Conversion disorder (a term that describes what was previously called hysteria) refers to motor or sensory symptoms, or both, that resemble a neurological disease, but that do not originate from or cannot be explained by a known physical disease.

To find reliable tools that can guide the difficult diagnosis of conversion disorder.

Bibliographic review

The exact prevalence of the disorder is unknown. It is estimated that approximately 5% of referrals to neurology are for this disorder. Approximately one third of patients referred to the neurologist have symptoms that cannot be explained by an organic disease. Involuntary movements are the most common motor manifestations of the conversive syndrome, being tremor one of the most frequent manifestations. The first differential diagnosis of conversion disorder is neurological disease. It is currently not necessary for the diagnosis to assess whether or not the symptoms are produced intentionally, as the assessment of conscious intentionality is unreliable. The neurological examination is the fundamental tool for the diagnostic approach, being even more enlightening than the complementary tests. Hoover’s sign, Babinski’s combined leg flexion, plantar flexion of the ankle, tremor and its distraction and synchronisation manoeuvres, as well as the clinical differences between epileptic seizures and non-epileptic seizures of psychogenic origin, are some of the reliable tools for a correct diagnosis.

The diagnosis of the disease should be one of exclusion. There must be clinical data showing clear evidence of incompatibility with a neurological disease and conversion symptoms do not correspond to known physiological mechanisms and anatomical pathways.

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Autoimmune encephalitis are inflammatory diseases of the CNS mediated by antibodies that attack neurotransmitter receptors or proteins on the surface of neurons, usually in the limbic system. The clinic is different according to the antineuronal Ac involved.

To make a correct differential diagnosis between autoimmune encephalitis and primary psychiatric pathologies that may be similar in symptoms through a complete study of the patient including anamnesis, physical examination, imaging tests, cerebrospinal fluid and serum studies.

Description of a clinical case. A 31-year-old female patient, with no previous history of interest, was brought to the emergency department for a suspected seizure. The previous days she had presented emotional lability, difficulty in concentration and reading, blurred vision, confusion and hemicranial headache. Two days later she returned to the emergency room for insomnia, dysarthria, difficulty in reading, comprehension, naming, and excessive rumination of her problems. Incoherent and repetitive language. The Emergency service requested to rule out a conversive disorder.

Neuropsychiatric manifestations (anxiety, depression, behavioral disturbances, insomnia, memory deficits, psychomotor agitation, mania, auditory and visual hallucinations, delusions) are the first symptom in 70% of autoimmune encephalitis due to anti-NMDA antibodies and usually respond poorly to psychiatric treatment, making the treatment of the primary cause necessary for the remission of these symptoms.

Given their increasing recognition and prevalence, autoimmune causes should always be taken into account in behavioral changes, cognitive or consciousness impairment of subacute installation, especially in young patients and once infectious, metabolic and vascular causes have been ruled out with an appropriate complementary study.

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Conversion is the transformation of a conflict (unconscious) into a somatic symptom or a “non-verbal way of expressing psychological discomfort”, through somatizations. The disorder suggests a neurological or medical disease, associated psychological factors appear and is not produced intentionally.

To describe a case of conversion disorder.

Retrospective review of clinical records and complementary test, including psychiatry, electrophysiology and neurology.

An 18-year-old boy came to the emergency room for paralysis. He has anesthesia of lower limbs. He shows indifference towards this symthoms.He denies any stressful situation. On examination, no psychotic or affective symptoms were observed. Belle indifference. Blood tests and a cranial CT scan were performed without alterations, so the patient was admitted for study. The electromyogram, lumbar puncture and cranial magnetic resonance show negative results. Suggestion is carried out, proving effective and recovering gait and sensitivity. These episodes are repeated up to 4 times until finally, during an interview with the family, episodes of bullying come to light. We work in therapy with a diagnosis of conversion disorder.

The most frequent symptoms in conversion disorder are mutism, paralysis, anesthesia, blindness and seizures. It is usually monosymptomatic for each patient. Diferencial diagnosis with neurological pathology should be made.

No significant relationships.