Podcast
Questions and Answers
What are the main components of the urinary system?
What are the main components of the urinary system?
- Heart, lungs, kidneys
- Kidneys, stomach, bladder
- Liver, pancreas, kidneys
- Kidneys, ureters, bladder, urethra (correct)
The upper urinary tract consists of the bladder and urethra.
The upper urinary tract consists of the bladder and urethra.
False (B)
What functional units are the kidneys made up of?
What functional units are the kidneys made up of?
Nephrons
The glomerulus is a tuft of capillaries covered with ______ cells.
The glomerulus is a tuft of capillaries covered with ______ cells.
Which part of the urinary system contains the glomerulus?
Which part of the urinary system contains the glomerulus?
Acute kidney disease and chronic kidney disease are the same condition.
Acute kidney disease and chronic kidney disease are the same condition.
Match the following terms with their definitions.
Match the following terms with their definitions.
The layer of epithelium lining ___________ is known as the parietal epithelium.
The layer of epithelium lining ___________ is known as the parietal epithelium.
Which component is NOT part of the filtration barrier?
Which component is NOT part of the filtration barrier?
Only proteins larger than 60kDa can pass through the filtration barrier into the ultrafiltrate.
Only proteins larger than 60kDa can pass through the filtration barrier into the ultrafiltrate.
What is the main function of the proximal tubule in the nephron?
What is the main function of the proximal tubule in the nephron?
The collecting duct becomes permeable to water in response to __________.
The collecting duct becomes permeable to water in response to __________.
Match the parts of the nephron to their main functions:
Match the parts of the nephron to their main functions:
Which statement correctly describes the loop of Henle's function?
Which statement correctly describes the loop of Henle's function?
Cattle possess unilobular kidneys.
Cattle possess unilobular kidneys.
What is the significance of the renal blood supply to the medulla?
What is the significance of the renal blood supply to the medulla?
A __________ ratio indicates a higher concentration capability in animals producing concentrated urine.
A __________ ratio indicates a higher concentration capability in animals producing concentrated urine.
Match the species to their kidney lobation type:
Match the species to their kidney lobation type:
Which hormone increases water reabsorption in the collecting duct?
Which hormone increases water reabsorption in the collecting duct?
Decreased blood supply to the kidneys can lead to dysfunction in other parts of the nephron.
Decreased blood supply to the kidneys can lead to dysfunction in other parts of the nephron.
What are the two main regions of the kidney as visible in a section?
What are the two main regions of the kidney as visible in a section?
Fluid that moves out of the loop of Henle into the medullary interstitium is maintained in a hypertonic state due to high concentrations of __________.
Fluid that moves out of the loop of Henle into the medullary interstitium is maintained in a hypertonic state due to high concentrations of __________.
Which part of the nephron is responsible for the highest level of water reabsorption?
Which part of the nephron is responsible for the highest level of water reabsorption?
What is the primary role of the kidneys concerning fluid balance?
What is the primary role of the kidneys concerning fluid balance?
Azotaemia is synonymous with renal failure.
Azotaemia is synonymous with renal failure.
What is the main consequence of impaired renal function in dehydrated animals?
What is the main consequence of impaired renal function in dehydrated animals?
The production of __________ urine in animals with renal failure is known as polyuria.
The production of __________ urine in animals with renal failure is known as polyuria.
Match the urine specific gravity (USG) categories with their descriptions:
Match the urine specific gravity (USG) categories with their descriptions:
Which hormones are produced by the kidneys?
Which hormones are produced by the kidneys?
Animals with renal failure produce concentrated urine.
Animals with renal failure produce concentrated urine.
What indicates that an animal may be experiencing primary polydipsia?
What indicates that an animal may be experiencing primary polydipsia?
Urine specific gravity (USG) indicates the __________ of dissolved solutes in urine.
Urine specific gravity (USG) indicates the __________ of dissolved solutes in urine.
Which of the following can lead to increased intravascular pressure in animals with renal insufficiency?
Which of the following can lead to increased intravascular pressure in animals with renal insufficiency?
The overall USG range for healthy animals is from 1.001 to 1.080.
The overall USG range for healthy animals is from 1.001 to 1.080.
What two metabolic waste products do the kidneys primarily excrete?
What two metabolic waste products do the kidneys primarily excrete?
The condition characterized by elevated blood levels of urea and creatinine is called __________.
The condition characterized by elevated blood levels of urea and creatinine is called __________.
What can a high urine specific gravity (USG) indicate?
What can a high urine specific gravity (USG) indicate?
Match the types of azotaemia with their descriptions:
Match the types of azotaemia with their descriptions:
What is urea primarily produced from?
What is urea primarily produced from?
Creatinine levels fluctuate significantly each day based on physical activity.
Creatinine levels fluctuate significantly each day based on physical activity.
What is a common cause of pre-renal azotaemia?
What is a common cause of pre-renal azotaemia?
Renal azotaemia occurs when _% of nephrons are damaged.
Renal azotaemia occurs when _% of nephrons are damaged.
Which of the following describes post-renal azotaemia?
Which of the following describes post-renal azotaemia?
Non-renal azotaemia is characterized by increased creatinine levels.
Non-renal azotaemia is characterized by increased creatinine levels.
What can influence the adaptation of kidneys in response to decreased nephrons?
What can influence the adaptation of kidneys in response to decreased nephrons?
Low serum potassium may occur in polyuric animals due to increased _ flow rate.
Low serum potassium may occur in polyuric animals due to increased _ flow rate.
What happens to phosphate excretion when the GFR falls to around 25% of normal?
What happens to phosphate excretion when the GFR falls to around 25% of normal?
What condition might occur as a result of renal secondary hyperparathyroidism?
What condition might occur as a result of renal secondary hyperparathyroidism?
Urea concentration in urinary filtrate is the same as in the _.
Urea concentration in urinary filtrate is the same as in the _.
Match the following types of azotaemia with their causes:
Match the following types of azotaemia with their causes:
Hyperphosphataemia can lead to soft tissue mineralisation in renal failure.
Hyperphosphataemia can lead to soft tissue mineralisation in renal failure.
