Page 680 - Small Animal Internal Medicine, 6th Edition

652 PART V Urinary Tract Disorders

other potential causes of hematuria (e.g., blood clots in the Nephrectomy should be considered if bleeding is docu-
kidney or bladder). Abdominal ultrasonography is useful to mented to be unilateral and has been intractable, with the
VetBooks.ir identify soft tissue lesions such as neoplasia and polypoid development of severe anemia. Nephrectomy resolves hema-
turia in dogs with unilateral renal hemorrhage, but some dogs
cystitis.
Idiopathic Renal Hematuria have been reported to develop hemorrhage from the contra-
lateral kidney at some point after nephrectomy. Thus the
The urinary bleeding in this disorder originates in the kidney, decision to perform nephrectomy should be weighed care-
but its cause is obscure. Renal hemorrhage usually is unilat- fully. Some affected dogs have intermittent periods of hem-
eral, but occasionally it may be bilateral. Large-breed dogs orrhage interspersed with long asymptomatic time periods.
(e.g., Weimaraners, Boxers, Labrador Retrievers) of both If there is no anemia or anemia is mild, then observation of
sexes often are affected. Most are younger than 5 years at the patient over time with monitoring of hematocrit may be
presentation, and approximately one-third of reported cases preferable to nephrectomy. Recently, endoscopically guided
have been in immature dogs (<1 year). sclerotherapy using solutions containing povidone iodine,
The owner typically reports severe macroscopic hematu- silver nitrate, or both has been used as a renal-sparing tech-
ria that does not appear to cause any discomfort to the dog nique to successfully control renal hemorrhage in dogs with
(i.e., no dysuria), and hematuria typically occurs throughout idiopathic renal hematuria.
urination. Blood clots also may be observed in the urine.
Bleeding may occur for days or weeks and then disappear DYSURIA
for months, only to return at a later time. There is no history Dysuria refers to painful or difficult urination and typically
of trauma, and no abnormalities are detected on physical is manifested as pollakiuria (excessively frequent passage of
examination. small volumes of urine) and stranguria (straining to urinate
The regenerative anemia may be acute (e.g., macrocytosis, because of spasm of the bladder and urethra). It usually is
polychromasia, reticulocytosis) or chronic, with evidence of associated with disorders of the lower urinary tract, espe-
iron deficiency (e.g., microcytosis, hypochromasia). Serum cially cystitis, urethritis, cystic calculi, bladder neoplasia, and
creatinine and blood urea nitrogen (BUN) concentrations obstruction of the urethra by calculi or neoplasia (Box 38.2).
are normal, urine specific gravity (USG) shows moderately Dysuria can also be associated with neoplastic and inflam-
concentrated urine, coagulation tests and platelet count are matory diseases of the genital tract (e.g., prostate gland,
normal, and urine culture is negative. Hydronephrosis and vagina). Frequent licking at the genital area often is observed
hydroureter, caused by obstructive blood clots, may be in dogs and cats with dysuric disorders. Dogs with perineal
observed on the affected side by diagnostic imaging studies. hernias will sometimes present for dysuria.
Filling defects caused by blood clots also sometimes can be During history taking, it is important to clarify what the
observed in the bladder. In female dogs, cystoscopy allows owner actually is observing. Many owners cannot readily
identification of the affected side by observation of normal differentiate a dog or cat that is straining to urinate from one
urine flowing from one ureteral opening as compared with that is straining to defecate. Thus owners sometimes believe
blood coming from the contralateral ureteral opening (Fig. that their animal is constipated when in fact it is straining to
38.3 and Video 38.1). urinate. Also, sometimes owners report that their dog is

A B

FIG 38.3
(A) Normal ureteral openings in the trigone region of the bladder of a normal dog on
cystoscopy. (B) Blood coming from a ureteral opening in the trigone region of the bladder
in a dog with idiopathic hematuria.