Pathology: Urinary
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Questions and Answers

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.

    False

    What functional units are the kidneys made up of?

    Nephrons

    The glomerulus is a tuft of capillaries covered with ______ cells.

    <p>epithelial</p> Signup and view all the answers

    Which part of the urinary system contains the glomerulus?

    <p>Kidney</p> Signup and view all the answers

    Acute kidney disease and chronic kidney disease are the same condition.

    <p>False</p> Signup and view all the answers

    Match the following terms with their definitions.

    <p>Uraemia = A toxic condition from failure of the kidneys to remove waste Azotaemia = An increase of nitrogenous waste in the blood Nephron = The functional unit of the kidney Bowman's capsule = The cup-like structure surrounding the glomerulus</p> Signup and view all the answers

    The layer of epithelium lining ___________ is known as the parietal epithelium.

    <p>Bowman's capsule</p> Signup and view all the answers

    Which component is NOT part of the filtration barrier?

    <p>Renal tubule cells</p> Signup and view all the answers

    Only proteins larger than 60kDa can pass through the filtration barrier into the ultrafiltrate.

    <p>False</p> Signup and view all the answers

    What is the main function of the proximal tubule in the nephron?

    <p>Isotonic reabsorption of sodium, albumin, glucose, and bicarbonate.</p> Signup and view all the answers

    The collecting duct becomes permeable to water in response to __________.

    <p>anti-diuretic hormone (ADH)</p> Signup and view all the answers

    Match the parts of the nephron to their main functions:

    <p>Proximal Tubule = Reabsorption of substances Loop of Henle = Water permeability Distal Convoluted Tubule = Sodium reabsorption under aldosterone Collecting Duct = Final concentration of urine</p> Signup and view all the answers

    Which statement correctly describes the loop of Henle's function?

    <p>It actively pumps Na ions out of the lumen.</p> Signup and view all the answers

    Cattle possess unilobular kidneys.

    <p>False</p> Signup and view all the answers

    What is the significance of the renal blood supply to the medulla?

    <p>It arises from vessels that pass through the glomerulus, making it susceptible to ischaemia.</p> Signup and view all the answers

    A __________ ratio indicates a higher concentration capability in animals producing concentrated urine.

    <p>high medullary to cortical</p> Signup and view all the answers

    Match the species to their kidney lobation type:

    <p>Dogs &amp; Cats = Unilobular Pigs &amp; Cattle = Multilobar Cattle = Externally lobated All species = Converging nephrons</p> Signup and view all the answers

    Which hormone increases water reabsorption in the collecting duct?

    <p>ADH</p> Signup and view all the answers

    Decreased blood supply to the kidneys can lead to dysfunction in other parts of the nephron.

    <p>True</p> Signup and view all the answers

    What are the two main regions of the kidney as visible in a section?

    <p>Cortex and medulla.</p> Signup and view all the answers

    Fluid that moves out of the loop of Henle into the medullary interstitium is maintained in a hypertonic state due to high concentrations of __________.

    <p>urea and sodium</p> Signup and view all the answers

    Which part of the nephron is responsible for the highest level of water reabsorption?

    <p>Proximal tubule</p> Signup and view all the answers

    What is the primary role of the kidneys concerning fluid balance?

    <p>They adjust the concentration of urine to maintain hydration levels.</p> Signup and view all the answers

    Azotaemia is synonymous with renal failure.

    <p>False</p> Signup and view all the answers

    What is the main consequence of impaired renal function in dehydrated animals?

    <p>They cannot concentrate urine, leading to progressive dehydration.</p> Signup and view all the answers

    The production of __________ urine in animals with renal failure is known as polyuria.

    <p>isotonic</p> Signup and view all the answers

    Match the urine specific gravity (USG) categories with their descriptions:

    <p>Hyposthenuria = USG &lt; 1.008 Isosthenuria = USG 1.008 – 1.012 Minimally concentrated = USG 1.012 – 1.030 (dogs) Optimally concentrated = USG &gt; 1.030 (dogs)</p> Signup and view all the answers

    Which hormones are produced by the kidneys?

    <p>Renin and erythropoietin</p> Signup and view all the answers

    Animals with renal failure produce concentrated urine.

    <p>False</p> Signup and view all the answers

    What indicates that an animal may be experiencing primary polydipsia?

    <p>Persistently dilute urine in the absence of overhydration.</p> Signup and view all the answers

    Urine specific gravity (USG) indicates the __________ of dissolved solutes in urine.

    <p>concentration</p> Signup and view all the answers

    Which of the following can lead to increased intravascular pressure in animals with renal insufficiency?

    <p>Over-hydration</p> Signup and view all the answers

    The overall USG range for healthy animals is from 1.001 to 1.080.