What is the role of remaining healthy nephrons in kidney failure?
What is the role of remaining healthy nephrons in kidney failure?
Increased PTH causes increased release of calcium and phosphate from _.
Increased PTH causes increased release of calcium and phosphate from _.
What is one effect of oliguria in pre-renal azotaemia?
What is one effect of oliguria in pre-renal azotaemia?
What is a common consequence of chronic kidney disease (CKD)?
What is a common consequence of chronic kidney disease (CKD)?
SDMA is a less sensitive marker for kidney function compared to creatinine.
SDMA is a less sensitive marker for kidney function compared to creatinine.
What is the main difference in how acute kidney injury and chronic kidney disease present clinically?
What is the main difference in how acute kidney injury and chronic kidney disease present clinically?
In cases of severe acute kidney injury, urine production may be categorized as ______ or ______.
In cases of severe acute kidney injury, urine production may be categorized as ______ or ______.
Match the following terms related to kidney conditions with their descriptions:
Match the following terms related to kidney conditions with their descriptions:
What best describes the glomerular filtration rate (GFR)?
What best describes the glomerular filtration rate (GFR)?
Chronic kidney disease is reversible under all circumstances.
Chronic kidney disease is reversible under all circumstances.
Name one disadvantage of using creatinine as a marker for renal function.
Name one disadvantage of using creatinine as a marker for renal function.
An excessive increase in thirst and urination is known as ______.
An excessive increase in thirst and urination is known as ______.
What is a consequence of unilateral renal aplasia?
What is a consequence of unilateral renal aplasia?
Kidney lesions always cause renal failure.
Kidney lesions always cause renal failure.
What is the significance of differentiating between azotaemia and renal failure?
What is the significance of differentiating between azotaemia and renal failure?
Fused kidneys may result in ______ of the kidneys.
Fused kidneys may result in ______ of the kidneys.
Match the following types of renal conditions with their definitions:
Match the following types of renal conditions with their definitions:
What condition is characterized by the presence of multiple cysts in the kidneys?
What condition is characterized by the presence of multiple cysts in the kidneys?
Horseshoe kidneys are usually functionally abnormal.
Horseshoe kidneys are usually functionally abnormal.
Name one bacterial infection that can lead to suppurative glomerulitis in neonatal foals.
Name one bacterial infection that can lead to suppurative glomerulitis in neonatal foals.
Leptospirosis is caused by several serovars of bacteria belonging to the species __________.
Leptospirosis is caused by several serovars of bacteria belonging to the species __________.
Which type of injury involves the interstitium of the kidneys rather than the glomeruli?
Which type of injury involves the interstitium of the kidneys rather than the glomeruli?
Renal cysts can only be congenital in nature.
Renal cysts can only be congenital in nature.
What is the clinical manifestation seen in foals infected with Actinobacillus equuli?
What is the clinical manifestation seen in foals infected with Actinobacillus equuli?
Chronic interstitial nephritis often includes __________ of the interstitium.
Chronic interstitial nephritis often includes __________ of the interstitium.
Which kidney condition is associated with marked hyperaemia due to inflammation?
Which kidney condition is associated with marked hyperaemia due to inflammation?
Interstitial fibrosis can only occur as a change due to chronic kidney disease.
Interstitial fibrosis can only occur as a change due to chronic kidney disease.
Which organ is commonly affected in conjunction with renal cysts in some dog breeds?
Which organ is commonly affected in conjunction with renal cysts in some dog breeds?
The inflammatory infiltrate in early interstitial nephritis includes ______ and plasma cells.
The inflammatory infiltrate in early interstitial nephritis includes ______ and plasma cells.
Match the following conditions with their characteristics:
Match the following conditions with their characteristics:
What term is used to describe kidneys with shrunken, distorted glomeruli and dilated tubules due to chronic kidney disease?
What term is used to describe kidneys with shrunken, distorted glomeruli and dilated tubules due to chronic kidney disease?
What is a common lesion in kidneys due to leptospirosis?
What is a common lesion in kidneys due to leptospirosis?
What is one of the primary causes of ischaemic tubular necrosis?
What is one of the primary causes of ischaemic tubular necrosis?
Toxic tubular necrosis can occur due to both direct tubular damage and secondary ischaemia.
Toxic tubular necrosis can occur due to both direct tubular damage and secondary ischaemia.
Name one type of nephrotoxin that can cause renal damage.
Name one type of nephrotoxin that can cause renal damage.
NSAIDs affect the kidneys by decreasing the production of __________.
NSAIDs affect the kidneys by decreasing the production of __________.
Match the following nephrotoxic agents with their effects:
Match the following nephrotoxic agents with their effects:
Which bacteria is frequently isolated from cases of canine pyelonephritis?
Which bacteria is frequently isolated from cases of canine pyelonephritis?
Acute kidney injury can result from NSAID overdoses in dehydrated animals.
Acute kidney injury can result from NSAID overdoses in dehydrated animals.
What condition results from the reflux of urine from the bladder to the renal pelvis?
What condition results from the reflux of urine from the bladder to the renal pelvis?
The primary mechanism of NSAID nephrotoxicity is the constriction of __________ arterioles.
The primary mechanism of NSAID nephrotoxicity is the constriction of __________ arterioles.
Match the following toxins with their sources:
Match the following toxins with their sources:
Which of the following conditions can predispose to urine reflux?
Which of the following conditions can predispose to urine reflux?
The renal medulla is well vascularized and provides a strong barrier to bacterial infection.
The renal medulla is well vascularized and provides a strong barrier to bacterial infection.
What feature of the female urethra makes females more prone to pyelonephritis?
What feature of the female urethra makes females more prone to pyelonephritis?
Oak buds and acorns cause acute tubular necrosis in __________.
Oak buds and acorns cause acute tubular necrosis in __________.
What is a common cause of papillary necrosis in horses?
What is a common cause of papillary necrosis in horses?
Papillary necrosis is usually asymptomatic in small animals.
Papillary necrosis is usually asymptomatic in small animals.
What condition is characterized by dilation of the renal pelvis?
What condition is characterized by dilation of the renal pelvis?
The most common primary renal tumor in dogs is ______.
