VT 121 lesson urinary disease

Terminology

  • Abbreviations

    • FLUTD: Feline Lower Urinary Tract Disease
    • GFR: Glomerular Filtration Rate
    • PU/PD: Polyuria/Polydipsia
    • CKD: Chronic Kidney Disease
    • IVP: Intravenous Pyelogram
    • BUN: Blood Urea Nitrogen
    • UTI: Urinary Tract Infection

  • Root Words

    • Nephro: Kidney
    • Glomerulo: Glomerulus
    • Cysto: Bladder
    • Urethro: Urethra
    • Pyelo: Renal Pelvis
    • Uria: Urination
    • Uro: Urine
    • Lith: Stone
    • Juxta: Near
    • Dys: Difficult or Bad
    • Iso: Same
    • Alka: High pH
    • -ectomy: Surgical removal
    • -itis: Inflammation
    • -iasis: Condition
    • -osis: Abnormal condition
    • -centesis: Surgical puncture to remove gas or fluid
    • -sthen: Strength
    • -stenosis: Stricture or narrowing
    • -gram: Picture

Urinary Terminology

  • ACE Inhibitor: Decreases blood pressure by inhibiting angiotensin and aldosterone.
  • Aldosterone: Stimulates retention of sodium, excretion of potassium, and increased blood pressure.
  • Angiotensin II: Stimulates the adrenal cortex to release aldosterone.
  • Azotemia: The presence of nitrogen-containing compounds in the blood.
  • Creatinine: A product of muscle metabolism produced at a constant rate and excreted by the kidney; blood levels indicate kidney function.
  • Crystalluria: The presence of crystals in urine.
  • Cystoscopy: Visual examination of the urinary bladder with a fiberoptic instrument.
  • Diuretics: Increase urine flow and sodium excretion, thus decreasing blood pressure.
  • Hyposthenuria: Low urine concentration.
  • Lithotripsy: Destruction of urinary calculi using ultrasonic waves traveling through water.
  • Magnesium Ammonium Phosphate: Mineral composition of a urinary crystal commonly known as struvite that forms in alkaline urine.
  • Nephrolith: Kidney stone.
  • Peritoneal Dialysis: Removal of blood waste products by fluid exchange through the peritoneum as a treatment for renal failure.
  • Pollakiuria: Increased frequency of urination without an increase in total production.
  • Stranguria: Slow, difficult, or painful urination.
  • Urinary Acidifier: Decreases the pH of urine to dissolve struvite uroliths.
  • Urinary Incontinence: Inability to control urination.

Introduction to the Urinary System

  • The primary function of the urinary system is to remove waste from the body.
  • Composed of:
    • Kidneys
    • Ureters
    • Bladder
    • Urethra
  • Functions:
    • Controls blood pressure
    • Regulates water and electrolyte balances
    • Plays a major role in red blood cell (RBC) production
  • Diseases affecting urinary system include:
    • Cystitis
    • Feline Uroliths
    • Urethral Plugs
    • Canine Urolithiasis
    • Renal Failure (Acute and Chronic)
    • Urinary Incontinence
    • Benign Prostatic Hypertrophy

Importance for Veterinary Technicians

  • Familiarization with urinary diseases is vital for RVTs as they are often the first to triage patients, whether over the phone or in clinic, helping to ask the right questions and identify clinical signs that can save lives.

Cystitis

Feline Idiopathic Cystitis (FIC)

  • Non-malignant inflammatory condition with no known cause, also called Feline Urological Syndrome (FUS) or Feline Lower Urinary Tract Disease (FLUTD).
  • Forms:
    • Ulcerative (Obstructive)
    • Non-ulcerative (Non-obstructive)
  • Commonly, the non-obstructive form is encountered; it typically resolves within 1-10 days.
Clinical Signs
  • Hematuria: frank blood or pink urine
  • Increased frequency of urination, with small volumes
  • Dysuria: painful urination
  • Inappropriate urination (e.g., outside litter box, on floors or sinks)
Diagnosis
  • Ultrasound: Examination of the bladder
  • Cystocentesis: Collection of a sterile urine sample
  • Complete urinalysis: Both dipstick and sediment examination
  • Negative urine culture
  • Radiographs: Possibly with contrast medium to visualize bladder wall
Treatment
  • Pain relief: Administered for patient comfort
  • Diet change: Encourage wet food or add water to dry food to dilute urine
  • Antibiotics: Only if bacteria detected in urinalysis
  • Anti-inflammatories: Medications like Meloxicam or Robenacoxib may be used cautiously if renal damage is present
Additional Information
  • There is no cure, and the disease may recur. It is self-limiting and usually resolves within 1-10 days.
  • Stress reduction is crucial for prevention of future episodes.
  • Providing cats with play and exercise opportunities can help.

