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Fanconi Syndrome 323

Before onset of azotemia, hyposthenuria is TREATMENT Possible Complications
frequently documented. Treatment Overview • Neurologic signs (seizures, ataxia, dementia,
VetBooks.ir DIAGNOSIS A treatment protocol known as the Gonto • Manipulation of electrolyte and acid-base Diseases and Disorders
or central blindness) of unknown cause occur
in ≈20% of dogs.
protocol is used by many owners of affected
Diagnostic Overview
cies if the disease is dynamic.
to replace substances excreted in excess in
Presence of glucosuria +/− ketonuria in the basenji dogs. The protocol, which is used balance can lead to overcorrection of deficien-
absence of hyperglycemia is a hallmark of the urine, has not been compared to other
Fanconi syndrome, but other tubular defects (potentially simpler) protocols to determine Recommended Monitoring
(proteinuria and aminoaciduria, increased whether it improves survival or quality of • Recheck serum biochemistry profile 8-10
fractional excretion of electrolytes) can also life. At a minimum, electrolyte and acid-base weeks (and venous blood gas no more than
occur. deficiencies should be corrected, and supportive 1 week) after starting therapy.
care for uremia (if present) should be provided. • CBC and serum biochemistry profile q 4-6
Differential Diagnosis months in stable patients and a venous blood
• Diabetes mellitus Acute General Treatment gas analysis should be performed as indicated
• Primary renal glucosuria (e.g., glucosuria • If patient is experiencing a uremic crisis (typically 1 week after adjustments and every
without aminoaciduria) (e.g., dehydrated, anorexic, vomiting), 2-3 months) for titration of electrolyte, alkali,
• Nephrogenic or central DI hospitalization is appropriate for manage- and nutritional supplementation.
• Renal tubular acidosis (distal or mixed) ment, including intravenous fluid therapy • Culture urine if indicated.
• AKI or CKD (all causes should be considered) (p. 169).
• Electrolyte supplementation as needed PROGNOSIS & OUTCOME
Initial Database • Address acid-base disorders as appropriate.
• Urinalysis • Discontinue potentially nephrotoxic drugs • For basenji dogs, life span is not substantially
○ Hyposthenuria, isosthenuria, or minimally (e.g., aminoglycosides) and eliminate exposure reduced from normal (median survival time,
concentrated urine (dogs < 1.030; cats < to ingested nephrotoxins (e.g., jerky treats). 5.25 years from diagnosis). End-stage CKD
1.035) • For severe gastrointestinal signs associated is the most common cause of death (40%).
○ Glucosuria is common. with jerky treat ingestion, hospitalization for • In other breeds, prognosis depends on
○ Proteinuria is common but mild. intravenous fluid therapy and appropriate ability to address underlying cause. Fanconi
○ Ketonuria is common. care for acute gastroenteropathy should be syndrome may be transient, depending on
○ Secondary UTI is common (p. 232). prioritized. the underlying cause.
• CBC: anemia occurs late in disease course
(with kidney failure). Chronic Treatment PEARLS & CONSIDERATIONS
• Serum biochemistry profile Use the Gonto protocol (https://basenjirescue
○ Normoglycemia is typical (despite .org/Fanconi/Fanconi-Protocol-2015.pdf): Comments
glucosuria). • Acidemia: oral sodium bicarbonate is Consumption of chicken jerky treats (especially
○ Hypophosphatemia (may be offset to titrated to keep venous pH within refer- those manufactured in China) has been linked to
normophosphatemia if renal failure) ence range. Starting dose 1-10 mEq/kg/day illness, notably Fanconi syndrome, in thousands
○ Hypokalemia is common. PO in divided doses q 8-12h, increased based of dogs over the past several years. A specific
○ Hyperchloremic metabolic acidosis on venous blood gas analyses performed q cause (e.g., pathogen, chemical) responsible
Venous blood gas preferred to measure- 3-5 days. Doses may exceed 11 mEq/kg/day. for the illness has not been identified. Owners
■
+
ment of PCO 2 for confirmation of • Hypokalemia: 5-15 mEq K /DOG PO total should be cautioned against feeding these treats.
metabolic acidosis. daily dose. Potassium gluconate, potassium
○ Azotemia (late finding) citrate Prevention
• Treat underlying disease associated with This is an inherited disease in basenji dogs. Dogs
Advanced or Confirmatory Testing acquired Fanconi syndrome as appropri- with this disease should not be bred, although
• In a basenji with glucosuria and normogly- ate (e.g., chelation for copper storage late onset of disease (3-8 years) complicates
cemia, no further confirmation is necessary. hepatopathy). reproductive planning.
• For other breeds
○ Urinary amino acids Nutrition/Diet Technician Tips
Cyanide nitroprusside–based array for See Gonto protocol: A careful diet history may reveal consumption
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cystinuria • Vitamin and mineral replacement: daily of jerky treats. Many clients are unaware of
Urine organic/amino acid excretion canine multivitamin (e.g., Pet-Tab Plus), the association with kidney disease and may
■
(http://research.vet.upenn.edu/ Pet-Cal (calcium, phosphorus, vitamin D have trouble determining the source of the
penngen) supplement), and weekly human multivi- ingredients used in treats.
○ Fractional excretion of electrolytes: (U x/ tamin with trace minerals (i.e., Centrum)
S x ) × (S cr /U cr ) × 100, where U x is urine have been advocated for dogs with polyuria SUGGESTED READING
concentration of electrolyte, S x is serum and polydipsia. Do not give Pet-Cal if Kerl ME: Renal tubular diseases. In Ettinger SJ, et al,
concentration of electrolyte, S cr is serum dog is azotemic because it will exacerbate editors: Textbook of veterinary internal medicine,
creatinine, and U cr is urine creatinine hyperphosphatemia, hypercalcemia, and ed 8, St. Louis, 2017, Elsevier, 1972-1977.
Elevated fractional excretion values are soft-tissue mineralization.
■ AUTHORS: Catherine E. Langston, DVM, DACVIM;
expected. • Some owners provide amino acid replace- Adam Eatroff, DVM, DACVIM
○ Heavy metal testing, if indicated ment: starting at 1 Amino Fuel tablet EDITOR: Leah A. Cohn, DVM, PhD, DACVIM
○ Leptospira spp serologic testing, if indicated (1000 mg) per week.

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