    <p>True</p> Signup and view all the answers

    What two metabolic waste products do the kidneys primarily excrete?

    <p>Urea and creatinine</p> Signup and view all the answers

    The condition characterized by elevated blood levels of urea and creatinine is called __________.

    <p>azotaemia</p> Signup and view all the answers

    What can a high urine specific gravity (USG) indicate?

    <p>Concentrated urine</p> Signup and view all the answers

    Match the types of azotaemia with their descriptions:

    <p>Pre-renal = Caused by inadequate blood flow to the kidneys Renal = Caused by damage to kidney tissue Post-renal = Caused by obstruction in the urinary tract</p> Signup and view all the answers

    What is urea primarily produced from?

    <p>Amino acid breakdown</p> Signup and view all the answers

    Creatinine levels fluctuate significantly each day based on physical activity.

    <p>False</p> Signup and view all the answers

    What is a common cause of pre-renal azotaemia?

    <p>Dehydration</p> Signup and view all the answers

    Renal azotaemia occurs when _% of nephrons are damaged.

    <p>75</p> Signup and view all the answers

    Which of the following describes post-renal azotaemia?

    <p>Increased retention of urea and creatinine due to urinary tract obstruction</p> Signup and view all the answers

    Non-renal azotaemia is characterized by increased creatinine levels.

    <p>False</p> Signup and view all the answers

    What can influence the adaptation of kidneys in response to decreased nephrons?

    <p>Type of electrolyte being excreted</p> Signup and view all the answers

    Low serum potassium may occur in polyuric animals due to increased _ flow rate.

    <p>urinary</p> Signup and view all the answers

    What happens to phosphate excretion when the GFR falls to around 25% of normal?

    <p>Phosphate excretion is impaired leading to hyperphosphataemia</p> Signup and view all the answers

    What condition might occur as a result of renal secondary hyperparathyroidism?

    <p>Fibrous osteodystrophy</p> Signup and view all the answers

    Urea concentration in urinary filtrate is the same as in the _.

    <p>blood</p> Signup and view all the answers

    Match the following types of azotaemia with their causes:

    <p>Pre-renal azotaemia = Dehydration Renal azotaemia = Compromised nephrons Post-renal azotaemia = Urinary tract obstruction Non-renal azotaemia = Increased protein breakdown</p> Signup and view all the answers

    Hyperphosphataemia can lead to soft tissue mineralisation in renal failure.

    <p>True</p> Signup and view all the answers

    What is the role of remaining healthy nephrons in kidney failure?

    <p>Increase excretion efficiency</p> Signup and view all the answers

    Increased PTH causes increased release of calcium and phosphate from _.

    <p>bones</p> Signup and view all the answers

    What is one effect of oliguria in pre-renal azotaemia?

    <p>Concentrated urine</p> Signup and view all the answers

    What is a common consequence of chronic kidney disease (CKD)?

    <p>Kidneys become small, firm, and pale</p> Signup and view all the answers

    SDMA is a less sensitive marker for kidney function compared to creatinine.

    <p>False</p> Signup and view all the answers

    What is the main difference in how acute kidney injury and chronic kidney disease present clinically?

    <p>Acute kidney injury presents suddenly and may lead to anuria, while chronic kidney disease develops over time and shows signs like hypertrophy of the parathyroids and anemia.</p> Signup and view all the answers

    In cases of severe acute kidney injury, urine production may be categorized as ______ or ______.

    <p>anuria; oliguria</p> Signup and view all the answers

    Match the following terms related to kidney conditions with their descriptions:

    <p>Renal aplasia = Complete failure of development of one or both kidneys Renal hypoplasia = Abnormally small kidneys with fewer functional nephrons Renal dysplasia = Abnormal architecture of the kidneys Ectopic kidneys = Kidneys that are misplaced in the body</p> Signup and view all the answers

    What best describes the glomerular filtration rate (GFR)?

    <p>The volume of plasma filtered by the nephrons over time</p> Signup and view all the answers

    Chronic kidney disease is reversible under all circumstances.

    <p>False</p> Signup and view all the answers

    Name one disadvantage of using creatinine as a marker for renal function.

    <p>Creatinine levels can be influenced by muscle mass and diet.</p> Signup and view all the answers

    An excessive increase in thirst and urination is known as ______.

    <p>polydipsia/polyuria</p> Signup and view all the answers

    What is a consequence of unilateral renal aplasia?

    <p>Compatible with life</p> Signup and view all the answers

    Kidney lesions always cause renal failure.

    <p>False</p> Signup and view all the answers

    What is the significance of differentiating between azotaemia and renal failure?

