Pathology: Urinary (short)

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What part of the kidney contains the glomeruli and convoluted tubules?

Papilla

Cortex (correct)

Ureter

Medulla

Functional renal reserve allows a kidney to cope with the loss of up to 50% of nephrons without compromising function.

False

Name the 3 components required to produce optimally concentrated urine.

Functional nephrons, ADH, Hypertonic medullary

The primary function of the kidney in maintaining body fluid balance is to __________.

regulate water levels Signup and view all the answers

Match the following kidney functions with their descriptions:

Body fluid balance = Regulation of water and electrolytes Excretion of metabolic waste = Removal of waste from protein breakdown Electrolyte balance = Maintaining proper levels of salts like Na, K, PO4 Hormone production = Production of erythropoietin (EPO) for red blood cell production Signup and view all the answers

What is the primary cause of nephrotic syndrome?

Loss of albumin in urine Signup and view all the answers

Amyloidosis in cats typically causes significant symptoms.

False Signup and view all the answers

What type of crystals does ethylene glycol form in the body?

Calcium oxalate crystals Signup and view all the answers

The most common uropathogen that causes cystitis is __________.

E. coli Signup and view all the answers

Match the following conditions with their respective descriptions:

Hydronephrosis = Obstruction of urine flow leading to kidney dilation Cystitis = Inflammation of the bladder Urolithiasis = Formation of stones within the urinary tract Papillary necrosis = Ischaemia of the kidney medulla Signup and view all the answers

Which of the following is a predisposing factor for urolithiasis?

Dehydration Signup and view all the answers

Acquired hydronephrosis is primarily caused by congenital defects.

False Signup and view all the answers

Name one clinical sign of ethylene glycol poisoning.

Collapsing or dehydration Signup and view all the answers

Chronic kidney disease is characterized by the production of high levels of __________ in the context of amyloidosis.

serum amyloid A Signup and view all the answers

Match the following types of tubular disease with their causes:

Ischemic tubular necrosis = Disruption of blood supply to the kidney Toxic necrosis = Direct action of toxins on the tubules Inflammatory nephrosis = Immune-mediated damage Tubular necrosis = General damage to tubular structure Signup and view all the answers

Which condition is NOT associated with nephrotic syndrome?

Excessive urination Signup and view all the answers

Urethral obstruction is the most common cause of urinary tract obstruction.

True Signup and view all the answers

What commonly causes papillary necrosis in horses?

NSAIDs Signup and view all the answers

The inflammation of the renal pelvis and parenchyma is known as __________.

pyelonephritis Signup and view all the answers

What happens when more than 75% of nephrons are damaged?

Inability to excrete urea and creatinine Signup and view all the answers

What triggers the release of ADH?

Increased plasma osmolarity Signup and view all the answers

Diabetes insipidus is characterized by an inability to produce concentrated urine.

True Signup and view all the answers

Hyperphosphatemia occurs after renal failure due to the kidneys' inability to excrete phosphate.

True Signup and view all the answers

What condition is characterized by compulsive drinking due to an abnormal function of the thirst center?

Psychogenic polydipsia Signup and view all the answers

What is the term used collectively for the symptoms of polydipsia, polyuria, azotemia, hyperphosphatemia, and anemia in chronic kidney disease?

uraemia Signup and view all the answers

Primary polyuria can be caused by a lack of ADH production or an ________ response to ADH.

abnormal Signup and view all the answers

When a patient has low urine output but high urinary specific gravity (>1.030), this indicates ______ azotemia.

pre-renal Signup and view all the answers

Match the following conditions with their corresponding descriptions:

Glomerulonephritis = Caused by immune complexes affecting the basement membrane Chronic Interstitial Nephritis = Shrunken, firm, and pale kidneys Ectopic kidneys = Kidneys in an abnormal location Renal Dysplasia = Abnormal architecture of the kidneys Signup and view all the answers

Match the conditions with their causes of PU/PD:

Diabetes mellitus = Osmotic diuresis due to high glucose Hypercalcaemia = Inhibited ADH action at collecting duct Cushing's disease = Increased cortisol levels Renal disease = Structural damage to nephrons Signup and view all the answers

What is the most common cause of osmotic diuresis?

Diabetes mellitus Signup and view all the answers

Which condition can lead to chronic kidney disease due to reduced blood flow?

Dehydration Signup and view all the answers

List two primary causes of primary polyuria.

Lack of ADH production, abnormal response to ADH Signup and view all the answers

Acute kidney disease is characterized by small, firm kidneys.

False Signup and view all the answers

Increased renal blood flow leads to decreased medullary hypertonicity.

True Signup and view all the answers

What is the consequence of reduced erythropoietin (EPO) production in chronic kidney disease?

non-regenerative anemia Signup and view all the answers

In chronic kidney disease, the kidneys often become ______ and small.

pale Signup and view all the answers

What is one of the primary causes of post-renal azotemia?

