Background: Elderly patients with urinary tract infection have been well known to often present with nonspecific deterioration with confusion, but without urinary tract specific symptoms. In case of completely unremarkable results of the laboratory tests, the diagnosis can be a real challenge.
Case Report: An 84-year old healthy woman presented with sudden onset of chest discomfort to a local hospital. Due to the development of speech disturbance and disorientation after the admission, she was referred to a tertiary care hospital for further evaluation. Laboratory tests including urinalysis, electrocardiogram, chest radiograph, computed tomography of the brain and lumbar puncture were normal. Alternating symptoms, such as chest discomfort and generalized weakness and cognitive impairment persisted. Six hours after admission, she developed fever and the third urinalysis taken 12 hours after the admission revealed a clear finding of urinary tract infection. Antimicrobial treatment led to resolution of symptoms within 24 hours.
Conclusions: Our case demonstrates the diversity of symptoms preceding laboratory changes in elderly patients with urinary tract infection and the dynamic changes in urinalysis in the very early stage. Repetitive urinalysis can be the key diagnostic tool leading to a successful treatment in elderly patients with atypical presentation.

Keywords: atypical illness presentation, elderly patients, urinary tract infection, Urinalysis