting the glomerulus

False, more often immune complexes get stuck in the glomerulus and activate complement

When immune complexes are deposited on the subepithelial (outer) side of the glomerulus, it is called what?

Membranous Glomerulonephropathy

When immune complexes are deposited on the luminal side of the glomerulus, it is called what?

Membranoproliferative glomerulonephritis

T/F: You want a picture for reference drawn by yours truly as I understand it

It is really just what side of the basement membrane they are on, inner or outer

Where is amyloid deposited in most breeds?

Glomeruli

In what breeds does amyloid deposit not in the glomeruli, and where does it deposit instead?

Shar-peis and cats; Medulla

How do glomeruli appear grossly on a kidney with amyloidosis?

Fine yellow spots

How can amyloidosis be confirmed?

Microscopically with congo red stain or apple green birefringence with polarized light

What is the basis of the pathogenesis for focal segmental glomerulosclerosis?

Podocyte injury leading to scarring

How does proteinuria affect the tubules?

Damages epithelium leading to fibrosis

What are the two major causes of acute tubular injury (ATI)?

Ischemia and nephrotoxins

Why are the tubules prone to damage?

High metabolic and oxygen demand

When injury leads to an increase of sodium in the distal tubules, causing a mechanism to reduce GFR, this process is called what?

Tubuloglomerular feedback

What metabolite of ethylene glycol is indicative of toxicity when identified in tissue or urine?

Calcium oxalate

What disease leads to diffuse dark brown discoloration of the kidney with orange-red granular casts on histology?

Copper Toxicity (sheep)

What is the main cause of pyelonephritis?

Ascending bacterial UTI (E. coli in small animals)

Why is the medulla vulnerable to bacterial infection?

It has reduced immune defense due to it's hypoxia and hypertonicity

Pyelonephritis is a source of (acute/chronic) lesions while pyonephrosis is a source of (acute/chronic) lesions

Acute; Chronic

The infiltration of what type of cells indicates chronic nephritis?

Mononuclear

Hydronephrosis is the morphologic consequence of what?

Urinary outflow obstruction

Renal infarction of what artery will create a wedge shaped necrosis of the cortex and medulla?

Arcuate

What is the typical cause of papillary necrosis?

NSAIDs (Especially horses)

Dysplasia of what structure will lead to fluid accumulation and polycystic kidney disease?

Tubules

The nephrons, glomeruli, and tubules are all created by what embryonic mass?

Metanephric blastema

Failure of the uteric bud to form or induction of metanephric blastema will lead to what disease?

Renal agenesis (ain't there)

How can you differentiate renal hypoplasia from chronic kidney disease, since both lead to reduced mass?

Hypoplasia should NOT have scarring or evidence of pre-existing disease

Fusion of opposite renal poles is called what?

Horseshoe kidneys

What finding is diagnostic for renal dysplasia?

Persistence of embyronic structures

What disease in pigs interferes with normal development of the lower urinary tract, leading to dysplasia?

Hypovitaminosis A

What is the most common primary renal tumor of dogs, cattle, and horses?

Carcinoma

Why are metastatic tumors more common in the kidneys?

Due to their filtration functions

What is the most common renal neoplasm in pigs and chickens?

Nephroblastoma

T/F: Nephroblastoma typically affects older animals

False, younger animals (from embryonic renal cells, aka nephroblasts)

Where are ectopic nephroblastoma's likely to occur in German Shepherds?

Spinal cord

What are five non-renal lesions associated with renal failure?

Tongue ulcers,

Uremic gastritis,

Sub-pleural mineralization (most common),

Uremic endocarditis, and

Fibrous osteodystrophy

Why does renal failure lead to sub-pleural mineralization?

Failing kidneys = more phosphate in blood

Phosphate binds calcium and gets stuck in soft tissue

What drug causes inhibition of PGE2 (a vasodilator), causing renal vasoconstriction and hypoxia (renal papillary necrosis)

NSAIDs

What synthetic PGE1 analog may prevent further GI ulceration from NSAIDs?

Misoprostal (not if pregnant)

T/F: Propylene glycol toxicity from antifreeze causes direct nephrotoxicity

False, ethylene glycol (eth = death)

When is ethylene glycol usually detectable in serum?

Between 30 minutes and 12 hours (not after 48 hours)

When will the patient enter acute intrinsic renal failure from ethylene glycol?

24 - 72 hours (Stage III)

What is the most toxic metabolite of ethylene glycol?

