Problem-oriented approach to Polyuria:Polydipsia

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Problem-oriented approach to PolyuriaPolydipsia

• Jill McClure, DVM, MS
• Diplomate ACVIM, ABVP

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Polyuriaincreased volume of urinePolydipsiain
creased intake of water

• normal water intake 1-2 ml/kg/hr
• normal urine production 1-2 ml/kg/hr

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PolyuriaPolydipsia

• either PU or PD can be primary with the other a
  secondary response
• PD without PU may accompany some conditions
• Foals normally have dilute, hyposthenuric urine

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Mechanisms of Diuresis

• water diuresis
• excessive H2O intake
• ADH deficiency
• ADH unresponsive
• ADH inhibition
• medullary washout

• solute diuresis
• non-absorbable solute
• excessive absorbable solute
• defective proximal tubule
• medullary washout
• aldosterone deficiency

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Minimum data base for PUPD

• History
• appetite
• previous disease
• previous drug therapy
• hair coat changes
• attitude and neurologic status

• Physical Exam
• document problem
• hydration status
• mucous membranes
• external genitalia
• rectal exam
• edema
• musculo-skeletal problems

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Minimum database for PUPD

• Laboratory
• CBC
• BUN, creatinine
• Albumin, protein
• blood glucose
• Electrolytes (Na,Cl,K,HCO3)
• Minerals (Ca,P)
• UA with fractional excretions

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Expanded database for PUPD

• water deprivation test
• ultrasound
• ---------------------------
• glucose tolerance
• sodium sulfanilite clearance
• insulin challenge
• assays for toxins
• renal biopsy

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PolyuriaPolydipsia
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PolyuriaPolydipsia
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PolyuriaPolydipsia
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PolyuriaPolydipsia
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PolyuriaPolydipsia

• Idiopathic
• psychogenic H2O drinker
• psychogenic salt eater
• CRF due to glomerulonephritis

• Metabolic
• hypercalcemia 2o to renal disease

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PolyuriaPolydipsia

• Iatrogenic
• IV fluid overload
• diuretics

• Neoplastic
• pituitary adenoma

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PolyuriaPolydipsia

• Toxic
• aminoglycosides
• NSAIDS
• cantharidin
• pigmenturia

• Vascular
• hypovolemia

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PolyuriaPolydipsia

• Inflammatory/infectious
• pyelonephritis
• Corynebacterium renale
• Streptococcus
• immune complex glomerulonephritis