Journal of Neurology & Neurosurgery- Lupine Publishers
Abstract
The processes of ageing and the related impairment of maintaining
homeostasis, understood as the loss of adaptive abilities, lead
to an increased susceptibility to developing delirium among the elderly.
The pathophysiological process of delirium development is
dependent on the presence of causative and predisposing factors; for
example, neurotransmission process disorders (cholinergic,
serotonin and dopaminergic regulation), resulting in metabolic
inefficiency of the brain. The symptoms of delirium differ in duration
and severity; there are 3 clinical subtypes of delirium: hypoactive,
hyperactive and mixed. Moreover, subsequent evaluations using
methodological tools have made it possible to distinguish an additional
subtype of delirium - the no-motor subtype. Recognizing
the delirium subtype is essential - it identifies high-risk patients,
has an effect on the procedures, treatment and further prognosis.
Medical personnel working with elderly patients ought to be well
familiar with the predisposing factors, non-pharmacological
procedures, treatment and prognosis of delirium; they also are required
to know how to differentiate between each del
Introduction
The process of ageing, resulting in decreased abilities to
maintain homeostasis, understood as the lack of capabilities to
adapt, leads to an increased susceptibility to developing delirium
among elderly patients [1]. The presence of triggering along with
existing predisposing factors causes acute or subacute impairment
of brain tissue metabolism, leading to specific brain failure.
Delirium is a neuropsychiatric disorder and is characterized
by changes in consciousness and impaired cognitive functions,
especially attention, orientation and thought processes [2,3]. These
symptoms differ in duration and severity and are the basis -after
taking the coexistent behavioral disorders into consideration-to
distinguish (according to the Lipowski model) 3 clinical subtypes
of delirium: hypoactive, hyperactive and mixed [4]. The clinical
subtypes are distinguished by psychomotor changes; subsequent
evaluations by means of methodological tools now enable the
identification of another subtype of delirium–the no-motor subtype
[5,6]. Recognizing the delirium subtype is essential - it enables highrisk
patients to be discerned, and has an effect on the procedures,
treatment and further prognosis.
Discussion
The basic pathophysiology of delirium relies on the metabolic
inefficiency of the brain, dependent on neurotransmission process
disorders, such as: cholinergic, serotonin and dopaminergic
regulation [7,8]. As a result of physiological changes (impaired brain
flow, increased activity of proinflammatory cytokines, changed
excitability of cholinergic receptors - in particular the receptors
of the neocortex and hippocampus [9] that occur in the organisms
of elderly patients, their intellectual abilities decline. Serotonin is
responsible for the correct development of cognitive functions,
wakefulness and state of mind, that is why serotonin deficiency
is seen as the basic pathomechanism of developing delirium [10].
Another neurotransmitter which is taken into consideration and
is crucial for the pathophysiological process is melatonin, whose
increased activity is connected with the hypoactive form of delirium
[11]. The clinical picture of delirium may manifest itself in the form
of three different motor subtypes, each differentiated by the range
of motor activities.
Among the factors predisposing the development delirium,
those recognised as the best predictors for all motor delirium
subtypes, enabling medical personnel to prognose changes in
the clinical state of the patient are impaired cognitive functions
and visuospatial disorders, diagnosed before hospitalization or
recognised during hospital admission [12]. The hyperactive or
hypoactive subtypes of delirium are believed to have different
etiologic background [13]. The hypoactive subtype is characterized
by: sluggishness, significant impediment to contact with the patient,
apathy, depression and somnolence. The patient with this clinical
type is calm, acquiescent - and that is why delirium is frequently
not diagnosed. The hypoactive subtype is commonly present in
severe somatic diseases (metabolic dysfunctions - liver and kidney
inefficiency), it exists along toxicosis, but also subdural hematoma
or brain tumors.
This subtype is connected with more severe cognitive
impairment - patients with hypoactive delirium have greater
dysfunctions in perception, attention or recalling, but there is
no significant difference in orientation or language functions
between groups of patients with other delirium subtypes [13].
The hyperactive subtype of delirium usually consists in excitation,
behavioral dysfunctions are highly expressed and psychotic
symptoms are also present. The hyperactive subtype is characterized
by: anxiety, hyperactivity, fast speech, irritability, manifestations of
aggression and prowess. The occurrence of the hyperactive subtype
of delirium causes accidental injuries (falls, fractures). This subtype
is commonly connected with addiction to alcohol or psychoactive
substances. Mixed delirium proceeds with changes (both increase
and decrease) in the level of patient agitation, accompanied by
disorganized thinking and very often resulting in a complete lack
of contact with the patient. Even bed-ridden patients get excited,
which is manifested by e.g. picking bedding, mindless manipulation
of venous and urinary catheters, removing underwear or tearing
diapers.
The incidence of the hyperactive subtype of delirium ranges
from 9% to 31%, whereas the hypoactive subtype varies from 19%
to 72% [13]. The occurrence of hypoactive and mixed subtypes
of delirium are responsible for longer hospitalization [14]. The
fluctuation of symptoms is characteristic for delirium and may help
indicate its subtypes. The daily fluctuation of symptoms in particular
subtypes differ from one another. In the mixed and hyperactive
subtypes of delirium there are greater ranges in the fluctuation of
all the symptoms, and in the mixed subtype this fluctuation mainly
concerns psychomotor activity [15]. Development of the motion
subtype of delirium is dependent on the influence of external factors
(for example the intake of cholinergic medicines) on individual
features of an elderly patient and current predisposing factors.
However, it is not clear how other delirium features affect
other motion subtypes [16]. Delirium research should consider
the differences in motor subtypes, enabling the improvement of
strategies for proceeding in clinically different states of delirium
and improvement of the measures of symptom severity and the risk
of death [17]. In everyday medical activities the delirium subtypes
are evaluated by means of DMSS-4 (Delirium Motor Subtype Scale
- version 4). The results obtained by means of DMSS-4 enable
quick assessment of the clinical delirium subtypes and are highly
compliant with the results of DMSS, a scale which has been used
since 2008 and was subjected to meticulous validation. The latest
version of this tool has been greatly simplified: it consists of 4
questions about the patient’s behavior and psychomotor activity.
According to the obtained results, which are short statements
- “yes” or “no”- a specific subtype of delirium is discerned [6].
The clinical subtypes of delirium disclosed by DMSS-4 are more
clearly determined, which can facilitate and improve proceeding
with delirium patients and also bring benefits in learning the
pathomechanisms of developing delirium [18].
Conclusion
Proceeding in delirium must include all the essential elements
in the development of the disease. Medical personnel working
with elderly patients ought to be well familiar with the delirium
predisposing factors, non-pharmacological procedures, treatment
and prognosis. In the case of a patient developing delirium, medical
personnel should apply tools enabling them to discern between
delirium subtypes, based on possible differences in the possible
fluctuation of symptoms and the resulting clinical implications and
further prognosis. Physicians should be aware that the hypoactive
subtype of delirium, which manifests itself only by symptoms of
hyperactivity (or alternating with these symptoms), indicates a
much worse prognosis for these patients [17].
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