Urinary tract obstruction Signup and view all the answers

Hyperkalaemia is a common finding in chronic kidney disease.

False Signup and view all the answers

What is the normal urine specific gravity range for isosthenuria?

1.008 - 1.012 Signup and view all the answers

Increased ______ from bones is a response to low calcium levels caused by hyperphosphatemia in renal failure.

parathyroid hormone Signup and view all the answers

What underlying condition can cause azotemia due to increased protein breakdown?

Starvation Signup and view all the answers

What is the most common cause of obstructive urinary issues in cats?

Feline idiopathic cystitis Signup and view all the answers

Urethral plugs are clumps of mucoid material that can obstruct the urethra.

True Signup and view all the answers

What is the best sample collection method for urinalysis?

Cystocentesis Signup and view all the answers

The __________ is the most common malignant tumor found in cats' urinary tracts.

transitional cell carcinoma Signup and view all the answers

Match the urinary conditions with their descriptions:

Feline idiopathic cystitis = Affects young to middle-aged overweight cats Urolithiasis = Obstruction from crystal clumps Bacterial cystitis = Rare cause in older cats Neoplasia = Malignant growths in the urinary tract Signup and view all the answers

What does isosthenuria indicate?

Same concentration as plasma Signup and view all the answers

Glucosuria can result from stress in cats.

False Signup and view all the answers

What is a common cause of bilirubin in the urine of cats?

Cholestatic liver disease Signup and view all the answers

Normal urine production requires normal __________ status.

thirst Signup and view all the answers

Match the urine characteristics with the corresponding interpretation:

pH 5.5 = Acidic urine, typical for carnivores pH 8.0 = Alkaline urine, possible UTI Trace protein = May indicate normal or mild issues High protein = Likely suggestive of glomerular disease Signup and view all the answers

What is indicated by the presence of large amounts of protein in urine?

Renal glomerular disease Signup and view all the answers

Blood in the urine can be caused by urinary tract hemorrhage.

True Signup and view all the answers

What test is used to distinguish between glomerular and tubular proteinuria?

Urinary protein:creatinine ratio (UPCR) Signup and view all the answers

Concentrated urine with __________ amount of protein is considered normal.

trace Signup and view all the answers

Which condition does NOT lead to glucosuria?

Stress in cats Signup and view all the answers

Elevated muscle enzymes in blood can suggest pre-renal proteinuria.

True Signup and view all the answers

Study Notes

Normal Renal Function

Upper urinary tract comprises the kidneys and ureters; Lower urinary tract consists of the bladder and urethra.
Kidney anatomy includes:
- Cortex: outer layer with glomeruli and convoluted tubules.
- Medulla: inner layer housing the loop of Henle and collecting ducts.
Collecting ducts converge into lobes, which may form single or multiple papillae depending on species.
Blood enters kidneys via renal artery; renal arterioles pass through glomeruli for filtration.

Nephron Function and Urine Concentration

Nephrons consist of glomerulus and tubules; filtration barrier keeps large molecules (cells, proteins) from entering urine.
Filtration is driven by blood pressure, allowing small, soluble, or negatively charged substances through.
Urine concentration mechanisms:
- Hypertonic medulla: promotes water movement into interstitial space.
- Collecting duct: ADH (antidiuretic hormone) increases water reabsorption.
Optimal concentrated urine requires functional nephrons, ADH, and a hypertonic medulla.
Functional reserve allows for the loss of up to two-thirds of nephrons without affecting renal function; >75% loss leads to renal failure.

Kidney Functions

Maintains body fluid balance.
Excretes metabolic waste, especially from protein breakdown.
Regulates electrolytes (PO4, K, Na).
Produces hormones like erythropoietin (EPO).

Kidney Dysfunction

Dysfunctions manifest as inability to concentrate urine, excrete waste, regulate electrolytes, or produce EPO.
Critical thresholds for urine concentrating ability:
- 66% damage: Inability to concentrate urine.
- 75% damage: Failure to maintain fluid balance.
Urine concentration measured via specific gravity:
- Isosthenuric: 1.008 - 1.012.
- Hyposthenuric: >1.012.

Altered Excretion Patterns

Azotemia indicates impaired urea and creatinine clearance due to nephron damage.
Hyperphosphatemia occurs with renal failure due to phosphate retention.
Potassium levels vary with kidney function: more excretion with high flow rates, leading to hypokalemia; conversely, low flow rates cause hyperkalemia.

Diagnostic Indicators of Renal Failure

Symptoms include polydipsia/polyuria or oliguria/anuria, isosthenuria, azotemia, hyperphosphatemia, and anemia.
Collectively referred to as uremia.

