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Glucosuria in Dogs

Glucosuria (or glycosuria) is the excretion of glucose into the urine. Normally, the kidneys are able to reclaim all of the filtered glucose from the urine into the bloodstream. Glucosuria therefore is nearly always due to kidney disorders, such as diabetes mellitus.

Symptoms and Types

Glucosuria is categorized as hyperglycemic (170–220 mg/dL) or normoglycemic, and subcategorized as transient or persistent. Symptoms will depend on the underlying disease, but some possible signs include:

• Diluted urine
• Increased thirst and drinking (polydipsia and polyuria, respectively)
• Renal failure (especially when associated with Fanconi's syndrome)
• Urinary tract disease
• Possible systemic disease (in hyperglycemic glucosuria)                   

Causes

Hyperglycemic glucosuria

• Transient
  • Stress-related hyperglycemia
  • Adverse drug reaction (e.g., epinephrine, morphine, and phenothiazines)
• Persistent
  • Systemic disease
  • Diabetes mellitus
  • Overactive adrenal gland (hyperadrenocorticism)
  • Sudden inflammation of the pancreas (acute pancreatitis)
  • Lesions in the central nervous system (brain, spine, etc.)
  • Adrenal gland tumor (pheochromocytoma)
  • Progesterone-associated hyperglycemia
  • Bacterial infection in the blood (sepsis)
  • Glucagonoma (tumor in the pancreas which secretes glucagon, a hormone which increases blood sugar)
  • Chronic liver failure
  • Etiologic agents such as heavy metal poisons, drugs, and chemicals

Normoglycemic glucosuria

• Congenital normoglycemic glucosuria
  • Primary renal glucosuria (Scottish terriers and mixed-breed dogs)
  • Congenital Fanconi’s syndrome (basenji, Norwegian elkhound, miniature Schnauzer)
  • Congenital diseases associated with kidney dysfunction (Norwegian elkhound)
• Acquired normoglycemic Glucosuria
  • Acute kidney failure
  • Fanconi’s syndrome secondary to heavy metal poisoning, drugs, and chemicals

Diagnosis

You will need to give a thorough history of your dog’s health to your veterinarian, including the onset and nature of the symptoms. He or she will then perform a complete physical examination as well as a complete blood count, biochemistry profile, electrolyte panel, and urinalysis to detect any underlying systemic diseases causing the glucosuria -- though often there is too little glucose present in the dog's urine to be detected. Hexokinase- or glucose dehydrogenase-based techniques are recommended for quantification of urinary glucose.