Lower urinary tract diseases Flashcards
Anuria
total lack of urine production
Red flag for acute severe kidney injury or acute kidney failure
Dysuria
difficulty passing urine - often reported with pollakiuria
There can be non-urinary causes for stopping whilst ridden and ‘posturing to urinate’ e.g. gastric ulceration and abdominal pain from other sources
Haematuria
presence of blood in the urine
Note that urine dipsticks cannot differentiate Hb from Mg molecules so are not always detecting haematuria rather pigmentiuria - confirm presence of red cells with microscopy
Oligouria
etymology Greek ‘few’ - reduced urine output
Sometimes absolute, sometimes only noted as a lack of expected urine output GIVEN fluid therapy
Pigmentiuria
change in the usual urine colour spectrum (pale to dark yellow)
Linked to whole blood, Hb, or myoglobin in the urine
Pollakiruria
etymology Greek ‘pollakis = many times’ - increased frequency of urination
Check with owners - is this truly increased volume (actually polyuria) or inncreased frequency. If the latter this is more likely to be bladder pain/detrusor hyperreactivity/cystitis
Stranguria
straining to pass urine
May be mistaken by owners as straining to pass urine, but is actually GI pain - gastric ulcers, meconium impaction (foal), intestinal neoplasia/abscess pulling on mesentery
Hyposthenuria
Urine specific gravity (USG) <1.008
Urine concentration is more dilute than plasma
Indicative of lack of kidney concentrating ability
In fact, it shows active secretion of water and is indicative of CKD, excessive water intake (psychogenic polydipsia), or diabetes insipidus
Isosthenuria
USG: 1.008 < USG > 1.014
Urine concentration is the same as plasma
Kidneys are neither conserving or secreting water
Could indicate a lack of kidney concentrating ability, or normal water intake for that individual
Also, worth checking if sedative drugs have been used to catheterise and obtain the urine sample, as this is the most common artefactual reason for urine that is isosthenuric, rather than more concentrated.
Hypersthenuria
USG > 1.014
Urine is more concentrated than plasma
Kidneys have normal concentrating ability
Maybe seen prior to anuria, and alongside oligouria
Might be a normal finding in horses with low water intake, but is a concern in a hypovolaemic patient, or one where acute kidney injury is suspected or indeed being treated
Approach to stranguria/pollakuria
Unusual owner reported problem
Mostly associated with inflammatory conditions of the bladder or urethra
E.g. urinary caliculi, cystitis, neoplasia
Urinalysis
Visual assessment of the bladder/urethral via endoscopy
If caused by a calculus, might be persistent or intermittent haematuria, perhaps after strenuous exercise
Primary urinary tract infection
Primary cases are very rare - check for inciting cause before dispensing antimicrobials
Normal flora of the vulva and sheath are protective
Bladder has usual mucous lining to protect
Inflammation/trauma (calculi, sabulous material) are usually the inciting cause because they interfere with usual protective mechanisms
Secondary cystitis causing stranguria/pollakuria
Urethra damage
○ Breeding
○ Parturition
○ Iatrogenic
Abnormal anatomy
Urolithiasis
Bladder paralysis
Bladder neoplasia
Sterile inflammatory cystitis that leads to opportunistic infection
Clinical signs alongside stranguria
Can be variable
Urine dribbling and staining from the detrusor hyperreactivity
Scalds the skin of the perineal area and medial aspect of pelvic limbs
The smell of stinky urine/ammonia
Proving the presence of urinary infection
Quantitative culture
○ Catheter not free catch
○ >10 leukocytes per high power field
§ 10,000 CFUs/mm
Gram -ve: E. coli, klebsiella, enterobacteriaceae
Gram +ve: staphylococcus, streptococcus, pseudomonas, (rarely Corynebacterium renale)
