Glucosuria without diabetes: key to the diagnosis of fragility fractures due to Fanconi syndrome

• Published in: BMJ case reports Vol. 2018; p. bcr-2017-223350
• Main Authors: Alacapa, Lilluck F, Sandoval, Mark Anthony Santiago, Dimacali, Coralie Therese D, Orillaza, Nathaniel Jr S
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 07.05.2018; BMJ Publishing Group
• Series: Case Report
• Subjects: Absorptiometry, Photon - methods; Acidosis; Bone diseases; Case reports; Diabetes; Diagnosis, Differential; Family medical history; Fanconi Syndrome - complications; Fanconi Syndrome - drug therapy; Fanconi Syndrome - pathology; Fanconi Syndrome - urine; Female; Fractures; Fractures, Bone - diagnostic imaging; Fractures, Bone - drug therapy; Fractures, Bone - etiology; Fractures, Bone - surgery; Glucose; Glycosuria - etiology; Humans; Hypokalemia - etiology; Hypokalemia - metabolism; Hypophosphatemia - etiology; Hypophosphatemia - metabolism; Kidney Tubules, Proximal - abnormalities; Kidney Tubules, Proximal - metabolism; Kidney Tubules, Proximal - pathology; Medical diagnosis; Metabolism; Middle Aged; Phosphorus - administration & dosage; Phosphorus - therapeutic use; Reminder of Important Clinical Lesson; Treatment Outcome; Urinalysis; Urine; Vitamin D; Vitamin deficiency; renal medicine; calcium and bone; orthopaedics; fluid electrolyte and acid-base disturbances
• ISSN: 1757-790X; 1757-790X
• DOI: 10.1136/bcr-2017-223350

A 64-year-old woman had fragility fractures which caused her to have gross deformities and confined her to bed. These were initially ascribed to vitamin D deficiency. However, despite correction of the deficiency, she did not improve. A review of previous records already showed glucosuria in the absence of diabetes, but this finding was overlooked. Eight years into the disease, it was realised that the glucosuria despite normal blood sugar could also mean that the patient was losing other substances needed for proper bone formation. Further investigations showed hypophosphataemia, renal phosphate wasting, hypokalaemia, mild metabolic acidosis, alkaline urine pH, hypouricaemia and aminoaciduria, all compatible with a proximal renal tubular defect (Fanconi syndrome). The fragility fractures were due to poor bone mineralisation because of hypophosphataemia induced by the inability of the kidneys to conserve phosphorus.