The most common primary renal tumor in dogs is ______.
What leads to ischaemic necrosis of the renal papilla?
What leads to ischaemic necrosis of the renal papilla?
Increased intra-renal pressure can lead to renal papillary necrosis.
Increased intra-renal pressure can lead to renal papillary necrosis.
Name a common malformation of the urinary bladder.
Name a common malformation of the urinary bladder.
Medullary amyloidosis primarily impacts which part of the kidney?
Medullary amyloidosis primarily impacts which part of the kidney?
Which species is commonly associated with ectopic ureters?
Which species is commonly associated with ectopic ureters?
Hydronephrosis can be caused by congenital abnormalities.
Hydronephrosis can be caused by congenital abnormalities.
What is a consequence of obstruction in the ureter?
What is a consequence of obstruction in the ureter?
Cystitis refers to inflammation of the ______.
Cystitis refers to inflammation of the ______.
Match the following terms related to kidney conditions:
Match the following terms related to kidney conditions:
In cats, the most common renal tumor is:
In cats, the most common renal tumor is:
What is the primary consequence of glomerular filtration barrier damage?
What is the primary consequence of glomerular filtration barrier damage?
Immune complexes in immune-mediated glomerulonephritis are always formed in situ.
Immune complexes in immune-mediated glomerulonephritis are always formed in situ.
What clinical syndrome can develop as a result of severe proteinuria and hypoalbuminaemia?
What clinical syndrome can develop as a result of severe proteinuria and hypoalbuminaemia?
The most common lesions observed in chronic immune-mediated glomerulonephritis are __________ and fibrosis.
The most common lesions observed in chronic immune-mediated glomerulonephritis are __________ and fibrosis.
Match the chronic disease with its related condition:
Match the chronic disease with its related condition:
Which of the following is a major cause of glomerular amyloidosis in domestic animals?
Which of the following is a major cause of glomerular amyloidosis in domestic animals?
Amyloid deposits disrupt the filtration barrier of the kidneys, leading to protein-losing nephropathy.
Amyloid deposits disrupt the filtration barrier of the kidneys, leading to protein-losing nephropathy.
What is typically observed grossly in affected kidneys with amyloidosis?
What is typically observed grossly in affected kidneys with amyloidosis?
The proximal tubules are most prone to ischaemic and toxic damage due to their __________ metabolic rate.
The proximal tubules are most prone to ischaemic and toxic damage due to their __________ metabolic rate.
Match the tubular disease with its cause:
Match the tubular disease with its cause:
What is a common histological finding in chronic immune-mediated glomerulonephritis?
What is a common histological finding in chronic immune-mediated glomerulonephritis?
The impact of tubular damage is less severe than damage to the glomerulus.
The impact of tubular damage is less severe than damage to the glomerulus.
What is the term used to describe tubular epithelial damage due to ischemia or toxins?
What is the term used to describe tubular epithelial damage due to ischemia or toxins?
Which of the following is NOT a predisposing factor for urinary tract infections (UTIs)?
Which of the following is NOT a predisposing factor for urinary tract infections (UTIs)?
In domestic animals, renal amyloidosis can involve either the glomerulus or the __________.
In domestic animals, renal amyloidosis can involve either the glomerulus or the __________.
Bacterial cystitis can be caused by E. coli and other uropathogens.
Bacterial cystitis can be caused by E. coli and other uropathogens.
What type of crystals have been historically most common in urolithiasis in cats?
What type of crystals have been historically most common in urolithiasis in cats?
Cystitis can be caused by chemical toxins such as ________.
Cystitis can be caused by chemical toxins such as ________.
Match the following uropathogens with their characteristics:
Match the following uropathogens with their characteristics:
Which of the following is a common consequence of urinary tract obstruction?
Which of the following is a common consequence of urinary tract obstruction?
Dilute urine can increase the risk of urolith formation.
Dilute urine can increase the risk of urolith formation.
What is a known effect of glucosuria on urinary tract health?
What is a known effect of glucosuria on urinary tract health?
Uroliths are formed through the ________ of various types of minerals.
Uroliths are formed through the ________ of various types of minerals.
Match the urinary calculi types with their common associations:
Match the urinary calculi types with their common associations:
What can produce ammonia in the bladder, leading to mucosal damage?
What can produce ammonia in the bladder, leading to mucosal damage?
The presence of crystals in urine is abnormal in all species.
The presence of crystals in urine is abnormal in all species.
In male cats, what is a common cause of urinary tract obstruction?
In male cats, what is a common cause of urinary tract obstruction?
The production of ________ has a significant impact on the formation of uroliths.
The production of ________ has a significant impact on the formation of uroliths.
What is the primary cause of obstructive urolithiasis in male cats?
What is the primary cause of obstructive urolithiasis in male cats?
Feline lower urinary tract disease (FLUTD) is a specific diagnosis.
Feline lower urinary tract disease (FLUTD) is a specific diagnosis.
What are the hallmarks of feline lower urinary tract disease (FLUTD)?
What are the hallmarks of feline lower urinary tract disease (FLUTD)?
The most common cause of feline lower urinary tract disease is __________.
The most common cause of feline lower urinary tract disease is __________.
Match the causes of feline lower urinary tract disease with their descriptions:
Match the causes of feline lower urinary tract disease with their descriptions:
Which type of urinary obstruction is particularly common in feline patients?
Which type of urinary obstruction is particularly common in feline patients?
All urinary tract obstructions are caused by uroliths.
All urinary tract obstructions are caused by uroliths.
What significant risk can occur if a urinary tract obstruction is not reversed?
What significant risk can occur if a urinary tract obstruction is not reversed?
The collection method used in urinalysis that is most likely to avoid bacterial contamination is __________.
The collection method used in urinalysis that is most likely to avoid bacterial contamination is __________.
What is the most common urinary tract tumor in cats?
What is the most common urinary tract tumor in cats?
Bacterial infections of the bladder are common in young healthy cats.
Bacterial infections of the bladder are common in young healthy cats.
What is a typical duration of clinical signs for feline idiopathic cystitis?
What is a typical duration of clinical signs for feline idiopathic cystitis?