    <p>It helps in determining the appropriate treatment and understanding prognosis.</p> Signup and view all the answers

    Fused kidneys may result in ______ of the kidneys.

    <p>compression</p> Signup and view all the answers

    Match the following types of renal conditions with their definitions:

    <p>Renal hypoplasia = Kidneys have not developed fully Ectopic kidneys = Kidneys located in an abnormal position Renal dysplasia = Kidneys with abnormal structural architecture Renal aplasia = Failure in developing one or both kidneys</p> Signup and view all the answers

    What condition is characterized by the presence of multiple cysts in the kidneys?

    <p>Polycystic kidney disease</p> Signup and view all the answers

    Horseshoe kidneys are usually functionally abnormal.

    <p>False</p> Signup and view all the answers

    Name one bacterial infection that can lead to suppurative glomerulitis in neonatal foals.

    <p>Actinobacillus equuli</p> Signup and view all the answers

    Leptospirosis is caused by several serovars of bacteria belonging to the species __________.

    <p>Leptospira interrogans</p> Signup and view all the answers

    Which type of injury involves the interstitium of the kidneys rather than the glomeruli?

    <p>Interstitial nephritis</p> Signup and view all the answers

    Renal cysts can only be congenital in nature.

    <p>False</p> Signup and view all the answers

    What is the clinical manifestation seen in foals infected with Actinobacillus equuli?

    <p>Fever, lethargy, and swollen hot joints</p> Signup and view all the answers

    Chronic interstitial nephritis often includes __________ of the interstitium.

    <p>fibrosis</p> Signup and view all the answers

    Which kidney condition is associated with marked hyperaemia due to inflammation?

    <p>Acutely inflamed glomeruli</p> Signup and view all the answers

    Interstitial fibrosis can only occur as a change due to chronic kidney disease.

    <p>False</p> Signup and view all the answers

    Which organ is commonly affected in conjunction with renal cysts in some dog breeds?

    <p>Liver</p> Signup and view all the answers

    The inflammatory infiltrate in early interstitial nephritis includes ______ and plasma cells.

    <p>neutrophils</p> Signup and view all the answers

    Match the following conditions with their characteristics:

    <p>Polycystic kidney disease = Inherited condition with multiple cysts Embolic glomerulitis = Inflammation caused by bacteria in glomeruli Chronic interstitial nephritis = Kidneys showing marked fibrosis Leptospirosis = Caused by Leptospira interrogans</p> Signup and view all the answers

    What term is used to describe kidneys with shrunken, distorted glomeruli and dilated tubules due to chronic kidney disease?

    <p>End-stage kidneys</p> Signup and view all the answers

    What is a common lesion in kidneys due to leptospirosis?

    <p>White spots in the cortex</p> Signup and view all the answers

    What is one of the primary causes of ischaemic tubular necrosis?

    <p>Severe anaemia</p> Signup and view all the answers

    Toxic tubular necrosis can occur due to both direct tubular damage and secondary ischaemia.

    <p>True</p> Signup and view all the answers

    Name one type of nephrotoxin that can cause renal damage.

    <p>Heavy metals</p> Signup and view all the answers

    NSAIDs affect the kidneys by decreasing the production of __________.

    <p>prostaglandins</p> Signup and view all the answers

    Match the following nephrotoxic agents with their effects:

    <p>Heavy Metals = Direct cellular damage NSAIDs = Reduced renal perfusion Aminoglycosides = Nephrotoxicity in dehydrated patients Oxalates = Tubular obstruction</p> Signup and view all the answers

    Which bacteria is frequently isolated from cases of canine pyelonephritis?

    <p>E.coli</p> Signup and view all the answers

    Acute kidney injury can result from NSAID overdoses in dehydrated animals.

    <p>True</p> Signup and view all the answers

    What condition results from the reflux of urine from the bladder to the renal pelvis?

    <p>Pyelonephritis</p> Signup and view all the answers

    The primary mechanism of NSAID nephrotoxicity is the constriction of __________ arterioles.

    <p>afferent</p> Signup and view all the answers

    Match the following toxins with their sources:

    <p>Grapes and raisins = Dogs Pollen from lilies = Cats Acorns = Cattle Oxalate-containing plants = Small animals</p> Signup and view all the answers

    Which of the following conditions can predispose to urine reflux?

    <p>Urethral obstruction</p> Signup and view all the answers

    The renal medulla is well vascularized and provides a strong barrier to bacterial infection.

    <p>False</p> Signup and view all the answers

    What feature of the female urethra makes females more prone to pyelonephritis?

    <p>Short length</p> Signup and view all the answers

    Oak buds and acorns cause acute tubular necrosis in __________.

    <p>cattle</p> Signup and view all the answers

    What is a common cause of papillary necrosis in horses?

