2022.Vol38.Iss1.EqUrinaryTractDisorders Flashcards
Imaging of the urinary tract
What is the reported reference size measures in thorough bred adults and foals
Adults:
ave length of both kidneys: 15-18 cm
right kidneylarge in width: 13.4-14 cm & depth 6.7-7.4 cm
Foals:
8-10.5 cm length
6.7-10.4cm width
Acute kidney injury and renal failure in horses
What is the MOA of aminophylline?
inhibits adenosine-> a potent afferent arteriole vasoconstrictor
Acute kidney injury and renal failure in horses
Why is mannitol controversial in the treatment of ARF?
can cause severe osmotic injury to the tubules
Urinary tract disorders of foals
how high can spurious hypercreatinemia syndrome get in foals?
occasionally >15 mg/dL
**generally decline to normal concentrations in 1-3 days of life
Urinary tract disorders of foals
What is the average time to the first urination in foals?
6 hours-colts
11 hours-fillies
Urinary tract disorders of foals
What is the normal urine output in a foal?
148 ml/kg per day
Urinary tract disorders of foals
Why do foals have increased protein in their urine?
within the first 36 hours of life
2-3+ proteinuria d/t colostrla ab absorption
Urinary tract disorders of foals
What is the size of foals kidneys on ultrasound?
5x10cm for a 50 kg foal
Urinary tract disorders of foals
A report in standard bred foals reported what the normal umbilical structures measure?
median umbilical vein diameter: 0.83 cm
median umbilical artery diameter: 0.61 cm
median urachal diameter of 1.07 cm
Urinary tract disorders of foals
When should a urinary catheter be passed in a foal?
a bladder diameter >10cm
**dummy foal bladder– poor detrusor tone or bladde sphincter dyssnergia can precede bladder rupture in foals
Urinary tract disorders of foals
What is the recommended percentage of chlorhexidine solution for dipping umbis?
0.5% chlorhexidine
Urinary tract disorders of foals
What level of creatinine in peritoneal fluid: serum is consistent with bladder rupture?
peritoneal fluid: serum Cr ratios >2
Urinary tract disorders of foals
What are recommended treatments prior to surgical correction for a ruptured bladder?
- draining urine from abdomen
- replace IV fluids wiht 0.9% NaCl to prevent hypotension & rapid fluid shifts
- Treat hyperkalemia: 50 ml Ca gluconate added to 1 L bag of 0.9% NaCL and 5-10% dextros esolution
Urinary tract disorders of foals
When is it safe to take a foal to surgery with hyperkalemia?
concentrations <5.5 mEq/L
Urinary tract disorders of foals
How does hydroureter syndrome present in foals?
-present 3-7 days old
C/S: encephalopathy, blindness, seziures
Na Concentrations <110 mEq/L
Polyuria and polydipsia in horses
List differentials for polyuria in horses
Polyuria and polydipsia in horses
How do you differentiate psychogenic polydipsia from diabetes insipidus?
water deprivation test (or modified if long-standing with resultant medullary washout)
Metabolic disorders associated with renal disease in horses
Signs of cerebral cortical dysfunction is seen in as a rare sequelae of renal failure caused by
uremia
**uremic encephalopathy
Metabolic disorders associated with renal disease in horses
What is the prognosis for foals showing signs of encephalopathy d/t hyponatremia and acute kidney injury?
Favorable prognosis– correction of sodium deficit
Metabolic disorders associated with renal disease in horses
What does uremic encephalopathy pathogenesis seen as histopathologically?
diffuse central nervous system Alzheimer type II astrogliosis
Metabolic disorders associated with renal disease in horses
What is the cause of renal tubular acidosis?
kidney unable to maintain normal acid-base homeostasis b/c of tubular defects in acid secretion or bicarbonate HCO 3- reabsorption
Metabolic disorders associated with renal disease in horses
What is the metabolic disturbance seen with renal tubular acidosis?
normal anion gap: hyperchloremic metabolic acidosis
**loss of serum bicarb results in a retention of chloride, so anion gap remains normal
Metabolic disorders associated with renal disease in horses
What are the types of renal tubular acidosis?
