The case of a 61 yo diabetic woman presenting with dysuria and lower abdominal pain is described. The incomplete resolution of the clinical picture after short antibiotic treatment and a strong suspect of autonomic neuropathy oriented to an anamnestic reevaluation that evidenced the presence of pneumaturia. The last was the key-symptom that guided to diagnostic imaging showing emphysematous cystitis while a gastroscopy confirmed the presence of autonomic neuropathy manifested by gastroparesis. Emphisematous cystitis is a characteristic infectious complication of diabetic patients induced by a persistent incomplete bladder emptying and bacterial glucose fermentation. The complete eradication of the infectious agent requires a long term antibiotic course and a prompt identification of this pathology.