Urinary 2 Flashcards

1
Q

Name two conditions that commonly cause hemoglobinuric nephrosis in dogs.

A

(1) IMHA (immune-mediated hemolytic anemia). (2) Leptospirosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In which species of domestic animal is glomerulonephritis the most common cause of renal failure?

A

Dogs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name one dog breed that has a familial/hereditary/genetic predisposition to renal amyloidosis.

A

Shar Pei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

You are performing a necropsy on a dog and notice that both kidneys are very darkly stained and that the renal pelvic fat is yellow. This dog has a history of passing red-brown urine. What is the most likely cause of this?

A

Hemoglobinuric nephrosis due to intravascular hemolysis (several causes, including IMHA in dogs, copper toxicity in sheep, leptospirosis in cattle & dogs & red maple toxicosis in horses). Myoglobinuric nephrosis is less likely because it tends not to stain fat yellow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain the pathogenesis of the hypercholesterolemia that may be seen in the nephrotic syndrome.

A

Loss of plasma proteins into urine –> liver responds by generalized increased protein production, and cholesterol production is also upregulated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Proteinuria, although suggestive of glomerular disease, is not exclusively caused by glomerular disease. What else can cause proteinuria?

A

Inflammation of the lower urinary tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which type of cell in the renal corpuscle is responsible for phagocytosis of deposited immune complexes?

A

Mesangial cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are the basement membranes of the glomerular capillary tufts different from basement membranes elsewhere in the body?

A

The glomerular basement membrane is thick (300-350 nm). Its negative charge and collagen network impede the passage of large protein molecules, most importantly albumin and hemoglobin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the typical gross appearance of a kidney affected by amyloidosis.

A

Grossly, kidneys affected by amyloid deposition are diffusely tan, waxy (firm), friable and of normal size or slightly enlarged.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What clinicopathologic finding is the hallmark of glomerular disease?

A

Proteinuria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is it deleterious to the glomerulus having immune complexes deposited in the glomerular basement membrane? Explain the pathogenesis.

A

Deposition in glomeruli –> Complement fixation –> Chemotaxis of neutrophils –> Release of harmful mediators of inflammation –> Continued damage by release of inflammatory mediators from monocytes in chronic stages. All this leads to thickening of the glomerular basement membrane. Paradoxically, this thickening makes the GBM “leaky”, probably due to changes in charge and pore size.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How often is the specific cause of glomerulonephritis in domestic animals identified?

A

Rarely.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

You are performing a necropsy on a foal and notice that both kidneys contain dozens to hundreds of randomly scattered pinpoint white foci. What is the most likely bacterial cause of this?

A

Actinobacillus equuli.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name a condition that commonly causes hemoglobinuric nephrosis in horses.

A

Red maple toxicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the two major categories of immune complex deposition in the glomerular basement membrane and which is by far the more common in domestic animals?

A

(1) Deposition of circulating antibody-antigen complexes that have formed in response to a variety of chronic diseases. (2) Autoantibodies directed at the glomerular basement membrane. Cause number 1 is by far the most common in domestic animals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name a condition that commonly causes hemoglobinuric nephrosis in cattle.

A

Leptospirosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which parts of the lily (leaves or flowers) are nephrotoxic to cats?

A

Both leaves and flowers are toxic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are the endothelial cells lining the glomerular capillary tufts different from endothelial cells elsewhere in the body?

A

Glomerular capillary endothelial cells have pores (fenestrations) in their cytoplasm that make them “leaky” (i.e., freely permeable to most blood constituents except red blood cells, white blood cells and platelets).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give two reasons why renal tubules are preferentially damaged by circulating toxins.

A

[Any two] (1) The kidneys receive 25% of cardiac output, therefore a circulating toxin inevitably reaches the kidneys. (2) Substances are filtered by the glomerulus and concentrated in the renal tubules. (3) Renal tubular epithelial cells are metabolically active (especially proximal convoluted tubules) so these are damaged first.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the most common cause of renal failure in dogs?

A

Immune-mediated glomerulonephritis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Draw a simple flowchart explaining the pathogenesis of renal ethylene glycol (antifreeze) toxicity.

A

Antifreeze ingested –> absorbed from gut –> metabolized in liver to various toxic metabolites –> filtered by glomeruli –> directly toxic to renal tubular epithelial cells –> calcium oxalate crystals precipitate in renal tubules –> tubular obstruction & mechanical damage to lining.

22
Q

What are the five major components of the nephrotic syndrome?

A

(1) Proteinuria. (2) Hypoalbuminemia. (3) Edema / ascites. (4) Hypercholesterolemia. (5) Hypercoagulability.

23
Q

You notice that a horse passes dark red-brown urine the day after an intense training session. What pigment is most likely responsible for this urine discoloration?

A

Myoglobin. This disease is exertional rhabdomyolysis or “Monday morning disease”.

24
Q

What is the most salient clinical sign of acute tubular necrosis?

A

Oliguria or anuria (i.e., scant or no urine production).

25
Q

Where, precisely, in the kidney is amyloid typically deposited in cats?

A

The renal medulla.

26
Q

What general condition is associated with pathologic deposition of amyloid in domestic animals?

A

Chronic inflammatory disease.

27
Q

Why is hemoglobin, which is not directly toxic to renal tubules, so commonly associated with acute tubular necrosis?

A

(1) If hemoglobin is released due to intravascular hemolysis then an animal becomes anemic and hypoxic. Renal tubules are very susceptible to hypoxic damage. (2) If hemoglobin is released due to intravascular hemolysis then it passes into the glomerular ultrafiltrate. Proximal tubules, which are already hypoxic due to anemia, then attempt to resorb this hemoglobin and are placed under an increased workload.