T1: impaired acid secretion, potassium wasiting; defect in H secretion by H-atpase or H/K ATPase or increased H permeability of the luminal membrane of the alpha intercalated cells results in a net H secretion
T2: proximately RTA: defect in reabsorption of filtered HCO3 d/t impaired HCO3 transport across basolateral membrane or d/t carbonic anhydrase inhibition
T3: RTA is rare (features of both T1 & T2)
Metabolic disorders associated with renal disease in horses
What are causes of renal tubular acidosis?
- primary (inherited)
- Secondary: meds, such as amphotericin B, ibuprofen, lithium or systemic diseases; recurrent nephrlithiasis, nephrocalcinosis,
Describe fanconi syndrome.
Subset of T2 renal tubular acidosis
-widespread PCT dysfunction, with defective resorption in glucose, aa, phosphate, potassium, sodium, calcium, mg uric acid, other organic acids
Smith: p979
Metabolic disorders associated with renal disease in horses
Besides, hyperchloremic metabolic acidosis, what other electrolyte abnormality is observed?
hypokalemia– d/t anorexia
**also during treatment with bicarb– will lead to hypokalemia
Metabolic disorders associated with renal disease in horses
At what rate can potassium chloride be supplemented?
maintenance: 20-40 mEq/L, not to exceed the rate of 0.5 mEq/kg/h
Metabolic disorders associated with renal disease in horses
List causes of severe hyponatremia in foals
(serum <122mEq/L)
diarrhea, uroperitoneum, renal disease, rhabdomyolysis, suspected transient pseudohypoaldosteronism, adrenal insufficiency, excessive water intake, iatrenogenic from excessive water enemas & hypotonic fluids
Metabolic disorders associated with renal disease in horses
What are C/S seen with hyponatremia in foals?
obtundation, ataxia, seizures, dec suckle reflex, hyperreactivity, central blindness, head tilt, opisthotonos, continuous chewing/tongue movement, grimacing, head pressing, circling, comatose
Metabolic disorders associated with renal disease in horses
Describe the two approaches to fluid therapy in the treatment of hyponatremic encephalopathy in foals.
- 3% hypertonic saline via infusion pump & remained met with 10% dextrose n water; restrict water/milk ingestion. once serum reaches 120 Meq/L, treat with balanced polyionic fluids
- calculate the deficit & replace.
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
NSAID toxicity pathogenesis at the kidney
focal coagulative ischemic necrosis of the renal crest & corresponding inner medulla
**prostaglandins are protective to the kidney causing vasodilation of afferent arteriole & inc renal perfusion
Chronic renal failure- causes, clinical findings, treatments & prognosis
What are the most common C/S of chronic kidney disease?
weight loss
pu/pd
ventral edema
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
What is the reference standard for evaluating kidney function & can be obtained using iohexol clearance time?
glomerular filtration rate
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
Creatinine is only elevated when what percentage of the nephrons are dysfunctionaL?
75%
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
Why is creatinine a better measurement of kidney function than urea?
urea: produced from protein catabolism, is reabsorbed in the PCT
VS
creatinine: produces from muscle, is filtered unhindered in the glomeruli
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
Marked proteinuria is considered a hallmark of what disease in horses?
glomerulonephritis
Relevant equine renal anatomy, physiology, and mechanisms of acute kidney injury: a review
On bloodwork what should make you highly suspicious of chronic kidney disease?
high creatinine & calcium
chronic renal failure- causes, clinical findings, treatments & prognosis
what is the most common cause of chronic renal disease in horses?
glomerulonephritis
chronic renal failure- causes, clinical findings, treatments & prognosis
List etiologies of chronic kidney disease
chronic renal failure- causes, clinical findings, treatments & prognosis
If renal biopsy identifies glomerulonephritis as a cause of CRD, what treatment is recommended
-resolve primary infection
-immunosupprsesive therapy: dex: -.1 mg/kg IV or IM daily for 3-5 days, followed by oral prednisolone 1 mg/kg BID for 2 weeks then tapered to 25% level
chronic renal failure- causes, clinical findings, treatments & prognosis
What are management suggestions in chronic kidney disease? (what is the primary focus)
proteinemia, hypertension, electrolyte derangements, nutrition
Discolored urine in horses and foals
how to differentiate hematuria/hemoglobinuria/pigmenturia on centrifugation?
