How does delirium cause death

Evaluating the mortality time course is important in assessing the severity of the mortality risk associated with a disease.

If patients with delirium die earlier in the month follow-up than patients without delirium, the mortality risk is worse than if patients died later in the year. Hence, the goal of this study is to estimate the impact of delirium on premature mortality among older hospitalized patients in the 12 months following discharge and to estimate the fraction of a year of life lost associated with delirium. The study sample consists of patients who were enrolled in a controlled trial of a delirium prevention intervention at an academic medical center from March 25, , through March 18, The study sample represents a prospective cohort study with longitudinal follow-up, which has been described previously.

Informed consent for participation and permission to acquire subsequent follow-up data were obtained from the patients or from a proxy for those with substantial cognitive impairment, according to procedures approved by the institutional review board of Yale University School of Medicine.

Delirium was ascertained daily during hospitalization. Patients who developed delirium while hospitalized were identified, and all patients were observed for up to 1 year following discharge to determine mortality rates. Baseline data on patient demographic characteristics, comorbidities, and functional status were obtained from primary data collected during the controlled trial.

Mortality tracking was complete for all patients. All deaths and dates of death were confirmed by review of medical records, death certificates, or Medicare enrollment and claims files. Delirium was ascertained using the confusion assessment method, 24 , 25 with delirium defined by the presence of acute onset and fluctuating course, inattention, and either disorganized thinking or altered level of consciousness.

Other study variables included demographic variables patient age, sex, minority status, years of education, marital status, and whether the patient was admitted from a nursing home , mental status measures whether the patient had delirium during hospitalization, whether the patient had dementia at admission, and Mini-Mental State Examination 26 score at admission , functional status measures impairment in activities of daily living [ADLs] 27 or instrumental ADLs 28 at admission , burden of illness measures APACHE [Acute Physiology and Chronic Health Evaluation] II score, 29 Charlson Comorbidity Index score, 30 and Burden of Illness Score for Elderly Persons 31 , and characteristics of the index hospitalization whether the patient received the delirium intervention, length of stay, and total cost.

Dementia was assessed using the modified Blessed Dementia Rating Scale 32 , 33 and the Mini-Mental State Examination, and was defined according to a definition used in previous studies 34 , 35 as a modified Blessed Dementia Rating Scale score of greater than 4 or a modified Blessed Dementia Rating Scale score of greater than 2 and a Mini-Mental State Examination score of less than 20 and duration of cognitive symptoms of at least 6 months.

Study group intervention status was used as an initial control variable in all models. First, proportions or means, where appropriate, were used to describe the demographic and clinical characteristics of the study population at enrollment and the mortality rates during the index hospitalization and 1-year follow-up. Next, mortality risk and the average fraction of a year of life lost associated with the occurrence of delirium during the index hospitalization were estimated using a 2-step regression model approach.

In the first step, a logistic regression model was used to calculate the probability of study participants surviving the index hospitalization according to delirium status. Because only 14 patients died during the index hospitalization, the only independent variable included in the logistic regression model was whether the patient had delirium.

In the second step, mortality among study participants who survived hospitalization was modeled using a Cox proportional hazards regression model in which the outcome was time to death and the censoring event was survival at the end of the 1-year follow-up. Delirium status during hospitalization was the main predictor in the Cox proportional hazards regression model.

All other variables previously described were considered as potential covariates, and were entered in a backward elimination selection process if they had an unadjusted association with the time to death outcome with a statistical significance of P less than.

Intervention status was used as an initial independent variable in all models. To estimate the mean number of days survived during the year of follow-up, we used the fact that the mean is equal to the area under the survival curve. First, the probability that a patient survived hospitalization was determined using logistic regression. Next, the survival function was estimated conditional on surviving hospitalization using the Cox proportional hazards regression model. To obtain the unconditional survival probability, we used the definition of conditional probability, which implies that the vector of survival curve estimates from the Cox proportional hazards regression model be multiplied by a corresponding vector of probability estimates of surviving hospitalization obtained from the logistic regression model.

The mean number of days was then obtained from these adjusted survival curves for the delirium and nondelirium groups by a process of Riemann integration, which estimated the areas under the curve. Dividing by days yielded the average fraction of a year survived for each group. Finally, subtracting the average fraction of a year survived by the delirium group from the comparable statistic for the nondelirium group provided an estimate of the average fraction of a year of life lost associated with having delirium during the index hospitalization.

