Common Medical and Physiological Causes
Delirium in older adults is rarely caused by a single factor. Instead, it often results from the brain being overwhelmed by one or more stressors, which can be particularly impactful due to age-related changes. The following are some of the most frequent triggers for this acute state of confusion.
Infections
Infections are a leading cause of sudden delirium, especially in older adults where they may not present with classic symptoms like fever. Instead, a urinary tract infection (UTI) might manifest solely as acute confusion, agitation, or lethargy. This is because the body's inflammatory response to the infection can disrupt normal brain function. Other common infections that can lead to delirium include:
- Pneumonia: A lung infection that can reduce oxygen flow to the brain.
- Sepsis: A life-threatening condition caused by the body's overwhelming response to an infection.
- Skin infections: Cellulitis or other skin-related issues can also trigger a systemic inflammatory response.
Medications and Polypharmacy
Medications are another significant factor in causing delirium. Older adults are more susceptible to adverse drug reactions and drug interactions, particularly when managing multiple chronic conditions (polypharmacy). Several types of medication are especially known to cause confusion:
- Anticholinergics: Drugs that block acetylcholine, a key neurotransmitter for memory and attention. These include some medications for allergies, sleep aids, and bladder control.
- Psychoactive Drugs: Includes sedatives, anxiolytics (like benzodiazepines), and opioids for pain.
- New or Increased Dosages: Any recent change in a medication regimen can trigger a reaction.
- Withdrawal: Suddenly stopping certain medications or alcohol can induce delirium.
Dehydration and Metabolic Imbalances
As people age, their sense of thirst can diminish, making them more prone to dehydration. Inadequate fluid intake or excessive fluid loss can lead to electrolyte imbalances (e.g., abnormal sodium or calcium levels), which can critically disrupt brain signals. Similarly, metabolic issues stemming from kidney or liver failure, or uncontrolled diabetes leading to low blood sugar, can also precipitate delirium.
Surgery and Anesthesia
The stress of surgery, particularly procedures like hip fracture repair or cardiac surgery, is a major risk factor for postoperative delirium. The effects of anesthesia, combined with pain and changes in routine, can overwhelm an older adult's system. Hospitalization itself, especially an ICU stay, is also an independent risk factor.
Environmental and Psychosocial Factors
An unfamiliar or overstimulating environment can disorient and confuse older individuals. This is particularly common during hospital stays where routine is disrupted, and there is increased noise and unfamiliar faces. Other contributing factors include:
- Sensory deprivation from lack of eyeglasses or hearing aids.
- Significant sleep deprivation or severe pain.
- Extreme psychological stress, anxiety, or grief.
Delirium vs. Dementia: A Comparison
While often mistaken for one another, delirium and dementia are distinct conditions. However, dementia is a significant predisposing factor for developing delirium, a state known as Delirium Superimposed on Dementia (DSD). A key difference is the speed of onset and course of symptoms.
| Feature | Delirium | Dementia |
|---|---|---|
| Onset | Acute, often within hours or days | Gradual, over months or years |
| Course | Fluctuates, with symptoms changing throughout the day | Progressive and stable, with a slow, persistent decline |
| Attention | Severely impaired, with difficulty focusing or maintaining attention | Relatively normal in early stages |
| Consciousness | Altered, can be hyper- or hypoactive | Normal until late stages |
| Reversibility | Often reversible with treatment of underlying cause | Generally irreversible, though some causes of cognitive decline are treatable |
Recognizing the Types of Delirium
Delirium can present in two main forms, one of which is frequently missed due to its less disruptive nature.
Hypoactive Delirium
This form is characterized by reduced psychomotor activity. The person may seem unusually quiet, lethargic, or withdrawn. They might sleep more, have less appetite, and respond more slowly to questions. Because these symptoms can be mistaken for depression or general fatigue, this type of delirium is often underdiagnosed.
Hyperactive Delirium
Easier to spot, hyperactive delirium involves heightened psychomotor activity. Symptoms include agitation, restlessness, and aggression. The person may experience hallucinations or delusions, exhibit rapid mood swings, or become uncooperative.
What to Do If You Suspect Delirium
If an elderly person suddenly shows signs of confusion or behavioral changes, it should be treated as a medical emergency. The following steps should be taken:
- Seek Immediate Medical Attention: Contact a healthcare provider or call emergency services right away.
- Provide Key Information: When speaking with medical staff, provide a timeline of the sudden mental status changes, a list of current medications (including over-the-counter and supplements), and a record of any recent illnesses or environmental changes.
- Offer a Calming Presence: Familiar faces can provide comfort. Staying with the person and offering gentle reassurance can help reduce agitation and anxiety.
- Manage the Environment: Ensure the person has their eyeglasses and hearing aids to improve sensory input. Help orient them by clearly and calmly explaining where they are.
For more detailed information on managing delirium, particularly in a hospital setting, reliable resources like the Health in Aging Foundation can provide valuable insights. Visit their website for tips on managing delirium in older adults.
Conclusion
Sudden delirium in the elderly is a serious and potentially life-threatening condition that warrants immediate medical evaluation. It is most often a sign of an acute underlying problem, such as an infection, adverse medication effect, dehydration, or surgery. By understanding the common causes and recognizing the signs, caregivers and family members can facilitate a quick diagnosis and proper treatment. Unlike dementia, delirium is often reversible, and prompt intervention is key to a positive outcome and preventing further cognitive decline.
