Urinary System Flashcards by Robin Spielman

Can nephrons regenerate?

They have limited ability.
Irreversible damage removes them from function forever.

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What is uremia?

Clinical syndrome of renal failure

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What are signs of uremia?

Azotemia
PU/PD
Vomiting
Weight loss
Depression

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Where are podocytes found?

In the filtration apparatus

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What causes prerenal azotemia?

Insufficient blood flow
Excessive production of urea
Dehydration

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What causes renal azotemia?

Renal tissue disease and failure of the filter

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What can cause post renal azotemia?

Blockage in bladder, ureters, urethra

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How does pituitary dependent diabetes insipidus affect ADH?

There will be insufficient ADH from the neurohypophysis:
Decreased secretion and synthesis

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How does lack of ADH production or release affect urine concentration?

Causes the inability to concentrate urine. Dilute urine can still be produced.
Normality restored by ADH
No azotemia

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How does lack or blockade of ADH receptors affect urine conentration?

AKA nephrogenic diabetes insipidus
Ability to make dilute urine
Inability to make concentrated urine
No response to ADH
No azotemia

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How does nephron insufficiency (renal failure) affect urine concentration?

Inability to concentrate or dilute urine
No response to ADH
Usually concurrent azotemia

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What does glomerular disease cause?

Damage results in loss of plasma ultrafiltration function
Contributes to degeneration and loss of other nephron segments

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What constitutes ultrafiltrate?

Salt
Ions
Water
Albumin
Glucose

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What effect can glomerulonephritis have on the podocytes?

Epithelial cell foot process effacement and detachment from antibodies, cytokines, toxins

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Causes of low or lost protein

Amyloidosis
UTI
Hepatic insufficiency (not producing enough protein)
Malnutrition (not consuming enough protein)
Protein losing enteropathy (losing protein in gut)
Chronic hemorrhage
Chronic inflammation

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Causes of glomerulonephritis

Pyometra: chronic inflammation, increased circulating ab-ag complexes
Viral antigens (FeLV, FIP)
Bacterial antigens
Microfilariae
Other antigens including self

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Glomerular Amyloidosis Types

AL Amyloid light chain
-Immunoglobulin light chain
AA amyloid associated
-Acute phase protein/serum amyloid A
Abeta Amyloid precursor protein
-Alzheimers

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Diabetic Nephropathy

Hyperglycemia
-Metabolic defect resulting in thickened glomerular basement membrane
-Nonenzymatic glycosylation of proteins
-Hemodynamic changes (increased GFR, hypertrophy)

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Causes of acute renal hemorrhage

Viral (herpes-turkey egg kidney)
Bacterial (embolic nephritis)
Trauma
Thrombosis
Anticoagulants

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What shape will a renal infarct usually be?

Pyramid

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How can NSAIDs affect the kidney?

NSAID administration > decr. in COX1 and COX 2 activity > decr. in prostaglandin release > decr. vasodilative effect of prosta > decr. blood flow to nephron > ischemia

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What is an end result of ischemic renal failure?

Reduced GFR > Oliguria

Via Vasoconstriction, tubule cell injury, obstruction by casts, tubular back leak…

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What is azotemia

High BUN and creatinine

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How would we diagnose tubular epithelial degeneration and necrosis?

Large number of granular and cellular casts in urine sediment from distal nephron segments

What kind of crystal form in ethylene glycol toxicosis?

Monohydrate crystals

What kind of toxicity do raisins and grapes cause?

Acute renal failure can lead to anuria from renal tubular degeneration and necrosis

What are 2 endogenous nephrotoxins?

Hemoglobin: intravascular hemolysis Myoglobin: myonecrosis, capture myopathy, extensive muscular trauma

Leptospirosis pathogenesis

Bacteremia Migrate thru vascular epithelium Persist in interstitial spaces Migrate to tubule lumens > intracellular in tubular epithelium Epithelial degeneration and necrosis Shed in urine Persist in environment

What is a sign that the pyelonephritis is acute vs chronic?