The state of increased urine production that can occur in animals with renal failure is known as __________.
The state of increased urine production that can occur in animals with renal failure is known as __________.
Match the types of urinary obstruction with their mechanisms:
Match the types of urinary obstruction with their mechanisms:
What is the primary purpose of noting the method of urine collection on the submission form?
What is the primary purpose of noting the method of urine collection on the submission form?
Urine collected in the early morning usually contains the highest yield of cells, casts, and/or bacteria.
Urine collected in the early morning usually contains the highest yield of cells, casts, and/or bacteria.
What should be done to preserve a urine sample if it cannot be analyzed within 30 minutes?
What should be done to preserve a urine sample if it cannot be analyzed within 30 minutes?
The specific gravity (SG) of urine helps to indicate the kidneys' ability to ________.
The specific gravity (SG) of urine helps to indicate the kidneys' ability to ________.
Match the urine specific gravity (USG) ranges with their corresponding conditions:
Match the urine specific gravity (USG) ranges with their corresponding conditions:
Which of the following options reflects the correct condition for urine that is red or red-brown and does not clear on centrifugation?
Which of the following options reflects the correct condition for urine that is red or red-brown and does not clear on centrifugation?
Refrigerating a urine sample is unnecessary if it will be analyzed within 30 minutes.
Refrigerating a urine sample is unnecessary if it will be analyzed within 30 minutes.
What is the typical characteristic of horse urine?
What is the typical characteristic of horse urine?
The presence of _______ in urine often indicates a urinary tract infection.
The presence of _______ in urine often indicates a urinary tract infection.
What happens to casts and neutrophils in hypotonic or alkaline urine?
What happens to casts and neutrophils in hypotonic or alkaline urine?
The optimal concentration of urine specific gravity for dogs is lower than that for cats.
The optimal concentration of urine specific gravity for dogs is lower than that for cats.
Name one factor that can affect the specific gravity of urine.
Name one factor that can affect the specific gravity of urine.
Urine that appears dark yellow-brown and produces a yellow froth when shaken is called ________.
Urine that appears dark yellow-brown and produces a yellow froth when shaken is called ________.
Match each type of urine abnormality with its associated indicator:
Match each type of urine abnormality with its associated indicator:
What is the most common cause of acute kidney injury?
What is the most common cause of acute kidney injury?
Chronic kidney disease is characterized by decreased production of erythropoietin (EPO).
Chronic kidney disease is characterized by decreased production of erythropoietin (EPO).
What condition is characterized by a loss of urinary concentrating ability and azotaemia?
What condition is characterized by a loss of urinary concentrating ability and azotaemia?
In chronic kidney disease, the kidneys can often maintain normal serum potassium and sodium levels due to the adaptation of the remaining __________.
In chronic kidney disease, the kidneys can often maintain normal serum potassium and sodium levels due to the adaptation of the remaining __________.
Match the following conditions with their correct descriptions:
Match the following conditions with their correct descriptions:
What happens when more than 75% of kidney function is lost?
What happens when more than 75% of kidney function is lost?
Acute kidney injury can develop slowly over time.
Acute kidney injury can develop slowly over time.
Name the hormone produced by the kidneys that stimulates erythrocyte production.
Name the hormone produced by the kidneys that stimulates erythrocyte production.
The kidneys have a significant amount of built-in __________, allowing them to compensate for lost tissue.
The kidneys have a significant amount of built-in __________, allowing them to compensate for lost tissue.
Match the following terms with their related effects:
Match the following terms with their related effects:
What is a common complication of uraemia?
What is a common complication of uraemia?
Anaemia is a feature of acute kidney injury.
Anaemia is a feature of acute kidney injury.
When does an animal enter a state of renal insufficiency?
When does an animal enter a state of renal insufficiency?
Uraemic toxins can cause __________ in endothelial cells, leading to further complications.
Uraemic toxins can cause __________ in endothelial cells, leading to further complications.
Which condition is commonly confirmed by measuring water consumption over 24 hours?
Which condition is commonly confirmed by measuring water consumption over 24 hours?
Pyometra can occur in both spayed and unspayed bitches.
Pyometra can occur in both spayed and unspayed bitches.
Name one common cause of Polyuria/Polydipsia (PU/PD).
Name one common cause of Polyuria/Polydipsia (PU/PD).
The endocrine testing for hyperthyroidism in cats typically measures ______ levels.
The endocrine testing for hyperthyroidism in cats typically measures ______ levels.
Match the following conditions with their respective characteristics:
Match the following conditions with their respective characteristics:
Which of the following diagnostic tests is considered a minimum baseline for diagnosing PU/PD?
Which of the following diagnostic tests is considered a minimum baseline for diagnosing PU/PD?
Increased water consumption in hospitalized animals is typically consistent with their normal drinking behavior.
Increased water consumption in hospitalized animals is typically consistent with their normal drinking behavior.
What does ADH stand for?
What does ADH stand for?
What is the defined daily water intake for polydipsia in dogs and cats?
What is the defined daily water intake for polydipsia in dogs and cats?
Polyuria is defined as daily urine output exceeding 50 mL/kg/day.
Polyuria is defined as daily urine output exceeding 50 mL/kg/day.
What hormone is responsible for increasing water reabsorption in the kidneys?
What hormone is responsible for increasing water reabsorption in the kidneys?
If an animal has severe watery diarrhoea, they will drink more water to maintain __________.
If an animal has severe watery diarrhoea, they will drink more water to maintain __________.
Match the following terms with their definitions:
Match the following terms with their definitions:
Which of the following factors do NOT need to be normal for an animal to produce a normal amount of urine?
Which of the following factors do NOT need to be normal for an animal to produce a normal amount of urine?
An animal can still produce normal urine if its renal tubular response to ADH is impaired.
An animal can still produce normal urine if its renal tubular response to ADH is impaired.
What physiological response causes ADH to be released into circulation?
What physiological response causes ADH to be released into circulation?
What is the main cause of diabetes insipidus?
What is the main cause of diabetes insipidus?
Psychogenic polydipsia is always a response to increased water loss.
Psychogenic polydipsia is always a response to increased water loss.
What is primary polydipsia?
