Confusion

Koech KMFri Feb 12, 2010

Confusion

• There’s no clear medical definition for confusion, • it’s a general term for a problem with coherent

thinking• Confused patients are unable to think with

normal speed, clarity, or coherence• Confusion is typically associated with a depressed

sensorium and a reduced attention span, and it is an essential component of delirium

Delirium vs acute confusional state

• No generally accepted consensus on distinction, generally the terms "acute confusional state" and "encephalopathy" are often used synonymously with delirium

• The term "acute confusional state" refers to an acute state of altered consciousness characterized by disordered attention along with diminished speed, clarity, and coherence of thought

• This definition encompasses delirium

• Some experts use "confusional state" to convey the additional meaning of reduced alertness and psychomotor activity . In this paradigm, delirium is a special type of confusional state characterized by increased vigilance, with psychomotor and autonomic overactivity; the delirious patient displays agitation, excitement, tremulousness, hallucinations, fantasies, and delusions

Delirium and acute confusional states

Delirium

• aka encephalopathy, acute confusional state• transient disorder of cognition and attention

accompanied by disturbances of the sleep-wake cycle and psychomotor behavior

• The key feature of delirium is the inability to maintain a coherent stream of thought or action, along with an impairment in attention and/or arousal

• Patients cannot keep attention focused, and this attentional disorder underlies many of the other cognitive deficits

• Delirious patients are distractible, may be hypersensitive to stimuli, and cannot prioritize important from irrelevant environmental sounds or sights

DSM-IV-TR• Disturbance of consciousness (ie, reduced clarity of

awareness of the environment) with reduced ability to focus, sustain, or shift attention

• A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a preexisting, established, or evolving dementia

• The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.

• Evidence from the history, physical examination, or laboratory findings shows that the disturbance is caused by the direct physiological consequences of a general medical condition

Additional features

• Psychomotor behavioral disturbances such as hypoactivity, hyperactivity with increased sympathetic activity, and impairment in sleep duration and architecture.

• Variable emotional disturbances, including fear, depression, euphoria, or perplexity.

Motoric subtypes

• Hypoactive delirium with low psychomotor behavioral activity

• Hyperactive delirium with high psychomotor activity

• Mixed delirium with features of both hypo- and hyperactivity

• Delirium without psychomotor behavioral changes

Epidemiology

• Locally, no figures• West – mostly on hospitalised patients• ~30% of older medical patients• ~10-50% among older surgical patients, the

higher being fracture and cardiac surgery patients, ICU upto 70%

• Tends to affect older males more

Risk factors

• Divided into– Those that increased baseline vulnerability– those that precipitate the disturbance

• Increased baseline vulnerability– underlying brain diseases- dementia, stroke,

Parkinson disease– Advanced age– Sensory impairment

• (Inouye et al- 5 independent risk factors)

Precipitating factors

• Drugs and toxins• Infections• Metabolic derangements• Brain disorders• Systemic organ failure• Physical disorders

AEIOU TIPS

• A-alcohol• E-epilepsy or exposure(heat stroke, hypothermia)• I-insulin• O-overdose or oxygen deficiency• U-uremia• T-trauma(shock, head injury)• I-infection• P-psychosis or poisoning• S-stroke

Pathophysiology

• Poorly understood• Generally:– Neurobiology of attention– Cortical versus subcortical mechanisms– Neurotransmitter and humoral mechanisms

Neurobiology of attention

• Arousal and attention -brain lesions involving the ascending reticular activating system (ARAS) from the mid-pontine tegmentum rostrally to the anterior cingulate regions.

• Attention -"nondominant" parietal and frontal lobes

• Insight and judgment-higher order integrated cortical function

Cortical vs subcortical mechanisms

• 1940s EEG studies-slowing of the dominant posterior alpha rhythm and appearance of abnormal slow-wave activity

• correlated with the level of consciousness and other observed behaviors regardless of the underlying etiology, suggesting a final common neural pathway

• major exception appeared to be that of delirium accompanying alcohol and sedative drug withdrawal, in which low voltage, fast-wave activity predominated

Cont…

• brainstem auditory evoked potential, somatosensory evoked potentials, and neuroimaging studies suggest an important role for subcortical (eg, thalamus, basal ganglia, and pontine reticular formation) as well as cortical structures in the pathogenesis of delirium

• Explains subcortical strokes and basal ganglia abnormalities (eg Parkinson)

Neurotransmitter and humoral mechanisms

• Acetylcholine plays a key role- anticholinergic drugs even on healthy volunteers induce delirium

• Medical condns precipitating delirium (hypoxia, hypoglycemia, and thiamine deficiency) reduce ACh synthesis

• Serum anticholinergic activity relates with severity• Alzheimer’s disease-loss of cholinergic neurons• Other neurotransmitters possible• Cytokines- ILs, IFNs, may explain sepsis

Presentation

• disturbance of consciousness• altered cognition• typically develops over a short period of time

and tends to fluctuate during the course of the day

• Others-psychomotor agitation, sleep-wake reversals, irritability, anxiety, emotional lability, and hypersensitivity to lights and sounds

Investigations

• CBC• U E C, LFTs, BGAs• Blood sugar• LPs• Cultures• Toxic screen, drug levels• EEG• CT, MRI

Management

• ABCDE• Evaluate for possible cause• Supportive– Correct abnormalities– Hydration, nutrition– Enhance mobility– Pain, skin, incontinence– Interpersonal and envtal manipulation– Restraint as last resort

• Specific management(dependent on cause)– Thiamine, glucose– Naloxone– Flumazenil– Antibiotics, antivirals– Low-dose haloperidol

• Preventive measures• Outcomes: variable, high mortality