As a confirmatory analysis, we also used a binomial regression model to calculate mortality risk ratios associated with delirium. The same independent variables that remained in the model previously described were included in the model, namely, delirium status, whether the patient had any impairment in ADLs, age, sex, Charlson Comorbidity Index score, and intervention status.

All analyses were performed using SAS statistical software, version 8. The characteristics of patients in the study sample are reported in Table 1. Of the patients in the study cohort, More patients who died had delirium compared with patients who survived the study period. Patients who died during the study period were also disproportionately men and nursing home residents.

In addition, patients who died generally had a higher burden of illness as indicated by higher rates of dementia, greater impairment in ADLs and instrumental ADLs, worse scores on the severity of illness and comorbidity measures, longer lengths of stay during the index hospitalization, and higher costs associated with the index hospitalization.

Documents such as a checkbook, recent letters, or notification of unpaid bills or missed appointments can indicate a change in mental function. If delirium is accompanied by agitation and hallucinations, delusions, or paranoia, it must be distinguished from a psychosis due to a psychiatric disorder, such as manic-depressive illness Bipolar Disorder In bipolar disorder formerly called manic-depressive illness , episodes of depression alternate with episodes of mania or a less severe form of mania called hypomania.

Mania is characterized People with a psychosis due to a psychiatric disorder do not have confusion or memory loss, and the level of consciousness does not change.

Psychotic behavior that begins during old age usually indicates delirium or dementia. During the physical examination, doctors check for signs of disorders that can cause delirium, such as infections and dehydration.

A neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system. People who may have delirium are given a mental status test Mental Status When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the nervous system.

First, they are asked questions to determine whether the main problem is being unable to pay attention. For example, they are read a short list and asked to repeat it. Doctors must determine whether people take in register what is read to them. People with delirium cannot. The mental status test also includes other questions and tasks, such as testing short-term and long-term memory, naming objects, writing sentences, and copying shapes. People with delirium may be too confused, agitated, or withdrawn to respond to this test.

Samples of blood and urine are usually taken and analyzed to check for disorders that doctors think may be causing delirium. For example, abnormalities in electrolyte and blood sugar levels and liver and kidney disorders are common causes of delirium. So doctors usually do blood tests to measure electrolyte and blood sugar levels and to evaluate how well the liver and kidneys are functioning.

If doctors suspect a thyroid disorder, tests may be done to evaluate how well the thyroid gland is functioning. Or if doctors suspect that certain drugs may be the cause, they may do tests to measure drug levels in the blood. These tests can help determine whether drug levels are high enough to have harmful effects and whether a person took an overdose.

Cultures Culture of Microorganisms Infectious diseases are caused by microorganisms, such as bacteria, viruses, fungi, and parasites. Doctors suspect an infection based on the person's symptoms, physical examination results, A chest x-ray may be done to determine whether pneumonia may be the cause of delirium, especially in older people who are breathing fast, whether or not they have a fever or cough.

Sometimes a test that records the brain's electrical activity electroencephalography Electroencephalography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography EEG is a simple, painless procedure in which Electrocardiography ECG , pulse oximetry using a sensor that measures oxygen levels in the blood , and a chest x-ray may be used to evaluate how well the heart and lungs are functioning.

In people with a fever or headache, a spinal tap Spinal Tap Spinal fluid is a liquid that surrounds your brain and spinal cord.

Spinal fluid helps cushion your brain if you hit your head or fall. Spinal fluid moves freely around your brain and spinal Such analysis helps doctors rule out infection of or bleeding around the brain and spinal cord as possible causes. Most people who have delirium are hospitalized.

However, when the cause of delirium can be corrected readily for example, when the cause is low blood sugar , people are observed for a short time in the emergency department and can then return home. Once the cause is identified, it is promptly corrected or treated. For example, doctors treat infections with antibiotics, dehydration with fluids and electrolytes given intravenously, and delirium due to stopping alcohol with benzodiazepines as well as measures to help people not start drinking alcohol again.

Prompt treatment of the disorder causing delirium usually prevents permanent brain damage and may result in a complete recovery. The environment is kept as quiet and calm as possible. It should be well-lit to enable people to recognize what and who is in their room and where they are.

Placing clocks, calendars, and family photographs in the room can help with orientation. At every opportunity, staff and family members should reassure people and remind them of the time and place. Procedures should be explained before and as they are done. People who need glasses or hearing aids should have access to them. People who have delirium are prone to many problems, including dehydration Dehydration Dehydration is a deficiency of water in the body.

