Haematuria is the presence of blood in the urine, which gives it a red colour.
It occurs in all species due to a variety of diseases and conditions.
It is important to distinguish haematuria from:
- haemoglobinuria and myoglobinuria. With haemoglobinuria, when the urine sample is spun down, the supernatant remains red/brown in colour. With haematuria a spun urine sample forms a reddish sediment. With myoglobinuria the spun sample appears clearer.
- porphyrin pigments in urine: common in rabbits due to porphyrin pigments in diet, dipstick will differentiate, or porphyrin pigments will fluoresce under a Wood's lamp.
Haematuria may be caused by local or systemic disease.
Systemic disease is rare, but includes bleeding disorders such as thrombocytopaenia, platelet dysfunction (von Willebrand's disease), defects in the coagulation cascade or bleeding due to toxins (lead toxicity). There will usually be evidence of bleeding from other areas.
Local disease is much more common and haemorrhage can occur at all levels of the urinary and reproductive tract, leading to haematuria.
Local causes include: bacterial cystitis, idiopathic cystitis, urinary calculi, pyelonephritis, prostatitis, polyps, bladder neoplasia, neoplasia of the renal pelvis, idiopathic renal haemorrhage, vascular anomalies, trauma.
Reproductive tract diseases include: pyometra, uterine neoplasia, endometrial venous aneurysms.
Haematuria can be diagnosed by using a dipstick for haemoglobin, but this will not differentiate haematuria from haemoglobinuria or myoglobinuria.
Urine sediment can be analysed to reveal red blood cells.
Clinical signs and physical examination may help localise the problem. The clinical signs of pollakiuria and dysuria indicate lower urinary tract inflammation but are not specific for a particular disorder.
Blood at the beginning of urination suggests bleeding from the bladder neck, urethra or genital tract. Blood present throughout urination is more consistent with diffuse bladder disease or upper urinary tract haemorrhage (kidneys and ureters). Also haemorrhage due to a bleeding disorder may present this way.
With focal lesions of the bladder or large dependent cystoliths, blood may enter urine at the end of voiding. Bleeding from the genital tract may occur independently of urination and may show blood clots.
Voided urine samples can be compared to samples collected during cystocentesis to establish the location of the disorder.
Radiographs, especially contrast studies, and ultrasonography may also be very helpful in identifying the urinary or genital tract pathology.
Full haematology and biochemistry may be indicated if the animal is showing systemic signs of illness. Usually, animals with lower urinary tract disorders do not exhibit these.
Cytology, biopsy or histopathology may be necessary if a mass is found or neoplasia is suspected.
This will depend on the underlying cause of the haematuria.
|Haematuria Learning Resources|
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|Rabbit Medicine and Surgery Q&A 20|
Wingfield, W. (2001) Veterinary emergency medicine secrets Elsevier Health Sciences
Richardson, V. (2000) Rabbits: health, husbandry and disease John Wiley and Sons
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