Fanconi Syndrome in a Maltese. Quantitative Approach to the Acid Base Analysis

Introduction
Fanconi syndrome (fS) is a rare disorder which is associated with a resorption defect of the proximal renal tubule, resulting in an excessive loss of bicarbonate, glucose, sodium, potassium, phosphate, calcium, water and amino acids1.

Clinical case
A 3-year-old female Maltese dog was presented for a 1 month history of inappetence, polyuria and polydipsia, and weight loss. Diagnostic tests showed euglycaemic glucosu- ria, hypophosphatemia, hyponatremia, hypokalemia, hyperchloremic metabolic acido- sis, proteinuria, aminoaciduria and increased urinary excretion of electrolytes, consist- ent with fanconi syndrome1. Quantitative approach to acid-base analysis2 on initial presentation showed that metabolic acidosis was mostly due to hyponatremia (increased free water effect) and bicarbonate deficit (increased chloride effect). Sodium bicarbonate and potassium gluconate were established as treatment. follow-up quanti- tative acid-base analyses were performed 1, 2 and 5 months after treatment initiation showing progressive improvement in metabolic acidosis. Seven months after initial presentation, the dog was examined for anorexia, vomiting, and severe dehydration. Quantitative approach to the acid-base analysis showed severe metabolic acidosis mostly due to hypoperfusion (increased lactate effect), unmeasured anions, and hyponatremia (increased free water effect). intravenous sodium chloride and sodium bicarbonate were given to correct dehydration, hyponatremia and metabolic acidosis. it was discharged 48 hours after presentation. the dog died 8 months after initial exami- nation. the necropsy showed diffuse renal tubular necrosis.

Discussion and conclusion
Conventional acid-base analysis characterizes the magnitude of metabolic abnormali- ties, but the relative contribution of individual metabolic processes is not further char- acterized 2. this is the first report of quantitative approach to the metabolic acidosis in fS. this approach could be a good tool to understand the individual factors that affect the acid-base balance in fS, to development of an appropriate therapeutic plan for each patient, and to monitoring treatment response.