after centrifugation hematuria will clear, vs hemoglobinuria and myoglobinuria will not
Discolored urine in horses and foals
Besides centrifugation of urine, what other diagnostic helps distinguish hematuria/hemoglobinuria
hemoglobinuria– serum will be pink discoloration d/t intravascular hemolysis
Discolored urine in horses and foals
What drugs will cause urine discoloration?
rifampin
phenoazopyridine
Discolored urine in horses and foals
How does timing of discoloration during micturition help distinguish location of lesion?
beginning to end: renal, ureteral, or bladder lesions
beginning only: distal urethra
end only: proximal urethra or bladder neck
Discolored urine in horses and foals
What should be ruled out with exercise associated hematuria?
cystoliths
**dx on rectal, U/S or cystoscopy
Discolored urine in horses and foals
Hematuria is a common C/S of a UTI, what bacteria are commonly isolated?
Proteus mirabilis
Escherichia coli
Klebsiella spp
Enterobacter spp
Discolored urine in horses and foals
verminous nephritis can be caused by which organism
halicephalobus gingivalis
Discolored urine in horses and foals
Halicephalobus gingivalis can enter through mucous membrane, invade and proliferate in what tissues?
kidneys
central nervous system
long bones
eyes
Discolored urine in horses and foals
What C/S can be seen with halicephalobus gingivalis infection?
encephalitis
renal dysfunction
weight loss
hematuria
polyuria
Discolored urine in horses and foals
What treatments are described for halicephalobus gingivalis?
larvicidal treatment can be attempted
**death of worms can cause inflammation–> renal failure
Discolored urine in horses and foals
Stallions/geldings can present with hemospermia/hematuria due to what condition?
urethral rent
Discolored urine in horses and foals
What is the common location for a urethral rent?
convex surface of the urethra at the level of the ischia arch, usu linear & corresponds with corpus spongiosum
Discolored urine in horses and foals
Methemoglobinuria is another cause of discolored urine producing brown-tinged color. List causes:
-nitrite & nitrate tox
**accumulating plants: red maple leaves, mint weed, sudan grass
Urinary Incontinence and urinary tract infections
What are neurologic causes of incontinence in horses?
EHV-1
polyneuritis equi
sacral/coccygeal trauma
Urinary Incontinence and urinary tract infections
list causes of urinary incontinence in horses
Urinary Incontinence and urinary tract infections
After how many days of antibiotic treatment should a patent umbilicus show improvement?
withint 5 to 7 days of treatment
Urinary Incontinence and urinary tract infections
What is the most common congenital abnormality of the equine urinary tract?
ectopic ureter
Urinary Incontinence and urinary tract infections
What are C/S of UMN bladder and where is the lesion location?
Lesion: Cr to sacral segments
C/S: inc urethral pressure– difficult to catheterize, tought bladder on rectal palpation
Urinary Incontinence and urinary tract infections
What are C/S of LMN bladder and where is the lesion location?
lesion: sacral/lumbosacral
C/S: urine dribbling– incomplete bladder voiding; loss of external anal sphincter tone, reduce or absent perineal reflex, tail paralysis, analgesia or hypalgesia of the perineum, atrophy of mm of hip & him limb, paresis of hind limbs; bladder can be evacuated by putting pressure on it per rectujm
Urinary Incontinence and urinary tract infections
What are possible treatments for UMN bladder?
sympatholytic drugs: phenoxybenzamine, acepromazine, prazosin (block alpha-1 rece4ptors in smooth mm of internal sphincter)
parasympathomimetic: bethanechol: stim detrusor mm
skeletal mm relaxants: benzodiazepines or dantroene to block the striated urethralis mm
Urinary Incontinence and urinary tract infections
What clinical signs are seen with polyneuritis equi?
perineal hyperesthesia, initially that progresses
hypalgesia/analgesia
paralysis of tail, rectum and bladder
penile prolapse & dribbiln go furine in males
mm atrophy of the gluteals & hind leg muscles (usu asymmetric)
asymmetric CN signs: paralysis of masticatory & facial mm, head tilt, nystagmus, tongue paralysis, dysphagia
Urinary Incontinence and urinary tract infections
What treatments are described for polyneuritis equi?
no effective treatment
**steroids may have some temporary improvement
Urinary Incontinence and urinary tract infections
C/S of symmetric ataxia, hind limb weakness, flaccid paralysis of the tail and urinary incontinence is consistent with which toxicity?
sorghum pastures, sudan grass and johnson grass