    <p>Prolonged use of NSAIDs</p> Signup and view all the answers

    Papillary necrosis is usually asymptomatic in small animals.

    <p>True</p> Signup and view all the answers

    What condition is characterized by dilation of the renal pelvis?

    <p>Hydronephrosis</p> Signup and view all the answers

    The most common primary renal tumor in dogs is ______.

    <p>renal adenocarcinoma</p> Signup and view all the answers

    What leads to ischaemic necrosis of the renal papilla?

    <p>Obstruction of blood supply</p> Signup and view all the answers

    Increased intra-renal pressure can lead to renal papillary necrosis.

    <p>True</p> Signup and view all the answers

    Name a common malformation of the urinary bladder.

    <p>Patent urachus</p> Signup and view all the answers

    Medullary amyloidosis primarily impacts which part of the kidney?

    <p>renal medulla</p> Signup and view all the answers

    Which species is commonly associated with ectopic ureters?

    <p>Dogs</p> Signup and view all the answers

    Hydronephrosis can be caused by congenital abnormalities.

    <p>True</p> Signup and view all the answers

    What is a consequence of obstruction in the ureter?

    <p>Increased intratubular pressure</p> Signup and view all the answers

    Cystitis refers to inflammation of the ______.

    <p>bladder</p> Signup and view all the answers

    Match the following terms related to kidney conditions:

    <p>Papillary necrosis = Asymptomatic Hydronephrosis = Dilation of renal pelvis Renal adenocarcinoma = Common in dogs Patent urachus = Connection from umbilicus to bladder</p> Signup and view all the answers

    In cats, the most common renal tumor is:

    <p>Lymphoma</p> Signup and view all the answers

    What is the primary consequence of glomerular filtration barrier damage?

    <p>Loss of protein in urine</p> Signup and view all the answers

    Immune complexes in immune-mediated glomerulonephritis are always formed in situ.

    <p>False</p> Signup and view all the answers

    What clinical syndrome can develop as a result of severe proteinuria and hypoalbuminaemia?

    <p>Nephrotic syndrome</p> Signup and view all the answers

    The most common lesions observed in chronic immune-mediated glomerulonephritis are __________ and fibrosis.

    <p>atrophy</p> Signup and view all the answers

    Match the chronic disease with its related condition:

    <p>Pyometra = Chronic bacterial infection Canine hepatitis = Viral infection Feline leukaemia = Viral infection Abyssinian cat = Genetic predisposition to amyloidosis</p> Signup and view all the answers

    Which of the following is a major cause of glomerular amyloidosis in domestic animals?

    <p>Chronic inflammatory disease</p> Signup and view all the answers

    Amyloid deposits disrupt the filtration barrier of the kidneys, leading to protein-losing nephropathy.

    <p>True</p> Signup and view all the answers

    What is typically observed grossly in affected kidneys with amyloidosis?

    <p>Enlarged, pale, and waxy appearance</p> Signup and view all the answers

    The proximal tubules are most prone to ischaemic and toxic damage due to their __________ metabolic rate.

    <p>highest</p> Signup and view all the answers

    Match the tubular disease with its cause:

    <p>Leptospirosis = Interstitial nephritis Pyelonephritis = Ascending infections Renal ischaemia = Reduced blood supply Nephrotoxins = Excretion of harmful substances</p> Signup and view all the answers

    What is a common histological finding in chronic immune-mediated glomerulonephritis?

    <p>Membranous thickening of the basement membrane</p> Signup and view all the answers

    The impact of tubular damage is less severe than damage to the glomerulus.

    <p>False</p> Signup and view all the answers

    What is the term used to describe tubular epithelial damage due to ischemia or toxins?

    <p>Nephrosis</p> Signup and view all the answers

    Which of the following is NOT a predisposing factor for urinary tract infections (UTIs)?

    <p>Frequent urination</p> Signup and view all the answers

    In domestic animals, renal amyloidosis can involve either the glomerulus or the __________.

    <p>medulla</p> Signup and view all the answers

    Bacterial cystitis can be caused by E. coli and other uropathogens.

    <p>True</p> Signup and view all the answers

    What type of crystals have been historically most common in urolithiasis in cats?

    <p>Struvite crystals</p> Signup and view all the answers

    Cystitis can be caused by chemical toxins such as ________.

    <p>Cyclophosphamide</p> Signup and view all the answers

    Match the following uropathogens with their characteristics:

    <p>E. coli = Possesses adhesion factors for urinary epithelium Proteus = Common cause of urease-producing infections Staphylococcus = Common in canine urinary tract infections Corynebacterium renale = Specific to cattle infections</p> Signup and view all the answers

    Which of the following is a common consequence of urinary tract obstruction?

