Urinary System IV Flashcards
Iodine in the kidney: what happens and what does it look like?
- Amyloid reacts with iodine and can give a BLACK colour
o Many little black dots
What should you think of if you find protein urea with NO inflammation with the urinary tract?
- Amyloidosis OR glomerular disease
What is amyloid?
- Protein that is normally made by the kidney
- *problem if it is misfolded
o Occurs in chronic conditions
Amyloid deposition in DOGS
- **in glomeruli
- Get high proteinuria
- *exception is shar-peis dogs (familial amyloidosis)
Amyloid deposition in cats
- *in medulla
- Low or no proteinuria
Suppurative glomerulitis
- Secondary to septicemia
- *many yellow dots in the kidney=suppurative (pus)
- Ex. Actionbacillus equuli infection in young foals
What are some diseases of the tubules?
- Fanconi-like syndrome
- Acute tubular necrosis due to
a. Ischemia
b. Nephrotoxins
You have a Basenji dog with polyuria and polydipsia, normoglycemia, and glucose urea, what is it?
- Fanconi-like syndrome
What is Fanconi-like syndrome?
- Inherited proximal tubule defect
- Abnormal structure of brush borders of proximal tubules
o Causes failure of resorption of glucose, AA, phosphorus and bicarbonate
What happens if a dog does not pee for a long time?
- Increased potassium
- *life threatening hyperkalemia
Acute tubular necrosis (nephrosis)
- Common cause of acute renal failure
- Usually get decreased or even no urine production
- Clinical presentation: oliguria or anuria
What does acute tubular necrosis result from?
- Severe and almost diffuse necrosis of proximal tubules
o First to receive what is in the filtrate and are metabolically very active
Why does acute tubular necrosis happen?
- Leakage of urine outside the tubules
- Blockage of tubules and backflow of urine
- Vasoconstriction and decreased GFR at glomerulus
What are the 2 main causes of acute tubular necrosis?
- Low renal perfusion
a. Cardiogenic, hypovolemic, septic or neurogenic - Toxins
Acute tubular necrosis GROSSLY
- Can be difficult to recognizes
- *cortex may be pale and bulge on cross section and be finely granular
What are the common examples of low perfusion leading to acute tubular necrosis in dogs and cats?
- Cardiac failure
- Deep anaesthesia
- Severe blood loss
- Profound dehydration
- Pigmentary nephrosis
What are the common examples of low perfusion leading to acute tubular necrosis in cattle?
- Endotoxemia
o Mastitis
o GI diseases (ex. severe enteritis and grain overload) - Pigmentary nephrosis
Hemoglobinuric nephrosis or myoglobinuricnephrosis
- Black or dark brown
- *too much Hg or Mg being delivered
- See dark brown urine
- *NOT directly toxic but can exacerbate ischemic injury to tubules
What can lead to hemoglobinuria?
- Intravascular hemolysis
o IMHA
o Chronic copper toxicity (sheep and cattle)
o Leptospirosis (cattle and dogs)
What can lead to myoglobinuria?
- Rhabdomyolysis
o Azoturia (horses)
o Capture myopathy (wild animals)
o Trauma (all species)
Acute tubular necrosis due to nephrotoxin: example
- Antifreeze contains ethylene glycol
o Metabolizes to toxic metabolites (glycolate and oxalate metabolites) - *damage to kidneys and affects CNS resulting in nervous signs
- *cats more susceptible but toxicity is LESS common
What do you use to diagnosis EG toxicity?
- Ca-oxalate crystals in urine=filtered through glomeruli and cause damage to
o May see hypocalcaemia as a result
o Can also see on histo-section=fluoresce under UV light - Hypocalcaemia
- Very high metabolic acidosis and very high anion gap
Why are renal tubules (especially proximal convoluted) susceptible to toxins?
- High metabolic activity
- Exposure to large volume of ultrafiltrate
Melamine toxicity
- Normal component of plastic (high nitrogen component)
o Some put it in food to make it look like there was protein in it
Raisins or grapes: dogs ONLY
- Unknown mechanism
- Acute tubular necrosis
- *not all dogs are affected equally
Lilly toxicity: cats
- Acute tubular necrosis
- *see at easter time
What are the 2 diseases of the renal pelvis?
- Hydronephorsis
- Pyelonephritis
Pyelonephritis
- Inflammation of renal PELVIS with extension into tubules and interstitium
- Ascending bacterial infection from lower UT
- *more common in FEMALES
- *form of suppurative tubulointerstitial nephritis