Although many people have no symptoms before a fall Preventing such problems requires meticulous care. Thus, people, particularly older people, may benefit from treatment managed by an interdisciplinary team Interdisciplinary care Providing medical care to older people can be complicated. People who are extremely agitated or who have hallucinations may injure themselves or their caregivers.

The following measures can help prevent such injuries:. Devices, such as intravenous lines, bladder catheters, or padded restraints, are not used if possible because they can further confuse and upset the person, increasing the risk of injury.

However, sometimes during hospitalization, padded restraints must be used—for example, to keep the person from pulling out intravenous lines and to prevent falls. Restraints are applied carefully by a staff member trained in their use, released at frequent intervals, and stopped as soon as possible because they can upset the person and worsen agitation.

Drugs are used to manage agitation only after all other measures have been ineffective. Two types of drugs are usually used to control agitation, but neither is ideal:. Antipsychotic drugs Antipsychotic drugs Schizophrenia is a mental disorder characterized by loss of contact with reality psychosis , hallucinations usually, hearing voices , firmly held false beliefs delusions , abnormal thinking However, they may prolong or worsen agitation, and some have anticholinergic effects Anticholinergic: What Does It Mean?

Newer antipsychotics, such as risperidone , olanzapine , and quetiapine have fewer side effects than older antipsychotics, such as haloperidol. But if used for a long time, the newer drugs may cause weight gain and abnormal fat lipid levels hyperlipidemia Dyslipidemia Dyslipidemia is a high level of lipids cholesterol, triglycerides, or both or a low high-density lipoprotein HDL cholesterol level.

Lifestyle, genetics, disorders such as low thyroid hormone Urination and thirst are In older people with psychosis and dementia, these drugs may increase the risk of stroke, and death. Benzodiazepines a type of sedative Drugs Used to Treat Anxiety Disorders Anxiety is a feeling of nervousness, worry, or unease that is a normal human experience. It is also present in a wide range of psychiatric disorders, including generalized anxiety disorder, Benzodiazepines are not used to treat delirium caused by other conditions because they can make people, particularly older people, more confused, drowsy, or both.

Doctors are careful when prescribing these drugs, particularly for older people. They use the lowest dose possible and stop the drug as soon as possible. Most people with delirium recover fully if the condition causing delirium is rapidly identified and treated.

Any delay decreases the chance of a full recovery. Even when delirium is treated, some symptoms may persist for many weeks or months, and improvement may occur slowly. In some people, delirium evolves into chronic brain dysfunction similar to dementia. Hospitalized people who have delirium are more likely to develop complications in the hospital including death than those who do not have delirium. Hospitalized people who have delirium, particularly older people, have a longer hospital stay, higher treatment costs, and a longer recovery time after they leave the hospital.

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Medical history Physical examination Mental status testing Testing. Depending on the cause of the delirium, treatment may include taking or stopping certain medications. In older adults, an accurate diagnosis is important for treatment, as delirium symptoms are similar to dementia, but the treatments are very different.

Your doctor will prescribe medications to treat the underlying cause of your delirium. For example, if your delirium is caused by a severe asthma attack, you might need an inhaler or breathing machine to restore your breathing. In some cases, your doctor may recommend that you stop drinking alcohol or stop taking certain medications such as codeine or other drugs that depress your system.

Counseling is also used as a treatment for people whose delirium was brought on by drug or alcohol use. In these cases, the treatment can help you abstain from using the substances that brought on the delirium. In all cases, counseling is intended to make you feel comfortable and give you a safe place to discuss your thoughts and feelings. Full recovery from delirium is possible with the right treatment.

It can take up to a few weeks for you to think, speak, and feel physically like your old self. You might have side effects from the medications used to treat this condition. Speak to your doctor about any concerns you may have. Alcohol withdrawal delirium AWD is the most serious form of alcohol withdrawal. Francis J Jr, et al. Diagnosis of delirium and confusional states. Francis J Jr. Delirium and acute confusional states: Prevention, treatment, and prognosis.

Getting started with long-distance caregiving. National Institute on Aging. Hshieh TT, et al. Effectiveness of multi-component non-pharmacologic delirium interventions: A meta-analysis. Blair GJ, et al. Nonpharmacologic and medication minimization strategies for the prevention and treatment of ICU delirium: A narrative review.

Journal of Intensive Care Medicine. In press. Overview of delirium and dementia. Accessed May 7, Caregiver Action Network.

Takahashi PY expert opinion.