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6 Medical Problems That Can Mimic Dementia — but Aren’t

Medications, infections and sleep issues can cause you to feel foggy or confused

woman removing a bottle of pills from the medicine cabinet

JGI/Tom Grill

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If you’re an older adult experiencing memory lapses, lack of focus or confusion — or you have a loved one with those symptoms — it’s natural to worry about dementia or Alzheimer’s disease.

But other treatable conditions can cause similar symptoms, and they can be easy for doctors to miss, says Ardeshir Hashmi, M.D., a geriatrician and section chief of Cleveland Clinic’s Center for Geriatric Medicine. 

“Sometimes there’s just a very superficial workup and then [the doctor says], ‘Here’s a pill for Alzheimer’s,’ ” Hashmi says. (While no drug has been proved to stop or slow the progression of dementia, there are several federally approved medications that can help manage the symptoms of Alzheimer’s.) “Before you make that conclusion, you should rule out all the other things that can be confused with dementia — things that are easily reversible.”  ​​


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Here are some common medical problems that can be mistaken for dementia.

1. Medication interactions or side effects

If someone complains of memory problems, Hashmi says his first question is always, “Did you recently start a new medication?”

Older adults are more likely than younger people to develop cognitive impairment as a side effect of a medication, and drug toxicity is the culprit in as many as 12 percent of patients who present with suspected dementia, research shows.

Many types of prescriptions and over-the-counter drugs can affect your cognition, but the most common include those for sleep, urinary incontinence, pain, anxiety and allergies. Taking too many medications (called polypharmacy) can also affect your ability to think clearly and remember things, Hashmi observes. Research from the Lown Institute shows that nearly half of older adults (42 percent) take five or more prescription medications.

Even a prescription you’ve been on for many years can trigger confusion. The reason why, Hashmi explains, is that your kidneys and liver become less effective at clearing drugs from your body as you get older, so a medication can build up in your system over time and cause problems.

2. A respiratory infection (including COVID-19)

Any untreated infection, Hashmi says, can cause delirium — a sudden change in alertness, attention, memory and orientation that can mimic dementia. When you have an infection, the white blood cells in your body rush to the infection site, causing a chemical change in the brain that makes some older adults feel drowsy, unfocused or confused.

Respiratory infections are harder to diagnose in people 65 and older because they are more likely to lack classic symptoms, such as a fever or a cough, Hashmi notes. In one study published in JAMA Network Open, for example, 37 percent of older COVID-19 patients who went to the emergency room with delirium had no typical COVID symptoms, like fever or shortness of breath.

Delirium tends to come on suddenly, whereas classic dementia usually progresses slowly, with subtle memory changes that gradually worsen over many years, Hashmi says. “Dementia is almost never sudden onset unless caused by a stroke. If you see a sudden change [in mental status], always think about delirium as a first cause. It is eminently treatable if you get to the trigger or underlying source of it, which is usually an infection.”

Patients have also reported difficulty concentrating, memory slips and attention deficits after they recover from a COVID-19 infection. In most patients, those symptoms subside after a few months.

3. A urinary tract infection

Urinary tract infections are another common cause of delirium and dementia-like symptoms in older adults. In surveys, about 1 in 10 women older than 65 and up to 30 percent of women over 85 reported having had a urinary tract infection in the past year. Men are also more likely to experience UTIs as they age.

Like respiratory infections, UTIs manifest differently in those older than 65 than in younger patients, says James M. Ellison, M.D., a geriatric psychiatrist and the Swank Foundation endowed chair in Memory Care and Geriatrics for ChristianaCare, a health care system in Delaware and Maryland.

In older adults, “some of the warning signals that help us make a correct diagnosis are altered or absent,” Ellison explains. “So, for example, an older adult with a UTI might experience a mental-status change without a fever or burning with urination.”

The good news is that most UTIs, and the accompanying cognitive issues, can be diagnosed with a simple urine test and then treated with an antibiotic, Ellison says.