Glyoxylic acid

What are clues in the history of ethylene glycol toxicity?

Acting drunk then comatose and vomitus fluoresces under Wood's lamp

T/F: Catachem testing for ethylene glycol involves detecting the metabolized form, oxalate

False, detects unmetabolized form (aka most of it)

When is inducing emesis and gastric lavage contraindicated for ethylene glycol toxicosis?

More than two hours from ingestion and severe depression

What is the gold standard for treatment of ethylene glycol toxicosis?

4-methylpyrazole (keeps EG from metabolizing)

What is the other, not gold standard (for some reason) option for treating ethylene glycol toxicosis?

Alcohol (the solution to all your problems)

Which lilies are NOT nephrotoxic?

Calla lily,

Peace lily, and

Lily of the valley

(Calla truce in the valley so we can be at peace)

What is the main sign of lily toxicity in cats?

Anuric renal failure

(Can't pee with Lily watching)

Other than emesis and activated charcoal, what is the mainstay of treatment for lily toxicity?

Aggressive fluid diuresis

(Need lots of water for plants)

What chemistry value is indicative of grape toxicity in dogs?

Hypercalcemia

T/F: Grape toxicity is dose dependent

False

T/F: Amyloid is deposited in the glomeruli of all affected species of amyloidosis

False, shar-pei's and abyssinians deposit in the medulla

Chronic inflammation causing the release of serum amyloid A (SAA) is called what?

Reactive amyloidosis (most common)

What is a characteristic sign of familial amyloidosis in shar-peis?

Swollen hock syndrome

T/F: Amyloidosis in shar-peis leads to massive proteinuria

False, may not be proteinuric since deposition is in the medulla

What is the suspected pathogenesis of minimal change glomeruopathy?

Loss of negative charge on podocytes

Hypoalbuminemia is commonly paired with what systemic sign?

Hypercoagulability (Albumin > Antithrombin, so losing Albumin = losing Antithrombin

What are the four features of nephrotic syndrome?

Hypoalbuminemia (lost in urine)

Proteinuria (where the albumin went)

Hypercholesterolemia (to make up for no albumin)

Edema (since no osmotic pressure due to no albumin)

What is the next step if you get a positive proteinuria on semi-quantitative tests (dipstick)?

Run a quantitative test (UPC)

What diagnostic must be done to confirm specific glomerular disease?

Biopsy

What is the mechanism of action of ACE inhibitors to reduce proteinuria?

Dilate efferent arteriole to reduce glomerular pressure

Under what mL/kg/hr is considered oliguric?

0.3

Over what mL/kg/hr is considered polyuric?

2.0

T/F: Elimination of factors in the maintenance phase of AKI improves the rate of recovery

False

T/F: Increased urine production corresponds with improved GFR

Not always, damaged tubules can't absorb, meaning more urine without improved GFR

Why does concurrent heart disease make kidney disease harder to treat?

Cuz heart wants less fluid (to not work as hard) and the kidney wants more fluid (to not work as hard)

What are the three most likely causes of death during initial management of acute kidney disease?

Hyperkalemia (bad)

Metabolic acidosis

Severe azotemia

What can you expect on an EKG for a patient with hyperkalemia?

Tall, tented T-waves and a prolonged PR interval

What fluids can be given to a patient with hyperkalemia since it does not affect serum potassium and is cardioprotective?

10% Calcium gluconate

What type of fluid can be given to correct hyperkalemia?

Dextrose due to it's insulin releasing properties

What bronchodilator has a side effect of hypokalemia, and thus can be used in hyperkalemia patients?

Terbutaline

What is the most aggressive treatment of hyperkalemia?

Sodium bicarbonate (worry about acid base balance)

T/F: You should introduce a renal diet while the patient is still recovering from kidney disease

False, don't want a food aversion

How often should you measure BP in patients with AKI?

2 to 4 times per day

What drugs are often avoided in AKI?

ACE inhibitors and angiotensin receptors due to them decreasing GFR

When calculating "ins and Outs," what should fluid volumes should be added together and given over 4 hour periods?

Measured volume of collected urine

Calculated insensible fluid loss (22 ml/kg/day)

Estimated ongoing losses

When is furosemide contraindicated to increase urine output?

Dehydration or concurrent aminoglycosides

What treatment can be done to anuric patients at risk of incompatability with life?

Dialysis

What is a major complication of peritoneal dialysis?

Peritonitis

What is a major complication of hemodialysis?

Hypotension

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Kid Knees!