    <p>Uraemia</p> Signup and view all the answers

    Dilute urine can increase the risk of urolith formation.

    <p>True</p> Signup and view all the answers

    What is a known effect of glucosuria on urinary tract health?

    <p>Increased bacterial growth</p> Signup and view all the answers

    Uroliths are formed through the ________ of various types of minerals.

    <p>condensation</p> Signup and view all the answers

    Match the urinary calculi types with their common associations:

    <p>Struvite = Urease-producing bacteria Calcium oxalate = Diet high in oxalates Silica = High-silica diets Cystine = Genetic defects in metabolism</p> Signup and view all the answers

    What can produce ammonia in the bladder, leading to mucosal damage?

    <p>Bacterial infection</p> Signup and view all the answers

    The presence of crystals in urine is abnormal in all species.

    <p>False</p> Signup and view all the answers

    In male cats, what is a common cause of urinary tract obstruction?

    <p>Plugs of mineral and matrix</p> Signup and view all the answers

    The production of ________ has a significant impact on the formation of uroliths.

    <p>urine pH</p> Signup and view all the answers

    What is the primary cause of obstructive urolithiasis in male cats?

    <p>Narrow urethra</p> Signup and view all the answers

    Feline lower urinary tract disease (FLUTD) is a specific diagnosis.

    <p>False</p> Signup and view all the answers

    What are the hallmarks of feline lower urinary tract disease (FLUTD)?

    <p>Dysuria, pollakiuria, haematuria, vocalisation, and inappropriate urination.</p> Signup and view all the answers

    The most common cause of feline lower urinary tract disease is __________.

    <p>feline idiopathic cystitis</p> Signup and view all the answers

    Match the causes of feline lower urinary tract disease with their descriptions:

    <p>Feline Idiopathic Cystitis = Common in overweight indoor cats Urolithiasis = Formation of bladder stones Bacterial cystitis = Rare but more common in older cats Neoplasia = Less common cause, requires older age for consideration</p> Signup and view all the answers

    Which type of urinary obstruction is particularly common in feline patients?

    <p>Urethral plugs</p> Signup and view all the answers

    All urinary tract obstructions are caused by uroliths.

    <p>False</p> Signup and view all the answers

    What significant risk can occur if a urinary tract obstruction is not reversed?

    <p>Post-renal azotaemia, collapse, or death.</p> Signup and view all the answers

    The collection method used in urinalysis that is most likely to avoid bacterial contamination is __________.

    <p>cystocentesis</p> Signup and view all the answers

    What is the most common urinary tract tumor in cats?

    <p>Transitional cell carcinoma</p> Signup and view all the answers

    Bacterial infections of the bladder are common in young healthy cats.

    <p>False</p> Signup and view all the answers

    What is a typical duration of clinical signs for feline idiopathic cystitis?

    <p>5-10 days</p> Signup and view all the answers

    The state of increased urine production that can occur in animals with renal failure is known as __________.

    <p>polyuria</p> Signup and view all the answers

    Match the types of urinary obstruction with their mechanisms:

    <p>Urothelial bladder diseases = Caused by neoplasms or masses Urolithiasis = Stone formation leading to urethral blockage Urethral plugs = Formation of mucoid masses obstructing the urethra Inflammatory diseases = Resulting from urethral trauma or spasm</p> Signup and view all the answers

    What is the primary purpose of noting the method of urine collection on the submission form?

    <p>To assist the pathologist in interpretation of results</p> Signup and view all the answers

    Urine collected in the early morning usually contains the highest yield of cells, casts, and/or bacteria.

    <p>True</p> Signup and view all the answers

    What should be done to preserve a urine sample if it cannot be analyzed within 30 minutes?

    <p>Refrigerate the sample.</p> Signup and view all the answers

    The specific gravity (SG) of urine helps to indicate the kidneys' ability to ________.

    <p>concentrate</p> Signup and view all the answers

    Match the urine specific gravity (USG) ranges with their corresponding conditions:

    <p>Isosthenuria = 1.008–1.012 Hyposthenuria = 1.001–1.007 Adequate concentration = &gt;1.030 (dog) Optimal concentration = &gt;1.035 (cat)</p> Signup and view all the answers

    Which of the following options reflects the correct condition for urine that is red or red-brown and does not clear on centrifugation?

    <p>Myoglobinuria</p> Signup and view all the answers

    Refrigerating a urine sample is unnecessary if it will be analyzed within 30 minutes.

    <p>True</p> Signup and view all the answers

    What is the typical characteristic of horse urine?

    <p>Cloudy due to high mucus and calcium carbonate crystals.</p> Signup and view all the answers

    The presence of _______ in urine often indicates a urinary tract infection.

