Acquired Fanconi-Like Proximal Renal Tubulopathy Associated with Klebsiella Pneumoniae Infection

Acquired Fanconi syndrome is a rare proximal renal tubular disorder associated with glucosuria, aminoaciduria, phosphaturia, electrolyte disturbance and metabolic acidosis, usually caused by drugs, toxins, or plasma cell disorders. Although infectious causes are rare, this is a case report of a 68-year-old man with altered sensorium due to metabolic encephalopathy secondary to dyselectrolytemia. Evaluation revealed severe hyponatremia, hypokalemia, hypocalcaemia, hypophosphatemia and hypomagnesemia. Urine examination showed proteinuria, normoglycemic glycosuria, inappropriate urinary electrolyte losses and impaired urine concentrating ability. Arterial blood gas analysis showed a normal anion gap metabolic acidosis with a positive urine anion gap suggesting a renal cause for the acidosis. This clinical and laboratory picture is consistent with Fanconi-like proximal tubulopathy. Radiological imaging showed cavitary lung consolidation and bilateral pyelonephritis. Sputum cultures grew Klebsiella pneumoniae. After excluding the usual causes of acquired Fanconi syndrome, the proximal tubular dysfunction was attributed to systemic infection. Following treatment with appropriate antibiotics for the infection and electrolyte replacement, the patient completely recovered clinically and biochemically. This case documents a systemic K. pneumoniae infection presenting with reversible Fanconi-like proximal tubulopathy highlighting the importance of exploring infectious causes in patients with unexplained proximal renal tubular dysfunction.

This case describes the first documented case of acquired Fanconi-like proximal tubulopathy secondary to a systemic Klebsiella pneumoniae infection and demonstrates complete reversibility of proximal tubular dysfunction, as evidenced by resolution of dyselectrolytemia after appropriate antibiotic treatment.It extends the spectrum of infectious causes of Fanconi syndrome to include Klebsiella, in addition to previously known causes such as Legionella, Streptococcus pneumoniae, and Leptospira.The electrolyte abnormalities were initially attributed to syndrome of inappropriate antidiuretic hormone secretion secondary to pneumonia before the proximal tubular dysfunction was identified leading to a diagnosis of acquired Fanconi like syndrome.