What is primary polydipsia?
The condition characterized by increased thirst that is not related to excessive fluid loss is known as __________.
The condition characterized by increased thirst that is not related to excessive fluid loss is known as __________.
Match the following conditions with their causes:
Match the following conditions with their causes:
What indication suggests nephrogenic diabetes insipidus?
What indication suggests nephrogenic diabetes insipidus?
Osmotic diuresis occurs when water is excessively reabsorbed in the kidneys.
Osmotic diuresis occurs when water is excessively reabsorbed in the kidneys.
What are two common causes of structural damage to nephrons?
What are two common causes of structural damage to nephrons?
A lack of functional nephrons can lead to the condition known as __________.
A lack of functional nephrons can lead to the condition known as __________.
Match the following terms with their descriptions:
Match the following terms with their descriptions:
Which factor can decrease medullary hypertonicity?
Which factor can decrease medullary hypertonicity?
Polyuria due to diabetes mellitus can be reversed once the infection is treated.
Polyuria due to diabetes mellitus can be reversed once the infection is treated.
What diagnostic test confirms diabetes insipidus?
What diagnostic test confirms diabetes insipidus?
A high urine specific gravity (USG) indicates __________ urine concentration.
A high urine specific gravity (USG) indicates __________ urine concentration.
What is a common feature observed in animals with diabetes insipidus?
What is a common feature observed in animals with diabetes insipidus?
Which of the following is NOT a characteristic symptom of hyperthyroidism in cats?
Which of the following is NOT a characteristic symptom of hyperthyroidism in cats?
Hypercalcaemia commonly causes PU/PD in cats.
Hypercalcaemia commonly causes PU/PD in cats.
What condition may result from persistent hypercalcaemia?
What condition may result from persistent hypercalcaemia?
In pyelonephritis, renal pelvic inflammation can disrupt the counter current mechanism resulting in __________.
In pyelonephritis, renal pelvic inflammation can disrupt the counter current mechanism resulting in __________.
Match the following conditions with their associated effects on renal function:
Match the following conditions with their associated effects on renal function:
What is the primary problem typically associated with primary polyuria?
What is the primary problem typically associated with primary polyuria?
Polydipsia is defined as a daily water intake exceeding 50 mL/kg/day.
Polydipsia is defined as a daily water intake exceeding 50 mL/kg/day.
What hormone is primarily responsible for increasing water reabsorption in the kidneys?
What hormone is primarily responsible for increasing water reabsorption in the kidneys?
Urine output exceeding __________ mL/kg/day is classified as polyuria.
Urine output exceeding __________ mL/kg/day is classified as polyuria.
Match the following conditions with their definitions:
Match the following conditions with their definitions:
Which of the following is a common characteristic of diseases causing polyuria and polydipsia in animals?
Which of the following is a common characteristic of diseases causing polyuria and polydipsia in animals?
Primary polydipsia is more commonly observed than primary polyuria.
Primary polydipsia is more commonly observed than primary polyuria.
What is the average normal water intake for dogs and cats in mL/kg/day?
What is the average normal water intake for dogs and cats in mL/kg/day?
Which of the following is a common cause of polydipsia in dogs?
Which of the following is a common cause of polydipsia in dogs?
Polydipsia can be confirmed with a 24-hour water monitor.
Polydipsia can be confirmed with a 24-hour water monitor.
What is the significance of urine specific gravity (USG) in diagnosing polyuria?
What is the significance of urine specific gravity (USG) in diagnosing polyuria?
Hyperadrenocorticism is commonly known as __________ disease.
Hyperadrenocorticism is commonly known as __________ disease.
Match the following conditions with their classification:
Match the following conditions with their classification:
Which drug class is associated with increased water consumption in animals?
Which drug class is associated with increased water consumption in animals?
Psychogenic polydipsia is a common cause of PU/PD in both dogs and cats.
Psychogenic polydipsia is a common cause of PU/PD in both dogs and cats.
What laboratory test can provide insight into low urine specific gravity in suspected cases of PU?
What laboratory test can provide insight into low urine specific gravity in suspected cases of PU?
In dogs, urine specific gravity is considered isosthenuric when it is between __________.
In dogs, urine specific gravity is considered isosthenuric when it is between __________.
Match each cause of PU/PD with its respective category (common/uncommon):
Match each cause of PU/PD with its respective category (common/uncommon):
Which of the following can affect the accuracy of water intake measurements in a home water monitor?
Which of the following can affect the accuracy of water intake measurements in a home water monitor?
High urine specific gravity indicates a low concentration of dissolved solutes in urine.
High urine specific gravity indicates a low concentration of dissolved solutes in urine.
What is a potential effect of increased dry food intake on water consumption?
What is a potential effect of increased dry food intake on water consumption?
The Na:K ratio of less than 25:1 may suggest __________.
The Na:K ratio of less than 25:1 may suggest __________.
What is the primary use of the modified water deprivation test?
What is the primary use of the modified water deprivation test?
The urine specific gravity (USG) of animals with chronic kidney disease will typically be greater than 1.030.
The urine specific gravity (USG) of animals with chronic kidney disease will typically be greater than 1.030.
What hormone is released from the pituitary gland to promote water reabsorption in the kidneys?
What hormone is released from the pituitary gland to promote water reabsorption in the kidneys?
PU/PD may be associated with chronic kidney disease when at least _____ of functional nephrons are lost.
PU/PD may be associated with chronic kidney disease when at least _____ of functional nephrons are lost.
Match the following conditions with their effects on urine concentration:
Match the following conditions with their effects on urine concentration:
What is a potential outcome of the modified water deprivation test for psychogenic polydipsia?
What is a potential outcome of the modified water deprivation test for psychogenic polydipsia?
Primary nephrogenic diabetes insipidus is very common in animals.
Primary nephrogenic diabetes insipidus is very common in animals.
What condition is characterized by a reduced ability of the kidneys to excrete ammonia, resulting in PU/PD?
What condition is characterized by a reduced ability of the kidneys to excrete ammonia, resulting in PU/PD?
The modified water deprivation test should only be done once conditions such as diabetes mellitus and __________ have been excluded.