    <p>bacteria</p> Signup and view all the answers

    What happens to casts and neutrophils in hypotonic or alkaline urine?

    <p>They disappear rapidly</p> Signup and view all the answers

    The optimal concentration of urine specific gravity for dogs is lower than that for cats.

    <p>True</p> Signup and view all the answers

    Name one factor that can affect the specific gravity of urine.

    <p>Dehydration or fluid therapy.</p> Signup and view all the answers

    Urine that appears dark yellow-brown and produces a yellow froth when shaken is called ________.

    <p>bilirubinuria</p> Signup and view all the answers

    Match each type of urine abnormality with its associated indicator:

    <p>Haematuria = Red and cloudy urine Myoglobinuria = Red-brown urine that does not clear Bilirubinuria = Dark yellow-brown urine with froth Pyuria = Cloudy urine due to bacteria</p> Signup and view all the answers

    What is the most common cause of acute kidney injury?

    <p>Widespread tubular damage from toxins</p> Signup and view all the answers

    Chronic kidney disease is characterized by decreased production of erythropoietin (EPO).

    <p>True</p> Signup and view all the answers

    What condition is characterized by a loss of urinary concentrating ability and azotaemia?

    <p>Uraemia</p> Signup and view all the answers

    In chronic kidney disease, the kidneys can often maintain normal serum potassium and sodium levels due to the adaptation of the remaining __________.

    <p>nephrons</p> Signup and view all the answers

    Match the following conditions with their correct descriptions:

    <p>Oliguria = Decreased urine production Hyperkalaemia = High potassium levels in the serum Anaemia = Reduced erythrocyte production Renal insufficiency = Loss of 2/3 to 3/4 kidney function</p> Signup and view all the answers

    What happens when more than 75% of kidney function is lost?

    <p>Patient enters renal failure</p> Signup and view all the answers

    Acute kidney injury can develop slowly over time.

    <p>False</p> Signup and view all the answers

    Name the hormone produced by the kidneys that stimulates erythrocyte production.

    <p>Erythropoietin (EPO)</p> Signup and view all the answers

    The kidneys have a significant amount of built-in __________, allowing them to compensate for lost tissue.

    <p>redundancy</p> Signup and view all the answers

    Match the following terms with their related effects:

    <p>Melaena = Dark, tarry feces due to gastrointestinal bleeding Thrombosis = Clot formation in blood vessels Uraemic odour = Distinctive smell associated with renal failure DIC = Disseminated intravascular coagulation</p> Signup and view all the answers

    What is a common complication of uraemia?

    <p>Gastrointestinal bleeding</p> Signup and view all the answers

    Anaemia is a feature of acute kidney injury.

    <p>False</p> Signup and view all the answers

    When does an animal enter a state of renal insufficiency?

    <p>When 2/3 to 3/4 of the total nephrons are damaged.</p> Signup and view all the answers

    Uraemic toxins can cause __________ in endothelial cells, leading to further complications.

    <p>vasculitis</p> Signup and view all the answers

    Which condition is commonly confirmed by measuring water consumption over 24 hours?

    <p>Polydipsia</p> Signup and view all the answers

    Pyometra can occur in both spayed and unspayed bitches.

    <p>False</p> Signup and view all the answers

    Name one common cause of Polyuria/Polydipsia (PU/PD).

    <p>Renal disease</p> Signup and view all the answers

    The endocrine testing for hyperthyroidism in cats typically measures ______ levels.

    <p>T4</p> Signup and view all the answers

    Match the following conditions with their respective characteristics:

    <p>Cushing's disease = Hyperadrenocorticism Addison's disease = Adrenal insufficiency Diabetes mellitus = High blood sugar levels Central diabetes insipidus = ADH deficiency</p> Signup and view all the answers

    Which of the following diagnostic tests is considered a minimum baseline for diagnosing PU/PD?

    <p>Urinalysis</p> Signup and view all the answers

    Increased water consumption in hospitalized animals is typically consistent with their normal drinking behavior.

    <p>False</p> Signup and view all the answers

    What does ADH stand for?

    <p>Antidiuretic hormone</p> Signup and view all the answers

    What is the defined daily water intake for polydipsia in dogs and cats?

    <p>Above 100 mL/kg/day</p> Signup and view all the answers

    Polyuria is defined as daily urine output exceeding 50 mL/kg/day.

    <p>True</p> Signup and view all the answers

    What hormone is responsible for increasing water reabsorption in the kidneys?

    <p>Antidiuretic hormone (ADH)</p> Signup and view all the answers

    If an animal has severe watery diarrhoea, they will drink more water to maintain __________.

