All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Confusion
Medical expert of the article
Last reviewed: 04.07.2025
Confusion of consciousness is a form of clouding of consciousness, which combines individual elements of its various syndromes, primarily amentia and delirium. Neurological causes of acute confusion most often occur in the form of amentive disorder. Disorientation (partial or complete) in place and time, one's own personality, increased distractibility, confusion, and an affect of bewilderment are observed. Attention is fixed with difficulty, perception and reactions are slow, there is inadequate emotionality, the presence of amorphous unstable illusions and hallucinations, fragmentary delusional experiences.
In patients with acute confusional states, it is often impossible to obtain a history. In this case, a large number of possible diagnoses must be considered. It should also be remembered that symptomatic therapy may change the picture and prevent the cause of acute confusional states from being established. Moreover, possible causes must be quickly grouped in order to reduce the number of diagnostic procedures. The following grouping of potential causes of acute confusion can be used: toxic, inflammatory, vascular, exacerbation of degenerative disease, metabolic, traumatic, other.
[ 1 ]
The main causes of confusion are:
- Alcohol withdrawal syndrome
- Drug intoxication
- Encephalitis
- Cerebrovascular diseases
- Alzheimer's disease
- Metabolic disorders
- Hidden bleeding (including intestinal)
- Epileptic twilight states
- Post-traumatic psychosis
- Artificial (post-resuscitation, after several ECT sessions).
Alcohol withdrawal syndrome
Alcohol intoxication is the most common. The state of acute confusion due to the intake of large amounts of alcohol is easily recognized. The full picture of alcohol withdrawal syndrome ("shaky state") should not pose a serious problem for diagnosis. Such patients are usually anxious and agitated, disoriented in time and place, do not understand the situation in which they find themselves if asked about it. Since the onset of withdrawal syndrome requires a long period of alcohol intake, then an examination will reveal an alcoholic tremor of the outstretched arms. The picture is complemented by icterus of the sclera and an enlarged liver on palpation. The most significant among laboratory studies are data indicating a violation of liver enzymes.
Drug intoxication
Tranquilizing drugs can also cause intoxication and thus confusion and disorientation. Such patients are not anxious or agitated, but rather have a decreased level of alertness. Eye symptoms are helpful in these cases: many drugs cause nystagmus and pupillary abnormalities.
Eye symptoms in case of intoxication
| Eye symptoms | Cause |
| Miosis | Morphine derivatives Reserpine Meprobamate Acetylcholinesterase inhibitors |
| Mydriasis | Belladonna alkaloids Chlorperphenazine Imipramine Botulism Cocaine |
| Nystagmus | Barbiturates Benzodiazepines Diphenin |
Tremor may be present, but there is no scleral icterus, and laboratory findings are unremarkable. Drug intoxication is usually recognizable on EEG: frontal (barbiturates) or generalized (benzodiazepines) beta waves, or dysrhythmic wave groups primarily in the temporal areas. Urine toxicology is helpful, but the test is usually long enough to be helpful on the spot. If serum antiepileptic drug levels can be determined by enzymatic methods, this also applies to barbiturates and benzodiazepines, the most commonly used drugs. Other psychotropic drugs such as lithium are also available.
[ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ]
Encephalitis
The next condition in which there is an acute onset of confusion is encephalitis. The presence of any febrile illness before the onset of encephalitis is not obligatory. Unfortunately, the first symptoms of the disease - confusion and EEG changes - are quite nonspecific. Neurological signs may not appear immediately. Hyperthermia is not always present. Pleocytosis in the cerebrospinal fluid is not yet detectable. Only an increase in the protein level helps to suggest a diagnosis of encephalitis. Serological data will be available in a week at the earliest.
Often, the diagnosis of encephalitis is established by excluding other possible causes. It is useful to pay attention to the acute onset of fever, headache, and altered consciousness. In the case of rapid deterioration of the patient's condition, it is advisable to begin therapy even when serological confirmation is still lacking.
[ 13 ], [ 14 ], [ 15 ], [ 16 ], [ 17 ]
Cerebrovascular diseases
The subgroup of vascular diseases includes conditions of various etiologies, which are usually easily differentiated. In ischemic stroke, mental disorders rarely predominate, while intracerebral hemorrhage may lead to confusion before the development of hemiplegia or brainstem syndrome. The diagnosis may be suspected if the patient has suffered from arterial hypertension for a long time. However, this circumstance should not be the only justification for performing a lumbar puncture. The increase in local plus generalized changes in the EEG can confirm the diagnosis, but only neuroimaging allows an accurate diagnosis. The onset of subarachnoid hemorrhage is sudden and, as a rule, causes headache in people who have never experienced confusion before. With very few exceptions, there is neck rigidity. Other meningeal signs appear later. Oculomotor and pupillomotor symptoms, subfebrile condition are often detected. During a lumbar puncture, blood is found in the cerebrospinal fluid, which becomes xanthochromic after centrifugation.
