AKI and Hematuria Flashcards
What are the most common causes of AKI in the horse?
Hypovolemia
Amikacin, tetracycline
Dehydration
Toxins
Flunixin
AKI
Any clinical or subclinical change to renal blood flow, urine output and GFR
AKI is a consequence of …
Poor renal perfusion for an extended period → hypoxic injury to the kindeys
How do you detect AKI?
UA and USG
Chem: Creat, protein, electrolytes, SDMA
Urine biochem: GGT, fractional excretion of electrolytes
Diagnostic imaging of AKI
Transabdominal or transrectal U/S:
Transrectal palpation of l. kidney
Endoscopy (urethra, bladder, ureter openings)
How to dx AKI
Persistence of azotemia with changes of UA ( casts, isosthenuria, protein, hematuria)
Response to tx after 48hr to see if reversible
Promote/ improve renal blood flow and GFR for AKI
IV fluid therapy- polyionic, isotonic crystalloids
Ad libitum water
How to tx AKI
COX-2 selective NSAIDs
Dietary management (protein and water)
What causes hematuria?
Urolithiasis
Urethral rents (geldings)
Urinary tract neoplasia
Cantharidin toxicosis
Pyelonephritis
Exercise-induced (empty bladder)
Nematodes causing hematuria
Kidney: Halocephalobis gingivalis and strongylus vulgaris
Urethral process: Drashia and habronema sp
What concentration of blood in the urine results in visible changes to urine color?
More than 5 RBCs/ HPF or 8 in a voided sample
1/2 mL blood/ liter of urine → gross hematuria
If you see pigmented urine on shavings or snow, is it always abnormal?
No it’s pyrocatechins
Substances in the urine oxidize in low temps producing different colors
Which plants can make urine change color?
Red clover: Porphyrins (red urine)
Alsike: brown urine
What drugs can make urine change color
Doxycycline: dark brown or black
Rifampin: red or orange (foals)
Metranidazole: brown
Describe your diagnostic plan for a horse that presents with hx of hematuria?
- Get hx: drugs administered, pasture, recent exercise, gait, color change throughout, near the end or at the end
- CBC, biochems, urinalysis
- Palpation per rectum
- Endoscopic exam of urethra and bladder
- Vesicular and renal U/S
- Renal bx
- Coagulation tests
What instrument is used to perform a bx?
Monopty bx device
What cause of hematuria results in more concentrated blood towards the end of urination?
Urolithiasis (cystic calculi)
What cause of hematuria results in more concentrated blood at the end of urination?
Urethral rents
What is urinary calculi made of?
Type 1: CaCO3 (yellow to green and spiculated and friable)
Type 2: CaCO3 and phosphate (smooth hard and white)
What should you check each time you find bladder stone?
A full diagnostic evaluation of the urinary tract with U/S, endoscopy and urine cx
How would you remove a bladder stone?
Perineal urethrostomy (geldings)
Urethral sphincterotomy (mare)
Laparacysttomy*
Endo catch 2, covidien
Urethral sphincterotomy
For mares
Removed with horse standing or incision cranial to sphincter
Laparaocystotomy
Specimen retrieval pouch (2 hr sx)***
Direct visualization of calculus, stabilization
No risk of rectal tear, perforation or incomplete removal
Not appropriate for type 2
Parainguinal Laparaocystotomy
Exteriorizing and suturing the bladder
Facilitated by manipulating the bladder with a hand inserted into the abdomen through a small ventral midline celiotomy
What suture patterns are used for parainguinal laparaocystotomy
Two layer closure: continuous inverting, cushing and lembert
Avoid mucosa
Local Anesthesia + hydro-distension
Exteriorizing the bladder
Instilling a local anesthetic solution into the bladder before sx then distending the bladder with fluid
What feeds should you avoid if you have a horse prone to bladder stones
Legume hay (alfalfa, lucerne)
Beet pulp
Which horses get urethral rents?
Geldings (hematuria)
Stallions (hemospermia)- American QH and frequently bred stallions
What is the mechanism of urethral rent formation and where do they occur?
Idiopathic @ ischiatic arch
Bulbospongiosus muscle contracts to expel urine from the urethrae at the end of urination → ↑ P within CSP
Presenting signs in the stallion
Infertility: RBCs affect motility and cell membrane of sperm
Hemospermia @ the end of ejaculation
Pain during ejaculation or erection
How do you confirm the dx of urethral rents?
Endoscopic exam of the urethra
How do you tx urethral rents?
Stallions: Extender added to semen to dilute conc., long sexual abstinence
Spontaneous healing in both
Temporary perineal urethrostomy and corpus spongiotomy
Temporary perineal urethrostomy
↓ pressure gradient between urethral lumen and CSP @ the end of urination
Transect the BS muscle to prevent ↑ pressures at the end of urination
Corpus spongiotomy
Ischial incision that extends to CSP but doesn’t enter the lumen
Avoids urethral fistula and stricture (urethrotomy)
TX OF CHOICE
Habronemiasis
Skin disease of Equidae caused by the larvae of the spirurid stomach worms in the genera Draschia and Habronema
Habronemiasis of the urethral process and lifecycle
Transmitted by house flies, face flies, and stable flies, that lay eggs in a horse’s manure →the larvae hatch in the manure and are ingested by the flies → the flies deposit the larvae around the horse’s lips, →swallowed and develop into adults in the stomach.
How do you tx Habronemiasis?
Prednisone, cydectin, ComBot, Spotton (fenthon), eqvalan
Which horses are predisposed to idiopathic hematuria
Arabians
CS of idiopathic hematuria
Sudden bleeding (hematuria + hematochezia)
Acute nephritis → chr. nephritis and tissue fibrosis → renal hypertension → severe hematuria
Tx of idiopathic hematuria
Antimicrobial drugs (3w min)
Repeated blood transfusions
Most common tumors in the kidney
Adenocarcinoma (renal cell carcinoma)* and lymphosarcoma
Most common tumors of the urinary bladder
Squamous cell carcinoma and transitional cell carcinoma
similar CS of those with calculi
Piroxicam (Feldene)
COX-2 inhibition (overexpressed in epithelial cancers)
COX-2 derived PGs responsible for tumor growth and metastasis and tumor angiogenesis
CS for blister beetle toxicosis
Vesicant/ mucosal irritant
Death + shock
Sweating profusely
↑ Hr, resp, temp, CRT
Bright red mm, hematuria
In which type of forage do blister beetles swarm?
Alfalfa fields during blooms
What is hemolytic uremic syndrome?
Verotoxins produced by E. coli
Endothelial damage in glomerular capillary loops and small arterioles → renal failure and hemorrhage
Most common cause of ulcerative cystitis
Inhibition of protective PGs by long term use of phenylbutazone (NSAIDs)
When a horse gets post-exercise hematuria with no underlying bladder dz, is the bladder normally full or empty pre-exercise?
Concussion of bladder during exercise
The bladder is empty (urinates right before exercise)
How does an osteochondroma of the os pubis result in hematuria?
Osteochondroma (benign bone tumor that outgrows at the end of the bone) protrudes and causes compression of the bladder
How do you detect osteochondroma?
U/S?
What causes the presence of a hematoma in the bladder of neonatal foals?
Associated with excessive umbilical ablation and trauma to the umbilicus