Azotemia Classification

Pre-renal: Dehydration reduces blood flow to kidneys, causing oliguria and concentrated urine.
Renal: >75% nephron damage leads to decreased urea/creatinine excretion and less concentrated urine.
Post-renal: Obstruction leads to reabsorption of waste products into blood.
Non-renal: Increased protein breakdown from various conditions.

Conditions Affecting the Upper Urinary Tract

Congenital abnormalities include renal aplasia, hypoplasia, dysplasia, and ectopic kidneys.
Vascular conditions: Embolic glomerulitis and interstitial nephritis due to infections (e.g., Leptospirosis).
Chronic interstitial nephritis leads to CKD, characterized by fibrosis and enlarged, firm kidneys.

Tubular and Medullary Diseases

Tubular disease can be inflammatory or necrotizing, caused by ischemia or toxins.
Oxalate-containing plants and ethylene glycol cause acute kidney injury through crystal formation.
Pyelonephritis arises from lower tract infections ascending to the renal pelvis.

Lower Urinary Tract Disease and Lesions

Congenital defects, such as ectopic ureters and patent urachus, can lead to infections and other complications.
Cystitis results from inflammation often caused by uropathogens; predisposing factors include trauma and urine pH changes.
Urolithiasis involves the formation of urinary calculi, with common types varying by species.

Urinary Tract Obstruction

Most obstructions occur at the urethra, often due to uroliths or plugs.
Common in males, especially with long urethras; may lead to severe complications if untreated.

Feline Lower Urinary Tract Disease (FLUTD)

A syndrome characterized by symptoms of cystitis, with multiple potential causes including idiopathic cystitis, urolithiasis, bacterial cystitis, and neoplasia.

Urinalysis

Cystocentesis is the preferred method for urine sample collection.
Use of specific gravity (USG) assists in assessing kidney function; normal values depend on hydration status.
Urine chemistry tests provide insights into protein, glucose, bilirubin, and blood presence.

Proteinuria Interpretation

Assess protein levels to differentiate between pre-renal, renal, and post-renal causes.
UPCR used for distinguishing renal disease: <0.5 normal; >1 indicates glomerular disease.

Glucosuria and Bilirubin

Presence of glucose indicates hyperglycemia, often from diabetes or stress.
Bilirubin in urine suggests possible cholestatic liver disease, notably in cats.

Importance of the Hypothalamic-Pituitary-Renal Axis

ADH regulates urine concentration; dysfunction can lead to primary polyuria or polydipsia.### Lack of ADH Production
Lesions in the pituitary gland lead to a lack of Antidiuretic Hormone (ADH) production; this is uncommon.
Acquired conditions in dogs often stem from trauma, while cats may have space-occupying lesions.
Diagnosis often relies on exclusion methods; a positive response to synthetic ADH confirms the condition.

Abnormal Response to ADH

Abnormalities in the renal distal tubules and collecting ducts result in decreased responsiveness to ADH.
Reduced response leads to decreased water reabsorption and polyuria, which can be classified as primary or secondary.
Primary nephrogenic diabetes insipidus occurs when urine concentration does not exceed a specific gravity (SG) of 1.007, even after dehydration; this rare condition manifests early in life.
Secondary causes include:
- Hypercalcemia: high serum calcium impedes ADH action.
- E. coli endotoxins: these toxins reduce ADH sensitivity at the collecting duct but have reversible effects.

Structural Damage to Nephrons

Significant damage occurs once two-thirds of functional nephrons are compromised; resulting urine specific gravity (USG) becomes isosthenuric or minimally concentrated.

Osmotic Diuresis

Elevated levels of osmotically active substances in the tubular filtrate inhibit normal water resorption, leading to diuresis.
Diabetes mellitus is a common cause; excess glucose remains in urine, retaining water as a consequence.

Decreased Medullary Hypertonicity

Lowered levels of urea and sodium diminish medullary concentration due to:
- Decreased urea production associated with liver diseases.
- Increased renal blood flow, often due to prolonged polyuria from fluid overload.
- Systemic hyponatremia affecting overall sodium levels.

Approach to Diagnosing PU/PD

Begin with a comprehensive history and physical examination.
Confirm polydipsia by measuring water consumption over 24 hours, ideally in a normal home setting.
Conduct a diagnostic screen including urinalysis, hematology, and biochemistry.
Implement specific tests as necessary, such as T4 and ACTH measurements.

Most Common Causes of PU/PD

Renal disease.
Diabetes mellitus.
Hyperthyroidism, particularly in cats.
Hypercalcemia from various causes, including malignancies.
Cushing's disease (hyperadrenocorticism).
Pyometra, prostatitis, and urinary tract infections.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the anatomy and function of the renal system, including the structure of the upper and lower urinary tracts. This quiz covers important components such as the cortex, medulla, blood supply, and lobes of the kidneys. Ensure you understand kidney anatomy and its significance in overall renal function.