4. Sleep problems or disturbed sleep

Getting a good night’s rest is essential for protecting the brain as you age, Ellison says. Sleep gives our brain time to learn, store memories and filter out toxic substances. If your sleep-wake cycle is disturbed or you have insomnia, you may experience dementia-like symptoms such as trouble focusing, confusion, mental fatigue and irritability.

Studies have shown that insomnia affects 30 to 48 percent of older people. If you are struggling to get shut-eye, experts recommend limiting or eliminating daytime naps, restricting the use of alcohol and caffeine in the evening, and following a consistent sleep schedule and other good sleep hygiene habits. If those remedies don’t work, cognitive behavioral therapy can help. Ellison cautions against the use of sleep medications except in the very short term and under a doctor’s guidance.

Some older adults also suffer from sleep apnea, a sleep-related breathing problem that can deprive your brain of the oxygen it needs while you slumber, possibly causing long-term damage. Many patients don’t realize they have the condition, Ellison says. Inform your doctor if you have signs of apnea, such as loud snoring, waking up gasping or choking, uncontrolled high blood pressure, a morning headache or a dry mouth upon waking.

If you are diagnosed with sleep apnea, using a continuous positive airway pressure machine (CPAP) while you snooze has been shown to be an effective treatment, Ellison says.

5. Dehydration

Dehydration can also look like dementia, and it’s common in older patients, Hashmi says. As you age, your body’s ability to retain water in blood vessels decreases, and your thirst mechanism isn’t as strong, so it’s easy to get dehydrated without realizing it. If you take diuretics or laxatives, they can further contribute to water loss.

If someone you love seems foggy or confused, check to see if their urine is dark yellow or brown, which can indicate a lack of fluids. Another sign of severe dehydration is a white coating on the tongue, Hashmi says. Intravenous fluids can often reverse cognitive problems caused by severe dehydration. “It’s amazing what a liter of IV fluid can do,” Hashmi adds. 

To prevent dehydration, older adults should aim to get at least 48 ounces of caffeine-free fluids (six 8-ounce glasses) a day.

6. Normal pressure hydrocephalus

Normal pressure hydrocephalus is a treatable disorder in which cerebrospinal fluid accumulates in the brain, disrupting and damaging nearby brain tissue and causing cognitive problems.

A neurologist can diagnose normal pressure hydrocephalus using brain imaging and cerebrospinal fluid tests. It’s commonly treated by inserting a flexible tube, called a shunt, into the brain to drain the fluid.

“We see a couple of cases every year,” Ellison says. “When we diagnose it, we’re always happy because it’s a condition you can treat. ... I’ve seen people improve dramatically.” 

Other disorders with dementia-like symptoms

Many other conditions, in addition to the ones above, can cause symptoms that mimic dementia or Alzheimer’s disease, including disorders of the heart, lungs, liver or kidneys, thyroid problems, sodium or vitamin B12 deficiency, some cancers, pain, constipation, heavy alcohol use and depression.

Many of those conditions are treatable, and cognitive symptoms can be reversed, as long as they are properly diagnosed, Ellison and Hashmi say. A routine metabolic blood test and a urinalysis, along with neuroimaging, will pick up many of those disorders.

If tests come back normal, experts suggest asking for a referral to a geriatrician who specializes in older adults, who will do a comprehensive assessment before accepting a diagnosis of Alzheimer’s disease or dementia.

“It’s very important for clinicians and patients to recognize that dementia is not a normal expected part of aging,” Ellison says. About 11 percent of adults 65 and older have Alzheimer’s disease, the most common form of dementia, according to the Alzheimer’s Association. “Everyone deserves a good workup to identify treatable and reversible conditions,” Ellison adds.

Michelle Crouch is a contributing writer who has covered health and personal finance for some of the nation's top consumer publications. Her work has appeared in Reader's Digest, Real Simple, Prevention, The Washington Post and The New York Times.​​