Page 948 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

CHAPTER 7

URINARY SYSTEM
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GENERAL PHYSICAL EXAMINATION caudal pole of the left kidney can all be palpated and
should be systematically assessed.
A thorough history should be taken before a physi- Physiologically, water consumption and urination
cal examination is performed. The clinician should vary with age and may be influenced by climate, diet
enquire about the duration and type of clinical signs, and the level of exercise. Water consumption and
medication(s) given, response to treatment, diet, urine output should be assessed over a 24-hour period.
reproductive status and number of animals on the A horse with normal renal function should produce
premises that are affected. A full physical exami- 5–20 litres of urine daily (15.30 ml/kg/day [6.8–13
nation should be performed because the clinical l/450 kg horse/day]) while consuming 20–35 litres of
signs of urinary tract diseases are non-specific and water (15–60 ml/kg/day [6.8–27 l/450 kg horse/day]).
many urinary tract diseases resemble acute and/or Increased water loss, either pathological (i.e. diar-
chronic lower gastrointestinal (GI) diseases. In the rhoea, haemorrhage, polyuria) or physiological (i.e.
male patient, the urethral orifice and urethra on sweating), should result in increased water intake.
the ventral aspect of the penis should be palpated.
The vaginal opening and perineum can be readily DIAGNOSTIC TESTS
examined in the female. In foals the umbilicus and
surrounding structures of the abdomen should also Urinalysis
be assessed. Hydration status should be clinically Urinalysis is required for the assessment of urinary
assessed and ideally, urination should be observed tract function. It defines the physical, chemical and
(Table 7.1). microscopic characteristics of the urine sample.
Palpation p/r should be performed in all animals Urinalysis results may be influenced by the method
of adequate size. The proximal urethra (located used for urine collection. Voided, mid-stream urine
cranial to the pelvic brim), bladder, ureters and the samples can be readily obtained but contamination

Table 7.1 Terminology used in urinary tract disease

Stranguria Slow and painful urination
Pollakiuria Abnormally frequent passage of urine
Dysuria Painful or difficult urination
Oliguria Reduced daily urine output
Polyuria Increased daily urine output
Anuria Complete cessation of urine output
Urinary incontinence Uncontrolled (involuntary) leakage of urine
Azotemia Presence of nitrogenous waste products in the blood
Isosthenuria Urine has the same SG/osmolality as that of plasma (SG between 1.008 and 1.012; 280–350 mOsm/kg)
Hyposthenuria Urine SG/osmolality less than that of plasma (<1.008; <280 mOsm/kg)