Delirium Symptoms

Symptoms of Delirium That Should Not Be Ignored

Sudden changes in mental state should not automatically be attributed to ageing or dementia. New or rapidly worsening symptoms of delirium require medical assessment, particularly in older adults, people with severe illness or those recovering from surgery. Some of these that should not be ignored are:

Why Do Delirium Symptoms Occur?

Delirium develops when normal communication between brain cells is temporarily disrupted, affecting attention, awareness and thinking. This disruption is usually triggered by an underlying medical condition rather than being a disease itself. Infections, inflammation, dehydration, low oxygen levels, electrolyte imbalance, abnormal blood glucose levels and certain medicines can interfere with brain function. These factors may also alter the activity of neurotransmitters such as acetylcholine and dopamine, making it difficult for the brain to process information normally.

Older adults are particularly vulnerable because age-related changes in the brain reduce their ability to cope with physical stress. People with dementia or multiple health conditions may also have a higher risk of developing delirium. In many cases, delirium results from more than one trigger, such as an infection combined with dehydration or medication side effects, causing symptoms that can fluctuate throughout the day.

Symptoms of Delirium That Require Immediate Medical Attention

Delirium itself requires prompt medical evaluation because it can be a sign of an underlying acute illness. Seek urgent medical attention if a person develops:

• Sudden severe confusion or a rapid change in awareness

• Loss of consciousness or difficulty waking the person

• New weakness, facial drooping or difficulty speaking

• Seizures

• Severe difficulty breathing

• Chest pain or signs of a serious heart problem

• High fever with severe confusion or a marked deterioration in condition

• Severe agitation that creates an immediate risk of injury

• New confusion following a significant head injury

• Symptoms suggesting severe alcohol withdrawal, such as marked agitation, hallucinations or seizures

• Inability to recognise close family members

• Persistent inability to stay awake

A sudden change in mental status should not be managed through self-diagnosis. The person may need urgent medical assessment to identify and treat the underlying cause.

Symptoms of Delirium Based on Type

Delirium is classified as hyperactive, hypoactive and mixed presentations. Hypoactive delirium may be particularly difficult to recognise because the person may appear quiet or sleepy rather than visibly confused or agitated. Some symptoms of delirium based on types are:

Symptoms of Delirium-Specific Conditions

Delirium can also occur in specific clinical settings or situations. The symptoms may overlap, but the context in which they develop can differ. Some of these symptoms include:

Delirium has many possible triggers, including infections, surgery, medicines, dehydration, metabolic problems and organ failure. Alcohol withdrawal-related delirium is a specific medical emergency and should be managed urgently.

Symptoms of Delirium in Children

Delirium can occur in children, particularly during severe illness or in hospital settings, although the presentation and assessment may differ from that in adults. Children may show the following symptoms:

• Sudden changes in attention or awareness

• Confusion or disorientation

• Unusual agitation or restlessness

• Withdrawal or reduced interaction

• Changes in sleep and behaviour

• Difficulty recognising familiar people or surroundings

• Hallucinations or unusual perceptions

• Rapid changes between alertness and drowsiness

• Infants may simply become unusually irritable

A sudden change in a child's behaviour or mental state should be assessed by a healthcare professional, especially when it occurs alongside fever, infection, injury or another acute illness.

Can You Have Delirium Without Symptoms?

Delirium is generally recognised through a noticeable change from a person's usual mental state, so it is not completely symptom-free. However, symptoms can be subtle, particularly in hypoactive delirium. A person may appear simply tired, quiet, withdrawn or less responsive. This can make delirium harder to identify, especially when the person already has dementia or another condition affecting memory and thinking.

Symptoms can also fluctuate, meaning the person may appear relatively well at one point and become clearly confused or inattentive later. For this reason, information from family members, caregivers and healthcare staff about recent changes from the person's usual behaviour can be valuable.

When Can Delirium Symptoms Become Life-Threatening?

Delirium can be associated with serious underlying medical conditions, so the level of risk depends largely on what is causing the symptoms.

Delirium is considered a serious clinical syndrome because it can indicate an underlying acute problem. Prompt evaluation is important to identify potentially reversible causes.

How are Delirium Symptoms Diagnosed?

A healthcare professional will perform certain diagnostic or assessment tests to confirm the diagnosis of delirium. The recommended tests are as follows: