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In this chapter, we focus on the main symptoms and causes of delirium, and how to do the workup and management. Delirium is extremely common in the general inpatient setting and a frequent reason for neurology consultation. We also discuss dementia and its features as well as some of the most important types of dementia, their etiology, workup, and management. It will be important to be able to differentiate delirium versus dementia on the wards and on the exam.
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Delirium has key symptoms that include inattention and a nonfocal exam, fluctuating activity level, altered consciousness. It is considered a medical emergency and can usually be resolved with control of primary etiology. It is often caused by
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Hypoxemia or metabolic derangements that lead to poor cerebral metabolism
Poor/delayed neurotransmitter balance and homeostasis
Drug effects on the central nervous system (CNS)
Inflammation that could increase cytokines in the brain
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WARDS TIP
A nonfocal exam refers to a neurological examination that does not reveal a specific locality to cognitive, motor, or sensory findings (eg, an infarct to the thalamus causing both sensory findings and some change in behavior). Descriptions like drowsiness or lethargy and altered consciousness are consistent with delirium.
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General approach is to identify reversible causes such as infection and metabolic derangement, or iatrogenic causes such as polypharmacy, and rule out CNS etiologies.
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Stroke, seizure, meningitis, autoimmune encephalitis, traumatic brain injury, hypertensive encephalopathy, intracranial hypertension
Infection, metabolic derangement:
Sepsis, hypoglycemia, adrenal insufficiency, diabetic ketoacidosis (DKA), hypothyroidism, vitamin deficiencies, symptomatic anemia
Common vitamin deficiencies:
Immunocompromised state or infection:
Organ failure:
Acute kidney injury, uremia, transaminitis, hyperammonemia, pancreatic insufficiency
Hyperammonemia theoretically but the serum level can be inconsistent
Perioperative:
Medication-induced or iatrogenic:
Anticholinergics, benzodiazepines, narcotics, antipsychotics, anti-Parkinson's disease medications
Polypharmacy: classically with several antiepileptic drugs
Adverse effects: chemotherapy, brain radiation
Substance abuse:
Cocaine, amphetamine, heroin, alcohol intoxication, or alcohol withdrawal
Toxins:
Psychiatric conditions:
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WARDS TIP
Consider medications, especially sedatives and anxiolytics. Ask about a patient's sleep pattern, especially how often vitals are collected overnight (interrupts their sleep!), metabolic panel, especially sodium and glucose (both hypo- and hyperglycemia), and if there is a reason for infection (eg, cough/SOB & URI or a foley & UTI).
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WARDS TIP
In dementia, the forest trail has fallen trees preventing one from passing through. A person may have moments of clarity, but specific cognitive path(way)s are inaccessible. In delirium, there is a dense fog throughout the forest. The path(way)s are accessible but difficult to find.
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