Canine Cystitis (Bacterial Cystitis)

  • Bacterial UTIs are the most common cause of cystitis in canines.
  • Normally, the urinary tract is sterile, with natural defenses against bacteria.
  • UTIs often arise when bacteria ascend the urethra into the bladder, adhering to the mucosal lining.
  • In healthy individuals, bacteria are non-pathogenic, but may cause disease in immunocompromised patients.
Clinical Signs
  • Hematuria (frank blood or pink urine)
  • Increased frequency of urination, small volumes
  • Dysuria (painful urination)
  • Frequent licking of the urethral area
Diagnosis
  • Cystocentesis: Collection of a sterile urine sample
  • Urinalysis: Shows increased WBCs and bacteria
  • Urine culture and sensitivity: Determines type of bacteria and antibiotic susceptibility.
Treatment
  • Preventative measures:
    • Only use indwelling urinary catheters when necessary with closed systems (e.g., for Lepto cases).
    • Avoid urinary tract trauma during surgeries.
    • Use the most effective, least toxic, and least expensive antibiotics.
    • Duration: 5-7 days for acute infections; up to 4 weeks for chronic infections.
Antibiotics Commonly Used
  • Amoxicillin
  • Cephalexin (Keflex)
  • Trimethoprim-sulfonamide (TMS)
  • Enrofloxacin (Baytril)
Additional Information
  • Uncomplicated UTIs may resolve without treatment.
  • Proper antibiotic administration is critical; relapses and drug resistance can occur with improper dosing or duration.
  • Male dogs may have UTIs due to prostate gland infections. Repeat urine cultures during treatment are critical, especially after prolonged courses of antibiotics.

Feline Uroliths and Urethral Plugs

Feline Uroliths

  • Life-threatening emergencies can occur when cats cannot urinate, commonly seen due to uroliths or urethral plugs.
  • Uroliths (bladder stones) can form anywhere within the urinary tract and consist of multiple minerals:
    • Struvite (~60%)
    • Calcium oxalate (27%)
    • Ammonium urate (5.5%)
    • Cystine
    • Mixed mineral
  • There is no defined cause for urolith formation, but factors such as breed, diet, age, and weight influence susceptibility.
  • Altered urinary pH can lead to stone formation.
Symptoms of Uroliths
  • Range from asymptomatic to complete obstruction (blocked).
  • Clinical signs include:
    • Hematuria (frank blood or pink urine)
    • Dysuria (painful urination)
    • Inappropriate urination (e.g., outside the litter box)
    • Straining to urinate (might appear constipated)
    • Crying during litter box use (pain)
    • Vomiting
    • Collapse and potentially death
Diagnosis
  • Some stones may show on radiographs; others may not.
  • Ultrasonography: Visualizes uroliths in urinary tract.
  • Double contrast study: May assist in diagnosis.
  • Urinary catheterization: Small uroliths can sometimes be collected.
  • Stones should be analyzed in a lab for appropriate treatment.
Treatment

  • Medical Management:

    • Diet change to decrease urinary pH (aim for pH of 6 to 6.3). For example, use Hills Prescription Diet Feline s/d to dissolve struvite uroliths and prevent recurrence.
    • Dissolving can take 4-8 weeks; regular radiographs (every 2-4 weeks) should monitor progress.
    • Antibiotics may be necessary for secondary infections from urolith damage.

  • Surgical Management:

    • Cystotomy (surgical removal of stones) if diet change does not work.
    • Post-surgery, radiographs should confirm all stones are removed.
Treatment for Obstructive Uroliths
  • Surgical Intervention: Uroliths lodged in the urethra must be removed; retrograde movement back into the bladder can be facilitated.
  • Techniques include using an open-ended urinary catheter and gentle sterile saline flushing.
  • Urine flow resumption is essential, and dietary changes are critical for stone dissolution.
  • Antibiotics for secondary infections must be monitored with urine culture and sensitivity.
  • Close observation for recurrence of obstruction is vital.
Surgical Considerations
  • Perineal Urethrostomy (PU): If obstruction can't be cleared or recurs frequently, PU may be considered, but it's associated with risks like increased bladder infections and strictures.
Additional Information
  • Surgery may be needed if stones resist dissolution.
  • Prescriptive diet only, without treats.
  • Wet food addition dilutes urine, beneficial for patients.
  • Regular rechecks with radiography and urinalysis are necessary.

