A sudden bout of confusion, agitation, or hallucinations in an older adult may look like dementia — but it could actually be something else: an infection.

Urinary tract infections (UTIs), in particular, are a common culprit. In older adults, especially those with or at risk for cognitive decline, infections like UTIs can trigger abrupt changes in mental status, often referred to as “delirium.”

How UTIs Affect the Brain

Unlike younger adults, seniors don’t always show typical UTI symptoms like burning or frequent urination. Instead, they may suddenly:

• Become disoriented or forgetful
• Exhibit personality changes
• Experience visual hallucinations or paranoia
• Sleep more or become unusually drowsy
• Show increased agitation or restlessness

This is due to the body’s inflammatory response to infection, which can disrupt brain function. The risk is even higher in people already living with dementia, whose brains are more vulnerable to stressors like illness or dehydration.

Is It Dementia or Delirium?

Dementia and infection-related delirium can look similar — but there are key differences:

• Delirium is sudden, fluctuates throughout the day, and is often reversible.
• Dementia is gradual, progressive, and typically irreversible.

In many cases, an infection can unmask underlying dementia, leading to the first noticeable symptoms.

What Should You Do If You Notice Sudden Confusion?

Seek medical attention immediately. UTIs, pneumonia, and even mild infections can affect cognition in older adults. With prompt treatment — usually antibiotics and hydration — mental clarity often returns to baseline.

Family members and caregivers should also ensure:

• Regular monitoring for infections
• Proper hydration and hygiene
• A clear understanding of “baseline” behavior to spot changes early

Final Thoughts

Infections like UTIs can mimic or worsen dementia symptoms, but the good news is they’re treatable. Recognizing the signs of infection-related delirium can help avoid misdiagnosis and lead to faster recovery and better outcomes for individuals at risk.