Equine Urogenital Flashcards
Which kind of horses usually get urethritis?
What presenting signs may they have?
Usually older geldings with preputial or distal urethral conditions
Look for underlying conditions eg trauma, neoplasia
Owners present for malodorous sheath, swelling
May have red discharge on legs
How would you treat urethritis?
Clean urethral fossa +/- apply very mild topical antibacterial agents
(Urethral fossa accumulates crystals)
Give some initiating causes of cystitis
Urolithiasis, neoplasia, paralysis, catheterisation (primary bacterial cystitis is really rare)
How do you diagnose cystitis?
Urine sediment examination (>10 leucocytes/HPF+ >20 organisms/HPF)
Urolithiasis is more likely in which horses?
Geldings
Where are uroliths usually found?
Bladder
May also be in the kidneys or ureters
What are uroliths usually composed of?
Calcium carbonate
What are the 3 forms of urolithiasis?
- Yellow-green spiculated stone, easily fragmented
- Grey-white smooth stones-harder and contain more phosphate
- Sabulous urolithiasis-sludge usually secondary to bladder paralysis
Give some clinical signs of dysuria in horses
May see urine dribbling or scalding
(Owner may misinterpret for oestrus behaviour in females)
Less commonly may see colic or tenesmus
Give some factors which contribute to urolith formation?
- Tissue damage (eg secondary to renal damage)
- Prolonged transit time (eg neurological conditions)
- Nidus formation (eg area of necrotic tissue, leucocytes or desquamated epithelial cells)
- Reduced inhibition of crystal growth (mucous is a natural inhibitor)
Nephroliths and ureteroliths usually occur secondary to which other problems?
eg pyelonephritis, tubular necrosis, papillary necrosis (NSAIDs)
How do nephroliths and ureteroliths occur?
Obstruction causes dilation of the renal pelvis -> hydronephrosis
What can happen if both kidneys are affected by nephroliths or ureteroliths?
Renal failure
What frequently accompanies the calculi seen with nephroliths/ureteroliths?
Bacterial infection
How do you diagnose nephroliths/ureteroliths?
Palpation and/or US
What clinical signs may you see in a horse with cystic or urethral calculi?
Dysuria eg haematuria, stranguria, pollakiuria, pyuria
May see posturing to urinate (differentiate from oestrus in mare)
May see colic, urine scalding, loss of condition
How would you diagnose cystic or urethral calculi?
Palpation or endoscopy
How would you remove cystic and urethral calculi?
Surgically eg laparotomy, perineal urethrotomy in males
Females: calculi can be retrieved by forceps or hands after epidural
What should you give a horse after removing cystic/urethral calculi?
Antibiotics
Urinary acidifiers could be given but horses wont eat them
Don’t feed alfalfa as want to decrease calcium excretion
Salt to increase water consumption and diuresis
What is the normal water intake of a horse?
20L/day
Can increase to 90L with exercise/hot conditions
Give some differential diagnoses for PUPD in the horse
Most common: -Renal failure/disease -Cushings -Psychogenic water consumption (stereotypie) Less common: -Diabetes insipidus -Diabetes mellitus -Miscellaneous eg endotoxaemia
Describe the pathogenesis of PUPD with PPID/Cushings disease
Glucosuria and osmotic diuresis
Antagonism of ADH by cortisol
Impingement on the posterior pituitary, decreasing ADH
What range of urine specific gravity indicates renal failure?
1.008-1.010
Is a horse in renal failure if its specific gravity is <1.008? Why?
No because the kidney is still functioning as it is actively diluting the urine
What 2 things must be present to confirm renal failure?
Isosthenuria (check specific gravity)
Azotaemia (high blood urea and creatinine) with PUPD