Psychotic disorders can have the onset in late adolescence or early adulthood and can be due to chromosomal disorders, use of drugs or alcohol or an illness, sometimes bacterial infections from which Leptospirosis has a front place in temperate areas, in the hot season.
The authors present the case of a 17 year old adolescent that was admitted on the Child and Adolescent Psychiatry ward as an emergency for delirium of negation, performance anxiety, false recognitions, disorganised delusions, nightmares, aggression towards parents, symptoms that had a sudden onset 4 days ago, after she came back from the holiday spent with her parents. At the psychiatric exam she presents: delusions of persecution, attention deficits, slight temporal-spatial disorientation, suspicion, illusion of recognition, guilt, suicide ideation, depersonalization, derealisation, irritability. She does not present specific clinical symptoms for an infection, but after the laboratory tests the serology was positive for anti-Leptospirosis antibodies (IgM 10x the normal values), directing us towards a diagnosis of asymptomatic leptospirosis. Antibiotic (cephalosporin for 7 days) and antipsychotic (haloperidol) treatment was initiated, with a favourable evolution.
At the one month follow up she presents increased depressive symptoms: anhedonia, abulia, suicidal ideation and suicide threats, low self-esteem, insomnia, nightmares. Antidepressant treatment is initiated. The laboratory tests show that the antibody titer has signficantly decreased.
The particularity of the case comes from the fact that even though we have no clinical symptoms of an infection, the epidemiological investigation was positive – she went on holiday with her parents, where she bathed in a hot swimming pool, the antibodies were positive for an infection and the psychotic symptoms remitted in a short while after antibiotic and antipsychotic treatment.