Diseases of Urinary System

Urinary System• Anatomy/Location

– Kidneys– Ureters– Bladder– Urethra

• Function– Remove waste– Maintain homeostasis

• acid/base• electrolytes• fluid balance

– Hormone production• erythropoietin

Urinary System

– Infections usually due to ascending organism– Usually resistant to bacterial infection

• Frequent urination flushes bacteria• Urethral/ureteral peristalsis• Glucosaminoglycans in mucosa• pH

Feline CystitisCause unknown; virus suspected; usually

not bacterial; recurrence likelySelf-limiting (7-10 d), so any appropriate

treatment appears to help

• Signs– Frequent urinations (sm vol)– Hematuria– Dysuria– Inappropriate urination (sinks,

tubs are a favorite)• Dx

– Urinalysis/culture to r/o bacteria as cause

– X-rays to r/o calculi; contrast studies show thickened wall

• Rx– Avoid unnecessary antibiotics– Change diet from dry to moist

• Salt food to ↑ water intake

– Reduce stress from other cats, kids, etc (hiding places)

• Client info– Disease is self-limiting– May be recurring problem– No definitive cure– Reduce stress

Feline Cystitis

Canine Cystitis (Bacterial Cystitis)

• Signs– ↑ frequency of urination– Hematuria– Dysuria– Cloudy urine; abnormal color– Frequent licking of urethral area

• Dx– Urinalysis: ↑WBC’s, bacteria– Urine culture/sensitivity

• Collect by cystocentesis(?)– Mid-stream collection

• Rx– Avoid unnecessary use of indwelling urinary catheters

• Use closed system

– Antibiotics according to sensitivity • Treat acute infections x 10-14 d

• Subsequent infections x 4-6 w

– Avoid trauma to urinary tract during surgery

• Client info– Many uncomplicated urinary tract infections resolve without Rx– Give antibiotics as directed for the time prescribed

• Relapses are common due to inadequate treatment

– Prostate may be source of recurring infections in male dogs– Urine cultures should be repeated during treatment to assess

effect

Canine Cystitis (Bacterial Cystitis)

Close system

Feline Uroliths and Urethral Plugs

“Plugged” male cats are commonly seen in SA practiceWill be fatal if not relieved

• Uroliths (bladder stones) found anywhere in urinary tract– Formed from minerals in diet– Some are radiopaque (Ca++ oxalate, urate, struvite) and can be

seen on x-ray– Some are radiolucent and require double contrast (air, dye)

• Uroliths damage bladder, making it more susceptible to bacterial infection, hematuria

• Uroliths can form plugs in urethra of males– Bladder will fill with urine– Kidneys will stop working– Blood/body will become toxic (azotemic)

• Signs (more severe if obstruction has occurred)– Hematuria– Dysuria/ frequent urination– Urinating in strange places (sink, tub)– Straining to urinate– Vomiting– Collapse, death

Feline Uroliths and Urethral Plugs

• Dx– Palpation of bladder (obstructed is full and tight)– X-rays may show uroliths on routine films

• Double contrast studies may be indicated

– Ultrasonography can locate position of urolith– Urolith analysis to determine its constituents

Double contrast cystogram (with stones)pneumocystogram

Feline Uroliths and Urethral Plugs

US of bladder stone

• Rx– Medical treatment (chronic, non-obstructed)

• Dissolve struvite uroliths (most common; ~60%) by acidifying urine and feeding diet low in Mg (Vit C, S/D)

– Should resolve in 4-8 wk

– Re x-ray, and continue diet 1 mo after uroliths gone

• Antibiotics according to culture/sensitivity

Feline Uroliths and Urethral Plugs

• Medical treatment (obstructed)– Anesthetize (short acting)

• ***USE LESS ANESTHESIA IN AZOTEMIC CATS***

– Pass ‘silver needle’ (soft metal, atraumatic) or Tom cat catheter and back flush

– Sew catheter in place for 1-3 d (??)

Feline Uroliths and Urethral Plugs

• Surgical treatment (chronic obstructers)– Perineal urethrostomy

• New opening for urethra is created proximal to narrowing• Urethral opening looks like a female• E collar till sutures removed

Feline Uroliths and Urethral Plugs

Urolithiasis (Canine)

Smaller incidence in dogs than cats

Uroliths damage mucosa of urinary tract making it susceptible to infection

Uroliths can obstruct urine flow in males

• Signs– Dysuria– Hematuria

• Dx– Urinalysis

• Crystalluria• Hematuria• ↑ bacteria

– X-rays (double contrast ?)– Do stone analysis

Canine UrolithsUrolith Breed Sex Contributing factors Rx

Struvite min sch female (80%) alkaline urine acidify urine(Mg Ammonium Phos (MAP—triple phosphate)

(~50% of all stones) cats bacteria→urease→↑pH antibiotics

minerals (diet) Only Hill’s s/d (dissolve)

↑Na, ↓protein (ammonia)

↑H2O intake (flush stones

acidy urine

Calcium Oxalate cats males diet high in protein Sx removal (only Rx)

(30-50% of min sch hypercalcemia ↓ dietary Ca (milk)

all stones) Lhasa, Yorkie Cushing’s Dis ↓ dietary Na

min pood use of cortisone Hill’s u/d, w/d, k/d

Shih Tzu acid urine

Urates Dalmatians males ↑ uric acid from kidneys Allopurinol

E bulldogs acid urine (gout in humans)

min schnauzer K+ Citrate (↑ urine pH)

