Psychiatry · Neurocognitive Disorders
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Delirium is characterized by an acute onset and fluctuating course of disturbed attention and altered level of consciousness.
The Confusion Assessment Method (CAM) is the gold standard diagnostic tool requiring the presence of acute onset, inattention, and either disorganized thinking or altered consciousness.
Metabolic disturbances, including hypoxia, hypoglycemia, and electrolyte imbalances, are the most common reversible causes of delirium in hospitalized patients.
Anticholinergic medications, benzodiazepines, and opioids are high-risk pharmacologic triggers that should be discontinued in patients with acute delirium.
Non-pharmacologic interventions, such as early mobilization, reorientation, and sleep-wake cycle normalization, are the first-line management strategies.
Antipsychotics like haloperidol or quetiapine are reserved strictly for patients with severe agitation that poses an immediate safety risk to themselves or staff.
Delirium is a medical emergency associated with increased mortality, functional decline, and prolonged hospital length of stay.
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An 82-year-old male is brought to the emergency department by his daughter due to sudden onset confusion. The patient was baseline functional yesterday but became disoriented to time and place and inattentive during a family dinner this evening. His medical history is significant for hypertension and benign prostatic hyperplasia, for which he recently started diphenhydramine for sleep. On examination, he is agitated, has fluctuating levels of arousal, and exhibits disorganized thinking. Vital signs are stable, and a fingerstick glucose is 110 mg/dL.
What is the most appropriate next step in the management of this patient?
Discontinue the offending medication (diphenhydramine) and implement non-pharmacologic reorientation strategies.
The patient presents with the classic triad of acute onset, inattention, and fluctuating consciousness, diagnostic of delirium; the most high-yield management step is identifying and removing the offending anticholinergic agent.
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Etiology / Epidemiology
Acute onset in elderly hospitalized patients; triggered by infection, metabolic derangement, or polypharmacy.
Clinical Manifestations
Fluctuating waxing and waning consciousness with sun-downing and impaired attention.
Diagnosis
Confusion Assessment Method (CAM) is the gold standard; requires acute onset, inattention, and disorganized thinking.
Treatment
Identify and treat underlying cause; Haloperidol for severe agitation; avoid benzodiazepines except in alcohol withdrawal.
Prognosis
Associated with increased mortality and long-term cognitive decline.
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Epidemiology & Etiology
Common in ICU patients and post-operative elderly. Primary triggers include I WATCH DEATH mnemonic: Infection, Withdrawal, Acute metabolic, Trauma, CNS pathology, Hypoxia, Deficiencies, Endocrine, Acute vascular, Toxins, Heavy metals.
Pertinent Anatomy
Involves the reticular activating system and non-dominant hemisphere, leading to global cortical dysfunction. Disruption of cholinergic pathways is central to the clinical presentation.
Pathophysiology
Characterized by a neurotransmitter imbalance, specifically acetylcholine deficiency and dopamine excess. Systemic inflammation and cytokine release disrupt the blood-brain barrier, causing global neuronal metabolic stress.
Clinical Manifestations
Patients exhibit fluctuating levels of consciousness and sun-downing (worsening at night). Inattention is the hallmark; patients cannot sustain focus on tasks. Red flags include hallucinations, paranoia, and aggressive behavior requiring immediate safety intervention.
Diagnosis
The Confusion Assessment Method (CAM) is the clinical gold standard. Diagnosis requires: 1) Acute onset/fluctuating course, 2) Inattention, AND either 3) Disorganized thinking or 4) Altered level of consciousness. Mini-Mental State Exam (MMSE) is useful for baseline cognitive assessment.
Treatment
Prioritize non-pharmacologic interventions (reorientation, sleep hygiene, early mobilization). Use Haloperidol for severe agitation or patient safety. Avoid benzodiazepines as they worsen delirium, except in cases of alcohol or sedative withdrawal.
Prognosis
Delirium is a strong predictor of increased mortality and prolonged hospital stays. Survivors face a high risk of long-term cognitive impairment and functional decline post-discharge.
Differential Diagnosis
Dementia: chronic, progressive, stable attention
Depression: pseudodementia, intact attention
Psychosis: clear sensorium, organized thought
Wernicke Encephalopathy: ataxia, ophthalmoplegia, confusion
Non-convulsive Status Epilepticus: requires EEG for diagnosis