Acute: Neutrophils Chronic: macrophages and fibrosis

What is considered end-stage renal failure?

75-80 % of total renal function lost GFR < 5%

What are non-renal lesions of renal failure?

Dehydration, acidosis, azotemia Anemia (erythropoietin deficiency) Renal secondary hyperparathyroidism Soft tissue mineralization

Common epithelial neoplasms of the kidney

Renal adenomas Renal carcinomas: most common, older dogs Transitional cell papillomas (renal pelvis) Transitional cell carcinomas (pelvis and lower urinary tract)

How can some renal epithelial tumors cause secondary, absolute, inappropriate polycythemia?

Can produce too much erythropoietin

What are some primary mesenchymal tumors of the kidney?

Fibroma (benign) Fibrosarcoma (malignant) Hemangiosarcoma Metastatic carcinomas and sarcoma

What are urinary tract host defense mechanisms?

Mucosal immunity (cellular and humoral) Urine flow pH -acid Osmolality - high solute conc, Urea Epithelial barrier

What is the vesicoureteral junction?

Where the ureters enter into the bladder

Urethral developmental anomalies

Aplasia and ectopic ureters Hypoplasia Patent urachus

How does failure of bladder to store manifest?

1. irritable or spastic detrusor muscle 2. Reduced bladder capacity 3. Reduced urethral tone 4. Incontinence or frequency

How does failure of bladder to empty manifest?

1. Atony of detrusor muscle 2. Urethral obstruction or spasm 3. Anuria, dysuria, or incontinence

Traumatic causes of acute cystitis

Calculi Iatrogenic (cysto) Parturition Bacterial hydrolysis of urea > ammonia damages mucosa Glucosuria > proliferation of bacteria

What effect does bracken fern have on the urinary tract?

Enzootic hematuria Can cause transitional cell carcinoma

Common uroliths in dogs

Struvite Oxalate Purines (urate, uric acid, xanthine)

Common uroliths in horses

Ca carbonate

Feline Lower Urinary Tract Disease (FLUTD)

Male predisposition Obstructive urolithiasis -urethra Bladder distention -necrosis, hemorrhage Acute hemorrhagic cystitis Rupture

Presentation of urinary bladder neoplasia

Dysuria Hematuria (ulceration) Obstruction

What is the most common location for transitional cell carcinomas?

Trigone of the bladder

Risk factors for transitional cell carcinoma

Topical insecticides Industrial waste Female Obesity Breed (scotties) Urine retention

Can kidneys undergo hyperplasia to regenerate?

What is the regenerative capacity of the kidney?

Limited Hypertrophy NOT hyperplasia Selective tubular epithelial repair

What are common ways for the filtration barrier integrity to be disrupted?

Ag/ab complexes (Type III hypersensitivity) Autoimmunity

Stable protein deposits in the kidney can cause what?

Glomerular damage and can interfere with glomerular filtration AB/ag complexes Amyloid (visualized w/ congo red) Dogs: Primarily glomerular Cats: Primarily medullary

Diabetic nephropathy

Microvascular complications Diabetic glomerulonephropathy Assoc. w/ chronic, uncontrolled hyperglycemia -Formation and accumulation of advanced glycation end-products, collagen, and fibronectin Assoc. w/ hemodynamic distrubances

What is the kidney's susceptibility to vascular damage determined by?

Normal anatomy High blood flow Consequence is altered function (GFR) and structure

Ischemic renal failure can result from ______?

Primary or secondary obstruction of blood flow

What is a typical gross sign of nephrosis?

Renal pallor

What is nephrosis?

Acute tubular degeneration and necrosis

What can cause uroliths?

Diet Anatomic variability (males more common) Urine conc. and pH Presence of infection Structural defects that favor infection or urine stasis Foreign bodies Conc of certain drugs in urine