Visual hallucinations and capgras delirium in a patient with right occipito-temporal ischemic stroke

The ability to recognize an individual’s face and determine whether it is familiar or unfamiliar is an adaptive skill that develops during the first few months of life. In patients suffering from Capgras syndrome, this capacity is impaired, temporarily in relation to an acute organic pathology or chronically triggering a generally positive adaptive attitude. Through a real case of an 81-year-old patient who presents a neurological focal point accompanied by visual hallucinations and a disorder in the perception of a relative as “strange”; this peculiar syndrome is introduced, generally underdiagnosed, which can facilitate the location of dysfunctional brain areas and relate it to the rest of higher cognitive functions. This delirium is an example of how the brain makes a “logical response”; to a serious lack of information connection. We will also talk about several physio-pathological theories in this respect and their relationship with certain acute pathologies and other chronic ones such as schizophrenia or dementia.


INtrODUctION
The capacity of the human being to recognize the face of an individual and to determine whether it is familiar or unknown is not present from birth, is developing and perfecting throughout the first years of life. and it is this ability to connect visual information with the emotional memory it triggers that is affected in Capgras patients.
Next, through the introduction of a real case, we propose to develop this peculiar delirium, generally underdiagnosed, which can, on the one hand, facilitate the location of lesions or dysfunctional areas in the context of an organic pathology; and, on the other hand, better understand how the human brain works through the evaluation of higher cognitive functions than those we usually explore.
For its development the ethical norms were fulfilled, the ethical committee of the Sector of Alcañiz did not put inconveniences to its publication and the informed consent of the patient was collected in writing for the publication of the clinical case.

DEscrIPtION OF tHE cAsE
This is an 81-year-old woman referred for acute episode of confusion with false recognition of the environment and her daughter for four hours.
Relevant antecedents include hypertension of difficult control with four antihypertensives, diabetes mellitus type II of years of evolution in treatment with oral antidiabetics and mixed hyperlipidemia. Independent for basic activities of daily living. No traits of depression or anxiety or psychiatric disorders. stroke scale): 3 points. Oriented on the three spheres (person, time, space). To the exploration it presented homonym left hemianopsia accompanied by left sensory extinction. The strength and coordination of both sides were preserved; and the left cutaneous-plantar reflex was indifferent. The rest of the general exploration didn't reveal any more information.

Exploration
she also referred to visual hallucinations in the left hemicampus and a false recognition of his daughter as a stranger. "she looks like my daughter, but I'm sure she's not. she worries about me, but doctor, she's not my daughter". The rest of the family recognizes and identifies them correctly.

FIGURE 1. Right occipito-temporal hypodensity
Within a few days of admission, neurological symptoms, hallucinations and alterations of perception disappeared and she was discharged asymptomatically. In the subsequent controls by Neurology did not recur either.
The episode was labeled a right occipito-temporal ischemic stroke associated with an acute delirious syndrome.

DIscUssIONs
Capgras syndrome is a small, well-organized delirium in which the patient believes that a person, usually a family member or close friend, has been replaced by an impostor identical to that person.
It is usually sudden onset and transitory, although there are also described cases of chronic or episodic character. They are related to a scarce emotional component, which is generally positive which triggers an adaptive behavior to said delirium (1). although they are the least known, the best known are those who ended up in divorces, fights or homicides. And finally, this delirium usually coincides with other hallucinations, both visual and auditory, or other identification failure syndromes -such as Fregoli syndrome, intermetamorphosis or déjà-vu.
It frequently occurs in paranoid schizophrenia, but in 25-40% it can appear in relation to organic damage such as dementia -2-30% in alzheimer's disease; 8-17% Lewy body disease; epilepsy or cerebrovascular disease.
Do not forget to rule out organic pathology (2) that can lead to or facilitate it such as severe anemia, electrolyte disorders, vitamin deficiencies, endocrine pathology, malnutrition or significant dehydration, intoxications, infections or septic processes, cerebrovascular pathology, etc.. a good anamnesis must be carried out, addressing the psycho-neurological spectrum, environment and socio-familiar situation and a previous functional The question that this pathology evokes is: Is everything we perceive real? since the times of Platon and aristotle of ancient Greece, man has been searching for the keys to consciousness and yet all attempts remain mere conjectures and approximations... it is in the twentieth century that it is discovered that the visual pathway is the one that can give us better information about how our psyche works.
We highlight Bruce and Young and Burton's "facial processing model" (3) in which they define two fundamental components located in the right temporal lobe, more specifically in the fusiform gyrus and the perihypocampic and amygdala areas; these are (4): 1) facial recognition units (FRU), which act as a memory fingerprint store for previously known faces, 2) and personal identity nodes (PINs) which store emotional memory relating to people/animals/known things/places that has been acquired in multiple contexts and integrated into a single representation that is stored in memory.
The visual pathway is intact ("that's my daughter's face") but the channel of emotional vision, which is a distinct anatomical pathway -parietal right -, does not allow connecting the information of the face with the associated emotional component ("inside me I'm sure it's not my daughter") (5,6). any computer would understand it as a system failure and block itself, but the brain, which cannot afford it, decides to give the control to the left cerebral hemisphere, which interprets it as an impersonation ("ergo is someone who has disguised himself as my daughter").
It is a clear example that all illnesses have two dimensions: psychological and physical; and that there is a fine line between neurology and psychia-try. The more we know about how our brains work, the more we realize how much we have to discover and study.

cONcLUsIONs
In the event of an atypical symptom or a symptom that the family identifies as different from the usual, an in-depth study must be initiated to rule out the causative organic pathology. It is important to know the previous functional, emotional and nutritional basal state. It is usually a transitory disorder that after solving the triggering cause is resolved without sequelae or risk of recurrence. But it can also be chronicled for years going unnoticed by the adaptive attitude incurred by the mourner.