In bilateral strokes in the posterior cerebral artery territory, visual loss and confusion are common. Anosognosia may be present in acute cortical blindness. Such patients do not respond to visual stimuli, auditory stimuli attract the gaze, but this is not a very accurate fixation. In addition, patients deny the existence of blindness and describe their surroundings if asked to do so, resorting to confabulations that complement the confusion. Optokinetic nystagmus is absent.
Multi-infarct dementia can lead to periodic states of confusion. A series of small (sometimes large) strokes leads to a gradual deterioration of various cognitive functions, such as memory, speech, attention, which forms multi-infarct dementia. Episodes of night confusion are often observed. Emotionality is flattened, complacency appears, sometimes pathological laughter and crying develop.
In this situation, the subsequent stroke leaves the patient in a state of confusion. Diagnosis is based on the characteristic anamnesis and neurological deficits that correspond to the lesion in one or another vascular pool. Neuroimaging examination reveals residual effects of previous strokes.
In practice, it is very important to distinguish "atherosclerotic" patients who do not have a history of multi-infarct dementia, are quite balanced, reasonable elderly people. Only after, for example, surgery under general anesthesia can they wake up in a state of deep confusion, as well as during any acute illness. MRI reveals signs of past "silent" infarctions, usually lacunar.
Alzheimer's disease
In contrast, Alzheimer's disease is characterized by a progressive neuropsychological deficit. Mild neurological symptoms may be present (especially in mixed dementia). At first, emotional reactions are preserved, as are the patients' usual social skills. The onset of acute confusion is often associated with changes in the patient's life, such as moving, losing a loved one, or being hospitalized. Neuroimaging data indicate a global decrease in brain volume. Neuropsychological testing confirms the diagnosis.
[ 18 ], [ 19 ], [ 20 ], [ 21 ], [ 22 ], [ 23 ]
Metabolic disorders
Acute confusion due to metabolic disorders is almost impossible to diagnose clinically. Of course, it is well known that fluttering tremor, i.e. asterixis, is observed in liver and kidney pathology and other metabolic disorders. However, as a rule, the diagnosis is based on laboratory data. In the presence of acute confusion of unknown etiology, screening for metabolic disorders is necessary.
The list of main causes, which is certainly not complete, includes: diabetes mellitus, Addison's disease, dehydration, hypercalcemia, hyperinsulinism, hyper- and hypoparathyroidism, porphyria, respiratory acidosis and thiamine deficiency, renal and hepatic failure, chronic lung diseases, etc. Metabolic encephalopathies are usually accompanied by a tendency to slow down bioelectrical activity on the EEG.
[ 24 ], [ 25 ], [ 26 ], [ 27 ], [ 28 ]
Hidden bleeding
In this regard, it should be noted that hidden bleeding, including intestinal bleeding, can lead to such a decrease in the number of circulating red blood cells that the result will be global cerebral hypoxia, debuting with a state of confusion without neuropsychological disorders or a decrease in the level of wakefulness. Characteristic is pallor and, especially, tachycardia in a sitting position; in case of intestinal bleeding - black feces. More often, hidden internal bleeding leads to fainting.
Epileptic twilight states
Twilight states of epileptic nature may occur not only in patients who are aware of their illness, but also after the first seizure. They may follow a major seizure or a series of seizures. In this case, the patient is disoriented in time and cannot correctly assess the situation. The patient may have delusional disorders, a vague sense of danger, incorrect interpretation of even neutral movements of people around him, and aggression.
In continuous series of complex partial seizures, aggressiveness is not typical. Patients often move slowly, perform inappropriate actions, and give the impression of partial wakefulness. Diagnosis is greatly facilitated if oral automatisms such as chewing, swallowing, and/or stereotypical hand movements are present, as is often observed in isolated partial complex seizures. Definitive diagnosis is based on patient observation and EEG.
[ 32 ], [ 33 ], [ 34 ], [ 35 ], [ 36 ], [ 37 ], [ 38 ]
Post-traumatic psychosis
The condition of post-traumatic psychosis is often undiagnosed when it occurs when a patient awakens from post-traumatic loss of consciousness in a surgical ward. Characteristic features are anxiety, restlessness, and an illusory, disturbed interpretation of the environment. Patients tend to leave their bed or even leave the ward, despite strict instructions to remain in bed. This is often regarded as a violation of the regime, and the pathological nature of the condition is not recognized.
Artificial state of confusion
Sometimes, in the post-resuscitation state or after several sessions of electroconvulsive therapy, a transient state of confusion with disorientation and inappropriate behavior develops.
[ 42 ]
Who to contact?