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Questions and Answers
What is defined as water intake greater than 90-100 mL/kg/day in dogs?
What is defined as water intake greater than 90-100 mL/kg/day in dogs?
Polyuria is characterized by urine output less than 50 mL/kg/day in both dogs and cats.
Polyuria is characterized by urine output less than 50 mL/kg/day in both dogs and cats.
False
Name one condition that is a consistent feature of PU/PD.
Name one condition that is a consistent feature of PU/PD.
Diabetes mellitus
In dogs and cats, high __________ can increase water intake due to increased digestibility.
In dogs and cats, high __________ can increase water intake due to increased digestibility.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Which of the following is a cause of primary nephrogenic diabetes insipidus?
Which of the following is a cause of primary nephrogenic diabetes insipidus?
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Diabetes insipidus is primarily caused by an excess of arginine vasopressin.
Diabetes insipidus is primarily caused by an excess of arginine vasopressin.
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What is the main hormone responsible for water homeostasis in the body?
What is the main hormone responsible for water homeostasis in the body?
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___ and polydipsia often occur together in dogs with diseases such as diabetes mellitus.
___ and polydipsia often occur together in dogs with diseases such as diabetes mellitus.
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Match the following conditions with their potential impact on water regulation:
Match the following conditions with their potential impact on water regulation:
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Which disorder primarily results from a deficiency in arginine vasopressin?
Which disorder primarily results from a deficiency in arginine vasopressin?
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Cats are generally reported to have higher incidences of polyuria compared to dogs.
Cats are generally reported to have higher incidences of polyuria compared to dogs.
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Name one potential cause of secondary nephrogenic diabetes insipidus.
Name one potential cause of secondary nephrogenic diabetes insipidus.
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The condition known as _________ can lead to impaired response of the kidneys to arginine vasopressin.
The condition known as _________ can lead to impaired response of the kidneys to arginine vasopressin.
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Match the symptoms of polyuria with their causes:
Match the symptoms of polyuria with their causes:
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Which of the following conditions is NOT a common cause of polyuria and polydipsia in cats?
Which of the following conditions is NOT a common cause of polyuria and polydipsia in cats?
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Syndrome of inappropriate diuresis can lead to increased water loss in dogs.
Syndrome of inappropriate diuresis can lead to increased water loss in dogs.
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What role does arginine vasopressin play in the kidneys?
What role does arginine vasopressin play in the kidneys?
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Increased excretion of urine due to osmotic agents occurring in conditions like diabetes mellitus is called _______.
Increased excretion of urine due to osmotic agents occurring in conditions like diabetes mellitus is called _______.
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What typically causes polydipsia in dogs and cats?
What typically causes polydipsia in dogs and cats?
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Polydipsia is defined as water intake exceeding 90-100 mL/kg/day in dogs.
Polydipsia is defined as water intake exceeding 90-100 mL/kg/day in dogs.
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What is the term used for increased urine output that exceeds 50 mL/kg/day in dogs and cats?
What is the term used for increased urine output that exceeds 50 mL/kg/day in dogs and cats?
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Increased water intake can occur due to high ___ content in diets.
Increased water intake can occur due to high ___ content in diets.
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Match the following conditions with their potential impact on water regulation:
Match the following conditions with their potential impact on water regulation:
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Which of the following is a common cause of secondary nephrogenic diabetes insipidus?
Which of the following is a common cause of secondary nephrogenic diabetes insipidus?
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Central diabetes insipidus is primarily caused by a deficiency in arginine vasopressin.
Central diabetes insipidus is primarily caused by a deficiency in arginine vasopressin.
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Name a disease commonly associated with polyuria and polydipsia in dogs.
Name a disease commonly associated with polyuria and polydipsia in dogs.
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The condition in which the kidneys cannot effectively respond to arginine vasopressin is called __________.
The condition in which the kidneys cannot effectively respond to arginine vasopressin is called __________.
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Match the following conditions to their potential effects on water homeostasis:
Match the following conditions to their potential effects on water homeostasis:
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Which of the following mechanisms can lead to disrupted osmotic gradients in the kidneys?
Which of the following mechanisms can lead to disrupted osmotic gradients in the kidneys?
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Polyuria and polydipsia are commonly reported in cats.
Polyuria and polydipsia are commonly reported in cats.
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What is the role of arginine vasopressin in water homeostasis?
What is the role of arginine vasopressin in water homeostasis?