Feline Urethral Plugs

  • Risk factors of uroliths can also lead to urethral plugs, which are mixtures of minerals and proteins rather than stones.
  • Plugs include red blood cells (RBCs), white blood cells (WBCs), bacteria, sperm, and epithelial cells.
  • More prevalent in male cats due to urethra shape.
Clinical Signs
  • Straining to urinate and crying during litter box use.
  • Vomiting and dehydration may occur; risks severe enough to lead to collapse or death if untreated within 3-6 days.
Diagnosis
  • Bladder examination: Will appear large and firm.
  • History of straining without urine output.
  • Radiographs: Large bladder may be visualized.
  • Elevated levels of BUN, Creatinine, Potassium, Phosphate, and Calcium may be seen.
Treatment
  • Obstruction relief: Administer pain meds; patient might need sedation.
  • Manual massage and bladder compression techniques are often ineffective.
  • Catheter placement: A sterile urinary catheter may be used to retro-pulse the plug back into the bladder, allowing urine flow to resume.
  • Indwelling catheter setup must be sterile and closed; allows monitoring of "ins and outs".
Post-Care Monitoring
  • Watch closely for urination ability after catheter removal.
  • Re-obstruction potential.

Surgical Intervention

  • If obstruction persists, Perineal Urethrostomy (PU) surgery may be performed. Cats that experience blockages may undergo this surgery preemptively due to high risk of recurrence.

Canine Urolithiasis

Composition and Formation

  • Not as common as in felines but when formed, they are often magnesium ammonium phosphate stones.
  • Less commonly, stones can consist of calcium oxalate, urate, cysteine, and calcium phosphate.
  • Bladder stones form from urine high in mineral concentration; minerals deposit around pre-existing crystals.
Clinical Significance
  • Uroliths may remain small and pass through or cause partial/full obstruction, and increase UTI susceptibility due to trauma.
Types of Canine Uroliths

  • Struvite (Magnesium Ammonium Phosphate):

    • Caused by urinary infections from specific bacteria that produce alkaline urine conditions favorable to stone formation, primarily Staphylococci and Proteus.
    • Common in female dogs age 3-8, who comprise 80% of cases.
    • Smooth, pyramid-shaped and radiopaque.
    • Treatment: Dietary change to prescription food can resolve stones in approximately 1-3 months, combined with appropriate antibiotics.

  • Calcium Oxalate:

    • Found mostly in male dogs 5-12 years; breeds at risk include miniature schnauzers, Lhasa Apsos, Yorkshire terriers, miniature poodles, shih tzus, and Bichon frises.
    • Increased animal protein diets can contribute.
    • Stones have sharp projections, are also radiopaque, and usually multiple small stones are present.
    • Treatment: Requires cystotomy for stone removal; dietary change to low protein, low minerals, and high water intake is crucial.

  • Urate Stones:

    • Associated with Dalmatians due to excessive uric acid excretion and can manifest in other breeds such as English Bulldogs and Schnauzers.
    • Common in male dogs age 3-6 years.
    • Typically, yellow-green, smooth, and radiolucent (can be detected via ultrasound).
    • Clinical Signs: Hematuria and dysuria.
    • Diagnosis: Urinalysis shows crystalluria and bacteria, thus revealing the acidic pH condition for stone formation.
    • Treatment: Diet change to low purine, managing pH levels, antibiotics for infections, potential use of allopurinol, and cystotomy when medically insufficient.
Additional Management for Urolithiasis
  • Dietary changes may be lifelong, limiting treats and table scraps.
  • Regular monitoring for recurrence is necessary, including repeated ultrasound to monitor dissolution of stones.

Renal Disease

  • One of the most common conditions seen; primary functions of the kidneys include filtration and waste removal.
  • Composed of numerous nephrons, once damaged, they cannot regenerate. -.classifications:
    • Acute Kidney Injury (AKI)
    • Chronic Kidney Disease (CKD)

Acute Kidney Injury (AKI)

