Urinary 1 Flashcards
What is the single underlying cause of renal papillary necrosis?
Ischemia.
What are 3 potential sources for emboli that could lead to renal infarction (i.e., that originated outside the kidney)?
(1) Emboli from cardiac valvular endocarditis. (2) Thromboembolism due to sepsis. (3) Emboli from neoplasms. (4) Bacterial emboli.
Explain how renal failure leads to renal fibrous osteodystrophy.
Renal disease –> Reduced glomerular filtration rate (GFR) –> Phosphorus retained in body –> Ca and P interact and precipitate –> Decreased available calcium –> Increased parathyroid hormone release in response –> Calcium resorption from bone –> Renal osteodystrophy (“rubberjaw”)
You are performing a necropsy on a dog and notice gritty, white, horizontal (ladder-like) streaks in the pleura of the intercostal spaces. What does this suggest?
These lesions occur due to soft tissue deposition of calcium secondary to uremia / renal failure. Intercostal mineralization is characterized, particularly in dogs, by calcification of the subpleural connective tissue of the cranial intercostal spaces.
Explain the difference between primary and secondary renal papillary necrosis in terms of the cause.
(1) Primary: Caused by non-steroidal anti-inflammatory drugs (NSAIDS). (2) Secondary: Caused by reduction of renal medullary blood flow for some reason other than NSAIDS, such as fibrosis, calculi in renal pelvis or lower urinary tract obstruction.
Draw a flow chart explaining the pathogenesis of soft tissue mineralization in animals in renal failure.
Renal disease –> Reduced glomerular filtration rate (GFR) –> Phosphorus retained in body –> Ca and P interact and precipitate –> Soft tissue mineralization.
Explain the pathogenesis of the oral ulceration that may be seen in a uremic animal.
(1) Endothelial damage (vasculitis) caused by azotemia leads to thrombosis and infarction of blood vessels. (2) Caustic injury to epithelium is secondary to the production of large concentrations of ammonia after splitting of salivary urea by bacteria.
Compare the appearance of an acute versus chronic renal infarct caused by blockage of an interlobar artery.
(1) Acute: Red, swollen and hemorrhagic. (2) Chronic: Pale, shrunken and fibrotic.
Describe the gross appearance of the characteristic subpleural lesions seen in a uremic dog or cat.
Gritty, white, horizontal (ladder-like) streaks of mineralization are seen in the subpleural connective tissue of the intercostal spaces.
What is the characteristic renal lesion in a puppy that has died of herpesviral infection?
Ecchymotic hemorrhages are common in the renal cortex of neonatal puppies infected with herpesvirus.
What, in general terms, causes post-renal failure/disease?
Inadequate discharge of urine from the kidney.
Explain the pathogenesis of the gastric ulceration that may be seen in a uremic animal.
(1) Endothelial damage (vasculitis) caused by azotemia leads to thrombosis and infarction of blood vessels. (2) Caustic injury to epithelium is secondary to the production of large concentrations of ammonia after splitting of gastric urea by bacteria.
Describe the characteristic shape of a renal infarct caused by blockage of glomerular capillary tuft.
Pinpoint.
What are the two major factors that determine the gross appearance of a renal infarct?
(1) The size of the blocked vessel. (2) The age of the lesion.
What is the term for enlargement of the parathyroid glands seen in animals in renal failure?
Renal secondary hyperparathyroidism.
Explain the pathogenesis of the pulmonary edema that may be seen in a uremic animal.
Endothelial damage (vasculitis) caused by azotemia leads to edema.
Describe the characteristic shape of a renal infarct caused by blockage of an interlobar artery.
Wedge-shaped, with the point at the interlobar artery and the wide base at the renal surface.
Give two reasons why the kidneys are prone to infarction.
(1) Kidneys have an end-arterial supply, with little collateral circulation. (2) Kidneys receive 25% of cardiac output and, therefore, emboli are likely to reach the renal arteries.
Explain the pathogenesis of the large intestinal hemorrhage and ulceration that may be seen in a uremic horse or cow.
Endothelial damage (vasculitis) caused by azotemia leads to (1) edema and (2) thrombosis and infarction of blood vessels.
Explain, in terms of the unique vasculature of the kidney, why the medullary tubules are so susceptible to ischemic injury.
The blood supply to medullary tubules is entirely dependent on an intact glomerular circulatory system. For example, a thrombus near a glomerulus may lead to ischemic necrosis of the tubules associated with that glomerulus.