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Increased __________ and/or pressure can contribute to polyuria in some cases.
Increased __________ and/or pressure can contribute to polyuria in some cases.
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Match the following drugs to their potential effect on urine concentration:
Match the following drugs to their potential effect on urine concentration:
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Which of the following conditions is NOT typically associated with polyuria in cats?
Which of the following conditions is NOT typically associated with polyuria in cats?
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Osmotic diuresis occurs when there is an increase in solutes in the renal tubular lumen.
Osmotic diuresis occurs when there is an increase in solutes in the renal tubular lumen.
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What is the potential consequence of a severely protein- or salt-restricted diet on kidney function?
What is the potential consequence of a severely protein- or salt-restricted diet on kidney function?
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Dogs with chronic kidney disease exhibit reduced numbers of functional __________ capable of responding to AVP.
Dogs with chronic kidney disease exhibit reduced numbers of functional __________ capable of responding to AVP.
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What is the primary factor causing polyuria in dogs with diabetes mellitus?
What is the primary factor causing polyuria in dogs with diabetes mellitus?
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Study Notes
Polyuria and Polydipsia Definitions
- Polyuria (PU) is urine output greater than 50 mL/kg/day in both dogs and cats.
- Polydipsia (PD) is water intake exceeding 90-100 mL/kg/day in dogs and >50 mL/kg/day in cats.
Environmental and Dietary Influences
- Water intake increases with high temperatures, exercise, and feeding.
- Dogs fed dry food consume more water than those fed canned food; the difference is less pronounced in cats.
- Diets with higher digestibility, protein, or salt content increase water intake.
- Water source type (still or flowing) can affect intake in some cats.
Pathophysiology Overview
- Polyuria results from excessive water intake (primary polydipsia) or impaired urine concentration (primary polyuria).
- PU/PD is a symptom of certain diseases (e.g., diabetes mellitus, chronic kidney disease, hyperthyroidism).
- Association between PU/PD and specific diseases can be less clear in some cases.
Primary Polydipsia (PP)
- PP is a group of disorders where increased thirst is the primary cause of polyuria.
- Secondary polyuria is a response to avoid fluid overload.
- Psychogenic polydipsia is a term sometimes used for PP in animals with potential psychological conditions affecting drinking.
- Possible causes in dogs and cats include behavioral issues or altered hypothalamic thirst center function due to other conditions.
- PP may contribute to PU in hyperthyroidism and hepatic failure; linked to GI disease in dogs.
Primary Polyuria
- Antidiuretic hormone (AVP) regulates water balance; it increases renal collecting duct permeability to water, promoting water reabsorption.
- Disruptions in AVP function or kidney response to AVP can lead to polyuria and secondary polydipsia.
- Diabetes insipidus (DI) is a condition with AVP deficiency, either central (insufficient AVP), or nephrogenic (kidney's impaired AVP response).
- Primary nephrogenic DI is a rare genetic disorder causing severe PU/PD.
- Secondary nephrogenic DI, more common in animals, is caused by various diseases or certain medications.
Disruption of Osmotic Gradient
- Osmolar agents in the kidney can disrupt water reabsorption, causing polyuria in diseases like diabetes mellitus, chronic kidney disease, and certain kidney disorders.
- Medullary washout, decreased renal medullary tonicity, can contribute to PU, due to prolonged PU/PD conditions or medication/dietary factors.
Other Mechanisms
- Increased intravascular volume can lead to PU.
- Some cases of PU are associated with specific tumors but the mechanisms involved aren't fully understood.
Multiple Mechanisms
- Multiple problems can cause PU/PD.
- Conditions like chronic kidney disease can have several combined causes for PU/PD symptoms.
Polyuria and Polydipsia in Cats
- Some diseases causing PU/PD in dogs have not been documented in cats, potentially due to different tolerance to dehydration and the difficulty in estimating fluid intake in outdoor/multiple water source accessing cats.
Diagnostic Approach
- Ensuring the presence of PU/PD is crucial before diagnostic testing.
- Careful history-taking is important to rule out other issues (i.e., behavioral problems, incontinence, frequent urination).
- Water intake measurement is needed to confirm PD, excluding non-urinary fluid losses or excessive panting.
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Description
Test your knowledge on polyuria and polydipsia definitions, environmental influences, and pathophysiology in animals. This quiz focuses on recognizing symptoms and their associations with specific diseases. Ideal for veterinary students and pet owners alike.
