Delirium other diagnostic studies
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Delirium Microchapters |
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Diagnosis |
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Treatment |
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Delirium On the Web |
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American Roentgen Ray Society Images of Delirium |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vishal Khurana, M.B.B.S., M.D. [2]; Pratik Bahekar, MBBS [3]
Overview
Investigations
To identify underlying etiology following investigations are recommended:
- Complete blood count
- Serum Calcium
- Kidney function tests
- Electrolytes
- Liver function tests
- Blood sugar level
- Thyroid function tests
- Chest X‑ray
- ECG
- Blood cultures
- Urinalysis
If indicated:
- EEG
- CT head
- B12 and folate levels
- Arterial blood gases
- Specific cultures eg urine, sputum
- Lumbar puncture
EEG
EEG shows diffuse slowing. EEG is useful to differentiate delirium from following condtions:
- dementia
- non‑convulsive status epilepticus and temporal lobe epilepsy
- focal intracranial lesion, or it's a global abnormality.
As exact EEG changes in delirium are not yet identified, EEG is not used to diagnose delirium. Identification of the most informative electrode, and use of fewer electrodes will increase the usefulness of EEG in delirium. Continuous EEG monitoring has proven to be a feasible approach in the management of Epilepsy, therefore EEG beholds a great potential to improve detection rates of delirium. EEG changes in delirium are most prominent in the posterior regions. Delirium shows slowing of background activity, however, slowing of background activity is also observed in deep sleep and dementia. EEG recording of sleep shows K complexes and sleep-spindles whereas EEG recorded with eyes open (active EEG) in delirium have the relative power in the delta and the upper half of the alpha frequency band significantly different from dementia. These differences can be exploited to differentiate delirium from sleep and dementia.
There are many practical limitations of EEG studies in delirium. The exact effects of drugs like haloperidol on EEG are unknown, this poses a problem to study EEG characteristics of delirium, as haloperidol is the most widely used medicine in the management of delirium. Also, because of the very fluctuating nature of delirium, many studies suffer from time gap between diagnosis of delirium and EEG recordings.
the relative power of the theta frequency band was most frequently studied, and, without exception, different between delirium and non-delirium subjects.A future study should determine whether the relative power of the theta frequency band is indeed the most affected EEG characteristic.
mostfrequently studied variable was the relative power of thealpha frequency band (8 of 14 studies); next, the relativepower of the theta frequency band (7 of 14), the relativepower of the delta frequency band (5 of 14), and the peakfrequency (5 of 14).significantly different between delirium and nonpatients in all seven studies that investigated this variable. However, in two of these seven publications, onlythe lower part of the theta frequency band, and not thehigher part of the frequency band, was significantlyincreased in delirium.frequency band was related to delirium in 7 out of 8studies. One of these studies showed an increase in therelative power of the theta and a decrease in the relativepower of the alpha frequency band in several groups ofdelirium patients, but not in delirium/Parkinson’s disease of the theta, the alpha, and also the delta frequency band,were not only different between delirium and nondelirium patients, but also within patients before andduring an episode of delirium.
frequently studied variable was the relative power of the alpha frequency band (8 of 14 studies); next, the relative power of the theta frequency band (7 of 14), the relative power of the delta frequency band (5 of 14), and the peak frequency (5 of 14). The relative power of the theta frequency band was significantly different between delirium and non-delirium patients in all seven studies that investigated this variable. However, in two of these seven publications, only the lower part of the theta frequency band, and not the higher part of the frequency band, was significantly increased in delirium. 22,23 The relative power of the alpha frequency band was related to delirium in 7 out of 8 studies. One of these studies showed an increase in the relative power of the theta and a decrease in the relative power of the alpha frequency band in several groups of delirium patients, but not in delirium/Parkinson’s disease patients. 21 Two studies showed that the relative power of the theta, the alpha, and also the delta frequency band, were not only different between delirium and nondelirium patients, but also within patients before and during an episode of delirium. 24,25 Other variables that often differed between delirium and non-delirium patients included the relative power of the delta frequency band (increased in delirium in 5 of 5 investigations that studied this) and the peak frequency (decreased in delirium in 4 of 5 investigations that studied this; online supplement). Two studies focused on bispectral index (BIS) EEG monitoring during delirium. In both studies, the BIS was significantly decreased in delirium patients as compared with non-delirium controls. 20,31 Unfortunately, one study did not specify the number of delirium patients included
Lumbar puncture
Routine LP does not provide any benefit in management of delirium. However,it's helpful in suspected meningitis, ie delirium with
- Meningism
- Headache and fever[1]
References
- ↑ "http://www.bgs.org.uk/Word%20Downloads/delirium.doc". External link in
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