Dementia symptoms generally progress steadily. However, a person may experience a sudden worsening of dementia symptoms. This can be part of the disease progressing or a sign of a serious medical problem.

Dementia is a progressive, unpredictable group of diseases.

A sudden change in thinking or behavior can be the result of delirium, stroke, or other health conditions. In other cases, worsening symptoms may be a temporary result of stress or a change in routine.

Because people with dementia may not be able to communicate their symptoms clearly, it is important to treat their behavior as communication and as a sign that something may be wrong.

Read on to learn more about sudden worsening of dementia symptoms.

As a person’s condition progresses, they may need help reading or understanding information regarding their circumstances. This article contains details that may help caregivers identify and monitor symptom progression, side effects of drugs, or other factors relating to the person’s condition.

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Yes, dementia can suddenly get worse. Dementia and its symptoms are unpredictable. A person’s symptoms might be stable for a long time, then suddenly get worse. Alternatively, they might steadily worsen at a slow rate or a mixture of both.

Sudden worsening of symptoms can also be the result of another medical condition. It is not always possible to diagnose the cause based on symptoms alone, especially if a person with dementia has difficulty communicating.

It is important to speak with a doctor any time a person with dementia experiences sudden worsening symptoms.

In addition to dementia itself, there can be other causes of worsening symptoms.


Delirium is a state of confusion that comes on suddenly. It occurs due to an underlying physical cause. Some common causes of delirium include:

  • Infection: Infections are a common cause of delirium. People with dementia are especially vulnerable to urinary tract infections (UTIs).
  • Anesthesia and surgery: Anesthesia or the physical demands of undergoing a medical procedure may result in delirium. In some cases, delirium can persist after a person leaves the hospital.
  • Medication: Medication side effects cause around 39% of delirium cases. Medication withdrawal can also lead to delirium, so if a person has recently started or stopped a medication, this could be the reason.

People with advanced dementia may also develop delirium in response to more minor conditions, such as constipation, dehydration, or lack of sleep.

Because delirium can be difficult to distinguish from dementia, it is important to speak with a doctor about any signs of infection or sickness.

Doctors treat delirium by addressing the root cause and treating it. For example, they may prescribe antibiotics for an infection or change a person’s medication.

Stroke or brain injury

An injury to the brain, such as from a fall or a stroke, may cause symptoms that seem similar to dementia. Some signs of stroke to watch for include:

  • sudden confusion
  • difficulty speaking or understanding speech
  • inability to move one side of the face or body
  • sudden change in balance or coordination
  • sudden loss of vision
  • sudden and severe headache

If a person has these symptoms, immediately call 911 or the local emergency number.

People can also develop new or worsened dementia symptoms after a head injury.

Change in routine

People with dementia often rely on their routine as a source of comfort. A daily routine helps a person know what to expect. This means that a sudden disruption in routine may cause dementia symptoms to get worse. This is especially true if a person experiences stress.

Some changes that might trigger worsening symptoms include:

Sundowner’s syndrome

Sundowning, or sundowner’s syndrome, is the tendency for dementia symptoms to get worse as evening approaches. This change may appear sudden to caregivers. It can result in more confusion, agitation, or frustration. The person may also communicate less effectively.

Medications may help with specific symptoms, such as agitation or hallucinations. Exposure to natural light, a consistent routine, and compassionate support can also help ease symptoms.

Rapidly progressing dementia

Rapidly progressing dementia is a type of dementia that progresses much faster than is typical of more common dementias, such as Alzheimer’s disease. It typically occurs because of an underlying illness, such as prion disease, an autoimmune disease that attacks the brain, infection, or cancer.

Because doctors can treat some of these conditions, it is important for them to test for other potential causes to determine whether it is possible to treat this form of dementia.

There are many types of dementia, each with different features. As a result, there is no set of stages that applies to all of them.

Alzheimer’s disease is the most common form of dementia. It typically progresses as follows:

  • Early stage: A person may experience mild cognitive issues, such as difficulty remembering words, getting lost, or problems with short-term memory.
  • Middle stage: A person develops more significant cognitive problems that may affect their ability to perform daily self-care or live alone.
  • Late stage: The body begins to shut down. A person may not recognize others or speak. They may become incontinent and stop responding to their environment.

It is important to note that not everyone moves through these stages in the same way or at the same rate.

If someone with dementia experiences new or worsening symptoms, do not assume that this is typical or that symptoms are not treatable. Contact a doctor at the earliest opportunity.

If the person with dementia is able to speak or express themselves, ask them about their symptoms and experiences. Some strategies that can help with diagnosis include:

  • keeping a log of all new symptoms and when they occur
  • telling a doctor about any recent changes, such as a move to an assisted living facility
  • noting any bruises or other signs of injury

Learn more about caring for a person with Alzheimer’s disease.

The following are answers to frequently asked questions.

What are signs of end stage dementia?

In late stage dementia, a person’s body will begin to shut down. They may not speak, become incontinent, and stop responding to their environment. They may also have difficulty recognizing others.

What triggers dementia to get worse?

Dementia is a progressive disease, so it will gradually get worse over time. However, external factors, such as a brain injury or sudden change in routine, can trigger a sudden worsening of dementia symptoms.

Is it OK to let a person with dementia sleep all day?

In most cases, it is not beneficial to let someone with dementia sleep all day. Following a daily routine is important for maintaining function in people with dementia.

Does a person need a neurologist, primary care, or emergency room if there are symptoms of rapid decline?

Yes. It is important to contact a doctor as soon as a caregiver or loved one notices new dementia symptoms or a decline in functioning.

Dementia is a progressive disease. Sometimes, caregivers may notice a sudden worsening of dementia symptoms. This could be a natural part of the disease course, or it could indicate an underlying medical condition.

Sudden changes in awareness, thinking, mobility, or personality could be due to delirium, stroke, or simply a change in routine that has caused distress. Because some of these potential causes require immediate treatment, it is important to consult a doctor if a person’s dementia symptoms suddenly get worse.