Page 677 - Small Animal Internal Medicine, 6th Edition

PART FIVE Urinary Tract Disorders

Stephen P. DiBartola and Jodi L. Westropp

VetBooks.ir CHAPTER 38

Clinical Manifestations of

Urinary Disorders

Azotemia refers to an increased concentration of nonprotein The diagnosis of renal disease begins with a careful evalu-
nitrogenous compounds in blood, usually urea and creati- ation of the history and physical examination findings.
nine. Prerenal azotemia is a consequence of decreased renal
perfusion (e.g., severe dehydration, heart failure); postrenal History
azotemia results from interference with excretion of urine Take a complete history, including signalment (age, breed,
from the body (e.g., obstruction, uroabdomen). Primary sex, presenting complaint, husbandry, and review of body
renal azotemia is caused by parenchymal renal disease. The systems). The history of the presenting complaint should
term renal failure refers to the clinical syndrome that occurs include information about onset (acute or gradual), progres-
when the kidneys are no longer able to maintain their regula- sion (improving, unchanging, or worsening), and response
tory, excretory, and endocrine functions, resulting in reten- to previous therapy. Information about husbandry includes
tion of nitrogenous solutes and derangements of fluid, the animal’s immediate environment (indoor or outdoor),
electrolyte, and acid–base balance. Renal failure occurs when use (pet, breeding, show, or working animal), geographic
75% of more of the nephron population is nonfunctional. origin and travel history, exposure to other animals, vaccina-
Uremia refers to the constellation of clinical signs and bio- tion status, diet, and information about previous trauma,
chemical abnormalities associated with a critical loss of illness, or surgery.
functional nephrons. It includes the extrarenal manifesta- Questions relating to the urinary tract include those
tions of renal failure (e.g., uremic gastroenteritis, hyperpara- about changes in water intake and the frequency and volume
thyroidism). The term renal disease refers to the presence of of urination. Ask about pollakiuria, dysuria, or hematu-
morphologic or functional lesions in one or both kidneys, ria. Be careful to distinguish dysuria and pollakiuria from
regardless of extent. polyuria and to differentiate polyuria from urinary inconti-
nence. The distinction between pollakiuria and polyuria is
important because polyuria may be a sign of upper urinary
CLINICAL APPROACH tract disease, whereas pollakiuria and dysuria usually are
indicative of lower urinary tract disease. Nocturia may
Try to answer the following questions: be an early sign of polyuria but can also occur as a result
of dysuria. Polydipsia usually is more readily detected by
1. Is renal disease present? owners than is polyuria. Describe amounts in quantita-
2. Is the disease glomerular, tubular, interstitial, or a tive terms familiar to the owner, such as cups (≈250 mL/
combination? cup) or quarts (≈1 L/quart). Question the owner about
3. What is the extent of the renal disease? exposure of the animal to potential nephrotoxins such as
4. Is the disease acute or chronic? Reversible or irreversible? ethylene glycol in antifreeze, chicken jerky treats (dogs),
Progressive or nonprogressive? Easter lilies (cats only), aminoglycosides, and nonsteroidal
5. What is the current status of the patient’s renal function? antiinflammatory drugs.
6. Can the disease be treated?
7. Which nonurinary complicating factors are present and Physical Examination
require treatment (e.g., infection, electrolyte and acid–base Perform a complete physical examination, including fundic
disturbances, hypertension, dehydration, obstruction)? and rectal examinations. Pay close attention to hydration
8. What is the prognosis? status and to the presence of ascites or subcutaneous edema

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