The modified water deprivation test should only be done once conditions such as diabetes mellitus and __________ have been excluded.
Match the following tests with their purposes:
Match the following tests with their purposes:
What is the urine specific gravity range for healthy animals?
What is the urine specific gravity range for healthy animals?
Nephrogenic diabetes insipidus can be diagnosed by a lack of urine concentration after ADH administration.
Nephrogenic diabetes insipidus can be diagnosed by a lack of urine concentration after ADH administration.
What is the main factor that may lead to osmotic diuresis in diabetes mellitus?
What is the main factor that may lead to osmotic diuresis in diabetes mellitus?
In animals with hyperadrenocorticism, there may be a further increase in urine specific gravity following __________ administration.
In animals with hyperadrenocorticism, there may be a further increase in urine specific gravity following __________ administration.
What potential complication must be monitored for during the modified water deprivation test?
What potential complication must be monitored for during the modified water deprivation test?
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Study Notes
Overview of the Urinary System
- Comprises kidneys, ureters, bladder, and urethra with respective blood supplies.
- Divided into upper (kidney and ureters) and lower (bladder and urethra) urinary tracts, with differing disease presentations.
Normal Renal Function
- Guided lectures focus on fundamental concepts crucial for diagnosis and treatment.
- Emphasis on understanding renal tubular structure, dysfunction, and disease pathogenesis.
Functional Anatomy and Physiology of the Kidney
- Nephrons are functional units consisting of a glomerulus and a tubular system.
- Glomerulus filters blood, allowing water, salts, ions, and glucose to form ultrafiltrate; particle size and charge determine filtration.
- Filtration rate influenced by blood flow and pressure.
Nephron Structure and Function
- Proximal tubule reabsorbs sodium, albumin, glucose, and bicarbonate.
- Loop of Henle establishes a hypertonic interstitium, critical for urine concentration.
- Distal convoluted tubule reabsorbs sodium under aldosterone influence; collecting duct’s permeability is regulated by ADH for concentrated urine production.
Kidney Regions
- Cortex contains glomeruli and proximal tubules; medulla houses loops of Henle and collecting ducts.
- Medullary to cortical ratio indicates species adaptation for urine concentration (e.g., camelids have a ratio of 5:1).
Renal Blood Supply
- Receives 25-30% of cardiac output, with blood flowing through interlobar and arcuate arteries into the cortex.
- Afferent arterioles evolved into glomerulus capillaries; efferent arterioles form the vasa recta, crucial for medullary hypertonicity.
Functions of Normal Kidney
- Maintains fluid balance, excretes metabolic wastes, regulates electrolytes and acid-base balance.
- Produces hormones such as renin and erythropoietin.
Kidney Dysfunction and Uraemia
- Uraemia is characterized by clinical signs, biochemical changes, and gross lesions due to abnormal renal function.
- Azotaemia indicates elevated urea and creatinine levels; important distinction since not all azotaemia is due to renal failure.
Disruption of Fluid Balance
- Impaired kidneys struggle to concentrate urine in dehydration, leading to further fluid loss.
- Inability to dilute urine in over-hydration results in increased intravascular pressure and potential oedema.
Urine Specific Gravity (USG)
- USG measures kidney concentration ability; normal range varies by species.
- Hyposthenuria indicates dilute urine (<1.008), isosthenuria indicates no concentration ability (1.008-1.012); optimally concentrated urine >1.030 (dogs) or >1.035 (cats).
Altered Excretion of Metabolic Waste
- Renal failure leads to the accumulation of metabolic byproducts (urea, creatinine) detectable through blood assays.
- Urea produced in the liver, with kidney efficiency dependent on glomerular filtration rate.
Types of Azotaemia
- Pre-renal azotaemia occurs due to decreased blood flow; typically with oliguria and concentrated urine.
- Renal azotaemia arises when over 75% of nephrons are damaged.
- Post-renal azotaemia results from urinary tract obstructions; resolution depends on reversing the blockage.
- Non-renal azotaemia involves increased protein breakdown loads, not necessarily indicating renal failure.
Electrolyte Disturbances
- Failing kidneys adapt but have limits, particularly for sodium and potassium.
- Phosphate regulation is crucial; impaired excretion can lead to hyperphosphataemia and soft tissue mineralization.
- High phosphate levels stimulate parathyroid hormone production, causing bone mineralization and renal secondary hyperparathyroidism.
Conditions Indicating Kidney Disease
- Oliguria, polyuria, polydipsia often present with chronic kidney disease.
- USG aids in differentiation but cannot solely confirm renal failure; knowledge of hydration status is essential.### Hypercalcaemia and Hypophosphataemia in Horses
- Common in advanced renal failure; kidneys are primary excretors of calcium in horses.
Potassium and Sodium Regulation
- Tubular flow rate regulates potassium (K+) secretion; increased flow leads to K+ loss (hypokalaemia).
- Decreased flow (oliguria/anuria) retains K+ in serum (hyperkalaemia), often life-threatening in acute kidney injury.
- Chronic kidney disease (CKD) allows remaining nephrons to adapt and maintain normal serum potassium/sodium levels.
Anaemia and Erythropoietin (EPO)
- Kidneys produce EPO, which stimulates erythrocyte production in the bone marrow.
- CKD reduces EPO production, resulting in non-regenerative anaemia; acute kidney injury does not cause anaemia immediately.
Diagnosis of Kidney Disease
- Kidneys show various pathological changes: inflammation, necrosis, infarction, neoplasia.
- Not all lesions indicate dysfunction due to renal reserve capability; significant loss (>2/3 nephrons) leads to renal insufficiency.
- Renal failure occurs after >75% nephron loss, disrupting fluid balance and waste excretion.
Uraemia
- Refers to clinical signs and pathological changes in renal failure, including azotaemia.
- Gross lesions can occur in kidneys (renal lesions) or other systems (non-renal lesions).
- Caustic uraemic toxins damage endothelial cells, leading to complications like vasculitis and mucosal ulcers.
Acute vs Chronic Kidney Injury
- Acute kidney injury results from sudden, severe damage, often presenting with enlarged, painful kidneys.