Shih Tzu Hill’s u/d, ↑ dietary salt

York terrier

Canine Uroliths Struvite Calcium Oxalate UrateType of stone cannot be determined by appearance; chemical analysis is required

• Rx– Medical (objective is to dissolve stones)

• ↓ mineral intake in diet→↓ minerals in urine• ↑ urine acidity (nor for urates)

– Vit C– methionine (Methogel®)

• ↑ urine output– Add salt to diet– Furosemide

• Antibiotics for bacterial infection

– Surgical removal• Some uroliths are not amenable to Medical Rx• However, the cause of uroliths must be dealt with medically (prevention)

Urolithiasis (Canine)

• Client info– Special diet may be required for life-time– Table scraps/treats should be limited– Long-term antibiotics may be required– Uroliths may recur at any time– Always provide plenty of fresh water– Allow plenty of bathroom time and frequency

Urolithiasis (Canine)

What do you see? How many?

Urolithiasis (Canine)

What do you see? Flush toward bladder (8 times)

Saline flush

One in bladder, 2 in urethra

• What do you see?

Urolithiasis (Canine)

What do you see?

Urolithiasis (Canine)

Urolithiasis (Canine)

• ~20% of CO– Filtered by renal corpuscle– Reabsorbed by kidney tubules– Waste excreted as urine

• Renal Failure due to:– ↓ blood flow (hypoperfusion)– Damage to nephron

Renal Failure

An abrupt decrease in glomerular filtration → azotemia (↑ N toxins in blood)

• Causes– Damage to nephron (damaged nephrons do not regenerate; other nephrons

will hypertrophy)Any part of nephron may be damaged (when 1 part of nephron is lost, it is all lost)

• Nephrotoxic drugs– Aminoglycosides (gentamicin, streptomycin)– Cephalosporins (cephalexin, cephalothin)– Sulfanamides (Albon, Di-Trim)– Chemotherapeutic agents– Antifungal medications– Analgesics (acetaminophen)– Anesthetics (methoxyflurane [Metafane])– Ethylene glycol (antifreeze)

• Infections (nephritis)• Immune-mediated diseases (Glomerulonephritis)

– ↓ Renal perfusion• Shock• Hypovolemia/dehydration• Hypotension

Acute Renal Failure

• Signs (non-specific)– Kidneys are enlarged and painful on palpation– Signs of azotemia

• Anorexia, dehydrated• Vomiting/diarrhea• Weakness

– Fever

• Dx– Urinalysis—urine sediment/casts; low sp grav (unable to

conc urine)– CBC—dehydration (↑PCV), acidosis – Chem panel

• ↑ BUN, Creatinine• ↑K+, Phosphorus

Acute Renal Failure

• Rx (aim is to restore renal hemodynamics)• Relieve tubular obstruction• Discontinue any toxic drugs

– IV fluids (start with normal saline)• Correct dehydration• Correct acid/base (sodium bicarb) and electrolyte imbalance

– Diuretics to increase urine output

• Client info– Renal function may never be like it was before injury– Px is guarded– Care must be taken to avoid events that may

precipitate further damage to kidney• Appropriate diet• Adequate water access

Acute Renal Failure

Chronic Renal Failure

Common in older pets; cats appear to be more affected than dogs

Irreversible and progressive decline in renal function (nephron damage)

• Progressive– 1st function lost: Ability to concentrate urine

• PU, PD, nocturia– Loss of ADH response

– Other functions lost: Ability to cleanse blood• Azotemia (toxemia)

– Begins at ~75% of nephron loss

– ↑ BUN, Creatinine

• Anemia: erythropoietin secreted by kidneys

• Signs– Dull, lethargic, weak– Anorexia, wt loss– PU/PD cervical ventroflexion

• hypokalemia

– Sudden blindness

• Dx– Acidosis– Anemia– ↑ BUN, Creatinine– Hyperphosphatemia– Hypokalemia– Proteinuria

Chronic Renal Failure

• Rx– Fluids for dehydration (IV, SQ)– Potassium gluconate, calcium carbonate for electrolyte

imbalances– Sodium bicarb for pH adjustment– Diuretics (Furosemide)– Hormones

• Epoetin

– Vit B supplements

• Client info– CRF is progressive and irreversible– Rx is aimed at slowing its progress– SQ fluids at home are required to maintain hydration– Warm foods to improve palatability– Quality of life will decrease; euthanasia may have to be

considered

Chronic Renal Failure

Urinary IncontinenceLoss of voluntary control of micturition

• Causes– Neurogenic—loss of normal neural function causing a

paralyzed bladder– Ectopic ureters– Patient urachus– Endocrine imbalance (after spay)

• Signs– Urine leakage when pet is sleeping or exercising– Perianal area of pet is aslways wet– Concurrent urinary tract infection

• Dx– Urinalysis– X-rays/cystography– Chem panel to r/o PU from endocrine disease

Urinary Incontinence

• Rx (based on specific cause)– Surgical correction– Endocrine deficiency in spayed female

• Diethylstilbestrol (PO or inj)

– Phenylpropanolamine (for loss of sphincter tone)

• Client info– Doses will have to be adjusted for individual animals– Paralytic bladder incontinence may require manual

expression or catheterization several times a day

Urinary Incontinence