    <p>hydration</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Polydipsia = Increased water intake Polyuria = Increased urine output ADH = Hormone that promotes water reabsorption Renal axis = Mediates urine production</p> Signup and view all the answers

    Which of the following factors do NOT need to be normal for an animal to produce a normal amount of urine?

    <p>Exercise level</p> Signup and view all the answers

    An animal can still produce normal urine if its renal tubular response to ADH is impaired.

    <p>False</p> Signup and view all the answers

    What physiological response causes ADH to be released into circulation?

    <p>Decrease in blood volume or increase in plasma osmolality</p> Signup and view all the answers

    What is the main cause of diabetes insipidus?

    <p>Inadequate production of ADH</p> Signup and view all the answers

    Psychogenic polydipsia is always a response to increased water loss.

    <p>False</p> Signup and view all the answers

    What is primary polydipsia?

    <p>Inappropriate increase in thirst not related to water loss.</p> Signup and view all the answers

    The condition characterized by increased thirst that is not related to excessive fluid loss is known as __________.

    <p>primary polydipsia</p> Signup and view all the answers

    Match the following conditions with their causes:

    <p>Central diabetes insipidus = Lack of ADH production Nephrogenic diabetes insipidus = Inadequate response to ADH Osmotic diuresis = Excess glucose in urine Secondary nephrogenic diabetes insipidus = Hypercalcaemia or E.coli infection</p> Signup and view all the answers

    What indication suggests nephrogenic diabetes insipidus?

    <p>Urine remains dilute even with dehydration.</p> Signup and view all the answers

    Osmotic diuresis occurs when water is excessively reabsorbed in the kidneys.

    <p>False</p> Signup and view all the answers

    What are two common causes of structural damage to nephrons?

    <p>Acute kidney disease and chronic kidney disease.</p> Signup and view all the answers

    A lack of functional nephrons can lead to the condition known as __________.

    <p>renal azotaemia</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>Polyuria = Excessive urine production ADH = Hormone that increases water reabsorption USG = Measure of urine concentration Polyuria due to diabetes mellitus = Osmotic effect caused by glucose in urine</p> Signup and view all the answers

    Which factor can decrease medullary hypertonicity?

    <p>Systemic hyponatraemia</p> Signup and view all the answers

    Polyuria due to diabetes mellitus can be reversed once the infection is treated.

    <p>True</p> Signup and view all the answers

    What diagnostic test confirms diabetes insipidus?

    <p>ADH response test.</p> Signup and view all the answers

    A high urine specific gravity (USG) indicates __________ urine concentration.

    <p>high</p> Signup and view all the answers

    What is a common feature observed in animals with diabetes insipidus?

    <p>Increased water consumption</p> Signup and view all the answers

    Which of the following is NOT a characteristic symptom of hyperthyroidism in cats?

    <p>Diarrhea</p> Signup and view all the answers

    Hypercalcaemia commonly causes PU/PD in cats.

    <p>False</p> Signup and view all the answers

    What condition may result from persistent hypercalcaemia?

    <p>Hypercalcaemic nephropathy and renal failure</p> Signup and view all the answers

    In pyelonephritis, renal pelvic inflammation can disrupt the counter current mechanism resulting in __________.

    <p>isosthenuria</p> Signup and view all the answers

    Match the following conditions with their associated effects on renal function:

    <p>Hyperthyroidism = PU/PD, polyphagia, weight loss Hypercalcaemia = Inhibition of ADH actions Hypokalaemia = Decreased sensitivity to ADH Pyelonephritis = Renal pelvic inflammation and infection</p> Signup and view all the answers

    What is the primary problem typically associated with primary polyuria?

    <p>Increased urine output</p> Signup and view all the answers

    Polydipsia is defined as a daily water intake exceeding 50 mL/kg/day.

    <p>False</p> Signup and view all the answers

    What hormone is primarily responsible for increasing water reabsorption in the kidneys?

    <p>Antidiuretic hormone (ADH)</p> Signup and view all the answers

    Urine output exceeding __________ mL/kg/day is classified as polyuria.

    <p>50</p> Signup and view all the answers

    Match the following conditions with their definitions:

    <p>Polyuria = Increased volume of urine Polydipsia = Increased water intake Nocturia = Urination at night Incontinence = Inability to control urination</p> Signup and view all the answers

    Which of the following is a common characteristic of diseases causing polyuria and polydipsia in animals?

    <p>They are often due to a defect in the hypothalamic-pituitary-renal axis</p> Signup and view all the answers

    Primary polydipsia is more commonly observed than primary polyuria.

    <p>False</p> Signup and view all the answers

    What is the average normal water intake for dogs and cats in mL/kg/day?

    <p>50-70</p> Signup and view all the answers

    Which of the following is a common cause of polydipsia in dogs?