- CKD develops from repeated low-grade insults and features progressive kidney damage, often leading to small, firm kidneys with fibrous tissue.
- Differentiation between acute and chronic kidney injury is crucial for treatment and prognosis.
Renal Function Markers
- Glomerular filtration rate (GFR) is a key indicator of renal function but hard to measure directly.
- Creatinine is a traditional marker but has limitations; SDMA is a newer, more sensitive marker independent of diet and muscle mass.
Congenital Kidney Anomalies
- Renal aplasia/agenesis can be lethal if bilateral; unilateral cases are compatible with life.
- Renal hypoplasia involves smaller kidneys with fewer nephrons, while renal dysplasia denotes abnormal kidney architecture.
Vascular-Based Conditions
- Embolic glomerulitis occurs when bacteria lodge in capillaries; can cause severe inflammation and lesions.
- Example of suppurative glomerulitis is Actinobacillus equuli in foals, leading to systemic bacterial infection.
Interstitial Diseases
- Interstitial nephritis arises from infectious agents targeting interstitial vessels, resulting in acute or chronic inflammation.
- Leptospirosis leads to tubulointerstitial nephritis and chronic interstitial nephritis with characteristic gross lesions.
Glomerular Diseases
- Protein-losing nephropathies occur when the glomerular barrier is damaged, causing proteinuria and potential nephrotic syndrome.
- Immune-mediated glomerulonephritis is characterized by immune complexes damaging the filtration barrier.
Learning Objectives
- Recognize signs of renal dysfunction and differentiate between acute kidney injury and CKD.
- Develop diagnostic approaches for azotaemia and isosthenuria.
- Understand that azotaemia and isosthenuria alone do not imply renal failure.
- Interpret laboratory findings to distinguish types of azotaemia.### Glomerulonephritis
- Associated with chronic diseases leading to soluble immune complex formation.
- Common underlying diseases:
- Chronic bacterial infections (e.g., pyometra in dogs, streptococcal infections in horses)
- Viral infections (e.g., canine hepatitis, feline leukaemia, feline immunodeficiency virus, bovine viral diarrhoea)
- Certain neoplasms
- Lesions are often subtle with possible pitted or granular kidney surfaces and cortical atrophy.
- Histological forms include:
- Membranous: thickened basement membrane
- Proliferative: increased inflammatory cell infiltration
- Membranoproliferative: features of both membranous and proliferative types.
- Secondary changes: adhesions, glomerular fibrosis, interstitial fibrosis with lymphocyte infiltration.
- Clinical outcomes can include renal insufficiency and protein leakage.
Glomerular Amyloidosis
- Amyloid: glycoprotein deposit that can form in various chronic diseases.
- Main component in veterinary medicine: serum amyloid A from chronic inflammatory conditions.
- Often idiopathic, familial, or linked to chronic illnesses in dogs and cats.
- Genetic predisposition seen in breeds like Abyssinian cats and Shar Pei dogs.
- Affects glomeruli in dogs and medulla in cats, disrupting the filtration barrier and causing protein-losing nephropathy.
- Gross appearance: enlarged, pale, waxy kidneys; faintly granular cortex.
- Histologically: amyloid appears as eosinophilic material in glomeruli or medullary interstitium; stains orange with Congo red.
Tubular Diseases
- Tubules can be impacted by inflammatory reactions or primary damage from infections and toxins.
- Proximal tubules are especially vulnerable due to high metabolic activity.
- Ischaemic tubular necrosis results from severe anaemia, hypoxia, or renal vasoconstriction.
- Toxic tubular necrosis can stem from various nephrotoxins:
- Heavy metals
- Certain antibiotics (aminoglycosides are nephrotoxic)
- NSAIDs: reduce prostaglandin production, constrict afferent arterioles, leading to ischaemia.
- Plant toxins (e.g., grapes for dogs, lilies for cats, oak buds for cattle)
- Oxalates: can cause necrosis and tubular obstruction in vulnerable species.
Diseases of the Medulla and Pelvis
Pyelonephritis
- Inflammation of renal pelvis and parenchyma due to ascending infection from the lower urinary tract.
- Predisposing factors include bladder pressure, cystitis, or congenital sphincter malformations.
- Common pathogens include uropathogenic E. coli, Klebsiella, and Staphylococcus species.
- Grossly appears as dilated pelvis, purulent material, and hyperaemia in the cortex.
Papillary Necrosis
- Ischaemic necrosis of renal papillary tissue, often due to NSAID use.
- Common in horses; typically asymptomatic in small animals.
- Necropsy reveals sharply demarcated discoloration in the medulla.
Hydronephrosis
- Dilation of renal pelvis due to obstruction; can be congenital or acquired.
- Leads to increased intratubular pressure and potential tubular leakage and renal failure.
- Grossly, kidneys appear enlarged, cystic; dilation evident on radiographs.
Neoplasia
- Renal adenocarcinoma is the most common primary renal tumor in dogs; often metastasizes to lungs.
- Lymphoma is the most common renal tumor in cats, presenting as bilateral renomegaly with renal failure.
Lower Urinary Tract Lesions and Diseases
Congenital Anomalies
- Ectopic ureters predisposing to urinary infections in dogs.
- Patent urachus: failure of fetal urachus closure results in urine dribbling.
- Hydroureter and hydrourethra can arise from congenital or acquired obstructions (e.g., urinary stones).
Cystitis
- Inflammation of the bladder, leading to urination discomfort, hematuria, and incontinence.
- Causes include chemical toxins, bacterial infections, and mass formation in the bladder.
Bacterial Cystitis
- Uropathogens like E. coli and Klebsiella are common in infections; adhesion factors allow colonization.
- Predisposing factors for UTIs include trauma, glucosuria, urine stasis, and changes in urine composition.
Urolithiasis
- Formation of crystalline aggregates in the urinary tract, influenced by urinary stasis, dehydration, and supersaturation.
- Males are more prone to obstructions due to longer urethras; obstruction sites vary across species.
- Historically, struvite has been a common component of urinary crystals.
Definitions and Normal Values
- Normal water intake for dogs and cats: approximately 50-70 mL/kg/day.
