From the Guidelines
Elderly patients with delirium and a positive urine culture but no urinary tract symptoms should not be treated with antibiotics. This condition represents asymptomatic bacteriuria, which is common in older adults and does not typically require antibiotic treatment, as recommended by the Infectious Diseases Society of America in their 2019 clinical practice guideline update 1. Treating asymptomatic bacteriuria in the elderly does not improve outcomes and may lead to adverse effects including antibiotic resistance, Clostridioides difficile infection, and other medication side effects. The delirium is likely due to other causes that should be investigated, such as:
- Medication effects
- Metabolic disturbances
- Infection elsewhere in the body
- Environmental factors A comprehensive evaluation for the cause of delirium should include:
- Medication review
- Physical examination
- Appropriate laboratory tests If clinical deterioration occurs or if urinary symptoms develop, reassessment would be warranted. Unnecessary antibiotic use contributes to the growing problem of antibiotic resistance and can disrupt the normal microbiome, potentially causing more harm than benefit in this population, which is in line with the values and preferences outlined in the guideline, placing a high value on avoiding adverse outcomes of antimicrobial therapy 1.
From the Research
Treatment of Delirium in Elderly Patients with Positive Urine Culture
- The decision to treat an elderly patient with delirium and a positive urine culture but no urinary tract symptoms with antibiotics is complex and should be based on individual patient factors 2.
- There is limited evidence to support the use of antibiotics in this scenario, with some studies suggesting no improvement in delirium outcomes and potential worsening of outcomes with antibiotic treatment 2.
- A systematic review of 652 older adults found no significant effect of antibiotics on delirium outcomes in patients with pyuria or bacteriuria and without systemic signs of infection or genitourinary symptoms 2.
- The IOU Consensus Recommendations suggest that empirical treatment of uncomplicated cystitis in noncatheterized older nursing home residents should be based on individual patient factors, including renal function and potential drug-drug interactions 3.
- However, the use of certain antibiotics, such as trimethoprim, may be associated with adverse effects, including myoclonus and delirium, particularly in patients with impaired renal function or those taking certain medications, such as memantine 4.
Considerations for Antibiotic Treatment
- The presence of a positive urine culture does not necessarily indicate the need for antibiotic treatment, particularly in the absence of urinary tract symptoms 5, 6.
- The diagnosis of delirium can be complex, and the relationship between delirium and urinary tract infections is not fully understood 5, 6.
- Clinicians should carefully consider the potential benefits and risks of antibiotic treatment in elderly patients with delirium and a positive urine culture, taking into account individual patient factors and potential drug interactions 2, 3.