Urinary system pathology 4 Flashcards
Name the toxic disease of the lower urinary tract that primarily affects cattle
Enzootic haematuria
Enzootic haematuria is caused by…?
Grazing on bracken associated toxins
What are the toxic effects of Enzootic haematuria?
- Hyperplasia, metaplasia
- Haemorrhagic cystitis
- Haematuria
How does Enzootic haematuria affect the mucosa of the LUT?
Chronic squamous or mucosa metaplasia
- transitional epithelium becomes squamous
- thicker, keratin on the surface, develops goblet cells (mucus)
Where do tumours due to enzootic haematuria form?
Most commonly in the neck of the bladder - trigone area, adjacent to the urethral sphincter
Which are the signs of enzootic haematuria?
Chronic weight loss, common in cows with bladder tumours – inappetent due to pain in abdomen
Give examples of mesenchymal tumours of the bladder.
- Leiomyoma or Leiomyosarcoma – s.muscle
- Fibroma or fibrosarcoma
- Haemangioma or haemangiosarcoma
- Rhabdomyosarcoma
A rhabdomyosarcoma affects where in the LUT?
Urethral sphincter - forms from striated myocytes
- Young (<18m), large/giant breed dogs
Are mesenchymal or epithelial neoplasia’s of the LUT more common?
Epithelial
Give examples of epithelial tumours of the bladder.
- Transitional cell papilloma
- Squamous cell carcinoma
- Transitional cell carcinoma
Which epithelial neoplasm is the most invasive and neoplastic?
Transitional cell carcinoma
Briefly describe squamous cell carcinoma.
- Slow growing
- Infiltrative but less likely to metastasise (only in later stages)
- May be nodular, sessile or ulcerated
- May arise in metaplastic epithelium
Briefly describe transitional cell carcinoma.
- Highly invasive
- Nodular or plaque
- Primarily occurs at trigone
- Metastatic (in more than 50% of cases)
What animals are predisposed to bladder transitional cell carcinoma?
- Dogs
- Neutered males
- Older dogs 9+
- Females
- Airedale, Beagle + Scottie predisposed
Where does transitional cell carcinoma frequently metastasise to?
- lung
- sub-mandibular lymph node
- pelvic bones and vertebrae
How does transitional cell carcinoma appear grossly?
Multifocal to coalescing, raised, pink and reddened nodules, both on the mucosal and serosal surface
- Dramatic spread
How does transitional cell carcinoma appear histologically?
- Excessive proliferative folds in the lumen
- Active invasion of the connective tissue and muscle
- Dense numbers of tumour cells, inflammatory cells, mitotic figures
Define the following terms:
- Dysuria
- Anuria
- Oliguria
- Polyuria
- Polydipsia
- Dysuria = painful or difficult urine
- Anuria = no urine output
- Oliguria = low urine output
- Polyuria = high urine output
- Polydipsia = high water consumption
Define the following terms:
- Isothenuria
- Hyposthenuria
- Isothenuria = cannot form urine with a higher or a lower specific gravity (SG) than that of protein free plasma. SG of the urine becomes fixed around 1.010, irrespective of the fluid intake.
- Hyposthenuria = urine of low specific gravity
Define the following terms:
- Azotaemia
- Uraemia
Azotaemia – a higher than normal blood level of urea or other nitrogen containing compounds. The basic test is the blood urea nitrogen level (BUN).
Uraemia – the clinical syndrome of toxicosis from renal failure.
Chronic renal failure is common in which species?
Cats
What are the three critical requirements for renal function where damage to any of these can send the animal into renal failure?
- Adequate renal blood flow
- Sufficient functioning nephrons
- Expulsion of continuous urinary output
Describe pre-renal failure and its causes
- inadequate blood flow causes hypoperfusion
- haemorrhage, shock, cardiac failure
- Renal parenchyma undamaged initially.
- Potentially reversible if blood flow is restored before excessive anoxic damage occurs.
Describe intrinsic renal failure and its causes
- inflammation, toxins, neoplasia, fibrosis, congenital defects
- Damage occurs which requires time for repair or compensatory hypertrophy.
- Requires aggressive therapy to correct fluid + electrolyte balance
Describe post-renal failure and its causes
- LUT obstruction, inflammation, bladder dysfunction, bladder rupture
- may affect both kidneys causing anuria
Post-renal failure causes what changes in the blood?
Rapid rise in blood urea and creatinine
- Reduced GFR and renal blood flow
What is the renal reserve?
When does renal insufficiency occur?
When does renal failure occur?
- Up to 50% capacity is the renal reserve
- There is renal insufficiency when only 30-50% of the capacity remains
- When capacity falls below 30%
What is acute renal failure and give 3 example causes?
Sudden loss of 70-100% of capacity
- Ischaemia, toxins, outflow obstruction
What are the signs of acute renal failure?
- Anuria or oliguria (no or minor urine output)
- Isosthenuric urine - an inability to concentrate or dilute urine
Describe chronic renal failure
- Gradual loss of renal capacity
- Usually irreversible
What are the signs of chronic renal failure?
- Polyuria with polydipsia
- Hyposthenuria (dilute urine)
What are some of the effects of chronic renal failure?
- Build-up of waste products (urea, creatinine)
- Failure of acid-base regulation
- Failure of fluid volume regulation
- Death due to: Dehydration, acidosis, hyperkalaemia, pulmonary oedema, hypocalcaemia,
How would a kidney appear grossly at end stage chronic kidney failure?
Diffuse severe firm texture with shrunken kidney, interstitial fibrosis + scarring of the cortical surface.
How would a kidney appear histologically at end stage chronic kidney failure?
Tubules are widely separated by an increase in interstitial tissue which is probably inflammatory cells (fine purple stippling) and fibrous tissue. Eosinophilic material in dilated tubules.
Azotaemia is a biochemical finding of?
Increased urea and creatinine
How good is azotaemia as a measure of renal function?
Relatively insensitive - require 70% of renal function to be lost
Is uraemia better tolerated if it is rapid or chronic onset?
Chronic (speed of onset will affect tolerance to its effects)
What are the two types of pathological uraemia lesions?
Causative - primary disease process: pre-renal, intrinsic, post-renal
Resultant - secondary pathological changes as a result of toxaemia
Give examples of clinical signs resulting from uraemic toxicosis
- PU/PD
- Pallor
- Anorexia
- Weakness
- Muscle wasting
- Hypothermia
- Vomiting
Define Cachexia
Chronic weight loss due to poor appetite and proteinuria
List the secondary pathological changes associated with uraemia - 9 possibilities
- Cachexia
- Pulmonary oedema
- Haemorrhagic gastritis
- Fibrinous pericarditis
- Aortic and atrial thrombosis
- Soft tissue mineralisation
- Non-regenerative anaemia
- Secondary renal hyperparathyroidism
- Hypertension
How does uraemia cause pulmonary oedema?
Toxaemia damages pulmonary endothelium leading to leakage of plasma - firmer lung tissue which is radiolucent
How does uraemia cause haemorrhagic gastritis?
Uraemic vasculitis and thrombosis lead to necrosis and sloughing of the mucosa
How does uraemia cause non-regenerative anaemia?
- Reduced erythropoietin production
- Haemorrhage
- Toxic effect of uraemia on bone marrow RBC production
- Reduced RBC life span
- Pale mm colour
How does uraemia cause secondary renal hyperparathyroidism?
Parathyroid hormone overproduction
How can CRF cause blindness?
Intraocular haemorrhage developing from hypertension due to reduced renal blood flow