- Normal urine output for dogs and cats: typically 25-50 mL/kg/day.
- Polydipsia (PD): daily water intake exceeding 100 mL/kg/day.
- Polyuria (PU): daily urinary output greater than 50 mL/kg/day.
Mechanisms of PU/PD
- PU/PD can arise from:
- Increased thirst (primary polydipsia).
- Inability to produce concentrated urine (primary polyuria).
Factors Influencing Urine Production
- Key factors for normal urine output include:
- Thirst sensation.
- Production and release of Antidiuretic Hormone (ADH).
- Renal tubular response to ADH.
- Medullary hypertonicity.
- The hypothalamic-pituitary-renal axis is central to urine production.
Antidiuretic Hormone (ADH)
- Produced in the hypothalamus, stored in the posterior pituitary.
- Released in response to:
- Decrease in blood volume (≥10%).
- Increase in plasma osmolality (≥2%).
- ADH increases water reabsorption in the kidney's collecting ducts.
Increased Thirst (Primary Polydipsia)
- Increased drinking is often more noticeable than increased urine output.
- Diagnosis involves assessing if increased thirst is a physiological response to conditions like dehydration or heat.
- Psychogenic polydipsia: inappropriate drinking due to behavioral disorders or malfunction of the thirst center.
Failure to Concentrate Urine (Primary Polyuria)
- Causes include:
- Lack of ADH production (central diabetes insipidus).
- Abnormal response to ADH (nephrogenic diabetes insipidus).
- Structural damage to nephrons due to renal disease.
- Osmotic diuresis, commonly seen in diabetes mellitus.
- Decreased medullary hypertonicity from liver disease or systemic hyponatremia.
Diabetes Insipidus
- Central diabetes insipidus: caused by pituitary gland issues, often from trauma or lesions.
- Nephrogenic diabetes insipidus: kidneys fail to respond to ADH, can be congenital or acquired due to conditions (like hypercalcemia).
Diagnostic Approach to PU/PD
- Comprehensive history and physical examination are essential.
- Confirm polydipsia by measuring water intake over 24 hours.
- Initial diagnostic screen: urinalysis, hematology, biochemistry.
- Specific additional tests may include endocrine evaluations (e.g., T4 levels, ACTH response) and an ADH response test.
Common Causes of PU/PD
- More common causes:
- Renal disease.
- Diabetes mellitus.
- Psychogenic polydipsia.
- Uncommon or rare causes:
- Liver disease.
- Hyperthyroidism (especially in older cats).
- Addison's disease.
- Hypercalcemia (e.g., due to malignancy).
- Cushing's disease.
- Central/nephrogenic diabetes insipidus.
Key Clinical Points
- PU/PD is a common clinical presentation in dogs.
- Recognition of symptoms is crucial to develop a solid diagnostic approach.
- A clear understanding of the pathogenesis of urinary-related diseases is essential for accurate diagnosis in future studies and practice.
Definitions and Symptoms
- Polyuria: Increased urine volume and frequency.
- Polydipsia: Increased water intake; often compensatory for polyuria.
- Commonly observed: Primary polyuria leads to secondary polydipsia, not the reverse.
- Normal water intake for dogs and cats: 50-70 mL/kg/day; normal urine output: 25-50 mL/kg/day.
- Polydipsia: Water intake exceeding 100 mL/kg/day; for example, a 25 kg dog drinks over 2.5 L/day.
Associated Diseases
- Common Causes in Dogs:
- Diabetes mellitus
- Chronic kidney disease
- Liver disease
- Hyperadrenocorticism
- Endotoxaemia (e.g., pyometra, prostatitis)
- Hypercalcaemia
- Medications (steroids, diuretics)
- Common Causes in Cats:
- Diabetes mellitus
- Chronic kidney disease
- Liver disease
- Hyperthyroidism
- Endotoxaemia (pyelonephritis, cystitis, UTI)
Diagnostic Approach
- History: Inquire about changes in urination, thirst, incontinence, nocturia, weight changes, and any gastrointestinal symptoms.
- Physical Examination: Check peripheral lymph nodes, skin conditions, and perform abdominal palpation and rectal examination.
- 24-Hour Water Monitor: Confirm polydipsia by measuring total water intake; must control for diet and separate from other pets.
- Urinalysis:
- Specific gravity (SG): Isosthenuric urine (1.008 – 1.012) indicates severe polyuria.
- Use urine dipstick and sediment examination to identify glycosuria, proteinuria, or signs of infection.
- Haematology and Biochemistry:
- Look for hypercalcaemia, hyperglycaemia, renal azotaemia, and changes in enzyme levels.
- Perform T4 tests in cats to check for hyperthyroidism.
- Screening for Hyperadrenocorticism: Use ACTH stimulation test or low-dose dexamethasone suppression test.
- Imaging: Radiography and ultrasonography can identify masses or organ size changes.
Water Deprivation Test
- Conduct when other causes (renal disease, diabetes, etc.) are excluded.
- Assesses the ability to concentrate urine; involves withholding water and monitoring changes in specific gravity.
- Proper monitoring is critical to prevent complications.
Pathogenesis of PU/PD Causes
- Kidney Disease: Significant nephron loss leads to inability to concentrate urine, indicated by isosthenuria.
- Hepatic Insufficiency: Might affect renal concentrating ability due to altered ammonia processing.
- Diabetes Mellitus: High glucose levels in urine lead to osmotic diuresis.
- Hyperadrenocorticism: Inhibits ADH secretion and action; results in polyuria/polydipsia.
- Hypoadrenocorticism: Causes sodium wasting and renal medullary solute washout.
- Hyperthyroidism: Common in cats; characterized by PU/PD and hyperactivity; confirmed via T4 assays.
- Hypercalcaemia: Can disrupt ADH action, leading to nephropathy.
- Other Conditions: Pyelonephritis and infections may also cause PU/PD through different mechanisms.
Summary
- Polydipsia and polyuria are significant clinical signs often indicating serious underlying diseases.
- Thorough investigation through history, exams, laboratory tests, and imaging is necessary to identify the root causes.
- Early diagnosis and management are crucial to preventing complications associated with these conditions.
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