  • Characterized by a sudden decrease in glomerular filtration, causing toxin accumulation (azotemia), also known as acute renal failure.
  • Common causes:
  • Hypoperfusion: loss of blood supply
  • Nephrotoxic injury: exposure to certain nephrotoxic drugs
  • Ethylene Glycol toxicity.
Three Phases of AKI
  1. Induction Phase: Initial nephron injury occurs.
  2. Maintenance Phase: Damage to renal tubules develops.
  3. Recovery Phase: Improvement in renal function as functioning nephrons compensate (hypertrophy).
Risk Factors
  • Shock, hypovolemia, hypotension, dehydration, electrolyte imbalances, nephrotoxic drugs, systemic diseases, and patient age.
Signs of AKI
  • Anorexia, dehydration, vomiting & diarrhea, oliguria/polyuria, painful kidneys upon palpation, fever if infectious.
Diagnosis of AKI
  • Physical exam: Assess for history of toxin exposure; urinalysis and blood work revealing elevated BUN and Creatinine along with possible acidosis and elevated potassium/phosphorus.
Treatment for AKI
  • Dietary change to low protein renal diets.
  • IV fluid therapy to support kidney function.
  • Discontinue nephrotoxic drugs.
  • Use of GI protectants like Sucralfate; phosphate binders; diuretics like Furosemide/Mannitol.
Additional Considerations
  • Prognosis is often guarded; conditions causing AKI may require long-term treatment.
  • Efforts must focus on preventing kidney damage; renal diets and access to clean water are critical.

Chronic Kidney Disease (CKD)

  • This disease is progressive with irreversible nephron damage. Signs may not present until two-thirds of kidney function is impaired.
  • Most commonly observed in cats over age 10 and dogs over age 8.
Clinical Signs of CKD
  • Weight loss, anorexia, vomiting, diarrhea, constipation, dullness, lethargy, unkempt appearance, weakness, polyuria, and polydipsia (PU/PD).
Diagnosis of CKD
  • Blood and urine tests: elevated BUN, creatinine, and SDMA with inappropriately low specific gravity (<1.035); structural kidney changes evident on radiographs and ultrasound.
Treatment for CKD
  • Dietary modification to a prescription renal diet (low protein).
  • Supervisor administration of IV or subcutaneous (SQ) fluids; clients can be taught to do SQ at home.
  • Supportive care including medications for GI symptoms, phosphate binders, potassium supplementation, and erythropoietin/appetite stimulants.
Additional Information on CKD
  • CKD is progressive and irreversible; SQ fluids are essential for hydration. Treatment aims to slow disease progression and manage clinical signs.
  • Renal diets can be enhanced to improve palatability; consider warming foods or adding low-sodium liquids. While treatment can improve quality of life, patients will eventually decline, and euthanasia may need to be considered.

Urinary Incontinence

Overview

  • Common in older pets, urinary incontinence results from the loss of voluntary micturition control. The urethra is maintained by smooth muscle pressure, and incontinence develops when bladder pressure exceeds urethral pressure.
Causes of Incontinence
  • Neurological issues: spinal injuries, nerve damage, brain disease.
  • Bladder storage dysfunction: hyper-contractility.
  • UTIs or bladder tumors.
  • Urethral disorders: muscular failures causing leakage; hormonal influences, inflammation, or prostatic disease can contribute.
  • Anatomical defects or congenital defects in urethral closure mechanisms.
Clinical Signs
  • History of leakage during sleep (nocturia) or exercise.
  • Wet perineum.
  • Presence of urinary tract disease.
  • Higher likelihood in older spayed females and intact males.
Diagnosis
  • Urinalysis and bloodwork to rule out other conditions.
  • Imaging: radiographs/cystography for anatomical evaluations.
Treatment
  • Specific treatment based on incontinence type (e.g., Estrogen for spayed females with endocrine issues, Phenylpropanolamine for urethral sphincter weaknesses).
Additional Information
  • A complete physical examination and diagnostics are critical to determining the cause.
  • If due to trauma or inflammation, incontinence may self-resolve. Medications might need dosage adjustments and should consider any existing health issues to prevent complications.
  • For paralytic bladders, manual expression or frequent catheterization may be required.

Diseases of the Prostate

Benign Prostatic Hyperplasia (BPH)

  • The prostate gland, being the only accessory sex gland in male dogs, enlarges in response to male sex hormones throughout life.
  • Intact males over 5 years old have a higher risk of prostatic diseases.
Clinical Signs of BPH
  • Difficult urination with increased frequency and small volume output.
  • Hematuria, dysuria, and difficulty defecating.
  • Serosanguinous discharge may be noted from the penis.
Diagnosis of BPH
  • Rectal examination for prostate palpation.
  • Radiographs/ultrasound for enlargement, cysts, or abscesses.
  • Biopsy may be needed for definitive diagnosis.
Treatment of BPH
  • Neutering is the most effective treatment for BPH.
  • Antibiotics based on culture and sensitivity; not all can reach prostate tissues (e.g. Enrofloxacin being a commonly used option).
  • Chemical castration (Finasteride) can be utilized for breeding males.
Additional Information
  • Castration can prevent or treat BPH irrespective of the dog's age.
  • Prostate cancer risks exist in intact males.