    <p>Diabetes mellitus</p> Signup and view all the answers

    Polydipsia can be confirmed with a 24-hour water monitor.

    <p>True</p> Signup and view all the answers

    What is the significance of urine specific gravity (USG) in diagnosing polyuria?

    <p>USG helps assess the concentration of urine, indicating possible kidney issues.</p> Signup and view all the answers

    Hyperadrenocorticism is commonly known as __________ disease.

    <p>Cushing's</p> Signup and view all the answers

    Match the following conditions with their classification:

    <p>Diabetes mellitus = Common Primary renal glycosuria = Uncommon Hypoadrenocorticism = Uncommon Chronic kidney disease = Common</p> Signup and view all the answers

    Which drug class is associated with increased water consumption in animals?

    <p>Diuretics</p> Signup and view all the answers

    Psychogenic polydipsia is a common cause of PU/PD in both dogs and cats.

    <p>False</p> Signup and view all the answers

    What laboratory test can provide insight into low urine specific gravity in suspected cases of PU?

    <p>Urinalysis</p> Signup and view all the answers

    In dogs, urine specific gravity is considered isosthenuric when it is between __________.

    <p>1.008 and 1.012</p> Signup and view all the answers

    Match each cause of PU/PD with its respective category (common/uncommon):

    <p>Hypercalcaemia = Uncommon Liver disease = Common Cystitis = Common Neoplasia = Uncommon</p> Signup and view all the answers

    Which of the following can affect the accuracy of water intake measurements in a home water monitor?

    <p>Both A and B</p> Signup and view all the answers

    High urine specific gravity indicates a low concentration of dissolved solutes in urine.

    <p>False</p> Signup and view all the answers

    What is a potential effect of increased dry food intake on water consumption?

    <p>It can increase water consumption.</p> Signup and view all the answers

    The Na:K ratio of less than 25:1 may suggest __________.

    <p>hypoadrenocorticism</p> Signup and view all the answers

    What is the primary use of the modified water deprivation test?

    <p>To determine the cause of increased urine output</p> Signup and view all the answers

    The urine specific gravity (USG) of animals with chronic kidney disease will typically be greater than 1.030.

    <p>False</p> Signup and view all the answers

    What hormone is released from the pituitary gland to promote water reabsorption in the kidneys?

    <p>ADH</p> Signup and view all the answers

    PU/PD may be associated with chronic kidney disease when at least _____ of functional nephrons are lost.

    <p>2/3</p> Signup and view all the answers

    Match the following conditions with their effects on urine concentration:

    <p>Diabetes Mellitus = Increased urinary glucose leading to osmotic diuresis Hyperadrenocorticism = Inhibition of ADH secretion Chronic Kidney Disease = Loss of concentrating ability due to nephron loss Central Diabetes Insipidus = Inability to release ADH from the pituitary gland</p> Signup and view all the answers

    What is a potential outcome of the modified water deprivation test for psychogenic polydipsia?

    <p>Urine will concentrate without ADH</p> Signup and view all the answers

    Primary nephrogenic diabetes insipidus is very common in animals.

    <p>False</p> Signup and view all the answers

    What condition is characterized by a reduced ability of the kidneys to excrete ammonia, resulting in PU/PD?

    <p>Hepatic Insufficiency</p> Signup and view all the answers

    The modified water deprivation test should only be done once conditions such as diabetes mellitus and __________ have been excluded.

    <p>renal disease</p> Signup and view all the answers

    Match the following tests with their purposes:

    <p>ACTH stimulation test = Evaluate adrenal function Low dose dexamethasone test = Assess cortisol suppression Modified water deprivation test = Differentiate causes of PU/PD Ultrasonography = Assess mass and organ size</p> Signup and view all the answers

    What is the urine specific gravity range for healthy animals?

    <p>1.001 to 1.080</p> Signup and view all the answers

    Nephrogenic diabetes insipidus can be diagnosed by a lack of urine concentration after ADH administration.

    <p>True</p> Signup and view all the answers

    What is the main factor that may lead to osmotic diuresis in diabetes mellitus?

    <p>Excess glucose</p> Signup and view all the answers

    In animals with hyperadrenocorticism, there may be a further increase in urine specific gravity following __________ administration.

    <p>ADH</p> Signup and view all the answers

    What potential complication must be monitored for during the modified water deprivation test?

    <p>Cerebral edema</p> Signup and view all the answers

    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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    Description

    Explore the complexities of the urinary system in this quiz, designed to enhance your understanding of its vital concepts and common diseases. Emphasizing core definitions and clinical applications, this resource serves as a comprehensive aid for students and practitioners alike. Prepare to diagnose and treat conditions related to this important bodily system.

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