28
Q

What type of disease, in general terms, most commonly results in immune complex deposition in the GBM in domestic animals?

A

Chronic inflammatory diseases that produce a persistent antigenemia.

29
Q

Explain in simple terms the pathogenesis of glomerulonephritis in dogs.

A

Deposition of circulating antibody-antigen complexes in the glomerular basement membrane –> Complement fixation –> Chemotaxis of neutrophils –> Release of harmful mediators of inflammation –> Glomerular damage.

30
Q

What renal disease or lesion is the single most important cause of ACUTE renal failure?

A

Acute tubular necrosis (usually due to nephrotoxins or ischemia).

31
Q

In general terms, what three characteristics of a substance prevent it from crossing the glomerular filtration barrier?

A

(1) Large size. (2) Negative charge. (3) Being bound to carrier proteins.

32
Q

What is the syndrome that may result from chronic, severe proteinuria?

A

Nephrotic syndrome.

33
Q

Grapes and raisins are toxic to which organ in dogs?

A

Kidneys.

34
Q

Explain the pathogenesis of the hypercoagulability that may be seen in the nephrotic syndrome.

A

Loss of anticoagulant antithrombin III into urine –> hypercoagulability –> thrombus formation.

35
Q

Name a condition that commonly causes hemoglobinuric nephrosis in sheep.

A

Chronic copper toxicity.

36
Q

A captured wild moose is noted to be passing red-brown discolored urine. What pigment is most likely responsible for this discoloration and what is the pathogenesis for the condition?

A

Myoglobin. This is capture myopathy. Damage to muscle caused by capture and attempts at escape –> release of myoglobin –> filtered by glomerulus –> myoglobinuria.

37
Q

What are the three components of the glomerular filtration barrier?

A

(1) Glomerular capillary endothelial cells. (2) Glomerular basement membrane. (3) Podocytes / visceral layer of Bowman’s capsule.

38
Q

Name one cat breed that has a familial/hereditary/genetic predisposition to renal amyloidosis.

A

Abyssinian.

39
Q

You are performing a necropsy on a dog and notice that both kidneys are pale tan, waxy and friable. What is the most likely cause of this?

A

Amyloidosis.

40
Q

Name the toxin in grapes and raisins that is nephrotoxic in dogs.

A

Tartaric acid

41
Q

Name four conditions or classes of condition that could lead to renal ischemia and, hence, acute tubular necrosis,

A

[Any four] (1) Decreased cardiac output (many causes of this, including heart failure, cardiac tamponade, arrhythmia etc.). (2) Intravascular volume depletion (many causes including dehydration, vomiting, blood loss etc.). (3) NSAID-induced interference with renal autoregulation during hypotension. (4) Altered renal and systemic vascular resistance (many causes, including hypothermia, anaphylaxis, sepsis, heatstroke). (5) Increased blood viscosity (e.g., polycythemia, multiple myeloma)

42
Q

Explain the pathogenesis of the ascites that may be seen in the nephrotic syndrome.

A

Loss of plasma proteins into urine –> decreased plasma oncotic pressure –> movement of fluid from circulation to interstitial space and body cavities.

43
Q

Lilies are toxic to which organ in cats?

A

Kidneys.

44
Q

Draw a simple flowchart explaining the pathogenesis of hemoglobinuric nephrosis.

A

There are two pathways, each beginning with intravascular hemolysis and ending in acute tubular necrosis. (1) Intravascular hemolysis –> Hypovolemia / Anemia / Hypoxia –> Tubular ischemia –> Acute tubular necrosis. (2) Intravascular hemolysis –> Hemoglobinemia –> Hemoglobin crosses into ultrafiltrate –> Increased demand on proximal tubules (resorption) –> Tubular ischemia –> Acute tubular necrosis.

45
Q

Explain how chronic heartworm infection in a dog may lead to glomerular disease.

A

Heartworm infection –> Chronic antigenemia –> formation of circulating antigen-antibody complexes (immune complexes) –> Deposition in glomerular basement membrane –> Complement fixation –> Chemotaxis of neutrophils –> Release of harmful mediators of inflammation –> Glomerular damage.

46
Q

What, in general terms, may give rise to the nephrotic syndrome?

A

Severe, chronic proteinuria due to glomerular disease.

47
Q

Explain how a chronic suppurative uterine infection (pyometra) in a dog may lead to glomerular disease.

A

Pyometra –> Chronic antigenemia –> formation of circulating antigen-antibody complexes (immune complexes) –> Deposition in glomerular basement membrane –> Complement fixation –> Chemotaxis of neutrophils –> Release of harmful mediators of inflammation –> Glomerular damage.

48
Q

Name the nephrotoxic compound that should be used to make plastic dinnerware instead of artificially bolstering the measured protein content of baby formula and pet food.

A

Melamine.

49
Q

Which type of amyloidosis (primary or secondary) most commonly leads to renal disease in domestic animals?

A

Secondary amyloidosis (reactive systemic amyloidosis) is the most common form of amyloidosis in animals. It is a complication of chronic inflammatory disease. The amyloid is derived from an acute phase protein synthesized by the liver in response to inflammation. [Primary amyloidosis is caused by immune dyscrasias and neoplasms. The amyloid is derived from excessive secretion of immunoglobulins, usually by a plasma cell neoplasm. Primary amyloidosis is rare in domestic animals.]

50
Q

What are the two major non-infectious categories of insult that can cause renal tubular necrosis?

A

(1) Toxins. (2) Ischemia.

51
Q

Where, precisely, in the kidney is amyloid typically deposited in dogs?

A

Glomeruli (except in the familial form in Shar Pei dogs).