Internal Medicine/Confusion and Delirium

Introduction

Delirium is a complex and multifaceted clinical syndrome characterized by acute and fluctuating changes in mental status. It is a common condition, particularly prevalent among elderly individuals, and is associated with significant morbidity, mortality, and healthcare costs. Diagnosing delirium relies on recognizing a constellation of clinical features, including an acute onset, inattention, disorganized thinking, and alterations in the level of consciousness.

Clinical Features of Delirium

Feature 1: Acute Onset One of the hallmark features of delirium is its abrupt onset. Patients with delirium often experience a rapid change in their mental status, with symptoms that can fluctuate in severity throughout the day. This sudden shift from baseline mental function is a key diagnostic criterion.

Feature 2: Inattention Inattention is a core component of delirium and is characterized by the patient's difficulty in focusing attention. They may become easily distractible or have trouble maintaining concentration. This feature is typically assessed through questions that evaluate the patient's ability to stay engaged in a conversation or follow instructions.

Feature 3: Disorganized Thinking Delirious individuals often exhibit disorganized or incoherent thinking patterns. This may manifest as rambling speech, irrelevant conversation, an unclear and illogical flow of ideas, or unpredictable shifts from one subject to another. Observing these cognitive disturbances can help clinicians recognize delirium.

Feature 4: Altered Level of Consciousness Another key feature of delirium is an altered level of consciousness. Patients may exhibit a range of states, from heightened alertness (vigilance) to drowsiness (lethargy), difficulty in arousal (stupor), or even complete unresponsiveness (coma). Any response other than "alert" signifies this feature.

Gathering Information

• In the evaluation of delirium, gathering information from reliable sources is crucial. Family members, caregivers, and nurses often provide valuable insights into the patient's baseline cognitive function and the onset of delirious symptoms.
• It's important to note that some patients, particularly those with pre-existing conditions such as dementia or longstanding depression, may be initially mistaken as delirious during their initial evaluation.
• Baseline cognitive impairment is not uncommon in patients with delirium. Even if there's no known history of cognitive issues, clinicians should maintain a high suspicion for underlying neurologic disorders contributing to delirium.
• Establishing the time course of cognitive change is not only essential for diagnosing delirium but also for identifying potential treatable causes, such as recent medication changes or signs of systemic infection.

Etiology of Delirium

Delirium is a syndrome with a broad range of potential causes. Understanding the underlying etiologies is critical for effective management. Here are some common contributors:

• Medications: One frequent culprit is medications, particularly those with anticholinergic or sedative properties. Nearly one-third of all delirium cases, especially in the elderly, are estimated to be secondary to medications. It's essential to review all prescription, over-the-counter, and herbal substances, including recent dosing or formulation changes.
• Systemic Infections: Infections, such as urinary tract infections or pneumonia, often contribute to delirium, especially in older adults. Acute cognitive decline in the context of a known infection can be a hallmark of delirium.
• Metabolic Abnormalities: Disturbances in electrolytes (sodium, calcium, magnesium), glucose, liver function, renal function, and vitamin levels (B12, thiamine) can lead to delirium. Even mild abnormalities can result in significant cognitive disturbances in susceptible individuals.
• Systemic Organ Failure: Organ failures, such as liver and renal failure, can manifest as delirium. Identifying these underlying conditions is crucial for appropriate management.
• Substance Abuse: In younger patients, delirium can be triggered by substance abuse, including illicit drugs and alcohol. Withdrawal from alcohol is a common cause of hyperactive delirium.

Laboratory and Diagnostic Evaluation

The diagnostic approach for delirium involves a stepwise process, guided by the patient's history and physical examination. Here are key considerations:

• Basic Screening Labs: Initial evaluations should include a complete blood count, electrolyte panel (including calcium and magnesium), liver function tests, and renal function tests. These tests help identify common metabolic and systemic causes of delirium.
• Systemic Infection Screening: For older patients, screening for systemic infections is essential. This includes urinalysis and culture, chest radiography, and blood cultures. Identifying an underlying infection is crucial for targeted treatment.
• Imaging: Brain imaging, such as magnetic resonance imaging (MRI) or computed tomography (CT), may be required when the initial evaluation is inconclusive. MRI is preferred due to its ability to detect acute ischemic strokes and provide neuroanatomic details.
• Lumbar Puncture: If central nervous system (CNS) infection is suspected, lumbar puncture should be performed after brain imaging. Spinal fluid examination can also help diagnose autoimmune, inflammatory, or neoplastic conditions.
• Electroencephalogram (EEG): EEG remains invaluable when seizures are suspected or when no clear cause is identified during initial workup.

Treatment of Delirium

The management of delirium is multifaceted and begins with addressing the underlying cause. Here's how delirium is typically managed:

• Treatment of Underlying Causes: Identifying and treating the root cause of delirium is paramount. For example, patients with systemic infections should receive appropriate antibiotics, and electrolyte imbalances should be corrected judiciously.
• Supportive Care: Supportive care measures are often highly effective. These include reorienting the patient through communication with nursing staff and family. Providing visual aids like clocks, calendars, and windows can reduce confusion.
• Sensory Aids: Ensuring that patients have access to sensory aids like glasses and hearing aids is crucial to prevent sensory isolation and promote engagement with the environment.
• Managing Sleep-Wake Cycles: Disturbances in sleep-wake cycles can contribute to delirium. During the day, well-lit environments and activities can help prevent daytime napping. At night, a quiet, dark setting with limited interruptions promotes proper rest. Melatonin may be considered to facilitate sleep.
• Mimicking the Home Environment: Allowing patients to have familiar items from home, such as bedding and clothing, can make the hospital environment less disorienting.
• Pain and Discomfort: Standard nursing practices should address pain, incontinence, and skin breakdown, as these can contribute to discomfort and confusion.
• Safety Measures: In some cases, patients may pose a safety threat to themselves or staff. Bed alarms and personal sitters are preferable to physical restraints. Chemical restraints (antipsychotic medications) should be used sparingly and only when patients display severe agitation and a potential for harm.
• Benzodiazepines: While benzodiazepines are often used to manage acute confusion, they should be limited to cases where delirium results from alcohol or benzodiazepine withdrawal.

Prevention of Delirium

Preventing delirium is of paramount importance due to its associated morbidity and healthcare costs. Strategies for prevention include:

• Identifying High-Risk Patients: Hospitals increasingly use screening tools to identify individuals at high risk for delirium. These tools help trigger standardized protocols for managing risk factors.
• Standardized Protocols: Once high-risk individuals are identified, hospitals implement protocols to manage factors that contribute to delirium risk. These may include addressing sleep-wake cycle disruptions, preventing immobility, managing visual and hearing impairments, addressing sleep deprivation, and ensuring adequate hydration.
• Medications for Prevention: While no specific medications have definitively proven effective for delirium prevention, melatonin and its agonist, ramelteon, have shown promise in small preliminary trials.
• ICU-Specific Strategies: In intensive care units (ICUs), efforts focus on identifying sedatives that are less likely to induce delirium in critically ill patients. Protocols for daily awakening, where sedative infusions are interrupted and patients are reoriented, are also under consideration.

Conclusion

Delirium is a complex and challenging clinical syndrome that demands prompt recognition and appropriate management. It poses significant risks to patients, particularly the elderly, and is associated with increased healthcare costs. Preventing delirium and promptly addressing it when it occurs are crucial steps toward improving patient outcomes and reducing the burden of this condition on healthcare systems.